org.springframework.richclient.application.splash.SimpleSplashScreen.java Source code

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Here is the source code for org.springframework.richclient.application.splash.SimpleSplashScreen.java

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/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.richclient.application.splash;

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import java.io.IOException;
import java.net.URL;

import javax.swing.JPanel;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;

/**
 * A lightweight splash-screen for display when a GUI application is being
 * initialized.
 * <p>
 * The splash screen renders an image in a Frame. It minimizes class loading so
 * it is displayed immediately once the application is started.
 * 
 * @author Keith Donald
 * @author Jan Hoskens
 */
public class SimpleSplashScreen extends AbstractSplashScreen {
    private Image image;

    private Resource imageResourcePath;

    private static final Log logger = LogFactory.getLog(SimpleSplashScreen.class);

    /**
     * Creates a new uninitialized {@code SimpleSplashScreen}.
     */
    public SimpleSplashScreen() {
        // do nothing
    }

    /**
     * Creates a new {@code SimpleSplashScreen} that will display the image at
     * the specified location.
     * 
     * @param imageResourcePath The location of the image file to be displayed
     * by this splash screen.
     * 
     * @see #setImageResourcePath(String)
     */
    public SimpleSplashScreen(Resource imageResourcePath) {
        setImageResourcePath(imageResourcePath);
    }

    /**
     * Creates a new {@code SimpleSplashScreen} that will display the given
     * image.
     * 
     * @param image the image to splash.
     * 
     * @throws IllegalArgumentException if {@code image} is null.
     */
    public SimpleSplashScreen(Image image) {
        Assert.notNull(image, "The splash screen image is required");
        this.image = image;
    }

    /**
     * Sets the location of the image to be displayed by this splash screen. If
     * the given path starts with a '/', it is interpreted to be relative to the
     * root of the runtime classpath. Otherwise it is interpreted to be relative
     * to the subdirectory of the classpath root that corresponds to the package
     * of this class.
     * 
     * @param path The path to the splash screen image.
     */
    public void setImageResourcePath(Resource path) {
        Assert.notNull(path, "The splash screen image resource path is required");
        this.imageResourcePath = path;
    }

    /**
     * Load image from path.
     * 
     * @param path Path to image.
     * @return Image
     * @throws IOException
     * 
     * @throws NullPointerException if {@code path} is null.
     */
    private Image loadImage(Resource path) throws IOException {
        URL url = path.getURL();
        if (url == null) {
            logger.warn("Unable to locate splash screen in classpath at: " + path);
            return null;
        }
        return Toolkit.getDefaultToolkit().createImage(url);
    }

    protected Image getImage() {
        if (image == null && imageResourcePath != null) {
            try {
                image = loadImage(imageResourcePath);
            } catch (IOException e) {
                logger.error("Unable to load image from resource " + imageResourcePath, e);
            }
        }
        return image;
    }

    /**
     * Simple Canvas that paints an image.
     */
    public class ImageCanvas extends JPanel {
        private static final long serialVersionUID = -5096223464173393949L;

        private Image image;

        /**
         * Creates a new {@code ImageCanvas} with the specified image. The size
         * of the canvas will be set to the size of the image.
         * 
         * @param image The image to be displayed by the canvas.
         * 
         * @throws NullPointerException if {@code image} is null.
         */
        public ImageCanvas(Image image) {
            this.image = image;

            loadImage();

            Dimension size = new Dimension(image.getWidth(null), image.getHeight(null));

            setSize(size);
            setPreferredSize(size);
            setMinimumSize(size);
        }

        private void loadImage() {
            MediaTracker mediaTracker = new MediaTracker(this);
            mediaTracker.addImage(image, 0);
            try {
                mediaTracker.waitForID(0);
            } catch (InterruptedException e) {
                logger.warn("Interrupted while waiting for splash image to load.", e);
            }
        }

        public void paintComponent(Graphics g) {
            g.clearRect(0, 0, getWidth(), getHeight());
            g.drawImage(image, 0, 0, this);
        }
    }

    /**
     * Returns a component that displays an image in a canvas.
     */
    protected Component createContentPane() {
        Image image = getImage();
        if (image != null) {
            return new ImageCanvas(image);
        }
        return null;
    }
}