1/*
2 * Copyright (c) 1999, 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
26package javax.management;
27
28// java import
29import java.io.Serializable;
30
31/**
32 * Allows a query to be performed in the context of a specific MBean server.
33 *
34 * @since 1.5
35 */
36public abstract class QueryEval implements Serializable {
37
38    /* Serial version */
39    private static final long serialVersionUID = 2675899265640874796L;
40
41    private static ThreadLocal<MBeanServer> server =
42        new InheritableThreadLocal<MBeanServer>();
43
44    /**
45     * <p>Sets the MBean server on which the query is to be performed.
46     * The setting is valid for the thread performing the set.
47     * It is copied to any threads created by that thread at the moment
48     * of their creation.</p>
49     *
50     * <p>For historical reasons, this method is not static, but its
51     * behavior does not depend on the instance on which it is
52     * called.</p>
53     *
54     * @param s The MBean server on which the query is to be performed.
55     *
56     * @see #getMBeanServer
57     */
58    public void setMBeanServer(MBeanServer s) {
59        server.set(s);
60    }
61
62    /**
63     * <p>Return the MBean server that was most recently given to the
64     * {@link #setMBeanServer setMBeanServer} method by this thread.
65     * If this thread never called that method, the result is the
66     * value its parent thread would have obtained from
67     * <code>getMBeanServer</code> at the moment of the creation of
68     * this thread, or null if there is no parent thread.</p>
69     *
70     * @return the MBean server.
71     *
72     * @see #setMBeanServer
73     *
74     */
75    public static MBeanServer getMBeanServer() {
76        return server.get();
77    }
78}
79