| /******************************************************************************* |
| * Copyright (c) 2006 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 |
| ******************************************************************************/ |
| |
| package org.eclipse.core.internal.databinding.observable; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.eclipse.core.databinding.observable.ChangeEvent; |
| import org.eclipse.core.databinding.observable.IChangeListener; |
| import org.eclipse.core.databinding.observable.IObservable; |
| import org.eclipse.core.databinding.observable.IStaleListener; |
| import org.eclipse.core.databinding.observable.StaleEvent; |
| import org.eclipse.core.internal.databinding.IdentityWrapper; |
| |
| /** |
| * @since 1.0 |
| * |
| */ |
| public class StalenessTracker { |
| |
| private Map staleMap = new HashMap(); |
| |
| private int staleCount = 0; |
| |
| private final IStalenessConsumer stalenessConsumer; |
| |
| private class ChildListener implements IStaleListener, IChangeListener { |
| public void handleStale(StaleEvent event) { |
| processStalenessChange((IObservable) event.getSource(), true); |
| } |
| |
| public void handleChange(ChangeEvent event) { |
| processStalenessChange((IObservable) event.getSource(), true); |
| } |
| } |
| |
| private ChildListener childListener = new ChildListener(); |
| |
| /** |
| * @param observables |
| * @param stalenessConsumer |
| */ |
| public StalenessTracker(IObservable[] observables, |
| IStalenessConsumer stalenessConsumer) { |
| this.stalenessConsumer = stalenessConsumer; |
| for (int i = 0; i < observables.length; i++) { |
| IObservable observable = observables[i]; |
| doAddObservable(observable, false); |
| } |
| stalenessConsumer.setStale(staleCount > 0); |
| } |
| |
| /** |
| * @param child |
| * @param callback |
| */ |
| public void processStalenessChange(IObservable child, boolean callback) { |
| boolean oldStale = staleCount > 0; |
| IdentityWrapper wrappedChild = new IdentityWrapper(child); |
| boolean oldChildStale = getOldChildStale(wrappedChild); |
| boolean newChildStale = child.isStale(); |
| if (oldChildStale != newChildStale) { |
| if (oldChildStale) { |
| staleCount--; |
| } else { |
| staleCount++; |
| } |
| staleMap.put(wrappedChild, newChildStale ? Boolean.TRUE : Boolean.FALSE); |
| } |
| boolean newStale = staleCount > 0; |
| if (callback && (newStale != oldStale)) { |
| stalenessConsumer.setStale(newStale); |
| } |
| } |
| |
| /** |
| * @param wrappedChild |
| */ |
| private boolean getOldChildStale(IdentityWrapper wrappedChild) { |
| Object oldChildValue = staleMap.get(wrappedChild); |
| boolean oldChildStale = oldChildValue == null ? false |
| : ((Boolean) oldChildValue).booleanValue(); |
| return oldChildStale; |
| } |
| |
| /** |
| * @param observable |
| */ |
| public void addObservable(IObservable observable) { |
| doAddObservable(observable, true); |
| } |
| |
| private void doAddObservable(IObservable observable, boolean callback) { |
| processStalenessChange(observable, callback); |
| observable.addChangeListener(childListener); |
| observable.addStaleListener(childListener); |
| } |
| |
| /** |
| * @param observable |
| */ |
| public void removeObservable(IObservable observable) { |
| boolean oldStale = staleCount > 0; |
| IdentityWrapper wrappedChild = new IdentityWrapper(observable); |
| boolean oldChildStale = getOldChildStale(wrappedChild); |
| if (oldChildStale) { |
| staleCount--; |
| } |
| staleMap.remove(wrappedChild); |
| observable.removeChangeListener(childListener); |
| observable.removeStaleListener(childListener); |
| boolean newStale = staleCount > 0; |
| if (newStale != oldStale) { |
| stalenessConsumer.setStale(newStale); |
| } |
| } |
| |
| } |