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Diffstat (limited to 'jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java')
| -rw-r--r-- | jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java | 261 |
1 files changed, 0 insertions, 261 deletions
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 deleted file mode 100644 index 2d5f814987..0000000000 --- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/model/value/CollectionPropertyValueModelAdapter.java +++ /dev/null @@ -1,261 +0,0 @@ -/******************************************************************************* - * 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 - * and is available at http://www.eclipse.org/legal/epl-v10.html. - * - * Contributors: - * Oracle - initial API and implementation - ******************************************************************************/ -package org.eclipse.jpt.utility.internal.model.value; - -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.CollectionChangeEvent; -import org.eclipse.jpt.utility.internal.model.listener.CollectionChangeListener; -import org.eclipse.jpt.utility.internal.model.listener.PropertyChangeListener; - -/** - * This abstract class provides the infrastructure needed to wrap - * a collection value model, "lazily" listen to it, and convert - * its change notifications into property value model change - * notifications. - * - * Subclasses must override: - * - #buildValue() - * to return the current property value, as derived from the - * current collection value - * - * Subclasses might want to override: - * - #setValue(Object) - * to manipulate the collection in some appropriate fashion - * - #itemsAdded(CollectionChangeEvent e) - * - #itemsRemoved(CollectionChangeEvent e) - * - #collectionChanged(CollectionChangeEvent e) - * to improve performance (by not recalculating the value, if possible) - */ -public abstract class CollectionPropertyValueModelAdapter - extends AbstractModel - implements PropertyValueModel -{ - /** - * Cache the current value so we can pass an "old value" when - * we fire a property change event. - * We need this because the value may be calculated and we may - * not able to derive the "old value" from the collection - * change event fired by the collection value model. - */ - protected Object value; - - /** The wrapped collection value model. */ - protected final CollectionValueModel collectionHolder; - - /** A listener that allows us to synch with changes to the wrapped collection holder. */ - protected final CollectionChangeListener collectionChangeListener; - - - // ********** constructor/initialization ********** - - /** - * Construct a property value model with the specified wrapped - * collection value model. - */ - protected CollectionPropertyValueModelAdapter(CollectionValueModel collectionHolder) { - super(); - this.collectionHolder = collectionHolder; - // our value is null when we are not listening to the collection holder - this.value = null; - this.collectionChangeListener = this.buildCollectionChangeListener(); - } - - @Override - protected ChangeSupport buildChangeSupport() { - return new SingleAspectChangeSupport(this, VALUE); - } - - protected CollectionChangeListener buildCollectionChangeListener() { - return new CollectionChangeListener() { - public void itemsAdded(CollectionChangeEvent e) { - CollectionPropertyValueModelAdapter.this.itemsAdded(e); - } - public void itemsRemoved(CollectionChangeEvent e) { - CollectionPropertyValueModelAdapter.this.itemsRemoved(e); - } - public void collectionCleared(CollectionChangeEvent e) { - CollectionPropertyValueModelAdapter.this.collectionCleared(e); - } - public void collectionChanged(CollectionChangeEvent e) { - CollectionPropertyValueModelAdapter.this.collectionChanged(e); - } - @Override - public String toString() { - return "collection change listener"; - } - }; - } - - - // ********** ValueModel implementation ********** - - /** - * Return the cached value. - */ - public Object value() { - return this.value; - } - - - // ********** PropertyValueModel implementation ********** - - public void setValue(Object value) { - throw new UnsupportedOperationException(); - } - - - // ********** extend change support ********** - - /** - * Extend to start listening to the wrapped collection if necessary. - */ - @Override - public synchronized void addPropertyChangeListener(PropertyChangeListener listener) { - if (this.hasNoListeners()) { - this.engageModel(); - } - super.addPropertyChangeListener(listener); - } - - /** - * Extend to start listening to the wrapped collection if necessary. - */ - @Override - public synchronized void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) { - if (propertyName == VALUE && this.hasNoListeners()) { - this.engageModel(); - } - super.addPropertyChangeListener(propertyName, listener); - } - - /** - * Extend to stop listening to the wrapped collection if necessary. - */ - @Override - public synchronized void removePropertyChangeListener(PropertyChangeListener listener) { - super.removePropertyChangeListener(listener); - if (this.hasNoListeners()) { - this.disengageModel(); - } - } - - /** - * Extend to stop listening to the wrapped collection if necessary. - */ - @Override - public synchronized void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) { - super.removePropertyChangeListener(propertyName, listener); - if (propertyName == VALUE && this.hasNoListeners()) { - this.disengageModel(); - } - } - - - // ********** queries ********** - - /** - * Return whether there are any listeners for the aspect. - */ - protected boolean hasListeners() { - return this.hasAnyPropertyChangeListeners(VALUE); - } - - /** - * Return whether there are any listeners for the aspect. - */ - protected boolean hasNoListeners() { - return ! this.hasListeners(); - } - - - // ********** behavior ********** - - /** - * Start listening to the collection holder. - */ - protected void engageModel() { - 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(); - } - - /** - * Build and return the current value, as derived from the - * current state of the wrapped collection. - */ - protected abstract Object buildValue(); - - /** - * Stop listening to the collection holder. - */ - protected void disengageModel() { - this.collectionHolder.removeCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener); - // clear out our value when we are not listening to the collection - this.value = null; - } - - @Override - public void toString(StringBuilder sb) { - sb.append(this.collectionHolder); - } - - - // ********** collection change support ********** - - /** - * Items were added to the wrapped collection holder; - * propagate the change notification appropriately. - */ - protected void itemsAdded(CollectionChangeEvent e) { - // by default, simply recalculate the value and fire an event - this.propertyChanged(); - } - - /** - * Items were removed from the wrapped collection holder; - * propagate the change notification appropriately. - */ - protected void itemsRemoved(CollectionChangeEvent e) { - // by default, simply recalculate the value and fire an event - this.propertyChanged(); - } - - /** - * The wrapped collection holder was cleared; - * propagate the change notification appropriately. - */ - protected void collectionCleared(CollectionChangeEvent e) { - // by default, simply recalculate the value and fire an event - this.propertyChanged(); - } - - /** - * The value of the wrapped collection holder has changed; - * propagate the change notification appropriately. - */ - protected void collectionChanged(CollectionChangeEvent e) { - // by default, simply recalculate the value and fire an event - this.propertyChanged(); - } - - /** - * The wrapped collection changed in some fashion. - * Recalculate the value and notify any listeners. - */ - protected void propertyChanged() { - Object old = this.value; - this.value = this.buildValue(); - this.firePropertyChanged(VALUE, old, this.value); - } - -} |