001 /* QueryEval.java -- An evaluation context for a MBean server query. 002 Copyright (C) 2007 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 package javax.management; 039 040 import java.io.Serializable; 041 042 /** 043 * Represents the evaluation context of a {@link MBeanServer} 044 * query by retaining the server used on a thread-by-thread 045 * basis. 046 * 047 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 048 * @since 1.5 049 */ 050 public class QueryEval 051 implements Serializable 052 { 053 054 /** 055 * Compatible with JDK 1.5 056 */ 057 private static final long serialVersionUID = 2675899265640874796L; 058 059 /** 060 * Stores the server used, on a 061 * thread-by-thread basis. 062 */ 063 private static InheritableThreadLocal<MBeanServer> server = 064 new InheritableThreadLocal<MBeanServer>(); 065 066 /** 067 * Returns the {@link MBeanServer} last supplied to the 068 * {@link #setMBeanServer(MBeanServer)} method. If this method 069 * has not been called for this thread, then the value will be 070 * inherited from any parent thread on which the method has 071 * been called. If the method has never been called, then 072 * <code>null</code> is returned. 073 * 074 * @return the server. 075 * @see #setMBeanServer(MBeanServer) 076 */ 077 public static MBeanServer getMBeanServer() 078 { 079 return server.get(); 080 } 081 082 /** 083 * Sets the {@link MBeanServer} on which the query will be 084 * performed. This value is inherited automatically by 085 * child threads. This method is only non-static for historical 086 * reasons; it makes no use of instance-related values. 087 * 088 * @param svr the server to use. 089 */ 090 public void setMBeanServer(MBeanServer svr) 091 { 092 server.set(svr); 093 } 094 095 }