[201159] model rework: CollectionValueModel

23 files changed, 543 insertions, 649 deletions

diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/ChangeSupport.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/ChangeSupport.java
index 63409420fd..4015998afa 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/ChangeSupport.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/ChangeSupport.java
@@ -18,6 +18,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
+import org.eclipse.jpt.utility.internal.ClassTools;
 import org.eclipse.jpt.utility.internal.CollectionTools;
 import org.eclipse.jpt.utility.internal.StringTools;
 import org.eclipse.jpt.utility.internal.model.event.CollectionChangeEvent;
@@ -49,17 +50,17 @@ import org.eclipse.jpt.utility.internal.model.listener.TreeChangeListener;
  * and custom "notifiers", with more to come, I'm sure....  ~bjv
  * 
  * NB2: This class will check to see if, during the firing of events, a listener
- * on the original list of listeners has been removed from the mast list of
- * listeners *before* it is notified. If the listener has been removed
+ * on the original, cloned, list of listeners has been removed from the master
+ * list of listeners *before* it is notified. If the listener has been removed
  * "concurrently" it will *not* be notified. (See the code that uses the
  * 'stillListening' local boolean flag.)
  * 
  * NB3: This class is serializable, but it will only write out listeners that
  * are also serializable while silently leaving behind listeners that are not.
  * 
- * TODO support a dispatcher per listener
- * TODO fire a STATE change event with *every* change?
- * TODO use objects (IDs?) instead of strings to identify aspects
+ * TODO support a dispatcher per listener?
+ * TODO fire a state change event with *every* change?
+ * TODO use objects (IDs?) instead of strings to identify aspects?
  */
 public class ChangeSupport
 	implements Serializable
@@ -68,11 +69,11 @@ public class ChangeSupport
 	/** The object to be provided as the "source" for any generated events. */
 	protected final Model source;
 
-	/** Maps a listener class to a collection of "generic" listeners for that class. */
+	/** Associate a listener class to a collection of "generic" listeners for that class. */
 	transient private GenericListenerList[] genericListeners = EMPTY_GENERIC_LISTENERS;
 		private static final GenericListenerList[] EMPTY_GENERIC_LISTENERS = new GenericListenerList[0];
 
-	/** Maps aspect names to child change support objects. */
+	/** Associate aspect names to child change support objects. */
 	private AspectChild[] aspectChildren = EMPTY_ASPECT_CHILDREN;
 		private static final AspectChild[] EMPTY_ASPECT_CHILDREN = new AspectChild[0];
 
@@ -97,8 +98,8 @@ public class ChangeSupport
 	// ********** internal behavior **********
 
 	/**
-	 * Add a listener that listens to all events appropriate to that listener,
-	 * regardless of the aspect name associated with that event.
+	 * Add a "generic" listener that listens to all events appropriate to that
+	 * listener, regardless of the aspect name associated with that event.
 	 * The listener cannot be null.
 	 */
 	protected <T extends ChangeListener> void addListener(Class<T> listenerClass, T listener) {
@@ -116,7 +117,7 @@ public class ChangeSupport
 	}
 
 	/**
-	 * Return the generic listener list for the specified listener class.
+	 * Return the "generic" listener list for the specified listener class.
 	 * Return null if the list is not present.
 	 */
 	protected GenericListenerList genericListenerList(Class<? extends ChangeListener> listenerClass) {
@@ -129,7 +130,7 @@ public class ChangeSupport
 	}
 
 	/**
-	 * Add the generic listener list for the specified listener class.
+	 * Add the "generic" listener list for the specified listener class.
 	 * Return the newly-built generic listener list.
 	 */
 	protected <T extends ChangeListener> GenericListenerList addGenericListenerList(Class<T> listenerClass, T listener) {
@@ -166,7 +167,7 @@ public class ChangeSupport
 			return null;
 		}
 		for (AspectChild aspectChild : this.aspectChildren) {
-			if (aspectChild.aspectName.equals(aspectName)) {
+			if (aspectChild.aspectName == aspectName) {
 				return aspectChild.child;
 			}
 		}
@@ -191,7 +192,8 @@ public class ChangeSupport
 	}
 
 	/**
-	 * Removes a listener that has been registered for all events appropriate to that listener.
+	 * Removes a "generic" listener that has been registered for all events
+	 * appropriate to that listener.
 	 */
 	protected <T extends ChangeListener> void removeListener(Class<T> listenerClass, T listener) {
 		synchronized (this) {
@@ -230,7 +232,7 @@ public class ChangeSupport
 	}
 
 	/**
-	 * Return the listeners for the specified listener class.
+	 * Return the "generic" listeners for the specified listener class.
 	 * Return null if there are no listeners.
 	 */
 	protected ChangeListener[] listeners(Class<? extends ChangeListener> listenerClass) {
@@ -248,6 +250,14 @@ public class ChangeSupport
 	}
 
 	/**
+	 * Return whether there are no "generic" listeners for the specified
+	 * listener class.
+	 */
+	protected <T extends ChangeListener> boolean hasNoListeners(Class<T> listenerClass) {
+		return ! this.hasAnyListeners(listenerClass);
+	}
+
+	/**
 	 * Return whether there are any listeners for the specified
 	 * listener class and aspect name.
 	 */
@@ -260,6 +270,14 @@ public class ChangeSupport
 			child.hasAnyListeners(listenerClass);
 	}
 
+	/**
+	 * Return whether there are no "generic" listeners for the specified
+	 * listener class and aspect name.
+	 */
+	protected <T extends ChangeListener> boolean hasNoListeners(Class<T> listenerClass, String aspectName) {
+		return ! this.hasAnyListeners(listenerClass, aspectName);
+	}
+
 
 	// ********** behavior **********
 
@@ -308,11 +326,10 @@ public class ChangeSupport
 	 */
 	public void fireStateChanged(StateChangeEvent event) {
 
-		StateChangeListener[] stateChangeListeners = null;
 		StateChangeListener[] targets = null;
 
 		synchronized (this) {
-			stateChangeListeners = this.stateChangeListeners();
+			StateChangeListener[] stateChangeListeners = this.stateChangeListeners();
 			if (stateChangeListeners != null) {
 				targets = stateChangeListeners.clone();
 			}
@@ -334,16 +351,16 @@ public class ChangeSupport
 	}
 
 	/**
-	 * Report a generic state change event to any registered state change listeners.
+	 * Report a generic state change event to any registered state change
+	 * listeners.
 	 */
 	public void fireStateChanged() {
 //		this.fireStateChange(new StateChangeEvent(this.source));
 
-		StateChangeListener[] stateChangeListeners = null;
 		StateChangeListener[] targets = null;
 
 		synchronized (this) {
-			stateChangeListeners = this.stateChangeListeners();
+			StateChangeListener[] stateChangeListeners = this.stateChangeListeners();
 			if (stateChangeListeners != null) {
 				targets = stateChangeListeners.clone();
 			}
@@ -458,12 +475,11 @@ public class ChangeSupport
 
 		String propertyName = event.propertyName();
 
-		PropertyChangeListener[] propertyChangeListeners = null;
 		PropertyChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			propertyChangeListeners = this.propertyChangeListeners();
+			PropertyChangeListener[] propertyChangeListeners = this.propertyChangeListeners();
 			if (propertyChangeListeners != null) {
 				targets = propertyChangeListeners.clone();
 			}
@@ -500,12 +516,11 @@ public class ChangeSupport
 			return;
 		}
 
-		PropertyChangeListener[] propertyChangeListeners = null;
 		PropertyChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			propertyChangeListeners = this.propertyChangeListeners();
+			PropertyChangeListener[] propertyChangeListeners = this.propertyChangeListeners();
 			if (propertyChangeListeners != null) {
 				targets = propertyChangeListeners.clone();
 			}
@@ -553,12 +568,11 @@ public class ChangeSupport
 			return;
 		}
 
-		PropertyChangeListener[] propertyChangeListeners = null;
 		PropertyChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			propertyChangeListeners = this.propertyChangeListeners();
+			PropertyChangeListener[] propertyChangeListeners = this.propertyChangeListeners();
 			if (propertyChangeListeners != null) {
 				targets = propertyChangeListeners.clone();
 			}
@@ -606,12 +620,11 @@ public class ChangeSupport
 			return;
 		}
 
-		PropertyChangeListener[] propertyChangeListeners = null;
 		PropertyChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			propertyChangeListeners = this.propertyChangeListeners();
+			PropertyChangeListener[] propertyChangeListeners = this.propertyChangeListeners();
 			if (propertyChangeListeners != null) {
 				targets = propertyChangeListeners.clone();
 			}
@@ -710,12 +723,11 @@ public class ChangeSupport
 
 		String collectionName = event.collectionName();
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -749,12 +761,11 @@ public class ChangeSupport
 			return;
 		}
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -795,12 +806,11 @@ public class ChangeSupport
 	public void fireItemAdded(String collectionName, Object addedItem) {
 //		this.fireItemsAdded(collectionName, Collections.singleton(addedItem));
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -845,12 +855,11 @@ public class ChangeSupport
 
 		String collectionName = event.collectionName();
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -884,12 +893,11 @@ public class ChangeSupport
 			return;
 		}
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -930,12 +938,11 @@ public class ChangeSupport
 	public void fireItemRemoved(String collectionName, Object removedItem) {
 //		this.fireItemsRemoved(collectionName, Collections.singleton(removedItem));
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -976,12 +983,11 @@ public class ChangeSupport
 	public void fireCollectionCleared(CollectionChangeEvent event) {
 		String collectionName = event.collectionName();
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -1012,12 +1018,11 @@ public class ChangeSupport
 	public void fireCollectionCleared(String collectionName) {
 //		this.fireCollectionCleared(new CollectionChangeEvent(this.source, collectionName));
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -1058,12 +1063,11 @@ public class ChangeSupport
 	public void fireCollectionChanged(CollectionChangeEvent event) {
 		String collectionName = event.collectionName();
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -1094,12 +1098,11 @@ public class ChangeSupport
 	public void fireCollectionChanged(String collectionName) {
 //		this.fireCollectionChanged(new CollectionChangeEvent(this.source, collectionName));
 
-		CollectionChangeListener[] collectionChangeListeners = null;
 		CollectionChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			collectionChangeListeners = this.collectionChangeListeners();
+			CollectionChangeListener[] collectionChangeListeners = this.collectionChangeListeners();
 			if (collectionChangeListeners != null) {
 				targets = collectionChangeListeners.clone();
 			}
@@ -1198,12 +1201,11 @@ public class ChangeSupport
 
 		String listName = event.listName();
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1237,12 +1239,11 @@ public class ChangeSupport
 			return;
 		}
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1283,12 +1284,11 @@ public class ChangeSupport
 	public void fireItemAdded(String listName, int index, Object addedItem) {
 //		this.fireItemsAdded(listName, index, Collections.singletonList(addedItem));
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1333,12 +1333,11 @@ public class ChangeSupport
 
 		String listName = event.listName();
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1372,12 +1371,11 @@ public class ChangeSupport
 			return;
 		}
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1418,12 +1416,11 @@ public class ChangeSupport
 	public void fireItemRemoved(String listName, int index, Object removedItem) {
 //		this.fireItemsRemoved(listName, index, Collections.singletonList(removedItem));
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1468,12 +1465,11 @@ public class ChangeSupport
 
