/[schmitzm]/branches/2.4.x/src/skrueger/geotools/RenderingExecutor.java
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revision 510 by alfonx, Thu Nov 5 17:39:37 2009 UTC revision 530 by alfonx, Thu Nov 19 09:31:14 2009 UTC
# Line 1  Line 1 
1  package skrueger.geotools;  package skrueger.geotools;
2    
 /*  
  *    GeoTools - The Open Source Java GIS Toolkit  
  *    http://geotools.org  
  *  
  *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)  
  *  
  *    This library is free software; you can redistribute it and/or  
  *    modify it under the terms of the GNU Lesser General Public  
  *    License as published by the Free Software Foundation;  
  *    version 2.1 of the License.  
  *  
  *    This library is distributed in the hope that it will be useful,  
  *    but WITHOUT ANY WARRANTY; without even the implied warranty of  
  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  
  *    Lesser General Public License for more details.  
  */  
   
   
3  import gtmig.org.geotools.swing.XMapPane;  import gtmig.org.geotools.swing.XMapPane;
4    
 import java.awt.AlphaComposite;  
 import java.awt.Color;  
 import java.awt.Composite;  
5  import java.awt.Graphics2D;  import java.awt.Graphics2D;
6  import java.awt.Rectangle;  import java.awt.Rectangle;
7  import java.util.concurrent.Callable;  import java.awt.geom.AffineTransform;
 import java.util.concurrent.CountDownLatch;  
 import java.util.concurrent.ExecutorService;  
 import java.util.concurrent.Executors;  
 import java.util.concurrent.Future;  
 import java.util.concurrent.ScheduledExecutorService;  
 import java.util.concurrent.ScheduledFuture;  
 import java.util.concurrent.TimeUnit;  
 import java.util.concurrent.atomic.AtomicBoolean;  
8    
9  import org.geotools.geometry.jts.ReferencedEnvelope;  import org.geotools.geometry.jts.ReferencedEnvelope;
10  import org.geotools.renderer.GTRenderer;  import org.geotools.renderer.GTRenderer;
11  import org.geotools.renderer.RenderListener;  import org.geotools.renderer.RenderListener;
 import org.geotools.swing.JMapPane;  
12  import org.opengis.feature.simple.SimpleFeature;  import org.opengis.feature.simple.SimpleFeature;
13    
 /**  
  * This class is used by {@code JMapPane} to handle the scheduling and running of  
  * rendering tasks on a background thread. It functions as a single thread, non-  
  * queueing executor, ie. only one rendering task can run at any given time and,  
  * while it is running, any other submitted tasks will be rejected.  
  * <p>  
  * Whether a rendering task is accepted or rejected can be tested on submission:  
  * <pre><code>  
  *     ReferencedEnvelope areaToDraw = ...  
  *     Graphics2D graphicsToDrawInto = ...  
  *     boolean accepted = renderingExecutor.submit(areaToDraw, graphicsToDrawInto);  
  * </code></pre>  
  *  
  * The status of the executor can also be checked at any time like this:  
  * <pre><code>  
  *     boolean busy = renderingExecutor.isRunning();  
  * </code></pre>  
  *  
  * While a rendering task is running it is regularly polled to see if it has completed  
  * and, if so, whether it finished normally, was cancelled or failed. The interval between  
  * polling can be adjusted which might be useful to tune the executor for particular  
  * applications:  
  * <pre><code>  
  *     RenderingExecutor re = new RenderingExecutor( mapPane );  
  *     re.setPollingInterval( 150 );  // 150 milliseconds  
  * </code></pre>  
  *  
  * @author Michael Bedward  
  * @since 2.7  
  * @source $URL: http://svn.osgeo.org/geotools/branches/2.6.x/modules/unsupported/swing/src/main/java/org/geotools/swing/RenderingExecutor.java $  
  * @version $Id: RenderingExecutor.java 34285 2009-10-30 10:48:49Z mbedward $  
  *  
  * @see JMapPane  
  */  
14  public class RenderingExecutor {  public class RenderingExecutor {
15    
16      private final XMapPane mapPane;          private volatile RenderThread renderThread;
17      private final ExecutorService taskExecutor;          private final XMapPane mapPane;
     private final ScheduledExecutorService watchExecutor;  
   
