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branches/1.0-gt2-2.6/src/skrueger/geotools/RenderingExecutor.java revision 524 by alfonx, Wed Nov 18 09:56:47 2009 UTC branches/2.3-KECK/src/skrueger/geotools/RenderingExecutor.java revision 1102 by alfonx, Thu Oct 14 09:44:10 2010 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;
 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;  
6    
7    import org.apache.log4j.Logger;
8  import org.geotools.geometry.jts.ReferencedEnvelope;  import org.geotools.geometry.jts.ReferencedEnvelope;
9  import org.geotools.renderer.GTRenderer;  import org.geotools.renderer.GTRenderer;
10  import org.geotools.renderer.RenderListener;  import org.geotools.renderer.RenderListener;
 import org.geotools.swing.JMapPane;  
11  import org.opengis.feature.simple.SimpleFeature;  import org.opengis.feature.simple.SimpleFeature;
12    
13    import schmitzm.geotools.gui.XMapPane;
14    
15  /**  /**
16   * 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
17   * 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  
18   */   */
19  public class RenderingExecutor {  public class RenderingExecutor {
20            private final static Logger LOGGER = Logger.getLogger(RenderingExecutor.class);
21            /**
22             * Instance to a {@link RenderThread} doing any work. It's volatile so the
23             * correct value will always be visible to any {@link Thread}
24             **/
25            private volatile RenderThread renderThread;
26    
27            private final XMapPane mapPane;
28    
29            public RenderingExecutor(XMapPane mapPane) {
30                    this.mapPane = mapPane;
31            }
32    
33            /**
34             * Submit a new rendering task. If no rendering task is presently running
35             * this new job will be accepted; otherwise it will be rejected and it
36             * returns <code>false</code>.
37             *
38             * @param envelope
39             *            the map area (world coordinates) to be rendered.
40             * @param graphics
41             *            the graphics object to draw on.
42             * @param paintArea
43             *            size of the area to paint the world into.
44             * @param worldToScreen
45             *            the {@link AffineTransform} from world coordinates to screen
46             *            coordinates.
47             * @param renderer
48             *            the {@link GTRenderer} to use.
49             *
50             * @return true if the rendering task was accepted; false if it was rejected
51             */
52            public synchronized boolean submit(ReferencedEnvelope envelope,
53                            Rectangle paintArea, Graphics2D graphics, final GTRenderer renderer
54            // , AffineTransform worldToScreen
55            ) {
56                    if (renderThread == null || !renderThread.isAlive()) {
57                            // System.out.println("is vacant... starting thread!");
58                            renderThread = null;
59    
60                            renderThread = new RenderThread(paintArea, graphics, renderer,
61                            // worldToScreen,
62                                            envelope);
63                            renderThread.start();
64    
65                            return true;
66                    } else {
67                            // System.out.println("is busy... requesting stop!");
68                            renderThread.getRenderer().stopRendering();
69                            return false;
70                    }
71            }
72    
73            /**
74             * For every new rendering job submitted and accepted, an instance of this
75             * {@link Thread} will be started.
76             *
77             */
78            class RenderThread extends Thread {
79    
80                    private final GTRenderer renderer;
81    
82                    public RenderThread(final Rectangle paintArea,
83                                    final Graphics2D graphics, GTRenderer renderer,
84                                    // AffineTransform worldToScreen,
85                                    ReferencedEnvelope mapEnv) {
86                            super(new RenderRun(paintArea, graphics, renderer, mapEnv
87                            // , worldToScreen
88                                            ));
89                            this.renderer = renderer;
90    
91                            setName("Render" + getName());
92    
93                            // System.out.println("starting render thread " + getName());
94                    }
95    
96                    public GTRenderer getRenderer() {
97                            return renderer;
98                    }
99    
100            }
101    
102            /**
103             * This {@link Runnable} will actually start the rendering
104             */
105            class RenderRun implements Runnable, RenderListener {
106                    private final Rectangle paintArea;
107                    private final Graphics2D graphics;
108                    // private final AffineTransform worldToScreen;
109                    private final GTRenderer renderer;
110                    private final ReferencedEnvelope mapEnv;
111    
112                    public RenderRun(Rectangle paintArea, Graphics2D graphics,
113                                    GTRenderer renderer, ReferencedEnvelope mapEnv
114                    // ,
115                    // AffineTransform worldToScreen
116                    ) {
117                            this.paintArea = paintArea;
118                            this.graphics = graphics;
119                            this.renderer = renderer;
120                            this.mapEnv = mapEnv;
121                            // this.worldToScreen = worldToScreen;
122                    }
123    
124                    @Override
125                    public void run() {
126                            long startT = System.currentTimeMillis();
127                            try {
128                                    renderer.addRenderListener(this);
129    //                              LOGGER.debug("start rendering...");
130    
131                                    // Clear the graphics context
132                                    graphics.setBackground(mapPane.getMapBackgroundColor());
133                                    graphics.clearRect(paintArea.x, paintArea.y, paintArea.width,
134                                                    paintArea.height);
135    
136                                    renderer.paint(graphics, paintArea, mapEnv);
137    
138                                    // Kill the reference to this Thread so #isRunning will say
139                                    // false directly
140                                    renderThread = null;
141                                    mapPane.onRenderingCompleted(System.currentTimeMillis()-startT);
142                            } catch (Exception e) {
143                                    mapPane.onRenderingFailed(e);
144                            } finally {
145                                    renderer.removeRenderListener(this);
146                            }
147                    }
148    
149                    @Override
150                    public void errorOccurred(Exception e) {
151                            mapPane.onRenderingFailed(e);
152                    }
153    
154                    @Override
155                    public void featureRenderer(SimpleFeature feature) {
156                    }
157    
158            }
159    
160            /**
161             * Ask to stop the rendering. May be called often.
162             */
163            public void cancelTask() {
164                    if (renderThread != null)
165                            synchronized (renderThread) {
166                                    if (renderThread.isAlive()) {
167                                            if (renderThread.getRenderer() != null)
168                                                    renderThread.getRenderer().stopRendering();
169                                    }
170                            }
171            }
172    
173            /**
174             * @return <code>true</code> if the {@link Thread} is busy rendering.
175             */
176            public boolean isRunning() {
177                    return (renderThread != null && renderThread.isAlive());
178            }
179    
180            /**
181             * Will stop rendering and remove the reference to the {@link Thread}.
182             */
183            public void dispose() {
184                    if (renderThread != null) {
185                            renderThread.renderer.stopRendering();
186                            renderThread = null;
187                    }
188            }
189    
     private final XMapPane mapPane;  
     private final ExecutorService taskExecutor;  
     private final ScheduledExecutorService watchExecutor;  
   
