bundles/org.simantics.browsing.ui.swt/src/org/simantics/browsing/ui/swt/ImageLoaderJob.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2013 Association for Decentralized Information Management\r
   3  * in 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.browsing.ui.swt;\r
  13 \r
  14 import java.util.concurrent.atomic.AtomicBoolean;\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 import org.eclipse.ui.progress.IProgressConstants;\r
  21 import org.simantics.DatabaseJob;\r
  22 \r
  23 /**\r
  24  * @author Tuukka Lehtonen\r
  25  */\r
  26 public class ImageLoaderJob extends DatabaseJob {\r
  27 \r
  28         private GraphExplorerImplBase ge;\r
  29         private AtomicBoolean isScheduled = new AtomicBoolean();\r
  30 \r
  31         public ImageLoaderJob(GraphExplorerImplBase ge) {\r
  32                 super("Image Loader");\r
  33                 this.ge = ge;\r
  34                 setSystem(true);\r
  35                 setUser(false);\r
  36                 setPriority(Job.DECORATE);\r
  37                 setProperty(IProgressConstants.NO_IMMEDIATE_ERROR_PROMPT_PROPERTY, Boolean.TRUE);\r
  38         }\r
  39 \r
  40         /**\r
  41          * Schedules the job with {@link Job#schedule()} if necessary, i.e. if\r
  42          * not already scheduled. This method avoids some unnecessary overhead\r
  43          * caused by repeatedly invoking {@link Job#schedule()}.\r
  44          * \r
  45          * @return <code>true</code> if scheduled, <code>false</code> otherwise\r
  46          */\r
  47         public boolean scheduleIfNecessary(long delay) {\r
  48                 if (isScheduled.compareAndSet(false, true)) {\r
  49                         schedule(delay);\r
  50                         return true;\r
  51                 }\r
  52                 return false;\r
  53         }\r
  54 \r
  55         @Override\r
  56         public boolean shouldRun() {\r
  57                 return ge != null;\r
  58         }\r
  59 \r
  60         @Override\r
  61         public boolean shouldSchedule() {\r
  62                 return ge != null;\r
  63         }\r
  64 \r
  65         @Override\r
  66         protected IStatus run(IProgressMonitor monitor) {\r
  67                 try {\r
  68                         isScheduled.set(false);\r
  69                         GraphExplorerImplBase ge = this.ge;\r
  70                         return (ge != null) ? ge.setPendingImages(monitor) : Status.CANCEL_STATUS;\r
  71                 } finally {\r
  72                         monitor.done();\r
  73                 }\r
  74         }\r
  75 \r
  76         public void dispose() {\r
  77                 ge = null;\r
  78         }\r
  79 }