jurt/com/sun/star/lib/uno/environments/remote/JobQueue.java

   1 /*
   2  * This file is part of the LibreOffice project.
   3  *
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   7  *
   8  * This file incorporates work covered by the following license notice:
   9  *
  10  *   Licensed to the Apache Software Foundation (ASF) under one or more
  11  *   contributor license agreements. See the NOTICE file distributed
  12  *   with this work for additional information regarding copyright
  13  *   ownership. The ASF licenses this file to you under the Apache
  14  *   License, Version 2.0 (the "License"); you may not use this file
  15  *   except in compliance with the License. You may obtain a copy of
  16  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  17  */
  18
  19 package com.sun.star.lib.uno.environments.remote;
  20
  21 import com.sun.star.lang.DisposedException;
  22
  23 /**
  24  * The <code>JobQueue</code> implements a queue for jobs.
  25  *
  26  * <p>For every jobs thread id exists a job queue which is registered
  27  * at the <code>ThreadPool</code>.</p>
  28  *
  29  * <p>A JobQueue is splitted in a sync job queue and an async job queue.
  30  * The sync job queue is the registered queue, it delegates async jobs
  31  * (put by <code>putjob</code>) into the async queue, which is only
  32  * known by the sync queue.</p>
  33  *
  34  * @see         com.sun.star.lib.uno.environments.remote.ThreadPool
  35  * @see         com.sun.star.lib.uno.environments.remote.Job
  36  * @see         com.sun.star.lib.uno.environments.remote.ThreadId
  37  * @since       UDK1.0
  38  */
  39 public class JobQueue {
  40     /**
  41      * When set to true, enables various debugging output.
  42      */
  43     private static final boolean DEBUG = false;
  44
  45     protected Job _head;                 // the head of the job list
  46     protected Job _tail;                 // the tail of the job list
  47
  48     protected ThreadId  _threadId;       // the thread id of the queue
  49     protected int       _ref_count = 0;  // the stack deepness
  50     protected boolean   _createThread;   // create a worker thread, if needed
  51     protected boolean   _createThread_now;   // create a worker thread, if needed
  52     protected Thread    _worker_thread;  // the thread that does the jobs
  53
  54     protected Object    _disposeId; // the active dispose id
  55     protected Object    _doDispose = null;
  56     protected Throwable _throwable;
  57
  58     protected JobQueue  _async_jobQueue; // chaining job qeueus for asyncs
  59     protected JobQueue  _sync_jobQueue;  // chaining job qeueus for syncs
  60
  61     protected boolean _active = false;
  62
  63     protected JavaThreadPoolFactory _javaThreadPoolFactory;
  64
  65     /**
  66      * A thread for dispatching jobs.
  67      */
  68     class JobDispatcher extends Thread {
  69         Object _disposeId;
  70
  71         JobDispatcher(Object disposeId) {
  72             super("JobDispatcher");
  73
  74             if(DEBUG) System.err.println("JobQueue$JobDispatcher.<init>:" + _threadId);
  75
  76             _disposeId = disposeId;
  77         }
  78
  79         ThreadId getThreadId() {
  80             return _threadId;
  81         }
  82
  83         @Override
  84         public void run() {
  85             if(DEBUG) System.err.println("ThreadPool$JobDispatcher.run: " + Thread.currentThread());
  86
  87             try {
  88                   enter(2000, _disposeId);
  89             } catch(Throwable throwable) {
  90                 if(_head != null || _active) { // there was a job in progress, so give a stack
  91                     System.err.println(getClass().getName() + " - exception occurred:" + throwable);
  92                     throwable.printStackTrace(System.err);
  93                 }
  94             }
  95             finally {
  96                 release();
  97             }
  98
  99             if(DEBUG) System.err.println("##### " + getClass().getName() + ".run - exit:" + _threadId);
 100         }
 101     }
 102
 103
 104     /**
 105      * Constructs a async job queue with the given thread id which belongs to
 106      * the given sync job queue.
 107      *
 108      * @param threadId         the thread id.
