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

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