001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common
008: * Development and Distribution License("CDDL") (collectively, the
009: * "License"). You may not use this file except in compliance with the
010: * License. You can obtain a copy of the License at
011: * http://www.netbeans.org/cddl-gplv2.html
012: * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
013: * specific language governing permissions and limitations under the
014: * License. When distributing the software, include this License Header
015: * Notice in each file and include the License file at
016: * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
017: * particular file as subject to the "Classpath" exception as provided
018: * by Sun in the GPL Version 2 section of the License file that
019: * accompanied this code. If applicable, add the following below the
020: * License Header, with the fields enclosed by brackets [] replaced by
021: * your own identifying information:
022: * "Portions Copyrighted [year] [name of copyright owner]"
023: *
024: * Contributor(s):
025: *
026: * The Original Software is NetBeans. The Initial Developer of the Original
027: * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
028: * Microsystems, Inc. All Rights Reserved.
029: *
030: * If you wish your version of this file to be governed by only the CDDL
031: * or only the GPL Version 2, indicate your decision by adding
032: * "[Contributor] elects to include this software in this distribution
033: * under the [CDDL or GPL Version 2] license." If you do not indicate a
034: * single choice of license, a recipient has the option to distribute
035: * your version of this file under either the CDDL, the GPL Version 2 or
036: * to extend the choice of license to its licensees as provided above.
037: * However, if you add GPL Version 2 code and therefore, elected the GPL
038: * Version 2 license, then the option applies only if the new code is
039: * made subject to such option by the copyright holder.
040: */
041:
042: package org.netbeans.spi.project.support.ant;
043:
044: import java.util.Map;
045: import javax.swing.event.ChangeEvent;
046: import javax.swing.event.ChangeListener;
047: import org.openide.util.ChangeSupport;
048: import org.openide.util.WeakListeners;
049:
050: /**
051: * Property provider that delegates to another source.
052: * Useful, for example, when conditionally loading from one or another properties file.
053: * @since org.netbeans.modules.project.ant/1 1.14
054: */
055: public abstract class FilterPropertyProvider implements
056: PropertyProvider {
057:
058: private PropertyProvider delegate;
059: private final ChangeSupport cs = new ChangeSupport(this );
060: private final ChangeListener strongListener = new ChangeListener() {
061: public void stateChanged(ChangeEvent e) {
062: //System.err.println("DPP: change from current provider " + delegate);
063: cs.fireChange();
064: }
065: };
066: private ChangeListener weakListener = null; // #50572: must be weak
067:
068: /**
069: * Initialize the proxy.
070: * @param delegate the initial delegate to use
071: */
072: protected FilterPropertyProvider(PropertyProvider delegate) {
073: assert delegate != null;
074: setDelegate(delegate);
075: }
076:
077: /**
078: * Change the current delegate (firing changes as well).
079: * @param delegate the initial delegate to use
080: */
081: protected final void setDelegate(PropertyProvider delegate) {
082: if (delegate == this .delegate) {
083: return;
084: }
085: if (this .delegate != null) {
086: assert weakListener != null;
087: this .delegate.removeChangeListener(weakListener);
088: }
089: this .delegate = delegate;
090: weakListener = WeakListeners.change(strongListener, delegate);
091: delegate.addChangeListener(weakListener);
092: cs.fireChange();
093: }
094:
095: public final Map<String, String> getProperties() {
096: return delegate.getProperties();
097: }
098:
099: public final synchronized void addChangeListener(
100: ChangeListener listener) {
101: // XXX could listen to delegate only when this has listeners
102: cs.addChangeListener(listener);
103: }
104:
105: public final synchronized void removeChangeListener(
106: ChangeListener listener) {
107: cs.removeChangeListener(listener);
108: }
109:
110: }
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