/[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 532 by alfonx, Thu Nov 19 10:39:48 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.  
  */  
   
   
 import gtmig.org.geotools.swing.XMapPane;  
   
 import java.awt.AlphaComposite;  
 import java.awt.Color;  
 import java.awt.Composite;  
3  import java.awt.Graphics2D;  import java.awt.Graphics2D;
4  import java.awt.Rectangle;  import java.awt.Rectangle;
5  import java.util.concurrent.Callable;  import java.awt.geom.AffineTransform;
6  import java.util.concurrent.CountDownLatch;  
7  import java.util.concurrent.ExecutorService;  import javax.swing.SwingUtilities;
 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    
14    import schmitzm.swing.SwingUtil;
15    
16  /**  /**
17   * This class is used by {@code JMapPane} to handle the scheduling and running of   * This class is used by {@link XMapPane} to start and stop the rendering a
18   * rendering tasks on a background thread. It functions as a single thread, non-   * {@link Thread} for rendering.
  * 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  
19   */   */
20  public class RenderingExecutor {  class RenderingExecutor {
21    
22      private final XMapPane mapPane;          /**
23      private final ExecutorService taskExecutor;           * Instance to a {@link RenderThread} doing any work. It's volatile so the
24      private final ScheduledExecutorService watchExecutor;           * correct value will always be visible to any {@link Thread}
25             **/
26      /** The default interval (milliseconds) for polling the result of a rendering task */          private volatile RenderThread renderThread;
27      public static final long DEFAULT_POLLING_INTERVAL = 100L;  
28            private final XMapPane mapPane;
29      private long pollingInterval;  
30            public RenderingExecutor(XMapPane mapPane) {
31      /*                  this.mapPane = mapPane;
32       * This latch is used to avoid a race between the cancellation of          }
33       * a current task and the submittal of a new task  
34       */          /**
35      private CountDownLatch cancelLatch;           * Submit a new rendering task. If no rendering task is presently running
36             * this new job will be accepted; otherwise it will be rejected and it
37      /**           * returns <code>false</code>.
38       * Constants to indicate the result of a rendering task           *
39       */           * @param envelope
40      public enum TaskResult {           *            the map area (world coordinates) to be rendered.
41          PENDING,           * @param graphics
42          COMPLETED,           *            the graphics object to draw on.
43          CANCELLED,           * @param paintArea
44          FAILED;           *            size of the area to paint the world into.
45      }           * @param worldToScreen
46             *            the {@link AffineTransform} from world coordinates to screen
47      private long numFeatures;           *            coordinates.
48             * @param renderer
49      /**           *            the {@link GTRenderer} to use.
50       * A rendering task           *
51       */           * @return true if the rendering task was accepted; false if it was rejected
52      private class Task implements Callable<TaskResult>, RenderListener {           */
53            public synchronized boolean submit(ReferencedEnvelope envelope,
54          private final ReferencedEnvelope envelope;                          Rectangle paintArea, Graphics2D graphics,
55          private final Rectangle paintArea;                          final GTRenderer renderer, AffineTransform worldToScreen) {
56          private final Graphics2D graphics;                  if (renderThread == null || !renderThread.isAlive()) {
57                            // System.out.println("is vacant... starting thread!");
58          private boolean cancelled;                          renderThread = null;
59          private boolean failed;  
60                  final private GTRenderer renderer;                          renderThread = new RenderThread(paintArea, graphics, renderer,
61                                            worldToScreen);
62          /**                          renderThread.start();
63           * Constructor. Creates a new rendering task  
64           *                          return true;
65           * @param envelope map area to render (world coordinates)                  } else {
66           * @param paintArea drawing area (image or display coordinates)a                          // System.out.println("is busy... requesting stop!");
67           * @param graphics graphics object used to draw into the image or display                          renderThread.getRenderer().stopRendering();
68           */                          return false;
69          public Task(final ReferencedEnvelope envelope, final Rectangle paintArea, final Graphics2D graphics, GTRenderer renderer) {                  }
70              this.envelope = envelope;          }
71              this.paintArea = paintArea;  
72              this.graphics = graphics;          /**
73              this.cancelled = false;           * For every new rendering job submitted and accepted, an instance of this
74              this.renderer = renderer;           * {@link Thread} will be started.