 109      * @see                    com.sun.star.lib.uno.environments.remote.ThreadId
 110      */
 111     JobQueue(JavaThreadPoolFactory javaThreadPoolFactory, ThreadId threadId) {
 112         _javaThreadPoolFactory = javaThreadPoolFactory;
 113         _threadId = ThreadId.createFresh();
 114
 115         _sync_jobQueue    = javaThreadPoolFactory.getJobQueue(threadId);
 116         if(_sync_jobQueue == null) {
 117             _sync_jobQueue = new JobQueue(javaThreadPoolFactory, threadId, true);
 118             _sync_jobQueue.acquire();
 119         }
 120
 121         _sync_jobQueue._async_jobQueue = this;
 122
 123         _createThread     = true;
 124         _createThread_now = true;
 125
 126         acquire();
 127
 128         if(DEBUG) System.err.println("##### " + getClass().getName() + " - init:" +  _threadId);
 129     }
 130
 131     /**
 132      * Constructs a sync job queue with the given thread id and the given thread.
 133      *
 134      * @param threadId        the thread id.
 135      * @param createThread    if true, the queue creates a worker thread if needed.
 136      * @see             com.sun.star.lib.uno.environments.remote.ThreadId
 137      */
 138     JobQueue(JavaThreadPoolFactory javaThreadPoolFactory, ThreadId threadId, boolean createThread){
 139         _javaThreadPoolFactory   = javaThreadPoolFactory;
 140         _threadId         = threadId;
 141         _createThread     = createThread;
 142         _createThread_now = createThread;
 143
 144         if(DEBUG) System.err.println("##### " + getClass().getName() + " - init:" +  _threadId + " " + createThread);
 145     }
 146
 147     /**
 148      * Gives the thread id of this queue.
 149      *
 150      * @return  the thread id.
 151      * @see     com.sun.star.lib.uno.environments.remote.ThreadId
 152      */
 153     ThreadId getThreadId() {
 154         return _threadId;
 155     }
 156
 157     synchronized void acquire() {
 158         // add only synchronous queues .
 159         if(_ref_count <= 0 && _sync_jobQueue == null )
 160             _javaThreadPoolFactory.addJobQueue(this);
 161
 162         ++ _ref_count;
 163     }
 164
 165     synchronized void release() {
 166         -- _ref_count;
 167
 168         if(_ref_count <= 0) {
 169             // only synchronous queues needs to be removed .
 170             if( _sync_jobQueue == null )
 171                 _javaThreadPoolFactory.removeJobQueue(this);
 172
 173
 174             if(_sync_jobQueue != null) {
 175                 _sync_jobQueue._async_jobQueue = null;
 176                 _sync_jobQueue.release();
 177             }
 178         }
 179     }
 180
 181     /**
 182      * Removes a job from the queue.
 183      *
 184      * @param  waitTime the maximum amount of time to wait for a job.
 185      * @return a job or null if timed out.
 186      */
 187     private Job removeJob(int waitTime) {
 188         if(DEBUG) System.err.println("##### " + getClass().getName() + ".removeJob:" + _head + " " + _threadId);
 189
 190         Job job = null;
 191         synchronized (this) {
 192             // wait max. waitTime time for a job to enter the queue
 193             boolean waited = false;
 194             while(_head == null && (waitTime == 0 || !waited)) {
 195                 if(_doDispose == _disposeId) {
 196                     _doDispose = null;
 197                     throw (DisposedException)
 198                         new DisposedException().initCause(_throwable);
 199                 }
 200
 201                 // notify sync queues
 202                 notifyAll();
 203
 204                 try {
 205                     // wait for new job
 206                     wait(waitTime);
 207                 } catch(InterruptedException interruptedException) {
 208                       throw new com.sun.star.uno.RuntimeException(getClass().getName() + ".removeJob - unexpected:" + interruptedException);
 209                 }
 210
 211                 // signal that we have already waited once
 212                 waited = true;
 213             }
 214
 215
 216             if(_head != null) {
 217                 Job current = _head;
 218                 _head    = _head._next;
 219
 220                 if(_head == null)
 221                     _tail = null;
 222
 223                 job = current;
 224                 _active = true;
 225             }
 226         }
 227
 228         // always wait for asynchron jobqueue to be finished !