 		String listName = event.listName();
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1507,12 +1503,11 @@ public class ChangeSupport
 			return;
 		}
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1553,12 +1548,11 @@ public class ChangeSupport
 	public void fireItemReplaced(String listName, int index, Object newItem, Object replacedItem) {
 //		this.fireItemsReplaced(listName, index, Collections.singletonList(newItem), Collections.singletonList(replacedItem));
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1603,12 +1597,11 @@ public class ChangeSupport
 
 		String listName = event.listName();
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1642,12 +1635,11 @@ public class ChangeSupport
 			return;
 		}
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1695,12 +1687,11 @@ public class ChangeSupport
 	public void fireListCleared(ListChangeEvent event) {
 		String listName = event.listName();
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1731,12 +1722,11 @@ public class ChangeSupport
 	public void fireListCleared(String listName) {
 //		this.fireListCleared(new ListChangeEvent(this.source, listName));
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1777,12 +1767,11 @@ public class ChangeSupport
 	public void fireListChanged(ListChangeEvent event) {
 		String listName = event.listName();
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1813,12 +1802,11 @@ public class ChangeSupport
 	public void fireListChanged(String listName) {
 //		this.fireListChanged(new ListChangeEvent(this.source, listName));
 
-		ListChangeListener[] listChangeListeners = null;
 		ListChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			listChangeListeners = this.listChangeListeners();
+			ListChangeListener[] listChangeListeners = this.listChangeListeners();
 			if (listChangeListeners != null) {
 				targets = listChangeListeners.clone();
 			}
@@ -1914,12 +1902,11 @@ public class ChangeSupport
 	public void fireNodeAdded(TreeChangeEvent event) {
 		String treeName = event.treeName();
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -1950,12 +1937,11 @@ public class ChangeSupport
 	public void fireNodeAdded(String treeName, Object[] path) {
 //		this.fireNodeAdded(new TreeChangeEvent(this.source, treeName, path));
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -1996,12 +1982,11 @@ public class ChangeSupport
 	public void fireNodeRemoved(TreeChangeEvent event) {
 		String treeName = event.treeName();
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -2032,12 +2017,11 @@ public class ChangeSupport
 	public void fireNodeRemoved(String treeName, Object[] path) {
 //		this.fireNodeRemoved(new TreeChangeEvent(this.source, treeName, path));
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -2078,12 +2062,11 @@ public class ChangeSupport
 	public void fireTreeCleared(TreeChangeEvent event) {
 		String treeName = event.treeName();
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -2114,12 +2097,11 @@ public class ChangeSupport
 	public void fireTreeCleared(String treeName, Object[] path) {
 //		this.fireTreeCleared(new TreeChangeEvent(this.source, treeName, path));
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -2167,12 +2149,11 @@ public class ChangeSupport
 	public void fireTreeChanged(TreeChangeEvent event) {
 		String treeName = event.treeName();
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -2203,12 +2184,11 @@ public class ChangeSupport
 	public void fireTreeChanged(String treeName, Object[] path) {
 //		this.fireTreeChanged(new TreeChangeEvent(this.source, treeName, path));
 
-		TreeChangeListener[] treeChangeListeners = null;
 		TreeChangeListener[] targets = null;
 		ChangeSupport child = null;
 
 		synchronized (this) {
-			treeChangeListeners = this.treeChangeListeners();
+			TreeChangeListener[] treeChangeListeners = this.treeChangeListeners();
 			if (treeChangeListeners != null) {
 				targets = treeChangeListeners.clone();
 			}
@@ -2321,20 +2301,23 @@ public class ChangeSupport
 	// ********** member classes **********
 
 	/**
-	 * Pair a listener class with its generic listeners.
+	 * Pair a listener class with its "generic" listeners.
 	 */
 	private static class GenericListenerList {
 		final Class<? extends ChangeListener> listenerClass;
 		ChangeListener[] listeners;
+
 		<T extends ChangeListener> GenericListenerList(Class<T> listenerClass, T listener) {
 			super();
 			this.listenerClass = listenerClass;
 			this.listeners = (ChangeListener[]) Array.newInstance(listenerClass, 1);
 			this.listeners[0] = listener;
 		}
+
 		void addListener(ChangeListener listener) {
 			this.listeners = CollectionTools.add(this.listeners, listener);
 		}
+
 		boolean removeListener(ChangeListener listener) {
 			int len = this.listeners.length;
 			if (len == 0) {
@@ -2347,9 +2330,16 @@ public class ChangeSupport
 			}
 			return (this.listeners.length + 1) == len;
 		}
+
 		boolean hasListeners() {
 			return this.listeners.length > 0;
 		}
+
+		@Override
+		public String toString() {
+			return StringTools.buildToStringFor(this, ClassTools.shortNameFor(this.listenerClass));
+		}
+
 	}
 
 	/**
@@ -2360,11 +2350,18 @@ public class ChangeSupport
 		final String aspectName;
 		final ChangeSupport child;
 		private static final long serialVersionUID = 1L;
+
 		AspectChild(String aspectName, ChangeSupport child) {
 			super();
 			this.aspectName = aspectName;
 			this.child = child;
 		}
+
+		@Override
+		public String toString() {
+			return StringTools.buildToStringFor(this, this.aspectName);
+		}
+
 	}
 
 }
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/SingleAspectChangeSupport.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/SingleAspectChangeSupport.java
index d7544a2805..af226f4bca 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/SingleAspectChangeSupport.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/SingleAspectChangeSupport.java
@@ -1,4 +1,4 @@
-/*******************************************************************************
+/*************************************************
  * Copyright (c) 2007 Oracle. All rights reserved.
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v1.0, which accompanies this distribution
@@ -6,7 +6,7 @@
  * 
  * Contributors:
  *     Oracle - initial API and implementation
- ******************************************************************************/
+ ************************************************/
 package org.eclipse.jpt.utility.internal.model;
 
 import java.util.Collection;
@@ -20,62 +20,63 @@ import org.eclipse.jpt.utility.internal.model.event.TreeChangeEvent;
 import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
 
 /**
- * This support class changes the behavior of the standard
+ * This change support class changes the behavior of the standard
  * ChangeSupport in several ways:
- * 	- All events fired by the source must specify the expected aspect name.
+ * 	- All events fired by the source must specify the single aspect name.
  * 	- Listeners are required to be either "generic" listeners or
- * 	    listeners of the aspect name.
- * 	- The "aspect-specific" listeners are stored alongside the "generic"
- *     listeners, improving performance a bit (in terms of both time and space)
+ * 	    listeners of the single aspect name.
  */
-public class SingleAspectChangeSupport extends ChangeSupport {
+public class SingleAspectChangeSupport
+	extends ChangeSupport
+{
 	private final String aspectName;
+
 	private static final long serialVersionUID = 1L;
 
+
+	// ********** constructor **********
+
 	public SingleAspectChangeSupport(Model source, String aspectName) {
 		super(source);
 		this.aspectName = aspectName;
 	}
 
 
-	// ******************** internal behavior ********************
+	// ********** internal behavior **********
 
 	private UnsupportedOperationException unsupportedOperationException() {
 		return new UnsupportedOperationException("This Model supports only changes for the aspect \"" + this.aspectName + "\"");
 	}
 
-	private void checkAspectName(String aName) {
-		if (aName != this.aspectName) {
-			throw new IllegalArgumentException("This Model supports only changes for the aspect \"" + this.aspectName + "\" : \"" + aName + "\"");
+	private void checkAspectName(String listenerAspectName) {
+		if (listenerAspectName != this.aspectName) {
+			throw new IllegalArgumentException("This Model supports only changes for the aspect \"" + this.aspectName + "\" : \"" + listenerAspectName + "\"");
 		}
 	}
 
 	@Override
-	protected <T extends ChangeListener> void addListener(String aName, Class<T> listenerClass, T listener) {
-		this.checkAspectName(aName);
-		// redirect to "generic" listeners collection
-		this.addListener(listenerClass, listener);
+	protected <T extends ChangeListener> void addListener(String listenerAspectName, Class<T> listenerClass, T listener) {
+		this.checkAspectName(listenerAspectName);
+		super.addListener(listenerAspectName, listenerClass, listener);
 	}
 
 	@Override
-	protected <T extends ChangeListener> void removeListener(String aName, Class<T> listenerClass, T listener) {
-		this.checkAspectName(aName);
-		// redirect to "generic" listeners collection
-		this.removeListener(listenerClass, listener);
+	protected <T extends ChangeListener> void removeListener(String listenerAspectName, Class<T> listenerClass, T listener) {
+		this.checkAspectName(listenerAspectName);
+		super.removeListener(listenerAspectName, listenerClass, listener);
 	}
 
 
-	// ******************** internal queries ********************
+	// ********** internal queries **********
 
 	@Override
-	protected boolean hasAnyListeners(Class<? extends ChangeListener> listenerClass, String aName) {
-		this.checkAspectName(aName);
-		// redirect to "generic" listeners collection
-		return this.hasAnyListeners(listenerClass);
+	protected boolean hasAnyListeners(Class<? extends ChangeListener> listenerClass, String listenerAspectName) {
+		this.checkAspectName(listenerAspectName);
+		return super.hasAnyListeners(listenerClass, listenerAspectName);
 	}
 
 
-	// ******************** state change support ********************
+	// ********** state change support **********
 
 	@Override
 	public void fireStateChanged(StateChangeEvent event) {
@@ -88,7 +89,7 @@ public class SingleAspectChangeSupport extends ChangeSupport {
 	}
 
 
-	// ******************** property change support ********************
+	// ********** property change support **********
 
 	@Override
 	public void firePropertyChanged(PropertyChangeEvent event) {
@@ -115,7 +116,7 @@ public class SingleAspectChangeSupport extends ChangeSupport {
 	}
 
 
-	// ******************** collection change support ********************
+	// ********** collection change support **********
 
 	@Override
 	public void fireItemsAdded(CollectionChangeEvent event) {
@@ -178,7 +179,7 @@ public class SingleAspectChangeSupport extends ChangeSupport {
 	}
 
 
-	// ******************** list change support ********************
+	// ********** list change support **********
 
 	@Override
 	public void fireItemsAdded(ListChangeEvent event) {
@@ -271,7 +272,7 @@ public class SingleAspectChangeSupport extends ChangeSupport {
 	}
 
 
-	// ******************** tree change support ********************
+	// ********** tree change support **********
 
 	@Override
 	public void fireNodeAdded(TreeChangeEvent event) {
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AbstractReadOnlyCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AbstractReadOnlyCollectionValueModel.java
index f8dd691623..a2838845d4 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AbstractReadOnlyCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AbstractReadOnlyCollectionValueModel.java
@@ -51,24 +51,24 @@ public abstract class AbstractReadOnlyCollectionValueModel
 
 	// ********** CollectionValueModel implementation **********
 
-	public void addItem(Object item) {
+	public void add(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void addItems(Collection items) {
+	public void addAll(Collection items) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItem(Object item) {
+	public void remove(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItems(Collection items) {
+	public void removeAll(Collection items) {
 		throw new UnsupportedOperationException();
 	}
 
 	public int size() {
-		return CollectionTools.size((Iterator) this.value());
+		return CollectionTools.size((Iterator) this.values());
 	}
 
 
@@ -76,7 +76,7 @@ public abstract class AbstractReadOnlyCollectionValueModel
 
 	@Override
 	public String toString() {
-		return StringTools.buildToStringFor(this, CollectionTools.collection((Iterator) this.value()));
+		return StringTools.buildToStringFor(this, CollectionTools.collection((Iterator) this.values()));
 	}
 