 //    /** The default interval (milliseconds) for polling the result of a rendering task */  
 //    public static final long DEFAULT_POLLING_INTERVAL = 300L;  
   
     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  
      * @param l  
      */  
         public RenderingExecutor(final XMapPane mapPane, long pollingInterval) {  
         taskRunning = new AtomicBoolean(false);  
         this.mapPane = mapPane;  
         taskExecutor = Executors.newSingleThreadExecutor();  
         watchExecutor = Executors.newSingleThreadScheduledExecutor();  
         this.pollingInterval = pollingInterval;  
         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()) {  
 //            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();  
                 }  
             }, pollingInterval, pollingInterval, TimeUnit.MILLISECONDS);  
   
             return true;  
         }  
   
         return false;  
     }  
   
     /**  
      * Cancel the current rendering task if one is running  
      */  
     public synchronized void cancelTask() {  
         if (isRunning()) {  
             task.cancel();  
               
             // Cancelling to often... can that be the reason?  
             if (cancelLatch.getCount() < 1) {  
                 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;  
                   
             case PENDING:  
                 mapPane.onRenderingPending();  
                 break;  
                   
         }  
     }  
   
     public synchronized boolean isRunning() {  
         return taskRunning.get();  
     }  
   
     @Override  
     protected void finalize() throws Throwable {  
         if (this.isRunning()) {  
             taskExecutor.shutdownNow();  
             watchExecutor.shutdownNow();  
         }  
     }  
       
     public void dispose() {  
         taskExecutor.shutdownNow();  
         watchExecutor.shutdownNow();  
     }  
190  }  }
   
Legend:
Removed from v.524  
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  Added in v.1102
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