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/*******************************************************************************
* 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.model.value;
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
* a list 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 list value
*
* Subclasses might want to override:
* - #itemsAdded(ListChangeEvent event)
* - #itemsRemoved(ListChangeEvent event)
* - #itemsReplaced(ListChangeEvent event)
* - #itemsMoved(ListChangeEvent event)
* - #listCleared(ListChangeEvent event)
* - #listChanged(ListChangeEvent event)
* to improve performance (by not recalculating the value, if possible)
*/
public abstract class ListPropertyValueModelAdapter<T>
extends AspectPropertyValueModelAdapter<T>
{
/** The wrapped list value model. */
protected final ListValueModel<?> listHolder;
/** A listener that allows us to synch with changes to the wrapped list holder. */
protected final ListChangeListener listChangeListener;
// ********** constructor/initialization **********
/**
* Construct a property value model with the specified wrapped
* list value model.
*/
protected ListPropertyValueModelAdapter(ListValueModel<?> listHolder) {
super();
this.listHolder = listHolder;
this.listChangeListener = this.buildListChangeListener();
}
protected ListChangeListener buildListChangeListener() {
return new ListChangeListener() {
public void itemsAdded(ListChangeEvent event) {
ListPropertyValueModelAdapter.this.itemsAdded(event);
}
public void itemsRemoved(ListChangeEvent event) {
ListPropertyValueModelAdapter.this.itemsRemoved(event);
}
public void itemsReplaced(ListChangeEvent event) {
ListPropertyValueModelAdapter.this.itemsReplaced(event);
}
public void itemsMoved(ListChangeEvent event) {
ListPropertyValueModelAdapter.this.itemsMoved(event);
}
public void listCleared(ListChangeEvent event) {
ListPropertyValueModelAdapter.this.listCleared(event);
}
public void listChanged(ListChangeEvent event) {
ListPropertyValueModelAdapter.this.listChanged(event);
}
@Override
public String toString() {
return "list change listener";
}
};
}
// ********** behavior **********
/**
* Start listening to the list holder.
*/
@Override
protected void engageModel_() {
this.listHolder.addListChangeListener(ListValueModel.LIST_VALUES, this.listChangeListener);
}
/**
* Stop listening to the list holder.
*/
@Override
protected void disengageModel_() {
this.listHolder.removeListChangeListener(ListValueModel.LIST_VALUES, this.listChangeListener);
}
@Override
public void toString(StringBuilder sb) {
sb.append(this.listHolder);
}
// ********** collection change support **********
/**
* Items were added to the wrapped list holder;
* propagate the change notification appropriately.
*/
protected void itemsAdded(ListChangeEvent event) {
// by default, simply recalculate the value and fire an event
this.propertyChanged();
}
/**
* Items were removed from the wrapped list holder;
* propagate the change notification appropriately.
*/
protected void itemsRemoved(ListChangeEvent event) {
// by default, simply recalculate the value and fire an event
this.propertyChanged();
}
/**
* Items were replaced in the wrapped list holder;
* propagate the change notification appropriately.
*/
protected void itemsReplaced(ListChangeEvent event) {
// by default, simply recalculate the value and fire an event
this.propertyChanged();
}
/**
* Items were moved in the wrapped list holder;
* propagate the change notification appropriately.
*/
protected void itemsMoved(ListChangeEvent event) {
// by default, simply recalculate the value and fire an event
this.propertyChanged();
}
/**
* The wrapped list holder was cleared;
* propagate the change notification appropriately.
*/
protected void listCleared(ListChangeEvent event) {
// by default, simply recalculate the value and fire an event
this.propertyChanged();
}
/**
* The value of the wrapped list holder has changed;
* propagate the change notification appropriately.
*/
protected void listChanged(ListChangeEvent event) {
// by default, simply recalculate the value and fire an event
this.propertyChanged();
}
}
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