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	package skrueger.geotools;
2
3	import java.awt.Graphics2D;
4	import java.awt.Rectangle;
5	import java.awt.geom.AffineTransform;
6
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	/**
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	private volatile RenderThread renderThread;
23
24	private final XMapPane mapPane;
25
26	public RenderingExecutor(XMapPane mapPane) {
27	this.mapPane = mapPane;
28	}
29
30	/**
31	* Submit a new rendering task. If no rendering task is presently running
32	* this new job will be accepted; otherwise it will be rejected and it
33	* returns <code>false</code>.
34	*
35	* @param envelope
36	* the map area (world coordinates) to be rendered.
37	* @param graphics
38	* 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	*
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	// System.out.println("is vacant... starting thread!");
54	renderThread = null;
55
56	renderThread = new RenderThread(paintArea, graphics, renderer,
57	worldToScreen, envelope);
58	renderThread.start();
59
60	return true;
61	} else {
62	// System.out.println("is busy... requesting stop!");
63	renderThread.getRenderer().stopRendering();
64	return false;
65	}
66	}
67
68	/**
69	* For every new rendering job submitted and accepted, an instance of this
70	* {@link Thread} will be started.
71	*
72	*/
73	class RenderThread extends Thread {
74
75	private final GTRenderer renderer;
76
77	public RenderThread(final Rectangle paintArea,
78	final Graphics2D graphics, GTRenderer renderer,
79	AffineTransform worldToScreen, ReferencedEnvelope mapEnv) {
80	super(new RenderRun(paintArea, graphics, renderer, mapEnv,
81	worldToScreen));
82	this.renderer = renderer;
83
84	setName("Render" + getName());
85
86	// System.out.println("starting render thread " + getName());
87	}
88
89	public GTRenderer getRenderer() {
90	return renderer;
91	}
92
93	}
94
95	/**
96	* This {@link Runnable} will actually start the rendering
97	*/
98	class RenderRun implements Runnable, RenderListener {
99	private final Rectangle paintArea;
100	private final Graphics2D graphics;
101	private final AffineTransform worldToScreen;
102	private final GTRenderer renderer;
103	private final ReferencedEnvelope mapEnv;
104
105	public RenderRun(Rectangle paintArea, Graphics2D graphics,
106	GTRenderer renderer, ReferencedEnvelope mapEnv,
107	AffineTransform worldToScreen) {
108	this.paintArea = paintArea;
109	this.graphics = graphics;
110	this.renderer = renderer;
111	this.mapEnv = mapEnv;
112	this.worldToScreen = worldToScreen;
113	}
114
115	@Override
116	public void run() {
117	try {
118	renderer.addRenderListener(this);
119	System.out.println("start rendering...");
120	// 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	renderer.paint(graphics, paintArea, worldToScreen);
132
133	// Kill the reference to this Thread so #isRunning will say
134	// false directly
135	renderThread = null;
136	mapPane.onRenderingCompleted();
137	} catch (Exception e) {
138	mapPane.onRenderingFailed(e);
139	} finally {
140	renderer.removeRenderListener(this);
141	}
142	}
143
144	@Override
145	public void errorOccurred(Exception e) {
146	mapPane.onRenderingFailed(e);
147	}
148
149	@Override
150	public void featureRenderer(SimpleFeature feature) {
151	}
152
153	}
154
155	/**
156	* Ask to stop the rendering. May be called often.
157	*/
158	public void cancelTask() {
159	if (renderThread != null && renderThread.isAlive()) {
160	// System.out.println("request stop for thread " +task.getName());
161	renderThread.getRenderer().stopRendering();
162	}
163	}
164
165	/**
166	* @return <code>true</code> if the {@link Thread} is busy rendering.
167	*/
168	public boolean isRunning() {
169	return (renderThread != null && renderThread.isAlive());
170	}
171
172	/**
173	* Will stop rendering and remove the reference to the {@link Thread}.
174	*/
175	public void dispose() {
176	if (renderThread != null) {
177	renderThread.renderer.stopRendering();
178	renderThread = null;
179	}
180	}
181
182	}