001/*
002 * $RCSfile: FacilityManager.java,v $
003 * $Revision: 1.1 $
004 * $Date: 2005/02/11 05:02:25 $
005 * $State: Exp $
006 *
007 * Class:                   MsgLoggerManager
008 *
009 * Description:             Manages common facilities across threads
010 *
011 *
012 *
013 * COPYRIGHT:
014 *
015 * This software module was originally developed by Raphaël Grosbois and
016 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
017 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
018 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
019 * Centre France S.A) in the course of development of the JPEG2000
020 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
021 * software module is an implementation of a part of the JPEG 2000
022 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
023 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
024 * Partners) agree not to assert against ISO/IEC and users of the JPEG
025 * 2000 Standard (Users) any of their rights under the copyright, not
026 * including other intellectual property rights, for this software module
027 * with respect to the usage by ISO/IEC and Users of this software module
028 * or modifications thereof for use in hardware or software products
029 * claiming conformance to the JPEG 2000 Standard. Those intending to use
030 * this software module in hardware or software products are advised that
031 * their use may infringe existing patents. The original developers of
032 * this software module, JJ2000 Partners and ISO/IEC assume no liability
033 * for use of this software module or modifications thereof. No license
034 * or right to this software module is granted for non JPEG 2000 Standard
035 * conforming products. JJ2000 Partners have full right to use this
036 * software module for his/her own purpose, assign or donate this
037 * software module to any third party and to inhibit third parties from
038 * using this software module for non JPEG 2000 Standard conforming
039 * products. This copyright notice must be included in all copies or
040 * derivative works of this software module.
041 *
042 * Copyright (c) 1999/2000 JJ2000 Partners.
043 *
044 *
045 *
046 */
047
048
049package jj2000.j2k.util;
050
051import java.util.Hashtable;
052
053/**
054 * This class manages common facilities for mutithreading environments, It can
055 * register different facilities for each thread, and also a default one, so
056 * that they can be referred by static methods, while possibly having
057 * different ones for different threads. Also a default facility exists that
058 * is used for threads for which no particular facility has been registerd
059 * registered.
060 *
061 * <P>Currently the only kind of facilities managed is MsgLogger.
062 *
063 * <P>An example use of this class is if 2 instances of a decoder are running
064 * in different threads and the messages of the 2 instances should be
065 * separated.
066 *
067 * <P>The default MsgLogger is a StreamMsgLogger that uses System.out as
068 * the 'out' stream and System.err as the 'err' stream, and a line width of
069 * 78. This can be changed using the registerMsgLogger() method.
070 *
071 * @see MsgLogger
072 *
073 * @see StreamMsgLogger
074 * */
075public class FacilityManager {
076
077    /** The loggers associated to different threads */
078    private final static Hashtable loggerList = new Hashtable();
079
080    /** The default logger, for threads that have none associated with them */
081    private static MsgLogger defMsgLogger =
082        new StreamMsgLogger(System.out,System.err,78);
083
084    /** The ProgressWatch instance associated to different threads */
085    private final static Hashtable watchProgList = new Hashtable();
086
087    /** The default ProgressWatch for threads that have none
088     * associated with them. */
089    private static ProgressWatch defWatchProg = null;
090
091    /** */
092    public static void registerProgressWatch(Thread t,ProgressWatch pw) {
093       if(pw==null) {
094            throw new NullPointerException();
095        }
096        if(t==null) {
097            defWatchProg = pw;
098        }
099        else {
100            watchProgList.put(t,pw);
101        }
102    }
103
104    /** 
105     * Returns the ProgressWatch instance registered with the current
106     * thread (the thread that calls this method). If the current
107     * thread has no registered ProgressWatch, then the default one is used. 
108     * */
109    public static ProgressWatch getProgressWatch() {
110        ProgressWatch pw = (ProgressWatch)
111            watchProgList.get(Thread.currentThread());
112        return (pw==null) ? defWatchProg : pw;
113    }
114
115    /**
116     * Registers the MsgLogger 'ml' as the logging facility of the
117     * thread 't'. If any other logging facility was registered with the
118     * thread 't' it is overriden by 'ml'. If 't' is null then 'ml' is taken
119     * as the default message logger that is used for threads that have no
120     * MsgLogger registered.
121     *
122     * @param t The thread to associate with 'ml'
123     *
124     * @param ml The MsgLogger to associate with therad ml
125     * */
126    public static void registerMsgLogger(Thread t, MsgLogger ml) {
127        if (ml == null) {
128            throw new NullPointerException();
129        }
130        if (t == null) {
131            defMsgLogger = ml;
132        }
133        else {
134            loggerList.put(t,ml);
135        }
136    }
137
138    /**
139     * Returns the MsgLogger registered with the current thread (the
140     * thread that calls this method). If the current thread has no registered
141     * MsgLogger then the default message logger is returned.
142     *
143     * @return The MsgLogger registerd for the current thread, or the
144     * default one if there is none registered for it.
145     *
146     *
147     * */
148    public static MsgLogger getMsgLogger() {
149        MsgLogger ml =
150            (MsgLogger) loggerList.get(Thread.currentThread());
151        return (ml == null) ? defMsgLogger : ml;
152    }
153
154    /**
155     * Returns the MsgLogger registered with the thread 't' (the thread
156     * that calls this method). If the thread 't' has no registered
157     * MsgLogger then the default message logger is returned.
158     *
159     * @param t The thread for which to return the MsgLogger
160     *
161     * @return The MsgLogger registerd for the current thread, or the
162     * default one if there is none registered for it.
163     *
164     *
165     * */
166    public static MsgLogger getMsgLogger(Thread t) {
167        MsgLogger ml =
168            (MsgLogger) loggerList.get(t);
169        return (ml == null) ? defMsgLogger : ml;
170    }
171}