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() {
                        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();
                        } 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	package skrueger.geotools;
2
3	import java.awt.Graphics2D;
4	import java.awt.Rectangle;
5	import java.awt.geom.AffineTransform;
6
7	import org.apache.log4j.Logger;
8	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	/**
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	private final static Logger LOGGER = Logger.getLogger(RenderingExecutor.class);
19	/**
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	private volatile RenderThread renderThread;
24
25	private final XMapPane mapPane;
26
27	public RenderingExecutor(XMapPane mapPane) {
28	this.mapPane = mapPane;
29	}
30
31	/**
32	* Submit a new rendering task. If no rendering task is presently running
33	* this new job will be accepted; otherwise it will be rejected and it
34	* returns <code>false</code>.
35	*
36	* @param envelope
37	* the map area (world coordinates) to be rendered.
38	* @param graphics
39	* 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	*
48	* @return true if the rendering task was accepted; false if it was rejected
49	*/
50	public synchronized boolean submit(ReferencedEnvelope envelope,
51	Rectangle paintArea, Graphics2D graphics, final GTRenderer renderer
52	// , AffineTransform worldToScreen
53	) {
54	if (renderThread == null \|\| !renderThread.isAlive()) {
55	// System.out.println("is vacant... starting thread!");
56	renderThread = null;
57
58	renderThread = new RenderThread(paintArea, graphics, renderer,
59	// worldToScreen,
60	envelope);
61	renderThread.start();
62
63	return true;
64	} else {
65	// System.out.println("is busy... requesting stop!");
66	renderThread.getRenderer().stopRendering();
67	return false;
68	}
69	}
70
71	/**
72	* For every new rendering job submitted and accepted, an instance of this
73	* {@link Thread} will be started.
74	*
75	*/
76	class RenderThread extends Thread {
77
78	private final GTRenderer renderer;
79
80	public RenderThread(final Rectangle paintArea,
81	final Graphics2D graphics, GTRenderer renderer,
82	// AffineTransform worldToScreen,
83	ReferencedEnvelope mapEnv) {
84	super(new RenderRun(paintArea, graphics, renderer, mapEnv
85	// , worldToScreen
86	));
87	this.renderer = renderer;
88
89	setName("Render" + getName());
90
91	// System.out.println("starting render thread " + getName());
92	}
93
94	public GTRenderer getRenderer() {
95	return renderer;
96	}
97
98	}
99
100	/**
101	* This {@link Runnable} will actually start the rendering
102	*/
103	class RenderRun implements Runnable, RenderListener {
104	private final Rectangle paintArea;
105	private final Graphics2D graphics;
106	// private final AffineTransform worldToScreen;
107	private final GTRenderer renderer;
108	private final ReferencedEnvelope mapEnv;
109
110	public RenderRun(Rectangle paintArea, Graphics2D graphics,
111	GTRenderer renderer, ReferencedEnvelope mapEnv
112	// ,
113	// AffineTransform worldToScreen
114	) {
115	this.paintArea = paintArea;
116	this.graphics = graphics;
117	this.renderer = renderer;
118	this.mapEnv = mapEnv;
119	// this.worldToScreen = worldToScreen;
120	}
121
122	@Override
123	public void run() {
124	try {
125	renderer.addRenderListener(this);
126	LOGGER.debug("start rendering...");
127
128	// Clear the graphics context
129	graphics.setBackground(mapPane.getMapBackgroundColor());
130	graphics.clearRect(paintArea.x, paintArea.y, paintArea.width,
131	paintArea.height);
132
133	renderer.paint(graphics, paintArea, mapEnv);
134
135	// Kill the reference to this Thread so #isRunning will say
136	// false directly
137	renderThread = null;
138	mapPane.onRenderingCompleted();
139	} catch (Exception e) {
140	mapPane.onRenderingFailed(e);
141	} finally {
142	renderer.removeRenderListener(this);
143	}
144	}
145
146	@Override
147	public void errorOccurred(Exception e) {
148	mapPane.onRenderingFailed(e);
149	}
150
151	@Override
152	public void featureRenderer(SimpleFeature feature) {
153	}
154
155	}
156
157	/**
158	* Ask to stop the rendering. May be called often.
159	*/
160	public void cancelTask() {
161	if (renderThread != null)
162	synchronized (renderThread) {
163	if (renderThread.isAlive()) {
164	if (renderThread.getRenderer() != null)
165	renderThread.getRenderer().stopRendering();
166	}
167	}
168	}
169
170	/**
171	* @return <code>true</code> if the {@link Thread} is busy rendering.
172	*/
173	public boolean isRunning() {
174	return (renderThread != null && renderThread.isAlive());
175	}
176
177	/**
178	* Will stop rendering and remove the reference to the {@link Thread}.
179	*/
180	public void dispose() {
181	if (renderThread != null) {
182	renderThread.renderer.stopRendering();
183	renderThread = null;
184	}
185	}
186
187	}