common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/model/value/ItemAspectListValueModelAdapter.java - dali/webtools.dali - Git at Google

 /*******************************************************************************
  * Copyright (c) 2007, 2015 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.common.utility.internal.model.value;

 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.EventObject;
 import java.util.IdentityHashMap;
 import java.util.Iterator;
 import java.util.ListIterator;

 import org.eclipse.jpt.common.utility.internal.StringBuilderTools;
 import org.eclipse.jpt.common.utility.internal.collection.ListTools;
 import org.eclipse.jpt.common.utility.internal.iterator.ReadOnlyListIterator;
 import org.eclipse.jpt.common.utility.internal.reference.SimpleIntReference;
 import org.eclipse.jpt.common.utility.model.Model;
 import org.eclipse.jpt.common.utility.model.event.ListAddEvent;
 import org.eclipse.jpt.common.utility.model.event.ListChangeEvent;
 import org.eclipse.jpt.common.utility.model.event.ListClearEvent;
 import org.eclipse.jpt.common.utility.model.event.ListMoveEvent;
 import org.eclipse.jpt.common.utility.model.event.ListRemoveEvent;
 import org.eclipse.jpt.common.utility.model.event.ListReplaceEvent;
 import org.eclipse.jpt.common.utility.model.value.CollectionValueModel;
 import org.eclipse.jpt.common.utility.model.value.ListValueModel;

 /**
  * Abstract list value model that provides behavior for wrapping a {@link ListValueModel}
  * (or {@link CollectionValueModel}) and listening for changes to aspects of the
  * <em>items</em> held by the list (or collection). Changes to the actual list
  * (or collection) are also monitored.
  *
  * This is useful if you have a collection of items that can be modified by adding
  * or removing items or the items themselves might change in a fashion that
  * might change the list or collection's external appearance.
  *
  * Subclasses need to override two methods:<ul>
  * <li>{@link #engageItem_(Model)}<p>
  *     begin listening to the appropriate aspect of the specified item and call
  *     {@link #itemAspectChanged(EventObject)} whenever the aspect changes
  * <li>{@link #disengageItem_(Model)}<p>
  *     stop listening to the appropriate aspect of the specified item
  * </ul>
  */
 public abstract class ItemAspectListValueModelAdapter<E>
 	extends ListValueModelWrapper<E>
 	implements ListValueModel<E>
 {

 	/**
 	 * Maintain a counter for each of the items in the
 	 * wrapped list holder we are listening to.
 	 */
 	protected final IdentityHashMap<E, SimpleIntReference> counters;


 	// ********** constructors **********

 	/**
 	 * Constructor - the list holder is required.
 	 */
 	protected ItemAspectListValueModelAdapter(ListValueModel<? extends E> listHolder) {
 		super(listHolder);
 		this.counters = new IdentityHashMap<E, SimpleIntReference>();
 	}

 	/**
 	 * Constructor - the collection holder is required.
 	 */
 	protected ItemAspectListValueModelAdapter(CollectionValueModel<? extends E> collectionHolder) {
 		this(new CollectionListValueModelAdapter<E>(collectionHolder));
 	}


 	// ********** ListValueModel implementation **********

 	public Iterator<E> iterator() {
 		return this.listIterator();
 	}

 	public ListIterator<E> listIterator() {
 		return new ReadOnlyListIterator<E>(this.listModel.listIterator());
 	}

 	public E get(int index) {
 		return this.listModel.get(index);
 	}

 	public int size() {
 		return this.listModel.size();
 	}

 	public Object[] toArray() {
 		return this.listModel.toArray();
 	}


 	// ********** behavior **********

 	/**
 	 * Start listening to the list holder and the items in the list.
 	 */
 	@Override
 	protected void engageModel() {
 		super.engageModel();
 		this.engageAllItems();
 	}

 	protected void engageAllItems() {
 		this.engageItems(this.listModel);
 	}

 	protected void engageItems(Iterable<? extends E> items) {
 		for (E item : items) {
 			this.engageItem(item);
 		}
 	}

 	protected void engageItem(E item) {
 		// listen to each item only once
 		SimpleIntReference counter = this.counters.get(item);
 		if (counter == null) {
 			counter = new SimpleIntReference();
 			this.counters.put(item, counter);
 			this.engageItem_((Model) item);
 		}
 		counter.increment();
 	}

