1 /*
2  * Copyright (c) 2005, 2008, 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  */
25 
26 package com.sun.tools.jdi;
27 
28 import com.sun.jdi.*;
29 
30 public class MonitorInfoImpl extends MirrorImpl
31     implements MonitorInfo, ThreadListener {
32 
33     /* Once false, monitorInfo should not be used.
34      * access synchronized on (vm.state())
35      */
36     private boolean isValid = true;
37 
38     ObjectReference monitor;
39     ThreadReference thread;
40     int  stack_depth;
41 
MonitorInfoImpl(VirtualMachine vm, ObjectReference mon, ThreadReferenceImpl thread, int dpth)42     MonitorInfoImpl(VirtualMachine vm, ObjectReference mon,
43                     ThreadReferenceImpl thread, int dpth) {
44         super(vm);
45         this.monitor = mon;
46         this.thread = thread;
47         this.stack_depth = dpth;
48         thread.addListener(this);
49     }
50 
51 
52     /*
53      * ThreadListener implementation
54      * Must be synchronized since we must protect against
55      * sending defunct (isValid == false) stack ids to the back-end.
56      */
threadResumable(ThreadAction action)57     public boolean threadResumable(ThreadAction action) {
58         synchronized (vm.state()) {
59             if (isValid) {
60                 isValid = false;
61                 return false;   /* remove this stack frame as a listener */
62             } else {
63                 throw new InternalException(
64                                   "Invalid stack frame thread listener");
65             }
66         }
67     }
68 
validateMonitorInfo()69     private void validateMonitorInfo() {
70         if (!isValid) {
71             throw new InvalidStackFrameException("Thread has been resumed");
72         }
73     }
74 
monitor()75     public ObjectReference monitor() {
76         validateMonitorInfo();
77         return monitor;
78     }
79 
stackDepth()80     public int stackDepth() {
81         validateMonitorInfo();
82         return stack_depth;
83     }
84 
thread()85     public ThreadReference thread() {
86         validateMonitorInfo();
87         return thread;
88     }
89 }
90