added ListenerList

1 files changed, 117 insertions, 0 deletions

diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/ListenerList.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/ListenerList.java
new file mode 100644
index 0000000000..f1c57fc781
--- /dev/null
+++ b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/ListenerList.java
@@ -0,0 +1,117 @@
+/*******************************************************************************
+ * Copyright (c) 2008 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
+ * and is available at http://www.eclipse.org/legal/epl-v10.html.
+ * 
+ * Contributors:
+ *     Oracle - initial API and implementation
+ ******************************************************************************/
+package org.eclipse.jpt.utility.internal;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.Array;
+import java.util.Arrays;
+import java.util.EventListener;
+
+/**
+ * Maintain a thread-safe list of listeners that does not allow duplicates.
+ */
+public class ListenerList<L extends EventListener>
+	implements Serializable
+{
+	private transient volatile L[] listeners;
+
+	private static final long serialVersionUID = 1L;
+
+
+	public ListenerList(Class<L> listenerClass) {
+		super();
+		this.listeners = this.buildEmptyArray(listenerClass);
+	}
+
+	@SuppressWarnings("unchecked")
+	private L[] buildEmptyArray(Class<L> listenerClass) {
+		return (L[]) Array.newInstance(listenerClass, 0);
+	}
+
+	public L[] getListeners() {
+		return this.listeners;
+	}
+
+	public int size() {
+		return this.listeners.length;
+	}
+
+	public boolean isEmpty() {
+		return this.listeners.length == 0;
+	}
+
+	public synchronized void add(L listener) {
+		if (listener == null) {
+			throw new NullPointerException();
+		}
+		if (CollectionTools.contains(this.listeners, listener)) {
+			throw new IllegalArgumentException("duplicate listener: " + listener); //$NON-NLS-1$
+		}
+		this.listeners = CollectionTools.add(this.listeners, listener);
+	}
+
+	public synchronized void remove(L listener) {
+		if (listener == null) {
+			throw new NullPointerException();
+		}
+		int index = CollectionTools.indexOf(this.listeners, listener);
+		if (index == -1) {
+			throw new IllegalArgumentException("unregistered listener: " + listener); //$NON-NLS-1$
+		}
+		this.listeners = CollectionTools.removeElementAtIndex(this.listeners, index);
+	}
+
+	public synchronized void clear() {
+		this.listeners = CollectionTools.clear(this.listeners);
+	}
+
+	@Override
+	public String toString() {
+		return Arrays.toString(this.listeners);
+	}
+
+
+	// ********** serialization **********
+
+	private synchronized void writeObject(ObjectOutputStream s) throws IOException {
+		// write out any hidden stuff
+		s.defaultWriteObject();
+
+		@SuppressWarnings("unchecked")
+		Class<L> listenerClass = (Class<L>) this.listeners.getClass().getComponentType();
+		s.writeObject(listenerClass);
+
+		// only write out serializable listeners
+		for (L listener : this.listeners) {
+			if (listener instanceof Serializable) {
+				s.writeObject(listener);
+			}
+		}
+
+		s.writeObject(null);
+    }
+
+	@SuppressWarnings("unchecked")
+	private synchronized void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException {
+		// read in any hidden stuff
+		s.defaultReadObject();
+
+		Class<L> listenerClass = (Class<L>) s.readObject();
+		this.listeners = this.buildEmptyArray(listenerClass);
+		Object o;
+		while ((o = s.readObject()) != null) {
+			this.add((L) o);
+		}
+	}
+
+}