com.google.gwt.user.client.ui.DelegatingChangeListenerCollection Maven / Gradle / Ivy
/*
* Copyright 2007 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.user.client.ui;
/**
* {@link ChangeListenerCollection} used to correctly hook up listeners which
* need to listen to events from another source.
*
* For example, {@link Composite} widgets often need to listen to events
* generated on their wrapped widget. Upon the firing of a wrapped widget's
* event, the composite widget must fire its own listeners with itself as the
* source of the event. To use a {@link DelegatingChangeListenerCollection},
* simply use the {@link DelegatingChangeListenerCollection} instead of a
* {@link ChangeListenerCollection}. For example, in {@link SuggestBox}, the
* following code is used to listen to change events on the {@link SuggestBox}'s
* underlying widget.
*
*
*
* public void addChangeListener(ChangeListener listener) {
* if (changeListeners == null) {
* changeListeners = new DelegatingChangeListenerCollection(this, box);
* }
* changeListeners.add(listener);
* }
*
*
* @deprecated Use {@link Widget#delegateEvent Widget.delegateEvent} instead
*/
@Deprecated
public class DelegatingChangeListenerCollection extends
ChangeListenerCollection implements ChangeListener {
private final Widget owner;
/**
* Constructor for {@link DelegatingChangeListenerCollection}.
*
* @param owner owner of listeners
* @param delegatedTo source of events
*/
public DelegatingChangeListenerCollection(Widget owner,
SourcesChangeEvents delegatedTo) {
this.owner = owner;
delegatedTo.addChangeListener(this);
}
public void onChange(Widget sender) {
fireChange(owner);
}
}