/* * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.tools.visualvm.core.datasupport; import com.sun.tools.visualvm.core.datasource.DataSource; import java.util.HashSet; import java.util.Iterator; import java.util.Set; /** * This is a utility class that can be used by similarly * to PropertyChangeSupport. All DataChangeSupport instances * uses dedicated thread to for all the work, so all events * is processed asynchronously. * * @author Tomas Hurka */ public final class DataChangeSupport<X> { private ChangeSupport<X> changeSupport; /** * Constructs a <code>DataChangeSupport</code> object. */ public DataChangeSupport() { changeSupport = new ChangeSupport(); } /** * Add a DataChangeListener to the listener list. * The same listener object may be added only once. * * @param listener The DataChangeListener to be added */ public void addChangeListener(final DataChangeListener<X> listener) { DataSource.EVENT_QUEUE.post(new Runnable() { public void run() { changeSupport.addChangeListener(listener); } }); } /** * Remove a DataChangeListener from the listener list. * * @param listener The DataChangeListener to be removed */ public void removeChangeListener(final DataChangeListener<X> listener) { DataSource.EVENT_QUEUE.post(new Runnable() { public void run() { changeSupport.removeChangeListener(listener); } }); } /** * Report a update to any registered listeners. * * @param current the set of currently available objects. * @param added the set of added objects since last event. * @param removed the set of removed objects since last event. */ public void fireChange(final Set<X> current, final Set<X> added, final Set<X> removed) { DataSource.EVENT_QUEUE.post(new Runnable() { public void run() { changeSupport.fireChange(current, added, removed); } }); } private static class ChangeSupport<X> { private Set<DataChangeListener<X>> listeners = new HashSet(); private Set<X> currentSet; private void addChangeListener(DataChangeListener<X> listener) { if (!listeners.add(listener)) { throw new IllegalArgumentException("Listener " + listener + " already registed"); // NOI18N } if (currentSet != null) { DataChangeEvent<X> event = new DataChangeEvent(currentSet, currentSet, null); listener.dataChanged(event); } } private void removeChangeListener(DataChangeListener<X> listener) { if (!listeners.remove(listener)) { throw new IllegalArgumentException("Listener " + listener + " not registered"); // NOI18N } } private void fireChange(Set<X> current, Set<X> added, Set<X> removed) { currentSet = current; if (listeners.isEmpty()) { return; } DataChangeEvent<X> event = new DataChangeEvent(current, added, removed); for (Iterator<DataChangeListener<X>> it = listeners.iterator(); it.hasNext();) { it.next().dataChanged(event); } } } }