 	/**
 	 * Start listening to the specified item.
 	 */
 	protected abstract void engageItem_(Model item);

 	/**
 	 * Stop listening to the list holder and the items in the list.
 	 */
 	@Override
 	protected void disengageModel() {
 		this.disengageAllItems();
 		super.disengageModel();
 	}

 	protected void disengageAllItems() {
 		this.disengageItems(this.listModel);
 	}

 	protected void disengageItems(Iterable<? extends E> items) {
 		for (E item : items) {
 			this.disengageItem(item);
 		}
 	}

 	protected void disengageItem(E item) {
 		// stop listening to each item only once
 		SimpleIntReference counter = this.counters.get(item);
 		if (counter == null) {
 			// something is wrong if this happens...  ~bjv
 			throw new IllegalStateException("missing counter: " + item); //$NON-NLS-1$
 		}
 		if (counter.decrement() == 0) {
 			this.counters.remove(item);
 			this.disengageItem_((Model) item);
 		}
 	}

 	/**
 	 * Stop listening to the specified item.
 	 */
 	protected abstract void disengageItem_(Model item);

 	@Override
 	public void toString(StringBuilder sb) {
 		StringBuilderTools.append(sb, this);
 	}


 	// ********** list change support **********

 	/**
 	 * Items were added to the wrapped list holder.
 	 * Forward the event and begin listening to the added items.
 	 */
 	@Override
 	protected void itemsAdded(ListAddEvent event) {
 		// re-fire event with the wrapper as the source
 		this.fireItemsAdded(event.clone(this, LIST_VALUES));
 		this.engageItems(this.getItems(event));
 	}

 	/**
 	 * Items were removed from the wrapped list holder.
 	 * Stop listening to the removed items and forward the event.
 	 */
 	@Override
 	protected void itemsRemoved(ListRemoveEvent event) {
 		this.disengageItems(this.getItems(event));
 		// re-fire event with the wrapper as the source
 		this.fireItemsRemoved(event.clone(this, LIST_VALUES));
 	}

 	/**
 	 * Items were replaced in the wrapped list holder.
 	 * Stop listening to the removed items, forward the event,
 	 * and begin listening to the added items.
 	 */
 	@Override
 	protected void itemsReplaced(ListReplaceEvent event) {
 		this.disengageItems(this.getOldItems(event));
 		// re-fire event with the wrapper as the source
 		this.fireItemsReplaced(event.clone(this, LIST_VALUES));
 		this.engageItems(this.getNewItems(event));
 	}

 	/**
 	 * Items were moved in the wrapped list holder.
 	 * No need to change any listeners; just forward the event.
 	 */
 	@Override
 	protected void itemsMoved(ListMoveEvent event) {
 		// re-fire event with the wrapper as the source
 		this.fireItemsMoved(event.clone(this, LIST_VALUES));
 	}

 	/**
 	 * The wrapped list holder was cleared.
 	 * Stop listening to the removed items and forward the event.
 	 */
 	@Override
 	protected void listCleared(ListClearEvent event) {
 		// we should only need to disengage each item once...
 		// make a copy to prevent a ConcurrentModificationException
 		Collection<E> keys = new ArrayList<E>(this.counters.keySet());
 		this.disengageItems(keys);
 		this.counters.clear();
 		// re-fire event with the wrapper as the source
 		this.fireListCleared(LIST_VALUES);
 	}

 	/**
 	 * The wrapped list holder has changed in some dramatic fashion.
 	 * Reconfigure our listeners and forward the event.
 	 */
 	@Override
 	protected void listChanged(ListChangeEvent event) {
 		// we should only need to disengage each item once...
 		// make a copy to prevent a ConcurrentModificationException
 		Collection<E> keys = new ArrayList<E>(this.counters.keySet());
 		this.disengageItems(keys);
 		this.counters.clear();
 		// re-fire event with the wrapper as the source
 		this.fireListChanged(event.clone(this));
 		this.engageAllItems();
 	}


