/*******************************************************************************
* Copyright (c) 2005, 2015 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
* Stefan Xenos <sxenos@gmail.com> - Bug 335792
*******************************************************************************/
package org.eclipse.core.databinding.observable.value;
import org.eclipse.core.databinding.observable.IObservablesListener;
/**
* Listener for pre-change events for observable values.
*
* @param <T>
* the type of value being observed
*
* @since 1.0
*
*/
@FunctionalInterface
public interface IValueChangingListener<T> extends IObservablesListener {
/**
* This method is called when the value is about to change and provides an
* opportunity to veto the change. The given event object must only be used
* locally in this method because it may be reused for other change
* notifications. The diff object referenced by the event is immutable and
* may be used non-locally.
*
* @param event
*/
public void handleValueChanging(ValueChangingEvent<T> event);
}