| /******************************************************************************* |
| * Copyright (c) 2008 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 237718) |
| * Matthew Hall - but 246626 |
| ******************************************************************************/ |
| |
| package org.eclipse.core.databinding.observable.value; |
| |
| import org.eclipse.core.databinding.observable.DecoratingObservable; |
| |
| /** |
| * An observable value which decorates another observable value. |
| * |
| * @param <T> |
| * |
| * @since 1.2 |
| */ |
| public class DecoratingObservableValue<T> extends DecoratingObservable |
| implements IObservableValue<T> { |
| private IObservableValue<T> decorated; |
| |
| private IValueChangeListener<T> valueChangeListener; |
| |
| /** |
| * Constructs a DecoratingObservableValue which decorates the given |
| * observable. |
| * |
| * @param decorated |
| * the observable value being decorated |
| * @param disposeDecoratedOnDispose |
| */ |
| public DecoratingObservableValue(IObservableValue<T> decorated, |
| boolean disposeDecoratedOnDispose) { |
| super(decorated, disposeDecoratedOnDispose); |
| this.decorated = decorated; |
| } |
| |
| public synchronized void addValueChangeListener( |
| IValueChangeListener<? super T> listener) { |
| addListener(ValueChangeEvent.TYPE, listener); |
| } |
| |
| public synchronized void removeValueChangeListener( |
| IValueChangeListener<? super T> listener) { |
| removeListener(ValueChangeEvent.TYPE, listener); |
| } |
| |
| protected void fireValueChange(ValueDiff<T> diff) { |
| // fire general change event first |
| super.fireChange(); |
| fireEvent(new ValueChangeEvent<T>(this, diff)); |
| } |
| |
| protected void fireChange() { |
| throw new RuntimeException( |
| "fireChange should not be called, use fireValueChange() instead"); //$NON-NLS-1$ |
| } |
| |
| protected void firstListenerAdded() { |
| if (valueChangeListener == null) { |
| valueChangeListener = new IValueChangeListener<T>() { |
| public void handleValueChange(ValueChangeEvent<T> event) { |
| DecoratingObservableValue.this.handleValueChange(event); |
| } |
| }; |
| } |
| decorated.addValueChangeListener(valueChangeListener); |
| super.firstListenerAdded(); |
| } |
| |
| protected void lastListenerRemoved() { |
| super.lastListenerRemoved(); |
| if (valueChangeListener != null) { |
| decorated.removeValueChangeListener(valueChangeListener); |
| valueChangeListener = null; |
| } |
| } |
| |
| /** |
| * Called whenever a ValueChangeEvent is received from the decorated |
| * observable. By default, this method fires the value change event again, |
| * with the decorating observable as the event source. Subclasses may |
| * override to provide different behavior. |
| * |
| * @param event |
| * the change event received from the decorated observable |
| */ |
| protected void handleValueChange(final ValueChangeEvent<T> event) { |
| fireValueChange(event.diff); |
| } |
| |
| public T getValue() { |
| getterCalled(); |
| return decorated.getValue(); |
| } |
| |
| public void setValue(T value) { |
| checkRealm(); |
| decorated.setValue(value); |
| } |
| |
| public Object getValueType() { |
| return decorated.getValueType(); |
| } |
| |
| /** |
| * @since 1.5 |
| */ |
| public Class<T> getValueClass() { |
| return decorated.getValueClass(); |
| } |
| |
| public synchronized void dispose() { |
| if (decorated != null && valueChangeListener != null) { |
| decorated.removeValueChangeListener(valueChangeListener); |
| } |
| decorated = null; |
| valueChangeListener = null; |
| super.dispose(); |
| } |
| } |