 }
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AspectAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AspectAdapter.java
index 5e4c6df31c..45aef0c618 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AspectAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/AspectAdapter.java
@@ -13,17 +13,14 @@ import org.eclipse.jpt.utility.internal.model.AbstractModel;
 import org.eclipse.jpt.utility.internal.model.ChangeSupport;
 import org.eclipse.jpt.utility.internal.model.SingleAspectChangeSupport;
 import org.eclipse.jpt.utility.internal.model.event.PropertyChangeEvent;
-import org.eclipse.jpt.utility.internal.model.listener.CollectionChangeListener;
-import org.eclipse.jpt.utility.internal.model.listener.ListChangeListener;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
 import org.eclipse.jpt.utility.internal.model.listener.PropertyChangeListener;
-import org.eclipse.jpt.utility.internal.model.listener.StateChangeListener;
-import org.eclipse.jpt.utility.internal.model.listener.TreeChangeListener;
 
 /**
  * This abstract extension of AbstractModel provides a base for adding 
  * change listeners (PropertyChange, CollectionChange, ListChange, TreeChange)
  * to a subject and converting the subject's change notifications into a single
- * set of change notifications for the aspect VALUE.
+ * set of change notifications for a common aspect (e.g. VALUE).
  * 
  * The adapter will only listen to the subject (and subject holder) when the
  * adapter itself actually has listeners. This will allow the adapter to be
@@ -31,7 +28,6 @@ import org.eclipse.jpt.utility.internal.model.listener.TreeChangeListener;
  */
 public abstract class AspectAdapter 
 	extends AbstractModel
-	implements ValueModel
 {
 	/**
 	 * The subject that holds the aspect and fires
@@ -50,10 +46,10 @@ public abstract class AspectAdapter
 	 * For now, this is can only be set upon construction and is
 	 * immutable.
 	 */
-	protected ValueModel subjectHolder;
+	protected final ValueModel subjectHolder;
 
 	/** A listener that keeps us in synch with the subjectHolder. */
-	protected PropertyChangeListener subjectChangeListener;
+	protected final PropertyChangeListener subjectChangeListener;
 
 
 	// ********** constructors **********
@@ -75,6 +71,7 @@ public abstract class AspectAdapter
 			throw new NullPointerException();
 		}
 		this.subjectHolder = subjectHolder;
+		this.subjectChangeListener = this.buildSubjectChangeListener();
 		// the subject is null when we are not listening to it
 		// this will typically result in our value being null
 		this.subject = null;
@@ -82,16 +79,10 @@ public abstract class AspectAdapter
 
 
 	// ********** initialization **********
-	
-	@Override
-	protected void initialize() {
-		super.initialize();
-		this.subjectChangeListener = this.buildSubjectChangeListener();
-	}
 
 	@Override
 	protected ChangeSupport buildChangeSupport() {
-		return new SingleAspectChangeSupport(this, VALUE);
+		return new LocalChangeSupport(this, this.listenerAspectName());
 	}
 
 	/**
@@ -129,12 +120,30 @@ public abstract class AspectAdapter
 	}
 
 	/**
+	 * Return the aspect's current value.
+	 */
+	protected abstract Object value();
+
+	/**
+	 * Return the class of listener that is interested in the aspect adapter's
+	 * changes.
+	 */
+	protected abstract Class<? extends ChangeListener> listenerClass();
+
+	/**
+	 * Return the name of the aspect adapter's aspect (e.g. VALUE).
+	 * This is the name of the aspect adapter's single aspect, not the
+	 * name of the subject's aspect the aspect adapter is adapting.
+	 */
+	protected abstract String listenerAspectName();
+
+	/**
 	 * Return whether there are any listeners for the aspect.
 	 */
 	protected abstract boolean hasListeners();
 
 	/**
-	 * Return whether there are any listeners for the aspect.
+	 * Return whether there are no listeners for the aspect.
 	 */
 	protected boolean hasNoListeners() {
 		return ! this.hasListeners();
@@ -170,14 +179,14 @@ public abstract class AspectAdapter
 	}
 
 	protected void engageSubjectHolder() {
-		this.subjectHolder.addPropertyChangeListener(VALUE, this.subjectChangeListener);
+		this.subjectHolder.addPropertyChangeListener(ValueModel.VALUE, this.subjectChangeListener);
 		// synch our subject *after* we start listening to the subject holder,
 		// since its value might change when a listener is added
 		this.subject = this.subjectHolder.value();
 	}
 
 	protected void disengageSubjectHolder() {
-		this.subjectHolder.removePropertyChangeListener(VALUE, this.subjectChangeListener);
+		this.subjectHolder.removePropertyChangeListener(ValueModel.VALUE, this.subjectChangeListener);
 		// clear out the subject when we are not listening to its holder
 		this.subject = null;
 	}
@@ -193,204 +202,77 @@ public abstract class AspectAdapter
 	}
 
 
-	// ********** extend change support **********
-	
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addStateChangeListener(StateChangeListener listener) {
-		if (this.hasNoListeners()) {
-			this.engageModels();
-		}
-		super.addStateChangeListener(listener);
-	}
-	
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeStateChangeListener(StateChangeListener listener) {
-		super.removeStateChangeListener(listener);
-		if (this.hasNoListeners()) {
-			this.disengageModels();
-		}
-	}
-	
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addPropertyChangeListener(PropertyChangeListener listener) {
-		if (this.hasNoListeners()) {
-			this.engageModels();
-		}
-		super.addPropertyChangeListener(listener);
-	}
-	
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {
-		if (propertyName == VALUE && this.hasNoListeners()) {
-			this.engageModels();
-		}
-		super.addPropertyChangeListener(propertyName, listener);
-	}
+	// ********** local change support **********
 
 	/**
-	 * Extend to stop listening to the models if appropriate.
+	 * Extend change support to start listening to the aspect adapter's
+	 * models (the subject holder and the subject itself) when the first
+	 * relevant listener is added.
+	 * Conversely, stop listening to the aspect adapter's models when the
+	 * last relevant listener is removed.
+	 * A relevant listener is a listener of the relevant type.
 	 */
-	@Override
-	public synchronized void removePropertyChangeListener(PropertyChangeListener listener) {
-		super.removePropertyChangeListener(listener);
-		if (this.hasNoListeners()) {
-			this.disengageModels();
-		}
-	}
+	protected class LocalChangeSupport extends SingleAspectChangeSupport {
+		private static final long serialVersionUID = 1L;
 
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) {
-		super.removePropertyChangeListener(propertyName, listener);
-		if (propertyName == VALUE && this.hasNoListeners()) {
-			this.disengageModels();
+		public LocalChangeSupport(AspectAdapter source, String aspectName) {
+			super(source, aspectName);
 		}
-	}
 
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addCollectionChangeListener(CollectionChangeListener listener) {
-		if (this.hasNoListeners()) {
-			this.engageModels();
+		protected boolean listenerIsRelevant(Class<? extends ChangeListener> listenerClass) {
+			return listenerClass == AspectAdapter.this.listenerClass();
 		}
-		super.addCollectionChangeListener(listener);
-	}
 
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
-		if (collectionName == VALUE && this.hasNoListeners()) {
-			this.engageModels();
+		protected boolean hasNoRelevantListeners(Class<? extends ChangeListener> listenerClass) {
+			return this.listenerIsRelevant(listenerClass)
+						&& this.hasNoListeners(listenerClass);
 		}
-		super.addCollectionChangeListener(collectionName, listener);
-	}
 
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeCollectionChangeListener(CollectionChangeListener listener) {
-		super.removeCollectionChangeListener(listener);
-		if (this.hasNoListeners()) {
-			this.disengageModels();
-		}
-	}
-
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
-		super.removeCollectionChangeListener(collectionName, listener);
-		if (collectionName == VALUE && this.hasNoListeners()) {
-			this.disengageModels();
+		protected boolean listenerIsRelevant(Class<? extends ChangeListener> listenerClass, String listenerAspectName) {
+			return this.listenerIsRelevant(listenerClass)
+						&& (listenerAspectName == AspectAdapter.this.listenerAspectName());
 		}
-	}
 
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addListChangeListener(ListChangeListener listener) {
-		if (this.hasNoListeners()) {
-			this.engageModels();
+		protected boolean hasNoRelevantListeners(Class<? extends ChangeListener> listenerClass, String listenerAspectName) {
+			return this.listenerIsRelevant(listenerClass, listenerAspectName)
+						&& this.hasNoListeners(listenerClass, listenerAspectName);
 		}
-		super.addListChangeListener(listener);
-	}
 
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addListChangeListener(String listName, ListChangeListener listener) {
-		if (listName == VALUE && this.hasNoListeners()) {
-			this.engageModels();
-		}
-		super.addListChangeListener(listName, listener);
-	}
 
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeListChangeListener(ListChangeListener listener) {
-		super.removeListChangeListener(listener);
-		if (this.hasNoListeners()) {
-			this.disengageModels();
-		}
-	}
+		// ********** overrides **********
 
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeListChangeListener(String listName, ListChangeListener listener) {
-		super.removeListChangeListener(listName, listener);
-		if (listName == VALUE && this.hasNoListeners()) {
-			this.disengageModels();
+		@Override
+		protected <T extends ChangeListener> void addListener(Class<T> listenerClass, T listener) {
+			if (this.hasNoRelevantListeners(listenerClass)) {
+				AspectAdapter.this.engageModels();
+			}
+			super.addListener(listenerClass, listener);
 		}
-	}
 
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addTreeChangeListener(TreeChangeListener listener) {
-		if (this.hasNoListeners()) {
-			this.engageModels();
+		@Override
+		protected <T extends ChangeListener> void addListener(String listenerAspectName, Class<T> listenerClass, T listener) {
+			if (this.hasNoRelevantListeners(listenerClass, listenerAspectName)) {
+				AspectAdapter.this.engageModels();
+			}
+			super.addListener(listenerAspectName, listenerClass, listener);
 		}
-		super.addTreeChangeListener(listener);
-	}
 
-	/**
-	 * Extend to start listening to the models if necessary.
-	 */
-	@Override
-	public synchronized void addTreeChangeListener(String treeName, TreeChangeListener listener) {
-		if (treeName == VALUE && this.hasNoListeners()) {
-			this.engageModels();
+		@Override
+		protected <T extends ChangeListener> void removeListener(Class<T> listenerClass, T listener) {
+			super.removeListener(listenerClass, listener);
+			if (this.hasNoRelevantListeners(listenerClass)) {
+				AspectAdapter.this.disengageModels();
+			}
 		}
-		super.addTreeChangeListener(treeName, listener);
-	}
 
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeTreeChangeListener(TreeChangeListener listener) {
-		super.removeTreeChangeListener(listener);
-		if (this.hasNoListeners()) {
-			this.disengageModels();
+		@Override
+		protected <T extends ChangeListener> void removeListener(String listenerAspectName, Class<T> listenerClass, T listener) {
+			super.removeListener(listenerAspectName, listenerClass, listener);
+			if (this.hasNoRelevantListeners(listenerClass, listenerAspectName)) {
+				AspectAdapter.this.disengageModels();
+			}
 		}
-	}
 
-	/**
-	 * Extend to stop listening to the models if appropriate.
-	 */
-	@Override
-	public synchronized void removeTreeChangeListener(String treeName, TreeChangeListener listener) {
-		super.removeTreeChangeListener(treeName, listener);
-		if (treeName == VALUE && this.hasNoListeners()) {
-			this.disengageModels();
-		}
 	}
 
