| /******************************************************************************* |
| * Copyright (c) 2009 Matthew Hall 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: |
| * Matthew Hall - initial API and implementation (bug 263691) |
| ******************************************************************************/ |
| |
| package org.eclipse.core.databinding.observable.value; |
| |
| import org.eclipse.core.databinding.observable.Diffs; |
| |
| /** |
| * An {@link IVetoableValue} decorator for an observable value. |
| * |
| * @since 1.2 |
| */ |
| public class DecoratingVetoableValue extends DecoratingObservableValue |
| implements IVetoableValue { |
| /** |
| * @param decorated |
| * @param disposeDecoratedOnDispose |
| */ |
| public DecoratingVetoableValue(IObservableValue decorated, |
| boolean disposeDecoratedOnDispose) { |
| super(decorated, disposeDecoratedOnDispose); |
| } |
| |
| public void setValue(Object value) { |
| checkRealm(); |
| Object currentValue = getValue(); |
| ValueDiff diff = Diffs.createValueDiff(currentValue, value); |
| boolean okToProceed = fireValueChanging(diff); |
| if (!okToProceed) { |
| throw new ChangeVetoException("Change not permitted"); //$NON-NLS-1$ |
| } |
| super.setValue(value); |
| } |
| |
| public synchronized void addValueChangingListener( |
| IValueChangingListener listener) { |
| addListener(ValueChangingEvent.TYPE, listener); |
| } |
| |
| public synchronized void removeValueChangingListener( |
| IValueChangingListener listener) { |
| removeListener(ValueChangingEvent.TYPE, listener); |
| } |
| |
| /** |
| * Notifies listeners about a pending change, and returns true if no |
| * listener vetoed the change. |
| * |
| * @param diff |
| * @return false if the change was vetoed, true otherwise |
| */ |
| protected boolean fireValueChanging(ValueDiff diff) { |
| checkRealm(); |
| |
| ValueChangingEvent event = new ValueChangingEvent(this, diff); |
| fireEvent(event); |
| return !event.veto; |
| } |
| } |