skrueger/geotools/RenderingExecutor.java

package skrueger.geotools;

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

import org.apache.log4j.Logger;
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 {
        private final static Logger LOGGER = Logger.getLogger(RenderingExecutor.class);
        /**
         * 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() {
                        long startT = System.currentTimeMillis();
                        try {
                                renderer.addRenderListener(this);
                                LOGGER.debug("start rendering...");

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

                                renderer.paint(graphics, paintArea, mapEnv);

                                // Kill the reference to this Thread so #isRunning will say
                                // false directly
                                renderThread = null;
                                mapPane.onRenderingCompleted(startT-System.currentTimeMillis());
                        } 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)
                        synchronized (renderThread) {
                                if (renderThread.isAlive()) {
                                        if (renderThread.getRenderer() != null)
                                                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	alfonx	555	import org.apache.log4j.Logger;
8	alfonx	510	import org.geotools.geometry.jts.ReferencedEnvelope;
9			import org.geotools.renderer.GTRenderer;
10			import org.geotools.renderer.RenderListener;
11			import org.opengis.feature.simple.SimpleFeature;
12
13	alfonx	532	/**
14			* This class is used by {@link XMapPane} to start and stop the rendering a
15			* {@link Thread} for rendering.
16			*/
17			class RenderingExecutor {
18	alfonx	555	private final static Logger LOGGER = Logger.getLogger(RenderingExecutor.class);
19	alfonx	532	/**
20			* Instance to a {@link RenderThread} doing any work. It's volatile so the
21			* correct value will always be visible to any {@link Thread}
22			**/
23	alfonx	530	private volatile RenderThread renderThread;
24	alfonx	532
25	alfonx	530	private final XMapPane mapPane;
26
27	alfonx	529	public RenderingExecutor(XMapPane mapPane) {
28			this.mapPane = mapPane;
29	alfonx	530	}
30	alfonx	510
31	alfonx	530	/**
32			* Submit a new rendering task. If no rendering task is presently running
33	alfonx	532	* this new job will be accepted; otherwise it will be rejected and it
34			* returns <code>false</code>.
35	alfonx	530	*
36			* @param envelope
37	alfonx	532	* the map area (world coordinates) to be rendered.
38	alfonx	530	* @param graphics
39	alfonx	532	* the graphics object to draw on.
40			* @param paintArea
41			* size of the area to paint the world into.
42			* @param worldToScreen
43			* the {@link AffineTransform} from world coordinates to screen
44			* coordinates.
45			* @param renderer
46			* the {@link GTRenderer} to use.
47	alfonx	530	*
48			* @return true if the rendering task was accepted; false if it was rejected
49			*/
50			public synchronized boolean submit(ReferencedEnvelope envelope,
51	alfonx	555	Rectangle paintArea, Graphics2D graphics, final GTRenderer renderer
52			// , AffineTransform worldToScreen
53			) {
54	alfonx	530	if (renderThread == null \|\| !renderThread.isAlive()) {
55	alfonx	532	// System.out.println("is vacant... starting thread!");
56			renderThread = null;
57	alfonx	510
58	alfonx	530	renderThread = new RenderThread(paintArea, graphics, renderer,
59	alfonx	555	// worldToScreen,
60	alfonx	544	envelope);
61	alfonx	530	renderThread.start();
62	alfonx	510
63	alfonx	530	return true;
64			} else {
65	alfonx	532	// System.out.println("is busy... requesting stop!");
66	alfonx	530	renderThread.getRenderer().stopRendering();
67	alfonx	532	return false;