 	// ********** item change support **********

 	/**
 	 * The specified item has a bound property that has changed.
 	 * Notify listeners of the change. The listeners will have to determine
 	 * whether the item aspect change is significant.
 	 */
 	protected void itemAspectChanged(@SuppressWarnings("unused") EventObject event) {
 		this.fireListChanged(LIST_VALUES, ListTools.arrayList(this.listModel, this.listModel.size()));
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2007, 2015 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.common.utility.internal.model.value;

	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.EventObject;
	import java.util.IdentityHashMap;
	import java.util.Iterator;
	import java.util.ListIterator;

	import org.eclipse.jpt.common.utility.internal.StringBuilderTools;
	import org.eclipse.jpt.common.utility.internal.collection.ListTools;
	import org.eclipse.jpt.common.utility.internal.iterator.ReadOnlyListIterator;
	import org.eclipse.jpt.common.utility.internal.reference.SimpleIntReference;
	import org.eclipse.jpt.common.utility.model.Model;
	import org.eclipse.jpt.common.utility.model.event.ListAddEvent;
	import org.eclipse.jpt.common.utility.model.event.ListChangeEvent;
	import org.eclipse.jpt.common.utility.model.event.ListClearEvent;
	import org.eclipse.jpt.common.utility.model.event.ListMoveEvent;
	import org.eclipse.jpt.common.utility.model.event.ListRemoveEvent;
	import org.eclipse.jpt.common.utility.model.event.ListReplaceEvent;
	import org.eclipse.jpt.common.utility.model.value.CollectionValueModel;
	import org.eclipse.jpt.common.utility.model.value.ListValueModel;

	/**
	* Abstract list value model that provides behavior for wrapping a {@link ListValueModel}
	* (or {@link CollectionValueModel}) and listening for changes to aspects of the
	* <em>items</em> held by the list (or collection). Changes to the actual list
	* (or collection) are also monitored.
	*
	* This is useful if you have a collection of items that can be modified by adding
	* or removing items or the items themselves might change in a fashion that
	* might change the list or collection's external appearance.
	*
	* Subclasses need to override two methods:<ul>
	* <li>{@link #engageItem_(Model)}<p>
	* begin listening to the appropriate aspect of the specified item and call
	* {@link #itemAspectChanged(EventObject)} whenever the aspect changes
	* <li>{@link #disengageItem_(Model)}<p>
	* stop listening to the appropriate aspect of the specified item
	* </ul>
	*/
	public abstract class ItemAspectListValueModelAdapter<E>
	extends ListValueModelWrapper<E>
	implements ListValueModel<E>
	{

	/**
	* Maintain a counter for each of the items in the
	* wrapped list holder we are listening to.
	*/
	protected final IdentityHashMap<E, SimpleIntReference> counters;


	// ******** constructors ********

	/**
	* Constructor - the list holder is required.
	*/
	protected ItemAspectListValueModelAdapter(ListValueModel<? extends E> listHolder) {
	super(listHolder);
	this.counters = new IdentityHashMap<E, SimpleIntReference>();
	}

	/**
	* Constructor - the collection holder is required.
	*/
	protected ItemAspectListValueModelAdapter(CollectionValueModel<? extends E> collectionHolder) {
	this(new CollectionListValueModelAdapter<E>(collectionHolder));
	}


	// ******** ListValueModel implementation ********

	public Iterator<E> iterator() {
	return this.listIterator();
	}

	public ListIterator<E> listIterator() {
	return new ReadOnlyListIterator<E>(this.listModel.listIterator());
	}

	public E get(int index) {
	return this.listModel.get(index);
	}

	public int size() {
	return this.listModel.size();
	}

	public Object[] toArray() {
	return this.listModel.toArray();
	}


	// ******** behavior ********

	/**
	* Start listening to the list holder and the items in the list.
	*/
	@Override
	protected void engageModel() {
	super.engageModel();
	this.engageAllItems();
	}

	protected void engageAllItems() {
	this.engageItems(this.listModel);
	}

	protected void engageItems(Iterable<? extends E> items) {
	for (E item : items) {
	this.engageItem(item);
	}
	}

	protected void engageItem(E item) {
	// listen to each item only once
	SimpleIntReference counter = this.counters.get(item);
	if (counter == null) {
	counter = new SimpleIntReference();
	this.counters.put(item, counter);
	this.engageItem_((Model) item);
	}
	counter.increment();
	}