     /** The default interval (milliseconds) for polling the result of a rendering task */  
     public static final long DEFAULT_POLLING_INTERVAL = 100L;  
   
     private long pollingInterval;  
   
     /*  
      * This latch is used to avoid a race between the cancellation of  
      * a current task and the submittal of a new task  
      */  
     private CountDownLatch cancelLatch;  
   
     /**  
      * Constants to indicate the result of a rendering task  
      */  
     public enum TaskResult {  
         PENDING,  
         COMPLETED,  
         CANCELLED,  
         FAILED;  
     }  
   
     private long numFeatures;  
   
     /**  
      * A rendering task  
      */  
     private class Task implements Callable<TaskResult>, RenderListener {  
   
         private final ReferencedEnvelope envelope;  
         private final Rectangle paintArea;  
         private final Graphics2D graphics;  
   
         private boolean cancelled;  
         private boolean failed;  
                 final private GTRenderer renderer;  
   
         /**  
          * Constructor. Creates a new rendering task  
          *  
          * @param envelope map area to render (world coordinates)  
          * @param paintArea drawing area (image or display coordinates)a  
          * @param graphics graphics object used to draw into the image or display  
          */  
         public Task(final ReferencedEnvelope envelope, final Rectangle paintArea, final Graphics2D graphics, GTRenderer renderer) {  
             this.envelope = envelope;  
             this.paintArea = paintArea;  
             this.graphics = graphics;  
             this.cancelled = false;  
             this.renderer = renderer;  
             failed = false;  
         }  
   
         /**  
          * Called by the executor to run this rendering task.  
          *  
          * @return result of the task: completed, cancelled or failed  
          * @throws Exception  
          */  
         public TaskResult call() throws Exception {  
             if (!cancelled) {  
                   
                 try {  
                     renderer.addRenderListener(this);  
                       
                     Composite composite = graphics.getComposite();  
                     //graphics.setComposite(AlphaComposite.Src);  
                     //graphics.setBackground(Color.WHITE);  
                     graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.CLEAR, 0.0f));  
                     graphics.fill(paintArea);  
                     graphics.setComposite(composite);  
   
   
                     numFeatures = 0;  
                     renderer.paint(graphics, mapPane.getVisibleRect(), envelope, mapPane.getWorldToScreenTransform());  
   
                 } finally {  
                     renderer.removeRenderListener(this);  
                 }  
             }  
   
             if (cancelled) {  
                 return TaskResult.CANCELLED;  
             } else if (failed) {  
                 return TaskResult.FAILED;  
             } else {  
                 return TaskResult.COMPLETED;  
             }  
         }  
   
         /**  
          * Cancel the rendering task if it is running. If called before  
          * being run the task will be abandoned.  
          */  
         public synchronized void cancel() {  
             if (isRunning()) {  
                 cancelled = true;  
                 renderer.stopRendering();  
             }  
         }  
   
         /**  
          * Called by the renderer when each feature is drawn.  
          *  
          * @param feature the feature just drawn  
          */  
         public void featureRenderer(SimpleFeature feature) {  
             // @todo update a progress listener  
             numFeatures++ ;  
         }  
   
         /**  
          * Called by the renderer on error  
          *  
          * @param e cause of the error  
          */  
         public void errorOccurred(Exception e) {  
                 renderingException = e;  
                 graphics.setColor(Color.white);  
                 graphics.drawString(e.getMessage(), 11, 11);  
                 graphics.drawString(e.getMessage(), 9, 9);  
                 graphics.setColor(Color.black);  
                 graphics.drawString(e.getMessage(), 10, 10);  
             failed = true;  
         }  
   