 }
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionAspectAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionAspectAdapter.java
index 0aaa8e7bd2..a5d6744158 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionAspectAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionAspectAdapter.java
@@ -16,6 +16,7 @@ import org.eclipse.jpt.utility.internal.CollectionTools;
 import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
 import org.eclipse.jpt.utility.internal.model.Model;
 import org.eclipse.jpt.utility.internal.model.event.CollectionChangeEvent;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
 import org.eclipse.jpt.utility.internal.model.listener.CollectionChangeListener;
 
 /**
@@ -35,7 +36,7 @@ import org.eclipse.jpt.utility.internal.model.listener.CollectionChangeListener;
  *     (e.g. UI) will need only to *get* the value
  * #addItems(Collection) and #removeItems(Collection)
  *     override these methods to improve performance, if necessary
- * #value()
+ * #values()
  *     override this method only if returning an empty iterator when the
  *     subject is null is unacceptable
  * #size()
@@ -49,10 +50,10 @@ public abstract class CollectionAspectAdapter
 	/**
 	 * The name of the subject's collection that we use for the value.
 	 */
-	protected String collectionName;
+	protected final String collectionName;
 
 	/** A listener that listens to the subject's collection aspect. */
-	protected CollectionChangeListener collectionChangeListener;
+	protected final CollectionChangeListener collectionChangeListener;
 
 
 	// ********** constructors **********
@@ -62,17 +63,7 @@ public abstract class CollectionAspectAdapter
 	 * and collection.
 	 */
 	protected CollectionAspectAdapter(String collectionName, Model subject) {
-		super(subject);
-		this.collectionName = collectionName;
-	}
-
-	/**
-	 * Construct a CollectionAspectAdapter for the specified subject holder
-	 * and collection.
-	 */
-	protected CollectionAspectAdapter(ValueModel subjectHolder, String collectionName) {
-		super(subjectHolder);
-		this.collectionName = collectionName;
+		this(new ReadOnlyPropertyValueModel(subject), collectionName);
 	}
 
 	/**
@@ -85,15 +76,19 @@ public abstract class CollectionAspectAdapter
 		this(subjectHolder, null);
 	}
 
-
-	// ********** initialization **********
-
-	@Override
-	protected void initialize() {
-		super.initialize();
+	/**
+	 * Construct a CollectionAspectAdapter for the specified subject holder
+	 * and collection.
+	 */
+	protected CollectionAspectAdapter(ValueModel subjectHolder, String collectionName) {
+		super(subjectHolder);
+		this.collectionName = collectionName;
 		this.collectionChangeListener = this.buildCollectionChangeListener();
 	}
 
+
+	// ********** initialization **********
+
 	/**
 	 * The subject's collection aspect has changed, notify the listeners.
 	 */
@@ -120,13 +115,13 @@ public abstract class CollectionAspectAdapter
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
 	/**
 	 * Return the value of the subject's collection aspect.
 	 * This should be an *iterator* on the collection.
 	 */
-	public Object value() {
+	public Iterator values() {
 		if (this.subject == null) {
 			return EmptyIterator.instance();
 		}
@@ -137,44 +132,41 @@ public abstract class CollectionAspectAdapter
 	 * Return the value of the subject's collection aspect.
 	 * This should be an *iterator* on the collection.
 	 * At this point we can be sure that the subject is not null.
-	 * @see #value()
+	 * @see #values()
 	 */
 	protected Iterator getValueFromSubject() {
 		throw new UnsupportedOperationException();
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
 	/**
 	 * Add the specified item to the subject's collection aspect.
 	 */
-	public void addItem(Object item) {
+	public void add(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * Add the specified items to the subject's collection aspect.
 	 */
-	public void addItems(Collection items) {
+	public void addAll(Collection items) {
 		for (Iterator stream = items.iterator(); stream.hasNext(); ) {
-			this.addItem(stream.next());
+			this.add(stream.next());
 		}
 	}
 
 	/**
 	 * Remove the specified item from the subject's collection aspect.
 	 */
-	public void removeItem(Object item) {
+	public void remove(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
 	/**
 	 * Remove the specified items from the subject's collection aspect.
 	 */
-	public void removeItems(Collection items) {
+	public void removeAll(Collection items) {
 		for (Iterator stream = items.iterator(); stream.hasNext(); ) {
-			this.removeItem(stream.next());
+			this.remove(stream.next());
 		}
 	}
 
@@ -191,20 +183,35 @@ public abstract class CollectionAspectAdapter
 	 * @see #size()
 	 */
 	protected int sizeFromSubject() {
-		return CollectionTools.size((Iterator) this.value());
+		return CollectionTools.size((Iterator) this.values());
 	}
 
 
 	// ********** AspectAdapter implementation **********
 
 	@Override
+	protected Object value() {
+		return this.values();
+	}
+
+	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return CollectionChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUES;
+	}
+
+	@Override
 	protected boolean hasListeners() {
-		return this.hasAnyCollectionChangeListeners(VALUE);
+		return this.hasAnyCollectionChangeListeners(VALUES);
 	}
 
 	@Override
 	protected void fireAspectChange(Object oldValue, Object newValue) {
-		this.fireCollectionChanged(VALUE);
+		this.fireCollectionChanged(VALUES);
 	}
 
 	@Override
@@ -230,19 +237,19 @@ public abstract class CollectionAspectAdapter
 	// ********** behavior **********
 
 	protected void itemsAdded(CollectionChangeEvent e) {
-		this.fireItemsAdded(e.cloneWithSource(this, VALUE));
+		this.fireItemsAdded(e.cloneWithSource(this, VALUES));
 	}
 
 	protected void itemsRemoved(CollectionChangeEvent e) {
-		this.fireItemsRemoved(e.cloneWithSource(this, VALUE));
+		this.fireItemsRemoved(e.cloneWithSource(this, VALUES));
 	}
 
 	protected void collectionCleared(CollectionChangeEvent e) {
-		this.fireCollectionCleared(VALUE);
+		this.fireCollectionCleared(VALUES);
 	}
 
 	protected void collectionChanged(CollectionChangeEvent e) {
-		this.fireCollectionChanged(VALUE);
+		this.fireCollectionChanged(VALUES);
 	}
 
 }
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionListValueModelAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionListValueModelAdapter.java
index d6ef0a1aa3..b73b1aa48c 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionListValueModelAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionListValueModelAdapter.java
@@ -235,7 +235,7 @@ public class CollectionListValueModelAdapter
 	// ********** behavior **********
 
 	protected void buildList() {
-		Iterator stream = (Iterator) this.collectionHolder.value();
+		Iterator stream = (Iterator) this.collectionHolder.values();
 		// if the new collection is empty, do nothing
 		if (stream.hasNext()) {
 			this.list.ensureCapacity(this.collectionHolder.size());
@@ -255,14 +255,14 @@ public class CollectionListValueModelAdapter
 	}
 
 	protected void engageModel() {
-		this.collectionHolder.addCollectionChangeListener(VALUE, this.collectionChangeListener);
+		this.collectionHolder.addCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener);
 		// synch our list *after* we start listening to the collection holder,
 		// since its value might change when a listener is added
 		this.buildList();
 	}
 
 	protected void disengageModel() {
-		this.collectionHolder.removeCollectionChangeListener(VALUE, this.collectionChangeListener);
+		this.collectionHolder.removeCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener);
 		// clear out the list when we are not listening to the collection holder
 		this.list.clear();
 	}
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java
index b827a51120..3228f4a0a0 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java
@@ -188,7 +188,7 @@ public abstract class CollectionPropertyValueModelAdapter
 	 * Start listening to the collection holder.
 	 */
 	protected void engageModel() {
-		this.collectionHolder.addCollectionChangeListener(VALUE, this.collectionChangeListener);
+		this.collectionHolder.addCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener);
 		// synch our value *after* we start listening to the collection,
 		// since the collection's value might change when a listener is added
 		this.value = this.buildValue();
@@ -204,7 +204,7 @@ public abstract class CollectionPropertyValueModelAdapter
 	 * Stop listening to the collection holder.
 	 */
 	protected void disengageModel() {
-		this.collectionHolder.removeCollectionChangeListener(VALUE, this.collectionChangeListener);
+		this.collectionHolder.removeCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener);
 		// clear out our value when we are not listening to the collection
 		this.value = null;
 	}
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModel.java
index acc3034ae3..79ce454cf5 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModel.java
@@ -10,34 +10,41 @@
 package org.eclipse.jpt.utility.internal.model.value;
 
 import java.util.Collection;
+import java.util.Iterator;
+
+import org.eclipse.jpt.utility.internal.model.Model;
 
 /**
- * Extend ValueModel to allow the adding and
- * removing of items in a collection value.
- * Typically the value returned from #value()
- * will be an Iterator.
+ * Interface used to abstract collection accessing and
+ * change notification and make it more pluggable.
  */
-public interface CollectionValueModel extends ValueModel {
+public interface CollectionValueModel extends Model {
+
+	/**
+	 * Return the collection's values.
+	 */
+	Iterator values();
+		String VALUES = "values";
 
 	/**
-	 * Add the specified item to the collection value.
+	 * Add the specified item to the collection.
 	 */
-	void addItem(Object item);
+	void add(Object item);
 
 	/**
-	 * Add the specified items to the collection value.
+	 * Add the specified items to the collection.
 	 */
-	void addItems(Collection items);
+	void addAll(Collection items);
 
 	/**
-	 * Remove the specified item from the collection value.
+	 * Remove the specified item from the collection.
 	 */
-	void removeItem(Object item);
+	void remove(Object item);
 
 	/**
-	 * Remove the specified items from the collection value.
+	 * Remove the specified items from the collection.
 	 */
-	void removeItems(Collection items);
+	void removeAll(Collection items);
 
 	/**
 	 * Return the size of the collection value.
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModelWrapper.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModelWrapper.java
index a75cfea75e..3045ee481b 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModelWrapper.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionValueModelWrapper.java
@@ -58,7 +58,7 @@ public abstract class CollectionValueModelWrapper
 
 	@Override
 	protected ChangeSupport buildChangeSupport() {
-		return new SingleAspectChangeSupport(this, VALUE);
+		return new SingleAspectChangeSupport(this, VALUES);
 	}
 
 	protected CollectionChangeListener buildCollectionChangeListener() {
@@ -90,7 +90,7 @@ public abstract class CollectionValueModelWrapper
 	 */
 	@Override
 	public synchronized void addCollectionChangeListener(CollectionChangeListener listener) {
-		if (this.hasNoCollectionChangeListeners(VALUE)) {
+		if (this.hasNoCollectionChangeListeners(VALUES)) {
 			this.engageModel();
 		}
 		super.addCollectionChangeListener(listener);
@@ -101,7 +101,7 @@ public abstract class CollectionValueModelWrapper
 	 */
 	@Override
 	public synchronized void addCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
-		if (collectionName == VALUE && this.hasNoCollectionChangeListeners(VALUE)) {
+		if (collectionName == VALUES && this.hasNoCollectionChangeListeners(VALUES)) {
 			this.engageModel();
 		}
 		super.addCollectionChangeListener(collectionName, listener);
@@ -113,7 +113,7 @@ public abstract class CollectionValueModelWrapper
 	@Override
 	public synchronized void removeCollectionChangeListener(CollectionChangeListener listener) {
 		super.removeCollectionChangeListener(listener);
-		if (this.hasNoCollectionChangeListeners(VALUE)) {
+		if (this.hasNoCollectionChangeListeners(VALUES)) {
 			this.disengageModel();
 		}
 	}
@@ -124,7 +124,7 @@ public abstract class CollectionValueModelWrapper
 	@Override
 	public synchronized void removeCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
 		super.removeCollectionChangeListener(collectionName, listener);
-		if (collectionName == VALUE && this.hasNoCollectionChangeListeners(VALUE)) {
+		if (collectionName == VALUES && this.hasNoCollectionChangeListeners(VALUES)) {
 			this.disengageModel();
 		}
 	}
@@ -135,26 +135,26 @@ public abstract class CollectionValueModelWrapper
 	/**
 	 * wrappers cannot be modified - the underlying model must be modified directly
 	 */
-	public void addItem(Object item) {
+	public void add(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void addItems(Collection items) {
+	public void addAll(Collection items) {
 		for (Iterator stream = items.iterator(); stream.hasNext(); ) {
-			this.addItem(stream.next());
+			this.add(stream.next());
 		}
 	}
 