 229         if(job != null && _async_jobQueue != null) {
 230             synchronized(_async_jobQueue) {
 231                 // wait for async queue to be empty and last job to be done
 232                 while(_async_jobQueue._active || _async_jobQueue._head != null) {
 233                     if(DEBUG) System.err.println("waiting for async:" + _async_jobQueue._head + " " +  _async_jobQueue._worker_thread);
 234
 235                     if(_doDispose == _disposeId) {
 236                         _doDispose = null;
 237                         throw (DisposedException)
 238                             new DisposedException().initCause(_throwable);
 239                     }
 240
 241                     try {
 242                         _async_jobQueue.wait();
 243                     } catch(InterruptedException interruptedException) {
 244                         throw new com.sun.star.uno.RuntimeException(getClass().getName() + ".removeJob - unexpected:" + interruptedException);
 245                     }
 246                 }
 247             }
 248         }
 249
 250         return job;
 251     }
 252
 253     /**
 254      * Puts a job into the queue.
 255      *
 256      * @param  job        the job.
 257      * @param  disposeId  a dispose id.
 258      */
 259     synchronized void putJob(Job job, Object disposeId) {
 260         if(DEBUG) System.err.println("##### " + getClass().getName() + ".putJob todoes: " + " job:" + job);
 261
 262         if(_tail != null)
 263             _tail._next = job;
 264         else
 265             _head = job;
 266
 267         _tail = job;
 268
 269         if(_worker_thread == null && _createThread && _createThread_now) { // if there is no thread, which dispatches and if shall create one, create one
 270
 271             acquire();
 272
 273             _createThread_now = false;
 274             new JobDispatcher(disposeId).start();
 275         }
 276
 277         // always notify possible waiters
 278         notifyAll();
 279     }
 280
 281     /**
 282      * Enters the job queue.
 283      *
 284      * @param  disposeId  a dispose id.
 285      * @return the result of the final job (reply).
 286      */
 287     Object enter(Object disposeId) throws Throwable {
 288         return enter(0, disposeId); // wait infinitly
 289     }
 290
 291     /**
 292      * Enters the job queue.
 293      *
 294      * @param  waitTime   the maximum amount of time to wait for a job (0 means wait infinitly).
 295      * @param  disposeId  a dispose id.
 296      * @return the result of the final job (reply).
 297      */
 298     Object enter(int waitTime, Object disposeId) throws Throwable {
 299         if(DEBUG) System.err.println("#####" + getClass().getName() + ".enter: " + _threadId);
 300
 301         boolean quit = false;
 302
 303         Object hold_disposeId = _disposeId;
 304         _disposeId = disposeId;
 305
 306         Object result = null;
 307
 308         Thread hold_worker_thread = _worker_thread;
 309         _worker_thread = Thread.currentThread();
 310
 311         while(!quit) {
 312             Job job = null;
 313
 314             try {
 315                 job = removeJob(waitTime);
 316
 317                 if(job != null) {
 318                     try {
 319                         result = job.execute();
 320                     }
 321                     finally {
 322                         _active = false;
 323                     }
 324
 325                     if (!job.isRequest()) {
 326                         job.dispose();
 327
 328                         quit = true;
 329                     }
 330
 331                     job = null;
 332                 }
 333                 else
 334                     quit = true;
 335
 336
 337             }
 338             finally { // ensure that this queue becomes disposed, if necessary
 339                 if(DEBUG) System.err.println("##### " + getClass().getName() + ".enter leaving: " + _threadId + " " + _worker_thread + " " + hold_worker_thread + " " + result);
 340
 341                 synchronized(this) {
 342                     if(job != null || (quit && _head == null)) {
 343                         _worker_thread = hold_worker_thread;
 344
 345                         _createThread_now = true;
 346
 347                         _disposeId = hold_disposeId;
 348
 349                         if(_sync_jobQueue != null)
 350                             notifyAll(); // notify waiters (e.g. this is an asyncQueue and there is a sync waiting)
 351                     }
 352                     else
 353                         quit = false;
 354
 355                 }
 356             }
 357         }
 358
 359         return result;
 360     }
 361
 362     /**
 363      * If the given disposeId is registered, interrups the worker thread.
 364      *
 365      * @param disposeId    the dispose id.
 366      */
 367     synchronized void dispose(Object disposeId, Throwable throwable) {
 368         if(_sync_jobQueue == null) { // dispose only sync queues
 369             _doDispose = disposeId;
 370             _throwable = throwable;
 371
 372             // get thread out of wait and let it throw the throwable
 373             if(DEBUG) System.err.println(getClass().getName() + ".dispose - notifying thread");
 374
 375             notifyAll();
 376         }
 377     }
 378 }
 379