     }  
   
     private AtomicBoolean taskRunning;  
     private Task task;  
     private Future<TaskResult> taskResult;  
     private ScheduledFuture<?> watcher;  
         private Exception renderingException;  
   
     /**  
      * Constructor. Creates a new executor to service the specified map pane.  
      *  
      * @param mapPane the map pane to be serviced  
      */  
     public RenderingExecutor(final XMapPane mapPane) {  
         taskRunning = new AtomicBoolean(false);  
         this.mapPane = mapPane;  
         taskExecutor = Executors.newSingleThreadExecutor();  
         watchExecutor = Executors.newSingleThreadScheduledExecutor();  
         pollingInterval = DEFAULT_POLLING_INTERVAL;  
         cancelLatch = new CountDownLatch(0);  
     }  
   
     /**  
      * Get the interval for polling the result of a rendering task  
      *  
      * @return polling interval in milliseconds  
      */  
     public long getPollingInterval() {  
         return pollingInterval;  
     }  
   
     /**  
      * Set the interval for polling the result of a rendering task  
      *  
      * @param interval interval in milliseconds (values {@code <=} 0 are ignored)  
      */  
     public void setPollingInterval(long interval) {  
         if (interval > 0) {  
             pollingInterval = interval;  
         }  
     }  
   
     /**  
      * Submit a new rendering task. If no rendering task is presently running  
      * this new task will be accepted; otherwise it will be rejected (ie. there  
      * is no task queue).  
      *  
      * @param envelope the map area (world coordinates) to be rendered  
      * @param graphics the graphics object to draw on  
      *  
      * @return true if the rendering task was accepted; false if it was  
      *         rejected  
      */  
     public synchronized boolean submit(ReferencedEnvelope envelope, Rectangle paintArea, Graphics2D graphics, final GTRenderer renderer) {  
         if (!isRunning() || cancelLatch.getCount() > 0) {  
             try {  
                 // wait for any cancelled task to finish its shutdown  
                 cancelLatch.await();  
             } catch (InterruptedException ex) {  
                 return false;  
             }  
   
             task = new Task(envelope, paintArea, graphics, renderer);  
             taskRunning.set(true);  
             taskResult = taskExecutor.submit(task);  
             watcher = watchExecutor.scheduleAtFixedRate(new Runnable() {  
   
                 public void run() {  
                     pollTaskResult();  
                 }  
             }, DEFAULT_POLLING_INTERVAL, DEFAULT_POLLING_INTERVAL, TimeUnit.MILLISECONDS);  
   
             return true;  
         }  
   
         return false;  
     }  
   
     /**  
      * Cancel the current rendering task if one is running  
      */  
     public synchronized void cancelTask() {  
         if (isRunning()) {  
             task.cancel();  
             cancelLatch = new CountDownLatch(1);  
         }  
     }  
   
     private void pollTaskResult() {  
         if (!taskResult.isDone()) {  
             return;  
         }  
   
         TaskResult result = TaskResult.PENDING;  
   
         try {  
             result = taskResult.get();  
         } catch (Exception ex) {  
             throw new IllegalStateException("When getting rendering result", ex);  
         }  
   
         watcher.cancel(false);  
         taskRunning.set(false);  
   
         switch (result) {  
             case CANCELLED:  
                 cancelLatch.countDown();  
                 mapPane.onRenderingCancelled();  
                 break;  
   
             case COMPLETED:  
                 mapPane.onRenderingCompleted();  
                 break;  
   
             case FAILED:  
                 mapPane.onRenderingFailed(renderingException);  
                 break;  
         }  
     }  
   
     public synchronized boolean isRunning() {  
         return taskRunning.get();  
     }  
   