 	/**
 	 * wrappers cannot be modified - the underlying model must be modified directly
 	 */
-	public void removeItem(Object item) {
+	public void remove(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItems(Collection items) {
+	public void removeAll(Collection items) {
 		for (Iterator stream = items.iterator(); stream.hasNext(); ) {
-			this.removeItem(stream.next());
+			this.remove(stream.next());
 		}
 	}
 
@@ -165,14 +165,14 @@ public abstract class CollectionValueModelWrapper
 	 * Start listening to the collection holder.
 	 */
 	protected void engageModel() {
-		this.collectionHolder.addCollectionChangeListener(VALUE, this.collectionChangeListener);
+		this.collectionHolder.addCollectionChangeListener(VALUES, this.collectionChangeListener);
 	}
 
 	/**
 	 * Stop listening to the collection holder.
 	 */
 	protected void disengageModel() {
-		this.collectionHolder.removeCollectionChangeListener(VALUE, this.collectionChangeListener);
+		this.collectionHolder.removeCollectionChangeListener(VALUES, this.collectionChangeListener);
 	}
 
 	@Override
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CompositeCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CompositeCollectionValueModel.java
index 1d12858258..9be509a43d 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CompositeCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CompositeCollectionValueModel.java
@@ -138,9 +138,9 @@ public class CompositeCollectionValueModel
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
-	public Object value() {
+	public Iterator values() {
 		return new CompositeIterator(this.buildCollectionsIterators());
 	}
 
@@ -152,9 +152,6 @@ public class CompositeCollectionValueModel
 		};
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
 	public int size() {
 		return this.size;
 	}
@@ -170,7 +167,7 @@ public class CompositeCollectionValueModel
 		// the following will trigger the firing of a number of unnecessary events
 		// (since we don't have any listeners yet),
 		// but it reduces the amount of duplicate code
-		this.addComponentSources((Iterator) this.collectionHolder.value());
+		this.addComponentSources((Iterator) this.collectionHolder.values());
 	}
 
 	@Override
@@ -178,7 +175,7 @@ public class CompositeCollectionValueModel
 		super.disengageModel();
 		// stop listening to the components...
 		for (Iterator stream = this.components.values().iterator(); stream.hasNext(); ) {
-			((CollectionValueModel) stream.next()).removeCollectionChangeListener(ValueModel.VALUE, this.componentListener);
+			((CollectionValueModel) stream.next()).removeCollectionChangeListener(CollectionValueModel.VALUES, this.componentListener);
 		}
 		// ...and clear the cache
 		this.components.clear();
@@ -214,7 +211,7 @@ public class CompositeCollectionValueModel
 		if (this.components.put(source, component) != null) {
 			throw new IllegalStateException("duplicate component: " + source);
 		}
-		component.addCollectionChangeListener(ValueModel.VALUE, this.componentListener);
+		component.addCollectionChangeListener(CollectionValueModel.VALUES, this.componentListener);
 		ArrayList componentCollection = new ArrayList(component.size());
 		if (this.collections.put(component, componentCollection) != null) {
 			throw new IllegalStateException("duplicate collection: " + source);
@@ -250,7 +247,7 @@ public class CompositeCollectionValueModel
 		if (component == null) {
 			throw new IllegalStateException("missing component: " + source);
 		}
-		component.removeCollectionChangeListener(VALUE, this.componentListener);
+		component.removeCollectionChangeListener(CollectionValueModel.VALUES, this.componentListener);
 		ArrayList componentCollection = (ArrayList) this.collections.remove(component);
 		if (componentCollection == null) {
 			throw new IllegalStateException("missing collection: " + source);
@@ -276,7 +273,7 @@ public class CompositeCollectionValueModel
 	protected void collectionChanged(CollectionChangeEvent e) {
 		// copy the keys so we don't eat our own tail
 		this.removeComponentSources(new ArrayList(this.components.keySet()).iterator());
-		this.addComponentSources((Iterator) this.collectionHolder.value());
+		this.addComponentSources((Iterator) this.collectionHolder.values());
 	}
 
 
@@ -323,7 +320,7 @@ public class CompositeCollectionValueModel
 	 * Update our cache.
 	 */
 	protected void addComponentItems(CollectionValueModel itemsHolder, ArrayList componentCollection) {
-		this.addComponentItems((Iterator) itemsHolder.value(), itemsHolder.size(), componentCollection);
+		this.addComponentItems((Iterator) itemsHolder.values(), itemsHolder.size(), componentCollection);
 	}
 
 	/**
@@ -332,7 +329,7 @@ public class CompositeCollectionValueModel
 	protected void addComponentItems(Iterator items, int itemsSize, ArrayList componentCollection) {
 		this.size += itemsSize;
 		componentCollection.ensureCapacity(componentCollection.size() + itemsSize);
-		this.addItemsToCollection(items, componentCollection, VALUE);
+		this.addItemsToCollection(items, componentCollection, CollectionValueModel.VALUES);
 	}
 
 	/**
@@ -363,7 +360,7 @@ public class CompositeCollectionValueModel
 	 */
 	protected void removeComponentItems(Iterator items, int itemsSize, ArrayList componentCollection) {
 		this.size -= itemsSize;
-		this.removeItemsFromCollection(items, componentCollection, VALUE);
+		this.removeItemsFromCollection(items, componentCollection, CollectionValueModel.VALUES);
 	}
 
 	/**
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/FilteringCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/FilteringCollectionValueModel.java
index e4d046aff3..fe6c6c250f 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/FilteringCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/FilteringCollectionValueModel.java
@@ -117,15 +117,12 @@ public class FilteringCollectionValueModel
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
-	public Object value() {
+	public Iterator values() {
 		return this.filteredItems.iterator();
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
 	public int size() {
 		return this.filteredItems.size();
 	}
@@ -151,7 +148,7 @@ public class FilteringCollectionValueModel
 	@Override
 	protected void itemsAdded(CollectionChangeEvent e) {
 		// filter the values before propagating the change event
-		this.addItemsToCollection(this.filter(e.items()), this.filteredItems, VALUE);
+		this.addItemsToCollection(this.filter(e.items()), this.filteredItems, VALUES);
 	}
 
 	@Override
@@ -159,18 +156,18 @@ public class FilteringCollectionValueModel
 		// do *not* filter the values, because they may no longer be
 		// "accepted" and that might be why they were removed in the first place;
 		// anyway, any extraneous items are harmless
-		this.removeItemsFromCollection(e.items(), this.filteredItems, VALUE);
+		this.removeItemsFromCollection(e.items(), this.filteredItems, VALUES);
 	}
 
 	@Override
 	protected void collectionCleared(CollectionChangeEvent e) {
-		this.clearCollection(this.filteredItems, VALUE);
+		this.clearCollection(this.filteredItems, VALUES);
 	}
 
 	@Override
 	protected void collectionChanged(CollectionChangeEvent e) {
 		this.synchFilteredItems();
-		this.fireCollectionChanged(VALUE);
+		this.fireCollectionChanged(VALUES);
 	}
 
 
@@ -204,7 +201,7 @@ public class FilteringCollectionValueModel
 	 */
 	protected void synchFilteredItems() {
 		this.filteredItems.clear();
-		CollectionTools.addAll(this.filteredItems, this.filter((Iterator) this.collectionHolder.value()));
+		CollectionTools.addAll(this.filteredItems, this.filter((Iterator) this.collectionHolder.values()));
 	}
 
 }
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListAspectAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListAspectAdapter.java
index 3786fa3720..c4ea16741b 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListAspectAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListAspectAdapter.java
@@ -17,6 +17,7 @@ import org.eclipse.jpt.utility.internal.CollectionTools;
 import org.eclipse.jpt.utility.internal.iterators.EmptyListIterator;
 import org.eclipse.jpt.utility.internal.model.Model;
 import org.eclipse.jpt.utility.internal.model.event.ListChangeEvent;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
 import org.eclipse.jpt.utility.internal.model.listener.ListChangeListener;
 
 /**
@@ -52,10 +53,10 @@ public abstract class ListAspectAdapter
 	/**
 	 * The name of the subject's list that we use for the value.
 	 */
-	protected String listName;
+	protected final String listName;
 
 	/** A listener that listens to the subject's list aspect. */
-	protected ListChangeListener listChangeListener;
+	protected final ListChangeListener listChangeListener;
 
 
 	// ********** constructors **********
@@ -65,17 +66,7 @@ public abstract class ListAspectAdapter
 	 * and list.
 	 */
 	protected ListAspectAdapter(String listName, Model subject) {
-		super(subject);
-		this.listName = listName;
-	}
-
-	/**
-	 * Construct a ListAspectAdapter for the specified subject holder
-	 * and list.
-	 */
-	protected ListAspectAdapter(ValueModel subjectHolder, String listName) {
-		super(subjectHolder);
-		this.listName = listName;
+		this(new ReadOnlyPropertyValueModel(subject), listName);
 	}
 
 	/**
@@ -88,15 +79,19 @@ public abstract class ListAspectAdapter
 		this(subjectHolder, null);
 	}
 
-
-	// ********** initialization **********
-
-	@Override
-	protected void initialize() {
-		super.initialize();
+	/**
+	 * Construct a ListAspectAdapter for the specified subject holder
+	 * and list.
+	 */
+	protected ListAspectAdapter(ValueModel subjectHolder, String listName) {
+		super(subjectHolder);
+		this.listName = listName;
 		this.listChangeListener = this.buildListChangeListener();
 	}
 
+
+	// ********** initialization **********
+
 	/**
 	 * The subject's list aspect has changed, notify the listeners.
 	 */
@@ -135,6 +130,7 @@ public abstract class ListAspectAdapter
 	 * Return the value of the subject's list aspect.
 	 * This should be a *list iterator* on the list.
 	 */
+	@Override
 	public Object value() {
 		if (this.subject == null) {
 			return EmptyListIterator.instance();
@@ -234,6 +230,16 @@ public abstract class ListAspectAdapter
 	// ********** AspectAdapter implementation **********
 
 	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return ListChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUE;
+	}
+
+	@Override
 	protected boolean hasListeners() {
 		return this.hasAnyListChangeListeners(VALUE);
 	}
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCollectionValueModelAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCollectionValueModelAdapter.java
index 0b679c57d8..aa39a47ad4 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCollectionValueModelAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCollectionValueModelAdapter.java
@@ -76,7 +76,7 @@ public class ListCollectionValueModelAdapter
 
