/*
* EventBasedChangeTracker.java
*
* Copyright (C) 2009-12 by RStudio, Inc.
*
* Unless you have received this program directly from RStudio pursuant
* to the terms of a commercial license agreement with RStudio, then
* this program is licensed to you under the terms of version 3 of the
* GNU Affero General Public License. This program is distributed WITHOUT
* ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
* AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
*
*/
package org.rstudio.studio.client.workbench.model;
import com.google.gwt.event.logical.shared.HasValueChangeHandlers;
import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
public class EventBasedChangeTracker<T> implements ChangeTracker
{
public EventBasedChangeTracker(HasValueChangeHandlers<T> source)
{
source_ = source;
source.addValueChangeHandler(new ValueChangeHandler<T>()
{
public void onValueChange(ValueChangeEvent<T> valueChangeEvent)
{
changed_ = true;
}
});
}
public boolean hasChanged()
{
return changed_;
}
public void reset()
{
changed_ = false;
}
public ChangeTracker fork()
{
EventBasedChangeTracker<T> ebct = new EventBasedChangeTracker<T>(source_);
ebct.changed_ = changed_;
return ebct;
}
protected boolean changed_ = false;
private final HasValueChangeHandlers<T> source_;
}