     @Override  
     protected void finalize() throws Throwable {  
         if (this.isRunning()) {  
             taskExecutor.shutdownNow();  
             watchExecutor.shutdownNow();  
         }  
     }  
 }  
18    
19            public RenderingExecutor(XMapPane mapPane) {
20                    this.mapPane = mapPane;
21            }
22    
23            /**
24             * Submit a new rendering task. If no rendering task is presently running
25             * this new task will be accepted; otherwise it will be rejected (ie. there
26             * is no task queue).
27             *
28             * @param envelope
29             *            the map area (world coordinates) to be rendered
30             * @param graphics
31             *            the graphics object to draw on
32             *
33             * @return true if the rendering task was accepted; false if it was rejected
34             */
35            public synchronized boolean submit(ReferencedEnvelope envelope,
36                            Rectangle paintArea, Graphics2D graphics,
37                            final GTRenderer renderer, AffineTransform worldToScreen) {
38                    System.out.println("submit..:");
39                    if (renderThread == null || !renderThread.isAlive()) {
40                            System.out.println("is vacant... starting thread!");
41    
42                            renderThread = new RenderThread(paintArea, graphics, renderer,
43                                            worldToScreen);
44                            renderThread.start();
45    
46                            return true;
47                    } else {
48                            System.out.println("is busy... requesting stop!");
49                            renderThread.getRenderer().stopRendering();
50                    }
51    
52                    return false;
53            }
54    
55            class RenderThread extends Thread {
56    
57                    private final GTRenderer renderer;
58    
59                    public RenderThread(final Rectangle paintArea,
60                                    final Graphics2D graphics, GTRenderer renderer,
61                                    AffineTransform worldToScreen) {
62                            super(new RenderRun(paintArea, graphics, renderer, worldToScreen));
63                            this.renderer = renderer;
64    
65                            System.out.println("starting render thread " + getName());
66                    }
67    
68                    public GTRenderer getRenderer() {
69                            return renderer;
70                    }
71    
72            }
73    
74            class RenderRun implements Runnable, RenderListener {
75                    private final Rectangle paintArea;
76                    private final Graphics2D graphics;
77                    private final AffineTransform worldToScreen;
78                    private final GTRenderer renderer;
79    
80                    public RenderRun(Rectangle paintArea, Graphics2D graphics,
81                                    GTRenderer renderer, AffineTransform worldToScreen) {
82                            this.paintArea = paintArea;
83                            this.graphics = graphics;
84                            this.renderer = renderer;
85                            this.worldToScreen = worldToScreen;
86                    }
87    
88                    @Override
89                    public void run() {
90                            try {
91                                    renderer.addRenderListener(this);
92                                    System.out.println("start rendering...");
93                                    try {
94                                            Thread.sleep(1000);
95                                    } catch (InterruptedException e) {
96                                            // TODO Auto-generated catch block
97                                            e.printStackTrace();
98                                    }
99                                    renderer.paint(graphics, paintArea, worldToScreen);
100    
101                                    mapPane.onRenderingCompleted();
102                            } finally {
103                                    renderer.removeRenderListener(this);
104                            }
105                    }
106    
107                    @Override
108                    public void errorOccurred(Exception e) {
109                            // System.out.println("rendering error");
110                            mapPane.onRenderingFailed(e);
111                    }
112    
113                    @Override
114                    public void featureRenderer(SimpleFeature feature) {
115                    }
116    
117            }
118    
119            public void cancelTask() {
120                    if (renderThread != null && renderThread.isAlive()) {
121                            // System.out.println("request stop for thread " +task.getName());
122                            renderThread.getRenderer().stopRendering();
123                    }
124            }
125    
126            public boolean isRunning() {
127                    // if (task != null)
128                    // System.out.println("is running "+task.getName()+" = true");
129                    return (renderThread != null && renderThread.isAlive());
130            }
131    
132            public void dispose() {
133                    if (renderThread != null) {
134                            renderThread.renderer.stopRendering();
135                            renderThread = null;
136                    }
137            }
138    
139    }
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