75              failed = false;           *
76          }           */
77            class RenderThread extends Thread {
78          /**  
79           * Called by the executor to run this rendering task.                  private final GTRenderer renderer;
80           *  
81           * @return result of the task: completed, cancelled or failed                  public RenderThread(final Rectangle paintArea,
82           * @throws Exception                                  final Graphics2D graphics, GTRenderer renderer,
83           */                                  AffineTransform worldToScreen) {
84          public TaskResult call() throws Exception {                          super(new RenderRun(paintArea, graphics, renderer, worldToScreen));
85              if (!cancelled) {                          this.renderer = renderer;
86                    
87                  try {                          setName("Render" + getName());
88                      renderer.addRenderListener(this);  
89                                                // System.out.println("starting render thread " + getName());
90                      Composite composite = graphics.getComposite();                  }
91                      //graphics.setComposite(AlphaComposite.Src);  
92                      //graphics.setBackground(Color.WHITE);                  public GTRenderer getRenderer() {
93                      graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.CLEAR, 0.0f));                          return renderer;
94                      graphics.fill(paintArea);                  }
95                      graphics.setComposite(composite);  
96            }
97    
98                      numFeatures = 0;          /**
99                      renderer.paint(graphics, mapPane.getVisibleRect(), envelope, mapPane.getWorldToScreenTransform());           * This {@link Runnable} will actually start the rendering
100             */
101                  } finally {          class RenderRun implements Runnable, RenderListener {
102                      renderer.removeRenderListener(this);                  private final Rectangle paintArea;
103                  }                  private final Graphics2D graphics;
104              }                  private final AffineTransform worldToScreen;
105                    private final GTRenderer renderer;
106              if (cancelled) {  
107                  return TaskResult.CANCELLED;                  public RenderRun(Rectangle paintArea, Graphics2D graphics,
108              } else if (failed) {                                  GTRenderer renderer, AffineTransform worldToScreen) {
109                  return TaskResult.FAILED;                          this.paintArea = paintArea;
110              } else {                          this.graphics = graphics;
111                  return TaskResult.COMPLETED;                          this.renderer = renderer;
112              }                          this.worldToScreen = worldToScreen;
113          }                  }
114    
115          /**                  @Override
116           * Cancel the rendering task if it is running. If called before                  public void run() {
117           * being run the task will be abandoned.                          try {
118           */                                  renderer.addRenderListener(this);
119          public synchronized void cancel() {                                  System.out.println("start rendering...");
120              if (isRunning()) {                                  // try {
121                  cancelled = true;                                  // Thread.sleep(1000);
122                  renderer.stopRendering();                                  // } catch (InterruptedException e) {
123              }                                  // e.printStackTrace();
124          }                                  // }
125    
126          /**                                  // Clear the graphics context
127           * Called by the renderer when each feature is drawn.                                  graphics.setBackground(mapPane.getMapBackgroundColor());
128           *                                  graphics.clearRect(paintArea.x, paintArea.y, paintArea.width,
129           * @param feature the feature just drawn                                                  paintArea.height);
130           */  
131          public void featureRenderer(SimpleFeature feature) {                                  renderer.paint(graphics, paintArea, worldToScreen);
132              // @todo update a progress listener  
133              numFeatures++ ;                                  // Invoked later, so when onRenderingCompleted is called, the Thread is not running anymore (#isRunning = false)
134          }                                  SwingUtilities.invokeLater(new Runnable() {
135                                            @Override
136          /**                                          public void run() {
137           * Called by the renderer on error                                                  mapPane.onRenderingCompleted();
138           *                                          };
139           * @param e cause of the error                                  });
140           */                          } finally {
141          public void errorOccurred(Exception e) {                                  renderer.removeRenderListener(this);
142                  renderingException = e;                          }
143                  graphics.setColor(Color.white);                  }
144                  graphics.drawString(e.getMessage(), 11, 11);  
145                  graphics.drawString(e.getMessage(), 9, 9);                  @Override
146                  graphics.setColor(Color.black);                  public void errorOccurred(Exception e) {
147                  graphics.drawString(e.getMessage(), 10, 10);                          // System.out.println("rendering error");
148              failed = true;                          mapPane.onRenderingFailed(e);
149          }                  }
150    
151      }                  @Override
152                    public void featureRenderer(SimpleFeature feature) {
153      private AtomicBoolean taskRunning;                  }
154      private Task task;  
155      private Future<TaskResult> taskResult;          }
156      private ScheduledFuture<?> watcher;  
157          private Exception renderingException;          /**
158             * Ask to stop the rendering. May be called often.
159      /**           */
160       * Constructor. Creates a new executor to service the specified map pane.          public void cancelTask() {
161       *                  if (renderThread != null && renderThread.isAlive()) {
162       * @param mapPane the map pane to be serviced                          // System.out.println("request stop for thread " +task.getName());
163       */                          renderThread.getRenderer().stopRendering();
164      public RenderingExecutor(final XMapPane mapPane) {                  }
165          taskRunning = new AtomicBoolean(false);          }
166          this.mapPane = mapPane;  
167          taskExecutor = Executors.newSingleThreadExecutor();          /**
168          watchExecutor = Executors.newSingleThreadScheduledExecutor();           * @return <code>true</code> if the {@link Thread} is busy rendering.
169          pollingInterval = DEFAULT_POLLING_INTERVAL;           */
170          cancelLatch = new CountDownLatch(0);          public boolean isRunning() {
171      }                  // if (task != null)
172                    // System.out.println("is running "+task.getName()+" = true");
173      /**                  return (renderThread != null && renderThread.isAlive());
174       * Get the interval for polling the result of a rendering task          }
175       *  
176       * @return polling interval in milliseconds          /**
177       */           * Will stop rendering and remove the reference to the {@link Thread}.
178      public long getPollingInterval() {           */
179          return pollingInterval;          public void dispose() {
180      }                  if (renderThread != null) {
181                            renderThread.renderer.stopRendering();
182      /**                          renderThread = null;
183       * Set the interval for polling the result of a rendering task                  }
184       *          }
      * @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();  
         }  
     }  
 }  
185    
186    }
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