	/**
	* Start listening to the specified item.
	*/
	protected abstract void engageItem_(Model item);

	/**
	* Stop listening to the list holder and the items in the list.
	*/
	@Override
	protected void disengageModel() {
	this.disengageAllItems();
	super.disengageModel();
	}

	protected void disengageAllItems() {
	this.disengageItems(this.listModel);
	}

	protected void disengageItems(Iterable<? extends E> items) {
	for (E item : items) {
	this.disengageItem(item);
	}
	}

	protected void disengageItem(E item) {
	// stop listening to each item only once
	SimpleIntReference counter = this.counters.get(item);
	if (counter == null) {
	// something is wrong if this happens... ~bjv
	throw new IllegalStateException("missing counter: " + item); //$NON-NLS-1$
	}
	if (counter.decrement() == 0) {
	this.counters.remove(item);
	this.disengageItem_((Model) item);
	}
	}

	/**
	* Stop listening to the specified item.
	*/
	protected abstract void disengageItem_(Model item);

	@Override
	public void toString(StringBuilder sb) {
	StringBuilderTools.append(sb, this);
	}


	// ******** list change support ********

	/**
	* Items were added to the wrapped list holder.
	* Forward the event and begin listening to the added items.
	*/
	@Override
	protected void itemsAdded(ListAddEvent event) {
	// re-fire event with the wrapper as the source
	this.fireItemsAdded(event.clone(this, LIST_VALUES));
	this.engageItems(this.getItems(event));
	}

	/**
	* Items were removed from the wrapped list holder.
	* Stop listening to the removed items and forward the event.
	*/
	@Override
	protected void itemsRemoved(ListRemoveEvent event) {
	this.disengageItems(this.getItems(event));
	// re-fire event with the wrapper as the source
	this.fireItemsRemoved(event.clone(this, LIST_VALUES));
	}

	/**
	* Items were replaced in the wrapped list holder.
	* Stop listening to the removed items, forward the event,
	* and begin listening to the added items.
	*/
	@Override
	protected void itemsReplaced(ListReplaceEvent event) {
	this.disengageItems(this.getOldItems(event));
	// re-fire event with the wrapper as the source
	this.fireItemsReplaced(event.clone(this, LIST_VALUES));
	this.engageItems(this.getNewItems(event));
	}

	/**
	* Items were moved in the wrapped list holder.
	* No need to change any listeners; just forward the event.
	*/
	@Override
	protected void itemsMoved(ListMoveEvent event) {
	// re-fire event with the wrapper as the source
	this.fireItemsMoved(event.clone(this, LIST_VALUES));
	}

	/**
	* The wrapped list holder was cleared.
	* Stop listening to the removed items and forward the event.
	*/
	@Override
	protected void listCleared(ListClearEvent event) {
	// we should only need to disengage each item once...
	// make a copy to prevent a ConcurrentModificationException
	Collection<E> keys = new ArrayList<E>(this.counters.keySet());
	this.disengageItems(keys);
	this.counters.clear();
	// re-fire event with the wrapper as the source
	this.fireListCleared(LIST_VALUES);
	}

	/**
	* The wrapped list holder has changed in some dramatic fashion.
	* Reconfigure our listeners and forward the event.
	*/
	@Override
	protected void listChanged(ListChangeEvent event) {
	// we should only need to disengage each item once...
	// make a copy to prevent a ConcurrentModificationException
	Collection<E> keys = new ArrayList<E>(this.counters.keySet());
	this.disengageItems(keys);
	this.counters.clear();
	// re-fire event with the wrapper as the source
	this.fireListChanged(event.clone(this));
	this.engageAllItems();
	}


	// ******** item change support ********

	/**
	* The specified item has a bound property that has changed.
	* Notify listeners of the change. The listeners will have to determine
	* whether the item aspect change is significant.
	*/
	protected void itemAspectChanged(@SuppressWarnings("unused") EventObject event) {
	this.fireListChanged(LIST_VALUES, ListTools.arrayList(this.listModel, this.listModel.size()));
	}

	}