skrueger/geotools/RenderingExecutor.java

package skrueger.geotools;

import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;

import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.renderer.GTRenderer;
import org.geotools.renderer.RenderListener;
import org.opengis.feature.simple.SimpleFeature;

/**
 * This class is used by {@link XMapPane} to start and stop the rendering a
 * {@link Thread} for rendering.
 */
class RenderingExecutor {

        /**
         * Instance to a {@link RenderThread} doing any work. It's volatile so the
         * correct value will always be visible to any {@link Thread}
         **/
        private volatile RenderThread renderThread;

        private final XMapPane mapPane;

        public RenderingExecutor(XMapPane mapPane) {
                this.mapPane = mapPane;
        }

        /**
         * Submit a new rendering task. If no rendering task is presently running
         * this new job will be accepted; otherwise it will be rejected and it
         * returns <code>false</code>.
         * 
         * @param envelope
         *            the map area (world coordinates) to be rendered.
         * @param graphics
         *            the graphics object to draw on.
         * @param paintArea
         *            size of the area to paint the world into.
         * @param worldToScreen
         *            the {@link AffineTransform} from world coordinates to screen
         *            coordinates.
         * @param renderer
         *            the {@link GTRenderer} to use.
         * 
         * @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, AffineTransform worldToScreen) {
                if (renderThread == null || !renderThread.isAlive()) {
                        // System.out.println("is vacant... starting thread!");
                        renderThread = null;

                        renderThread = new RenderThread(paintArea, graphics, renderer,
                                        worldToScreen, envelope);
                        renderThread.start();

                        return true;
                } else {
                        // System.out.println("is busy... requesting stop!");
                        renderThread.getRenderer().stopRendering();
                        return false;
                }
        }

        /**
         * For every new rendering job submitted and accepted, an instance of this
         * {@link Thread} will be started.
         * 
         */
        class RenderThread extends Thread {

                private final GTRenderer renderer;

                public RenderThread(final Rectangle paintArea,
                                final Graphics2D graphics, GTRenderer renderer,
                                AffineTransform worldToScreen, ReferencedEnvelope mapEnv) {
                        super(new RenderRun(paintArea, graphics, renderer, mapEnv,
                                        worldToScreen));
                        this.renderer = renderer;

                        setName("Render" + getName());

                        // System.out.println("starting render thread " + getName());
                }

                public GTRenderer getRenderer() {
                        return renderer;
                }

        }

        /**
         * This {@link Runnable} will actually start the rendering
         */
        class RenderRun implements Runnable, RenderListener {
                private final Rectangle paintArea;
                private final Graphics2D graphics;
                private final AffineTransform worldToScreen;
                private final GTRenderer renderer;
                private final ReferencedEnvelope mapEnv;

                public RenderRun(Rectangle paintArea, Graphics2D graphics,
                                GTRenderer renderer, ReferencedEnvelope mapEnv,
                                AffineTransform worldToScreen) {
                        this.paintArea = paintArea;
                        this.graphics = graphics;
                        this.renderer = renderer;
                        this.mapEnv = mapEnv;
                        this.worldToScreen = worldToScreen;
                }

                @Override
                public void run() {
                        try {
                                renderer.addRenderListener(this);
                                System.out.println("start rendering...");
                                // try {
                                // Thread.sleep(1000);
                                // } catch (InterruptedException e) {
                                // e.printStackTrace();
                                // }

                                // Clear the graphics context
                                graphics.setBackground(mapPane.getMapBackgroundColor());
                                graphics.clearRect(paintArea.x, paintArea.y, paintArea.width,
                                                paintArea.height);

                                renderer.paint(graphics, paintArea, worldToScreen);

                                // Kill the reference to this Thread so #isRunning will say
                                // false directly
                                renderThread = null;
                                mapPane.onRenderingCompleted();
                        } catch (Exception e) {
                                mapPane.onRenderingFailed(e);
                        } finally {
                                renderer.removeRenderListener(this);
                        }
                }

