| /******************************************************************************* |
| * Copyright (c) 2007, 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.model.value; |
| |
| import java.util.ListIterator; |
| 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.model.event.ListChangeEvent; |
| import org.eclipse.jpt.utility.model.listener.ListChangeListener; |
| import org.eclipse.jpt.utility.model.value.ListValueModel; |
| |
| /** |
| * This abstract class provides the infrastructure needed to wrap |
| * another list value model, "lazily" listen to it, and propagate |
| * its change notifications. |
| */ |
| public abstract class ListValueModelWrapper<E> |
| extends AbstractModel |
| { |
| |
| /** The wrapped list value model. */ |
| protected final ListValueModel<? extends E> listHolder; |
| |
| /** A listener that allows us to synch with changes to the wrapped list holder. */ |
| protected final ListChangeListener listChangeListener; |
| |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct a list value model with the specified wrapped |
| * list value model. |
| */ |
| protected ListValueModelWrapper(ListValueModel<? extends E> listHolder) { |
| super(); |
| if (listHolder == null) { |
| throw new NullPointerException(); |
| } |
| this.listHolder = listHolder; |
| this.listChangeListener = this.buildListChangeListener(); |
| } |
| |
| |
| // ********** initialization ********** |
| |
| @Override |
| protected ChangeSupport buildChangeSupport() { |
| return new SingleAspectChangeSupport(this, ListChangeListener.class, ListValueModel.LIST_VALUES); |
| } |
| |
| protected ListChangeListener buildListChangeListener() { |
| return new ListChangeListener() { |
| public void itemsAdded(ListChangeEvent event) { |
| ListValueModelWrapper.this.itemsAdded(event); |
| } |
| public void itemsRemoved(ListChangeEvent event) { |
| ListValueModelWrapper.this.itemsRemoved(event); |
| } |
| public void itemsReplaced(ListChangeEvent event) { |
| ListValueModelWrapper.this.itemsReplaced(event); |
| } |
| public void itemsMoved(ListChangeEvent event) { |
| ListValueModelWrapper.this.itemsMoved(event); |
| } |
| public void listCleared(ListChangeEvent event) { |
| ListValueModelWrapper.this.listCleared(event); |
| } |
| public void listChanged(ListChangeEvent event) { |
| ListValueModelWrapper.this.listChanged(event); |
| } |
| @Override |
| public String toString() { |
| return "list change listener"; |
| } |
| }; |
| } |
| |
| |
| // ********** extend change support ********** |
| |
| /** |
| * Extend to start listening to the nested model if necessary. |
| */ |
| @Override |
| public synchronized void addListChangeListener(ListChangeListener listener) { |
| if (this.hasNoListChangeListeners(ListValueModel.LIST_VALUES)) { |
| this.engageModel(); |
| } |
| super.addListChangeListener(listener); |
| } |
| |
| /** |
| * Extend to start listening to the nested model if necessary. |
| */ |
| @Override |
| public synchronized void addListChangeListener(String listName, ListChangeListener listener) { |
| if (listName == ListValueModel.LIST_VALUES && this.hasNoListChangeListeners(ListValueModel.LIST_VALUES)) { |
| this.engageModel(); |
| } |
| super.addListChangeListener(listName, listener); |
| } |
| |
| /** |
| * Extend to stop listening to the nested model if necessary. |
| */ |
| @Override |
| public synchronized void removeListChangeListener(ListChangeListener listener) { |
| super.removeListChangeListener(listener); |
| if (this.hasNoListChangeListeners(ListValueModel.LIST_VALUES)) { |
| this.disengageModel(); |
| } |
| } |
| |
| /** |
| * Extend to stop listening to the nested model if necessary. |
| */ |
| @Override |
| public synchronized void removeListChangeListener(String listName, ListChangeListener listener) { |
| super.removeListChangeListener(listName, listener); |
| if (listName == ListValueModel.LIST_VALUES && this.hasNoListChangeListeners(ListValueModel.LIST_VALUES)) { |
| this.disengageModel(); |
| } |
| } |
| |
| |
| // ********** behavior ********** |
| |
| /** |
| * Start listening to the list holder. |
| */ |
| protected void engageModel() { |
| this.listHolder.addListChangeListener(ListValueModel.LIST_VALUES, this.listChangeListener); |
| } |
| |
| /** |
| * Stop listening to the list holder. |
| */ |
| protected void disengageModel() { |
| this.listHolder.removeListChangeListener(ListValueModel.LIST_VALUES, this.listChangeListener); |
| } |
| |
| @Override |
| public void toString(StringBuilder sb) { |
| sb.append(this.listHolder); |
| } |
| |
| // minimize suppressed warnings |
| @SuppressWarnings("unchecked") |
| protected ListIterator<E> items(ListChangeEvent event) { |
| return (ListIterator<E>) event.items(); |
| } |
| |
| // minimize suppressed warnings |
| @SuppressWarnings("unchecked") |
| protected ListIterator<E> replacedItems(ListChangeEvent event) { |
| return (ListIterator<E>) event.replacedItems(); |
| } |
| |
| |
| // ********** list change support ********** |
| |
| /** |
| * Items were added to the wrapped list holder; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void itemsAdded(ListChangeEvent event); |
| |
| /** |
| * Items were removed from the wrapped list holder; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void itemsRemoved(ListChangeEvent event); |
| |
| /** |
| * Items were replaced in the wrapped list holder; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void itemsReplaced(ListChangeEvent event); |
| |
| /** |
| * Items were moved in the wrapped list holder; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void itemsMoved(ListChangeEvent event); |
| |
| /** |
| * The wrapped list holder was cleared; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void listCleared(ListChangeEvent event); |
| |
| /** |
| * The value of the wrapped list holder has changed; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void listChanged(ListChangeEvent event); |
| |
| } |