bundles/org.simantics/src/org/simantics/SleepingDatabaseJob.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2013 Association for Decentralized Information Management in\r
   3  * Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     Semantum Oy - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics;\r
  13 \r
  14 import java.util.concurrent.Semaphore;\r
  15 \r
  16 import org.eclipse.core.runtime.IProgressMonitor;\r
  17 import org.eclipse.core.runtime.IStatus;\r
  18 import org.eclipse.core.runtime.Status;\r
  19 import org.eclipse.core.runtime.jobs.Job;\r
  20 \r
  21 /**\r
  22  * A dummy database-family job that can be used for signaling that a large\r
  23  * database job is in progress although it is technically not running in a\r
  24  * {@link Job}.\r
  25  * \r
  26  * <p>\r
  27  * To start the job and wait for it to start, use\r
  28  * {@link #scheduleAndWaitForRunning()}. To end the job and wait for it to die,\r
  29  * use {@link #disposeAndJoin()}.\r
  30  * \r
  31  * @author Tuukka Lehtonen\r
  32  */\r
  33 public class SleepingDatabaseJob extends DatabaseJob {\r
  34 \r
  35     private final Semaphore start = new Semaphore(0);\r
  36     private final Semaphore end = new Semaphore(0);\r
  37 \r
  38     public SleepingDatabaseJob(String name) {\r
  39         super(name);\r
  40     }\r
  41 \r
  42     @Override\r
  43     protected final IStatus run(IProgressMonitor monitor) {\r
  44         start.release();\r
  45         try {\r
  46             return work(monitor);\r
  47         } finally {\r
  48             try {\r
  49                 end.acquire();\r
  50             } catch (InterruptedException e) {\r
  51                 // Some other party wanted to kill the job. So be it.\r
  52             }\r
  53         }\r
  54     }\r
  55 \r
  56     protected IStatus work(IProgressMonitor monitor) {\r
  57         return Status.OK_STATUS;\r
  58     }\r
  59 \r
  60     public SleepingDatabaseJob scheduleAndWaitForRunning() throws InterruptedException {\r
  61         schedule();\r
  62         start.acquire();\r
  63         start.release();\r
  64         return this;\r
  65     }\r
  66 \r
  67     public void scheduleAndWaitForRunningUninterruptibly() {\r
  68         schedule();\r
  69         start.acquireUninterruptibly();\r
  70         start.release();\r
  71     }\r
  72 \r
  73     public void disposeAndJoin() throws InterruptedException {\r
  74         end.release();\r
  75         join();\r
  76     }\r
  77 \r
  78     /**\r
  79      * @param name\r
  80      * @param runnable\r
  81      * @throws InterruptedException\r
  82      */\r
  83     public static void sleepWhile(String name, Runnable runnable) throws InterruptedException {\r
  84         SleepingDatabaseJob dbjob = new SleepingDatabaseJob(name);\r
  85         try {\r
  86             dbjob.scheduleAndWaitForRunning();\r
  87             runnable.run();\r
  88         } finally {\r
  89             dbjob.disposeAndJoin();\r
  90         }\r
  91     }\r
  92 \r
  93     /**\r
  94      * @param name\r
  95      * @param runnable\r
  96      * @throws InterruptedException\r
  97      */\r
  98     public static void sleepUninterruptiblyWhile(String name, Runnable runnable) {\r
  99         SleepingDatabaseJob dbjob = new SleepingDatabaseJob(name);\r
 100         try {\r
 101             dbjob.scheduleAndWaitForRunningUninterruptibly();\r
 102             runnable.run();\r
 103         } finally {\r
 104             try {\r
 105                 dbjob.disposeAndJoin();\r
 106             } catch (InterruptedException e) {\r
 107             }\r
 108         }\r
 109     }\r
 110 \r
 111 }\r