 	@Override
 	protected ChangeSupport buildChangeSupport() {
-		return new SingleAspectChangeSupport(this, VALUE);
+		return new SingleAspectChangeSupport(this, VALUES);
 	}
 
 	/**
@@ -111,29 +111,26 @@ public class ListCollectionValueModelAdapter
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
-	public Object value() {
+	public Iterator values() {
 		// try to prevent backdoor modification of the list
 		return new ReadOnlyIterator(this.collection);
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
-	public void addItem(Object item) {
+	public void add(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void addItems(Collection items) {
+	public void addAll(Collection items) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItem(Object item) {
+	public void remove(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItems(Collection items) {
+	public void removeAll(Collection items) {
 		throw new UnsupportedOperationException();
 	}
 
@@ -160,7 +157,7 @@ public class ListCollectionValueModelAdapter
 	 */
 	@Override
 	public void addCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
-		if (collectionName == VALUE && this.hasNoListeners()) {
+		if (collectionName == VALUES && this.hasNoListeners()) {
 			this.engageModel();
 		}
 		super.addCollectionChangeListener(collectionName, listener);
@@ -183,7 +180,7 @@ public class ListCollectionValueModelAdapter
 	@Override
 	public void removeCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
 		super.removeCollectionChangeListener(collectionName, listener);
-		if (collectionName == VALUE && this.hasNoListeners()) {
+		if (collectionName == VALUES && this.hasNoListeners()) {
 			this.disengageModel();
 		}
 	}
@@ -192,7 +189,7 @@ public class ListCollectionValueModelAdapter
 	// ********** queries **********
 
 	protected boolean hasListeners() {
-		return this.hasAnyCollectionChangeListeners(VALUE);
+		return this.hasAnyCollectionChangeListeners(VALUES);
 	}
 
 	protected boolean hasNoListeners() {
@@ -235,20 +232,20 @@ public class ListCollectionValueModelAdapter
 	}
 
 	protected void engageModel() {
-		this.listHolder.addListChangeListener(VALUE, this.listChangeListener);
+		this.listHolder.addListChangeListener(ValueModel.VALUE, this.listChangeListener);
 		// synch our collection *after* we start listening to the list holder,
 		// since its value might change when a listener is added
 		this.buildCollection();
 	}
 
 	protected void disengageModel() {
-		this.listHolder.removeListChangeListener(VALUE, this.listChangeListener);
+		this.listHolder.removeListChangeListener(ValueModel.VALUE, this.listChangeListener);
 		// clear out the collection when we are not listening to the list holder
 		this.collection.clear();
 	}
 
 	protected void itemsAdded(ListChangeEvent e) {
-		this.addItemsToCollection(e.items(), this.collection, VALUE);
+		this.addItemsToCollection(e.items(), this.collection, VALUES);
 	}
 
 	protected void removeInternalItems(Iterator items) {
@@ -258,7 +255,7 @@ public class ListCollectionValueModelAdapter
 			Object removedItem = items.next();
 			int index = this.lastIdentityIndexOf(removedItem);
 			this.collection.remove(index);
-			this.fireItemRemoved(VALUE, removedItem);
+			this.fireItemRemoved(VALUES, removedItem);
 		}
 	}
 
@@ -268,7 +265,7 @@ public class ListCollectionValueModelAdapter
 
 	protected void itemsReplaced(ListChangeEvent e) {
 		this.removeInternalItems(e.replacedItems());
-		this.addItemsToCollection(e.items(), this.collection, VALUE);
+		this.addItemsToCollection(e.items(), this.collection, VALUES);
 	}
 
 	protected void itemsMoved(ListChangeEvent e) {
@@ -279,7 +276,7 @@ public class ListCollectionValueModelAdapter
 		// put in empty check so we don't fire events unnecessarily
 		if ( ! this.collection.isEmpty()) {
 			this.collection.clear();
-			this.fireCollectionCleared(VALUE);
+			this.fireCollectionCleared(VALUES);
 		}
 	}
 
@@ -294,13 +291,13 @@ public class ListCollectionValueModelAdapter
 			Collection removedItems = this.collection;
 			// ...or we create a new one here (which is what we do)
 			this.collection = new ArrayList();
-			this.fireItemsRemoved(VALUE, removedItems);
+			this.fireItemsRemoved(VALUES, removedItems);
 		}
 
 		this.buildCollection();
 		// put in empty check so we don't fire events unnecessarily
 		if ( ! this.collection.isEmpty()) {
-			this.fireItemsAdded(VALUE, this.collection);
+			this.fireItemsAdded(VALUES, this.collection);
 		}
 	}
 
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCurator.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCurator.java
index 7af76872f3..5e329bf289 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCurator.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ListCurator.java
@@ -17,6 +17,8 @@ import org.eclipse.jpt.utility.internal.CollectionTools;
 import org.eclipse.jpt.utility.internal.iterators.ReadOnlyListIterator;
 import org.eclipse.jpt.utility.internal.model.Model;
 import org.eclipse.jpt.utility.internal.model.event.StateChangeEvent;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
+import org.eclipse.jpt.utility.internal.model.listener.ListChangeListener;
 import org.eclipse.jpt.utility.internal.model.listener.StateChangeListener;
 
 /**
@@ -33,41 +35,36 @@ import org.eclipse.jpt.utility.internal.model.listener.StateChangeListener;
 public abstract class ListCurator 
 	extends AspectAdapter
 	implements ListValueModel
-{	
+{
 	/** How the list looked before the last state change */
-	private List record;
-	
+	private final ArrayList record;
+
 	/** A listener that listens for the subject's state to change */
-	private StateChangeListener stateChangeListener;
-	
-	
-	// **************** Constructors ******************************************
-	
+	private final StateChangeListener stateChangeListener;
+
+
+	// ********** constructors **********
+
 	/**
 	 * Construct a Curator for the specified subject.
 	 */
 	protected ListCurator(Model subject) {
-		super(subject);
+		this(new ReadOnlyPropertyValueModel(subject));
 	}
-	
+
 	/**
 	 * Construct a curator for the specified subject holder.
 	 * The subject holder cannot be null.
 	 */
 	protected ListCurator(ValueModel subjectHolder) {
 		super(subjectHolder);
-	}
-	
-	
-	// **************** Initialization ****************************************
-	
-	@Override
-	protected void initialize() {
-		super.initialize();
 		this.record = new ArrayList();
 		this.stateChangeListener = this.buildStateChangeListener();
 	}
-	
+
+
+	// ********** initialization **********
+
 	/**
 	 * The subject's state has changed, do inventory and report to listeners.
 	 */
@@ -82,38 +79,39 @@ public abstract class ListCurator
 			}
 		};
 	}
-	
-	
-	// **************** ValueModel contract ***********************************
-	
+
+
+	// ********** ValueModel implementation **********
+
+	@Override
 	public Object value() {
 		return new ReadOnlyListIterator(this.record);
 	}
-	
-	
-	// **************** ListValueModel contract *******************************
-	
+
+
+	// ********** ListValueModel implementation **********
+
 	/**
 	 * Return the item at the specified index of the subject's list aspect.
 	 */
 	public Object getItem(int index) {
 		return this.record.get(index);
 	}
-	
+
 	/**
 	 * Return the size of the subject's list aspect.
 	 */
 	public int size() {
 		return this.record.size();
 	}
-	
+
 	/**
 	 * Unsupported in this implementation
 	 */
 	public void addItem(int index, Object item) {
 		throw new UnsupportedOperationException();
 	}
-	
+
 	/**
 	 * Unsupported in this implementation
 	 */
@@ -122,14 +120,14 @@ public abstract class ListCurator
 			this.addItem(index + i, items.get(i));
 		}
 	}
-	
+
 	/**
 	 * Unsupported in this implementation
 	 */
 	public Object removeItem(int index) {
 		throw new UnsupportedOperationException();
 	}
-	
+
 	/**
 	 * Unsupported in this implementation
 	 */
@@ -140,14 +138,14 @@ public abstract class ListCurator
 		}
 		return removedItems;
 	}
-	
+
 	/**
 	 * Unsupported in this implementation
 	 */
 	public Object replaceItem(int index, Object item) {
 		throw new UnsupportedOperationException();
 	}
-	
+
 	/**
 	 * Unsupported in this implementation
 	 */
@@ -158,18 +156,25 @@ public abstract class ListCurator
 		}
 		return replacedItems;
 	}
-	
-	
-	// ***************** AspectAdapter contract *******************************
-	
-	/**
-	 * Return whether there are any listeners.
-	 */
+
+
+	// ********** AspectAdapter implementation **********
+
+	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return ListChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUE;
+	}
+
 	@Override
 	protected boolean hasListeners() {
 		return this.hasAnyListChangeListeners(VALUE);
 	}
-	
+
 	/**
 	 * The aspect has changed, notify listeners appropriately.
 	 */
@@ -177,7 +182,7 @@ public abstract class ListCurator
 	protected void fireAspectChange(Object oldValue, Object newValue) {
 		this.fireListChanged(VALUE);
 	}
-	
+
 	/**
 	 * The subject is not null - add our listener.
 	 */
@@ -188,7 +193,7 @@ public abstract class ListCurator
 		// since its value might change when a listener is added
 		CollectionTools.addAll(this.record, this.getValueForRecord());
 	}
-	
+
 	/**
 	 * The subject is not null - remove our listener.
 	 */
@@ -198,33 +203,33 @@ public abstract class ListCurator
 		// clear out the list when we are not listening to the subject
 		this.record.clear();
 	}
-	
 
-	// **************** ListCurator contract **********************************
-	
+
+	// ********** ListCurator contract **********
+
 	/**
 	 * This is intended to be different from #ValueModel.getValue().
 	 * It is intended to be used only when the subject changes or the subject's state changes.
 	 */
 	protected abstract Iterator getValueForRecord();
-	
-	
-	// **************** Behavior **********************************************
-	
+
+
+	// ********** behavior **********
+
 	void submitInventoryReport() {
 		List newRecord = CollectionTools.list(this.getValueForRecord());
 		int recordIndex = 0;
-		
+
 		// add items from the new record
 		for (Iterator newItems = newRecord.iterator(); newItems.hasNext(); ) {
 			this.inventoryNewItem(recordIndex, newItems.next());
 			recordIndex ++;
 		}
-		
+
 		// clean out items that are no longer in the new record
 		for (recordIndex = 0; recordIndex < this.record.size(); ) {
 			Object item = this.record.get(recordIndex);
-			
+
 			if (! newRecord.contains(item)) {
 				this.removeItemFromInventory(recordIndex, item);
 			}
@@ -233,10 +238,10 @@ public abstract class ListCurator
 			}
 		}
 	}
-	
+
 	private void inventoryNewItem(int recordIndex, Object newItem) {
 		List rec = new ArrayList(this.record);
-		
+
 		if (recordIndex < rec.size() && rec.get(recordIndex).equals(newItem)) {
 			return;
 		}
@@ -248,11 +253,11 @@ public abstract class ListCurator
 			this.inventoryNewItem(recordIndex, newItem);
 		}
 	}
-	
+
 	private void addItemToInventory(int index, Object item) {
 		this.addItemToList(index, item, this.record, VALUE);
 	}
-	
+
 	private void removeItemFromInventory(int index, Object item) {
 		this.removeItemFromList(index, this.record, VALUE);
 	}
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/NullCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/NullCollectionValueModel.java
index 505518aa1c..441bb5278f 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/NullCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/NullCollectionValueModel.java
@@ -9,6 +9,8 @@
  ******************************************************************************/
 package org.eclipse.jpt.utility.internal.model.value;
 
