ContextAction.java revision 1472:c18cbe5936b8 
1/*
2 * Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25package com.sun.hotspot.igv.util;
26
27import java.awt.EventQueue;
28import org.openide.util.ContextAwareAction;
29import org.openide.util.Lookup;
30import org.openide.util.LookupEvent;
31import org.openide.util.LookupListener;
32import org.openide.util.Utilities;
33import org.openide.util.actions.CallableSystemAction;
34
35/**
36 *
37 * @author Thomas Wuerthinger
38 */
39public abstract class ContextAction<T> extends CallableSystemAction implements LookupListener, ContextAwareAction {
40
41    private Lookup context = null;
42    private Lookup.Result<T> result = null;
43
44    public ContextAction() {
45        this(Utilities.actionsGlobalContext());
46    }
47
48    public ContextAction(Lookup context) {
49        init(context);
50    }
51
52    private void init(Lookup context) {
53        this.context = context;
54        result = context.lookupResult(contextClass());
55        result.addLookupListener(this);
56        resultChanged(null);
57    }
58
59    public void resultChanged(LookupEvent e) {
60        if (result.allItems().size() != 0) {
61            update(result.allInstances().iterator().next());
62        } else {
63            update(null);
64        }
65    }
66
67    @Override
68    public void performAction() {
69        final T t = result.allInstances().iterator().next();
70
71        // Ensure it's AWT event thread
72        EventQueue.invokeLater(new Runnable() {
73
74            public void run() {
75                performAction(t);
76            }
77        });
78    }
79
80    public void update(T t) {
81        if (t == null) {
82            setEnabled(false);
83        } else {
84            setEnabled(isEnabled(t));
85        }
86    }
87
88    public boolean isEnabled(T context) {
89        return true;
90    }
91
92    public abstract Class<T> contextClass();
93
94    public abstract void performAction(T context);
95}
96