68	alfonx	530	}
69			}
70
71	alfonx	532	/**
72			* For every new rendering job submitted and accepted, an instance of this
73			* {@link Thread} will be started.
74			*
75			*/
76	alfonx	530	class RenderThread extends Thread {
77
78			private final GTRenderer renderer;
79
80			public RenderThread(final Rectangle paintArea,
81			final Graphics2D graphics, GTRenderer renderer,
82	alfonx	555	// AffineTransform worldToScreen,
83	alfonx	544	ReferencedEnvelope mapEnv) {
84	alfonx	555	super(new RenderRun(paintArea, graphics, renderer, mapEnv
85			// , worldToScreen
86	alfonx	544	));
87	alfonx	529	this.renderer = renderer;
88	alfonx	530
89	alfonx	532	setName("Render" + getName());
90
91			// System.out.println("starting render thread " + getName());
92	alfonx	529	}
93	alfonx	530
94			public GTRenderer getRenderer() {
95	alfonx	529	return renderer;
96			}
97
98	alfonx	530	}
99
100	alfonx	532	/**
101			* This {@link Runnable} will actually start the rendering
102			*/
103	alfonx	530	class RenderRun implements Runnable, RenderListener {
104			private final Rectangle paintArea;
105	alfonx	529	private final Graphics2D graphics;
106	alfonx	555	// private final AffineTransform worldToScreen;
107	alfonx	529	private final GTRenderer renderer;
108	alfonx	533	private final ReferencedEnvelope mapEnv;
109	alfonx	510
110	alfonx	529	public RenderRun(Rectangle paintArea, Graphics2D graphics,
111	alfonx	544	GTRenderer renderer, ReferencedEnvelope mapEnv
112	alfonx	555	// ,
113			// AffineTransform worldToScreen
114			) {
115	alfonx	530	this.paintArea = paintArea;
116			this.graphics = graphics;
117			this.renderer = renderer;
118	alfonx	533	this.mapEnv = mapEnv;
119	alfonx	555	// this.worldToScreen = worldToScreen;
120	alfonx	529	}
121	alfonx	530
122	alfonx	529	@Override
123			public void run() {
124	alfonx	580	long startT = System.currentTimeMillis();
125	alfonx	529	try {
126	alfonx	530	renderer.addRenderListener(this);
127	alfonx	555	LOGGER.debug("start rendering...");
128	alfonx	532
129			// Clear the graphics context
130			graphics.setBackground(mapPane.getMapBackgroundColor());
131			graphics.clearRect(paintArea.x, paintArea.y, paintArea.width,
132			paintArea.height);
133
134	alfonx	544	renderer.paint(graphics, paintArea, mapEnv);
135	alfonx	530
136	alfonx	539	// Kill the reference to this Thread so #isRunning will say
137			// false directly
138	alfonx	533	renderThread = null;
139	alfonx	580	mapPane.onRenderingCompleted(startT-System.currentTimeMillis());
140	alfonx	539	} catch (Exception e) {
141			mapPane.onRenderingFailed(e);
142	alfonx	530	} finally {
143			renderer.removeRenderListener(this);
144			}
145	alfonx	529	}
146	alfonx	530
147	alfonx	529	@Override
148			public void errorOccurred(Exception e) {
149			mapPane.onRenderingFailed(e);
150			}
151	alfonx	510
152	alfonx	529	@Override
153			public void featureRenderer(SimpleFeature feature) {
154			}
155	alfonx	510
156	alfonx	530	}
157
158	alfonx	532	/**
159			* Ask to stop the rendering. May be called often.
160			*/
161	alfonx	529	public void cancelTask() {
162	alfonx	555	if (renderThread != null)
163			synchronized (renderThread) {
164			if (renderThread.isAlive()) {
165			if (renderThread.getRenderer() != null)
166			renderThread.getRenderer().stopRendering();
167			}
168			}
169	alfonx	529	}
170	alfonx	510
171	alfonx	532	/**
172			* @return <code>true</code> if the {@link Thread} is busy rendering.
173			*/
174	alfonx	529	public boolean isRunning() {
175	alfonx	530	return (renderThread != null && renderThread.isAlive());
176	alfonx	529	}
177	alfonx	510
178	alfonx	532	/**
179			* Will stop rendering and remove the reference to the {@link Thread}.
180			*/
181	alfonx	529	public void dispose() {
182	alfonx	530	if (renderThread != null) {
183			renderThread.renderer.stopRendering();
184			renderThread = null;
185	alfonx	529	}
186			}
187	alfonx	510
188			}