                @Override
                public void errorOccurred(Exception e) {
                        mapPane.onRenderingFailed(e);
                }

                @Override
                public void featureRenderer(SimpleFeature feature) {
                }

        }

        /**
         * Ask to stop the rendering. May be called often.
         */
        public void cancelTask() {
                if (renderThread != null && renderThread.isAlive()) {
                        // System.out.println("request stop for thread " +task.getName());
                        renderThread.getRenderer().stopRendering();
                }
        }

        /**
         * @return <code>true</code> if the {@link Thread} is busy rendering.
         */
        public boolean isRunning() {
                return (renderThread != null && renderThread.isAlive());
        }

        /**
         * Will stop rendering and remove the reference to the {@link Thread}.
         */
        public void dispose() {
                if (renderThread != null) {
                        renderThread.renderer.stopRendering();
                        renderThread = null;
                }
        }

}
1	alfonx	510	package skrueger.geotools;
2
3			import java.awt.Graphics2D;
4			import java.awt.Rectangle;
5	alfonx	529	import java.awt.geom.AffineTransform;
6	alfonx	510
7			import org.geotools.geometry.jts.ReferencedEnvelope;
8			import org.geotools.renderer.GTRenderer;
9			import org.geotools.renderer.RenderListener;
10			import org.opengis.feature.simple.SimpleFeature;
11
12	alfonx	532	/**
13			* This class is used by {@link XMapPane} to start and stop the rendering a
14			* {@link Thread} for rendering.
15			*/
16			class RenderingExecutor {
17
18			/**
19			* Instance to a {@link RenderThread} doing any work. It's volatile so the
20			* correct value will always be visible to any {@link Thread}
21			**/
22	alfonx	530	private volatile RenderThread renderThread;
23	alfonx	532
24	alfonx	530	private final XMapPane mapPane;
25
26	alfonx	529	public RenderingExecutor(XMapPane mapPane) {
27			this.mapPane = mapPane;
28	alfonx	530	}
29	alfonx	510
30	alfonx	530	/**
31			* Submit a new rendering task. If no rendering task is presently running
32	alfonx	532	* this new job will be accepted; otherwise it will be rejected and it
33			* returns <code>false</code>.
34	alfonx	530	*
35			* @param envelope
36	alfonx	532	* the map area (world coordinates) to be rendered.
37	alfonx	530	* @param graphics
38	alfonx	532	* the graphics object to draw on.
39			* @param paintArea
40			* size of the area to paint the world into.
41			* @param worldToScreen
42			* the {@link AffineTransform} from world coordinates to screen
43			* coordinates.
44			* @param renderer
45			* the {@link GTRenderer} to use.
46	alfonx	530	*
47			* @return true if the rendering task was accepted; false if it was rejected
48			*/
49			public synchronized boolean submit(ReferencedEnvelope envelope,
50			Rectangle paintArea, Graphics2D graphics,
51			final GTRenderer renderer, AffineTransform worldToScreen) {
52			if (renderThread == null \|\| !renderThread.isAlive()) {
53	alfonx	532	// System.out.println("is vacant... starting thread!");
54			renderThread = null;
55	alfonx	510
56	alfonx	530	renderThread = new RenderThread(paintArea, graphics, renderer,
57	alfonx	533	worldToScreen, envelope);
58	alfonx	530	renderThread.start();
59	alfonx	510
60	alfonx	530	return true;
61			} else {
62	alfonx	532	// System.out.println("is busy... requesting stop!");
63	alfonx	530	renderThread.getRenderer().stopRendering();
64	alfonx	532	return false;
65	alfonx	530	}
66			}
67
68	alfonx	532	/**