+import java.util.Iterator;
+
 import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
 
 
@@ -51,7 +53,7 @@ public final class NullCollectionValueModel
 		return 0;
 	}
 
-	public Object value() {
+	public Iterator values() {
 		return EmptyIterator.instance();
 	}
 
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyAspectAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyAspectAdapter.java
index 8d0fd79516..1b4d206abb 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyAspectAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyAspectAdapter.java
@@ -14,6 +14,7 @@ import java.util.Collection;
 
 import org.eclipse.jpt.utility.internal.model.Model;
 import org.eclipse.jpt.utility.internal.model.event.PropertyChangeEvent;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
 import org.eclipse.jpt.utility.internal.model.listener.PropertyChangeListener;
 
 /**
@@ -52,10 +53,11 @@ public abstract class PropertyAspectAdapter
 	protected Object value;
 
 	/** The name of the subject's properties that we use for the value. */
-	protected String[] propertyNames;
+	protected final String[] propertyNames;
+		private static final String[] EMPTY_PROPERTY_NAMES = new String[0];
 
 	/** A listener that listens to the appropriate properties of the subject. */
-	protected PropertyChangeListener propertyChangeListener;
+	protected final PropertyChangeListener propertyChangeListener;
 
 
 	// ********** constructors **********
@@ -73,41 +75,19 @@ public abstract class PropertyAspectAdapter
 	 * and properties.
 	 */
 	protected PropertyAspectAdapter(String[] propertyNames, Model subject) {
-		super(subject);
-		this.propertyNames = propertyNames;
-	}
-
-	/**
-	 * Construct a PropertyAspectAdapter for the specified subject holder
-	 * and property.
-	 */
-	protected PropertyAspectAdapter(ValueModel subjectHolder, String propertyName) {
-		this(subjectHolder, new String[] {propertyName});
-	}
-
-	/**
-	 * Construct a PropertyAspectAdapter for the specified subject holder
-	 * and properties.
-	 */
-	protected PropertyAspectAdapter(ValueModel subjectHolder, String propertyName1, String propertyName2) {
-		this(subjectHolder, new String[] {propertyName1, propertyName2});
-	}
-
-	/**
-	 * Construct a PropertyAspectAdapter for the specified subject holder
-	 * and properties.
-	 */
-	protected PropertyAspectAdapter(ValueModel subjectHolder, String propertyName1, String propertyName2, String propertyName3) {
-		this(subjectHolder, new String[] {propertyName1, propertyName2, propertyName3});
+		this(new ReadOnlyPropertyValueModel(subject), propertyNames);
 	}
 
 	/**
 	 * Construct a PropertyAspectAdapter for the specified subject holder
 	 * and properties.
 	 */
-	protected PropertyAspectAdapter(ValueModel subjectHolder, String[] propertyNames) {
+	protected PropertyAspectAdapter(ValueModel subjectHolder, String... propertyNames) {
 		super(subjectHolder);
 		this.propertyNames = propertyNames;
+		this.propertyChangeListener = this.buildPropertyChangeListener();
+		// our value is null when we are not listening to the subject
+		this.value = null;
 	}
 
 	/**
@@ -125,20 +105,12 @@ public abstract class PropertyAspectAdapter
 	 * a new property.
 	 */
 	protected PropertyAspectAdapter(ValueModel subjectHolder) {
-		this(subjectHolder, new String[0]);
+		this(subjectHolder, EMPTY_PROPERTY_NAMES);
 	}
 
 
 	// ********** initialization **********
 
-    @Override
-	protected void initialize() {
-		super.initialize();
-		// our value is null when we are not listening to the subject
-		this.value = null;
-		this.propertyChangeListener = this.buildPropertyChangeListener();
-	}
-
 	/**
 	 * The subject's property has changed, notify the listeners.
 	 */
@@ -161,6 +133,7 @@ public abstract class PropertyAspectAdapter
 	/**
 	 * Return the value of the subject's property.
 	 */
+	@Override
 	public final Object value() {
 		return this.value;
 	}
@@ -189,6 +162,16 @@ public abstract class PropertyAspectAdapter
 
 	// ********** AspectAdapter implementation **********
 
+	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return PropertyChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUE;
+	}
+
     @Override
 	protected boolean hasListeners() {
 		return this.hasAnyPropertyChangeListeners(VALUE);
@@ -242,7 +225,7 @@ public abstract class PropertyAspectAdapter
 	}
 
 
-	// ********** queries **********
+	// ********** behavior **********
 
 	/**
 	 * Return the aspect's value.
@@ -264,9 +247,6 @@ public abstract class PropertyAspectAdapter
 		throw new UnsupportedOperationException();
 	}
 
-
-	// ********** behavior **********
-
 	protected void propertyChanged() {
 		Object old = this.value;
 		this.value = this.buildValue();
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyCollectionValueModelAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyCollectionValueModelAdapter.java
index d12426ad1b..ee28f98e1e 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyCollectionValueModelAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/PropertyCollectionValueModelAdapter.java
@@ -10,6 +10,7 @@
 package org.eclipse.jpt.utility.internal.model.value;
 
 import java.util.Collection;
+import java.util.Iterator;
 
 import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
 import org.eclipse.jpt.utility.internal.iterators.SingleElementIterator;
@@ -64,7 +65,7 @@ public class PropertyCollectionValueModelAdapter
 
 	@Override
 	protected ChangeSupport buildChangeSupport() {
-		return new SingleAspectChangeSupport(this, VALUE);
+		return new SingleAspectChangeSupport(this, VALUES);
 	}
 
 	/**
@@ -84,31 +85,28 @@ public class PropertyCollectionValueModelAdapter
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
-	public Object value() {
-		if (this.value == null) {
-			return EmptyIterator.instance();
-		}
-		return new SingleElementIterator(this.value);
+	public Iterator values() {
+		return (this.value == null) ?
+					EmptyIterator.instance()
+				:
+					new SingleElementIterator(this.value);
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
-	public void addItem(Object item) {
+	public void add(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void addItems(Collection items) {
+	public void addAll(Collection items) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItem(Object item) {
+	public void remove(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItems(Collection items) {
+	public void removeAll(Collection items) {
 		throw new UnsupportedOperationException();
 	}
 
@@ -135,7 +133,7 @@ public class PropertyCollectionValueModelAdapter
 	 */
 	@Override
 	public void addCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
-		if (collectionName == VALUE && this.hasNoListeners()) {
+		if (collectionName == VALUES && this.hasNoListeners()) {
 			this.engageModel();
 		}
 		super.addCollectionChangeListener(collectionName, listener);
@@ -158,7 +156,7 @@ public class PropertyCollectionValueModelAdapter
 	@Override
 	public void removeCollectionChangeListener(String collectionName, CollectionChangeListener listener) {
 		super.removeCollectionChangeListener(collectionName, listener);
-		if (collectionName == VALUE && this.hasNoListeners()) {
+		if (collectionName == VALUES && this.hasNoListeners()) {
 			this.disengageModel();
 		}
 	}
@@ -167,7 +165,7 @@ public class PropertyCollectionValueModelAdapter
 	// ********** queries **********
 
 	protected boolean hasListeners() {
-		return this.hasAnyCollectionChangeListeners(VALUE);
+		return this.hasAnyCollectionChangeListeners(VALUES);
 	}
 
 	protected boolean hasNoListeners() {
@@ -178,14 +176,14 @@ public class PropertyCollectionValueModelAdapter
 	// ********** behavior **********
 
 	protected void engageModel() {
-		this.valueHolder.addPropertyChangeListener(VALUE, this.propertyChangeListener);
+		this.valueHolder.addPropertyChangeListener(ValueModel.VALUE, this.propertyChangeListener);
 		// synch our value *after* we start listening to the value holder,
 		// since its value might change when a listener is added
 		this.value = this.valueHolder.value();
 	}
 
 	protected void disengageModel() {
-		this.valueHolder.removePropertyChangeListener(VALUE, this.propertyChangeListener);
+		this.valueHolder.removePropertyChangeListener(ValueModel.VALUE, this.propertyChangeListener);
 		// clear out the value when we are not listening to the value holder
 		this.value = null;
 	}
@@ -199,12 +197,12 @@ public class PropertyCollectionValueModelAdapter
 		if (this.value != null) {
 			Object oldValue = this.value;
 			this.value = null;
-			this.fireItemRemoved(VALUE, oldValue);
+			this.fireItemRemoved(VALUES, oldValue);
 		}
 		this.value = newValue;
 		// put in "empty" check so we don't fire events unnecessarily
 		if (this.value != null) {
-			this.fireItemAdded(VALUE, this.value);
+			this.fireItemAdded(VALUES, this.value);
 		}
 	}
 
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ReadOnlyCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ReadOnlyCollectionValueModel.java
index 4f1988ebde..8e1d02b2b0 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ReadOnlyCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ReadOnlyCollectionValueModel.java
@@ -10,6 +10,7 @@
 package org.eclipse.jpt.utility.internal.model.value;
 
 import java.util.Collection;
+import java.util.Iterator;
 
 /**
  * Implementation of CollectionValueModel that can be used for
@@ -43,10 +44,7 @@ public class ReadOnlyCollectionValueModel
 		return this.value.size();
 	}
 
-
-	// ********** ValueModel implementation **********
-
-	public Object value() {
+	public Iterator values() {
 		return this.value.iterator();
 	}
 
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/SimpleCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/SimpleCollectionValueModel.java
index 723c01d905..bfd6441cc0 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/SimpleCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/SimpleCollectionValueModel.java
@@ -11,6 +11,7 @@ package org.eclipse.jpt.utility.internal.model.value;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Iterator;
 
 import org.eclipse.jpt.utility.internal.HashBag;
 import org.eclipse.jpt.utility.internal.iterators.ReadOnlyIterator;
@@ -48,34 +49,31 @@ public class SimpleCollectionValueModel
 
 	@Override
 	protected ChangeSupport buildChangeSupport() {
-		return new SingleAspectChangeSupport(this, VALUE);
+		return new SingleAspectChangeSupport(this, VALUES);
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
-	public Object value() {
+	public Iterator values() {
 		// try to prevent backdoor modification of the collection
 		return new ReadOnlyIterator(this.value);
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
-	public void addItem(Object item) {
-		this.addItemToCollection(item, this.value, VALUE);
+	public void add(Object item) {
+		this.addItemToCollection(item, this.value, VALUES);
 	}
 
-	public void addItems(Collection items) {
-		this.addItemsToCollection(items, this.value, VALUE);
+	public void addAll(Collection items) {
+		this.addItemsToCollection(items, this.value, VALUES);
 	}
 
-	public void removeItem(Object item) {
-		this.removeItemFromCollection(item, this.value, VALUE);
+	public void remove(Object item) {
+		this.removeItemFromCollection(item, this.value, VALUES);
 	}
 
-	public void removeItems(Collection items) {
-		this.removeItemsFromCollection(items, this.value, VALUE);
+	public void removeAll(Collection items) {
+		this.removeItemsFromCollection(items, this.value, VALUES);
 	}
 
 	public int size() {
@@ -90,7 +88,7 @@ public class SimpleCollectionValueModel
 	 */
 	public void setValue(Collection value) {
 		this.value = ((value == null) ? new HashBag() : value);
-		this.fireCollectionChanged(VALUE);
+		this.fireCollectionChanged(VALUES);
 	}
 