69			* For every new rendering job submitted and accepted, an instance of this
70			* {@link Thread} will be started.
71			*
72			*/
73	alfonx	530	class RenderThread extends Thread {
74
75			private final GTRenderer renderer;
76
77			public RenderThread(final Rectangle paintArea,
78			final Graphics2D graphics, GTRenderer renderer,
79	alfonx	533	AffineTransform worldToScreen, ReferencedEnvelope mapEnv) {
80	alfonx	539	super(new RenderRun(paintArea, graphics, renderer, mapEnv,
81			worldToScreen));
82	alfonx	529	this.renderer = renderer;
83	alfonx	530
84	alfonx	532	setName("Render" + getName());
85
86			// System.out.println("starting render thread " + getName());
87	alfonx	529	}
88	alfonx	530
89			public GTRenderer getRenderer() {
90	alfonx	529	return renderer;
91			}
92
93	alfonx	530	}
94
95	alfonx	532	/**
96			* This {@link Runnable} will actually start the rendering
97			*/
98	alfonx	530	class RenderRun implements Runnable, RenderListener {
99			private final Rectangle paintArea;
100	alfonx	529	private final Graphics2D graphics;
101			private final AffineTransform worldToScreen;
102			private final GTRenderer renderer;
103	alfonx	533	private final ReferencedEnvelope mapEnv;
104	alfonx	510
105	alfonx	529	public RenderRun(Rectangle paintArea, Graphics2D graphics,
106	alfonx	539	GTRenderer renderer, ReferencedEnvelope mapEnv,
107			AffineTransform worldToScreen) {
108	alfonx	530	this.paintArea = paintArea;
109			this.graphics = graphics;
110			this.renderer = renderer;
111	alfonx	533	this.mapEnv = mapEnv;
112	alfonx	530	this.worldToScreen = worldToScreen;
113	alfonx	529	}
114	alfonx	530
115	alfonx	529	@Override
116			public void run() {
117			try {
118	alfonx	530	renderer.addRenderListener(this);
119			System.out.println("start rendering...");
120	alfonx	532	// try {
121			// Thread.sleep(1000);
122			// } catch (InterruptedException e) {
123			// e.printStackTrace();
124			// }
125
126			// Clear the graphics context
127			graphics.setBackground(mapPane.getMapBackgroundColor());
128			graphics.clearRect(paintArea.x, paintArea.y, paintArea.width,
129			paintArea.height);
130
131	alfonx	539	renderer.paint(graphics, paintArea, worldToScreen);
132	alfonx	530
133	alfonx	539	// Kill the reference to this Thread so #isRunning will say
134			// false directly
135	alfonx	533	renderThread = null;
136			mapPane.onRenderingCompleted();
137	alfonx	539	} catch (Exception e) {
138			mapPane.onRenderingFailed(e);
139	alfonx	530	} finally {
140			renderer.removeRenderListener(this);
141			}
142	alfonx	529	}
143	alfonx	530
144	alfonx	529	@Override
145			public void errorOccurred(Exception e) {
146			mapPane.onRenderingFailed(e);
147			}
148	alfonx	510
149	alfonx	529	@Override
150			public void featureRenderer(SimpleFeature feature) {
151			}
152	alfonx	510
153	alfonx	530	}
154
155	alfonx	532	/**
156			* Ask to stop the rendering. May be called often.
157			*/
158	alfonx	529	public void cancelTask() {
159	alfonx	530	if (renderThread != null && renderThread.isAlive()) {
160			// System.out.println("request stop for thread " +task.getName());
161			renderThread.getRenderer().stopRendering();
162	alfonx	529	}
163			}
164	alfonx	510
165	alfonx	532	/**
166			* @return <code>true</code> if the {@link Thread} is busy rendering.
167			*/
168	alfonx	529	public boolean isRunning() {
169	alfonx	530	return (renderThread != null && renderThread.isAlive());
170	alfonx	529	}
171	alfonx	510
172	alfonx	532	/**
173			* Will stop rendering and remove the reference to the {@link Thread}.
174			*/
175	alfonx	529	public void dispose() {
176	alfonx	530	if (renderThread != null) {
177			renderThread.renderer.stopRendering();
178			renderThread = null;
179	alfonx	529	}
180			}
181	alfonx	510
182			}