 	/**
@@ -102,7 +100,7 @@ public class SimpleCollectionValueModel
 		}
 		Collection items = new ArrayList(this.value);
 		this.value.clear();
-		this.fireItemsRemoved(VALUE, items);
+		this.fireItemsRemoved(VALUES, items);
 	}
 
 	@Override
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/TreeAspectAdapter.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/TreeAspectAdapter.java
index 44b96fd8a0..f3fe043e42 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/TreeAspectAdapter.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/TreeAspectAdapter.java
@@ -14,6 +14,7 @@ import java.util.Iterator;
 import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
 import org.eclipse.jpt.utility.internal.model.Model;
 import org.eclipse.jpt.utility.internal.model.event.TreeChangeEvent;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
 import org.eclipse.jpt.utility.internal.model.listener.TreeChangeListener;
 
 /**
@@ -39,10 +40,10 @@ public abstract class TreeAspectAdapter
 	/**
 	 * The name of the subject's tree that we use for the value.
 	 */
-	protected String treeName;
+	protected final String treeName;
 
 	/** A listener that listens to the subject's tree aspect. */
-	protected TreeChangeListener treeChangeListener;
+	protected final TreeChangeListener treeChangeListener;
 
 
 	// ********** constructors **********
@@ -52,8 +53,7 @@ public abstract class TreeAspectAdapter
 	 * and tree.
 	 */
 	protected TreeAspectAdapter(String treeName, Model subject) {
-		super(subject);
-		this.treeName = treeName;
+		this(new ReadOnlyPropertyValueModel(subject), treeName);
 	}
 
 	/**
@@ -63,17 +63,12 @@ public abstract class TreeAspectAdapter
 	protected TreeAspectAdapter(ValueModel subjectHolder, String treeName) {
 		super(subjectHolder);
 		this.treeName = treeName;
+		this.treeChangeListener = this.buildTreeChangeListener();
 	}
 
 
 	// ********** initialization **********
 
-    @Override
-	protected void initialize() {
-		super.initialize();
-		this.treeChangeListener = this.buildTreeChangeListener();
-	}
-
 	/**
 	 * The subject's tree aspect has changed, notify the listeners.
 	 */
@@ -143,6 +138,16 @@ public abstract class TreeAspectAdapter
 
 	// ********** AspectAdapter implementation **********
 
+	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return TreeChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUE;
+	}
+
     @Override
 	protected boolean hasListeners() {
 		return this.hasAnyTreeChangeListeners(VALUE);
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ValueModel.java
index fb85042e8c..0c2494773f 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/ValueModel.java
@@ -12,13 +12,13 @@ package org.eclipse.jpt.utility.internal.model.value;
 import org.eclipse.jpt.utility.internal.model.Model;
 
 /**
- * Interface used to abstract attribute accessing and
+ * Interface used to abstract property accessing and
  * change notification and make it more pluggable.
  */
 public interface ValueModel extends Model {
 
 	/**
-	 * Return the value.
+	 * Return the property's value.
 	 */
 	Object value();
 		String VALUE = "value";
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java
index 1190eb371a..2d7b69308b 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencePropertyValueModel.java
@@ -14,8 +14,11 @@ import java.util.prefs.PreferenceChangeListener;
 import java.util.prefs.Preferences;
 
 import org.eclipse.jpt.utility.internal.BidiStringConverter;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
+import org.eclipse.jpt.utility.internal.model.listener.PropertyChangeListener;
 import org.eclipse.jpt.utility.internal.model.value.AspectAdapter;
 import org.eclipse.jpt.utility.internal.model.value.PropertyValueModel;
+import org.eclipse.jpt.utility.internal.model.value.ReadOnlyPropertyValueModel;
 import org.eclipse.jpt.utility.internal.model.value.ValueModel;
 
 /**
@@ -45,7 +48,7 @@ public class PreferencePropertyValueModel
 	implements PropertyValueModel
 {
 	/** The key to the preference we use for the value. */
-	protected String key;
+	protected final String key;
 
 	/**
 	 * Cache the current (object) value of the preference so we
@@ -57,7 +60,7 @@ public class PreferencePropertyValueModel
 	 * The default (object) value returned if there is no value
 	 * associated with the preference.
 	 */
-	protected Object defaultValue;
+	protected final Object defaultValue;
 
 	/**
 	 * This converter is used to convert the preference's
@@ -66,7 +69,7 @@ public class PreferencePropertyValueModel
 	protected BidiStringConverter converter;
 
 	/** A listener that listens to the appropriate preference. */
-	protected PreferenceChangeListener preferenceChangeListener;
+	protected final PreferenceChangeListener preferenceChangeListener;
 
 
 	// ********** constructors **********
@@ -84,9 +87,7 @@ public class PreferencePropertyValueModel
 	 * the specified default value for the preference.
 	 */
 	public PreferencePropertyValueModel(Preferences preferences, String key, Object defaultValue) {
-		super(preferences);
-		this.key = key;
-		this.defaultValue = defaultValue;
+		this(new ReadOnlyPropertyValueModel(preferences), key, defaultValue);
 	}
 
 	/**
@@ -121,20 +122,15 @@ public class PreferencePropertyValueModel
 		super(preferencesHolder);
 		this.key = key;
 		this.defaultValue = defaultValue;
+		this.converter = BidiStringConverter.Default.instance();
+		this.preferenceChangeListener = this.buildPreferenceChangeListener();
+		// our value is null when we are not listening to the preference
+		this.value = null;
 	}
 
 
 	// ********** initialization **********
 
-	@Override
-	protected void initialize() {
-		super.initialize();
-		// our value is null when we are not listening to the preference
-		this.value = null;
-		this.converter = BidiStringConverter.Default.instance();
-		this.preferenceChangeListener = this.buildPreferenceChangeListener();
-	}
-
 	/**
 	 * A preference has changed, notify the listeners if necessary.
 	 */
@@ -157,6 +153,7 @@ public class PreferencePropertyValueModel
 	/**
 	 * Return the cached (converted) value.
 	 */
+	@Override
 	public synchronized Object value() {
 		return this.value;
 	}
@@ -185,6 +182,16 @@ public class PreferencePropertyValueModel
 	// ********** AspectAdapter implementation **********
 
 	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return PropertyChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUE;
+	}
+
+	@Override
 	protected boolean hasListeners() {
 		return this.hasAnyPropertyChangeListeners(VALUE);
 	}
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencesCollectionValueModel.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencesCollectionValueModel.java
index c67d351f34..52cdddaf62 100644
--- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencesCollectionValueModel.java
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/prefs/PreferencesCollectionValueModel.java
@@ -20,8 +20,11 @@ import java.util.prefs.Preferences;
 
 import org.eclipse.jpt.utility.internal.iterators.ArrayIterator;
 import org.eclipse.jpt.utility.internal.iterators.TransformationIterator;
+import org.eclipse.jpt.utility.internal.model.listener.ChangeListener;
+import org.eclipse.jpt.utility.internal.model.listener.CollectionChangeListener;
 import org.eclipse.jpt.utility.internal.model.value.AspectAdapter;
 import org.eclipse.jpt.utility.internal.model.value.CollectionValueModel;
+import org.eclipse.jpt.utility.internal.model.value.ReadOnlyPropertyValueModel;
 import org.eclipse.jpt.utility.internal.model.value.ValueModel;
 
 /**
@@ -35,10 +38,10 @@ public class PreferencesCollectionValueModel
 {
 
 	/** Cache the current preferences, stored in models and keyed by name. */
-	protected Map preferences;
+	protected final Map preferences;
 
 	/** A listener that listens to the preferences node for added or removed preferences. */
-	protected PreferenceChangeListener preferenceChangeListener;
+	protected final PreferenceChangeListener preferenceChangeListener;
 
 
 	// ********** constructors **********
@@ -47,7 +50,7 @@ public class PreferencesCollectionValueModel
 	 * Construct an adapter for the specified preferences node.
 	 */
 	public PreferencesCollectionValueModel(Preferences preferences) {
-		super(preferences);
+		this(new ReadOnlyPropertyValueModel(preferences));
 	}
 
 	/**
@@ -55,18 +58,13 @@ public class PreferencesCollectionValueModel
 	 */
 	public PreferencesCollectionValueModel(ValueModel preferencesHolder) {
 		super(preferencesHolder);
+		this.preferences = new HashMap();
+		this.preferenceChangeListener = this.buildPreferenceChangeListener();
 	}
 
 
 	// ********** initialization **********
 
-	@Override
-	protected void initialize() {
-		super.initialize();
-		this.preferences = new HashMap();
-		this.preferenceChangeListener = this.buildPreferenceChangeListener();
-	}
-
 	/**
 	 * A preferences have changed, notify the listeners.
 	 */
@@ -84,35 +82,32 @@ public class PreferencesCollectionValueModel
 	}
 
 
-	// ********** ValueModel implementation **********
+	// ********** CollectionValueModel implementation **********
 
 	/**
 	 * Return an iterator on the preference models.
 	 */
-	public synchronized Object value() {
+	public synchronized Iterator values() {
 		return this.preferences.values().iterator();
 	}
 
-
-	// ********** CollectionValueModel implementation **********
-
-	public void addItem(Object item) {
+	public void add(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void addItems(Collection items) {
+	public void addAll(Collection items) {
 		for (Iterator stream = items.iterator(); stream.hasNext(); ) {
-			this.addItem(stream.next());
+			this.add(stream.next());
 		}
 	}
 
-	public void removeItem(Object item) {
+	public void remove(Object item) {
 		throw new UnsupportedOperationException();
 	}
 
-	public void removeItems(Collection items) {
+	public void removeAll(Collection items) {
 		for (Iterator stream = items.iterator(); stream.hasNext(); ) {
-			this.removeItem(stream.next());
+			this.remove(stream.next());
 		}
 	}
 
@@ -123,14 +118,29 @@ public class PreferencesCollectionValueModel
 
 	// ********** AspectAdapter implementation **********
 
+	@Override
+	protected Object value() {
+		return this.values();
+	}
+
+	@Override
+	protected Class<? extends ChangeListener> listenerClass() {
+		return CollectionChangeListener.class;
+	}
+
+	@Override
+	protected String listenerAspectName() {
+		return VALUES;
+	}
+
     @Override
 	protected boolean hasListeners() {
-		return this.hasAnyCollectionChangeListeners(VALUE);
+		return this.hasAnyCollectionChangeListeners(VALUES);
 	}
 
     @Override
 	protected void fireAspectChange(Object oldValue, Object newValue) {
-		this.fireCollectionChanged(VALUE);
+		this.fireCollectionChanged(VALUES);
 	}
 
     @Override
@@ -198,12 +208,12 @@ public class PreferencesCollectionValueModel
 		if (newValue == null) {
 			// a preference was removed
 			PreferencePropertyValueModel preferenceModel = (PreferencePropertyValueModel) this.preferences.remove(key);
-			this.fireItemRemoved(VALUE, preferenceModel);
+			this.fireItemRemoved(VALUES, preferenceModel);
 		} else if ( ! this.preferences.containsKey(key)) {
 			// a preference was added
 			PreferencePropertyValueModel preferenceModel = this.buildPreferenceModel(key);
 			this.preferences.put(key, preferenceModel);
-			this.fireItemAdded(VALUE, preferenceModel);
+			this.fireItemAdded(VALUES, preferenceModel);
 		} else {
 			// a preference's value changed - do nothing
 		}