swtresourcemanager.java

一个基于JAVA技术的销售信息管理系统

package com.swtdesigner;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

/**
 * Utility class for managing OS resources associated with SWT controls such as
 * colors, fonts, images, etc.
 * 
 * !!! IMPORTANT !!! Application code must explicitly invoke the <code>dispose()</code>
 * method to release the operating system resources managed by cached objects
 * when those objects and OS resources are no longer needed (e.g. on
 * application shutdown)
 * 
 * This class may be freely distributed as part of any application or plugin.
 * <p>
 * Copyright (c) 2003 - 2005, Instantiations, Inc. <br>All Rights Reserved
 * 
 * @author scheglov_ke
 * @author Dan Rubel
 */
public class SWTResourceManager {

    /**
     * Dispose of cached objects and their underlying OS resources. This should
     * only be called when the cached objects are no longer needed (e.g. on
     * application shutdown)
     */
    public static void dispose() {
        disposeColors();
        disposeFonts();
        disposeImages();
        disposeCursors();
    }

    //////////////////////////////
    // Color support
    //////////////////////////////

    /**
     * Maps RGB values to colors
     */
    private static HashMap m_ColorMap = new HashMap();

    /**
     * Returns the system color matching the specific ID
     * @param systemColorID int The ID value for the color
     * @return Color The system color matching the specific ID
     */
    public static Color getColor(int systemColorID) {
        Display display = Display.getCurrent();
        return display.getSystemColor(systemColorID);
    }

    /**
     * Returns a color given its red, green and blue component values
     * @param r int The red component of the color
     * @param g int The green component of the color
     * @param b int The blue component of the color
     * @return Color The color matching the given red, green and blue componet values
     */
    public static Color getColor(int r, int g, int b) {
        return getColor(new RGB(r, g, b));
    }

    /**
     * Returns a color given its RGB value
     * @param rgb RGB The RGB value of the color
     * @return Color The color matching the RGB value
     */
    public static Color getColor(RGB rgb) {
        Color color = (Color) m_ColorMap.get(rgb);
        if (color == null) {
            Display display = Display.getCurrent();
            color = new Color(display, rgb);
            m_ColorMap.put(rgb, color);
        }
        return color;
    }

    /**
     * Dispose of all the cached colors
     */
    public static void disposeColors() {
        for (Iterator iter = m_ColorMap.values().iterator(); iter.hasNext();)
             ((Color) iter.next()).dispose();
        m_ColorMap.clear();
    }

    //////////////////////////////
    // Image support
    //////////////////////////////

	/**
	 * Maps image names to images
	 */
    private static HashMap m_ClassImageMap = new HashMap();

	/**
	 * Maps images to image decorators
	 */
    private static HashMap m_ImageToDecoratorMap = new HashMap();

    /**
     * Clears images loaded relative to the class with given name.
     */
    public static void clearImages(String className) {
		for (Iterator I = m_ClassImageMap.entrySet().iterator(); I.hasNext();) {
			Map.Entry entry = (Map.Entry) I.next();
			String key = (String) entry.getKey();
			if (key.startsWith(className + "|")) {
				try {
					((Image) entry.getValue()).dispose();
				} catch (Throwable e) {
				}
				I.remove();
			}
		}
	}
    
    /**
     * Returns an image encoded by the specified input stream
     * @param is InputStream The input stream encoding the image data
     * @return Image The image encoded by the specified input stream
     */
    protected static Image getImage(InputStream is) {
        Display display = Display.getCurrent();
        ImageData data = new ImageData(is);
        if (data.transparentPixel > 0)
            return new Image(display, data, data.getTransparencyMask());
        return new Image(display, data);
    }

    /**
     * Returns an image stored in the file at the specified path
     * @param path String The path to the image file
     * @return Image The image stored in the file at the specified path
     */
    public static Image getImage(String path) {
    	return getImage("default", path); //$NON-NLS-1$
    }

    /**
     * Returns an image stored in the file at the specified path
     * @param section The section to which belongs specified image
     * @param path String The path to the image file
     * @return Image The image stored in the file at the specified path
     */
    public static Image getImage(String section, String path) {
        String key = section + '|' + SWTResourceManager.class.getName() + '|' + path;
        Image image = (Image) m_ClassImageMap.get(key);
        if (image == null) {
            try {
                FileInputStream fis = new FileInputStream(path);
                image = getImage(fis);
                m_ClassImageMap.put(key, image);
                fis.close();
            } catch (Exception e) {
            	image = getMissingImage();
            	m_ClassImageMap.put(key, image);
            }
        }
        return image;
    }

    /**
     * Returns an image stored in the file at the specified path relative to the specified class
     * @param clazz Class The class relative to which to find the image
     * @param path String The path to the image file
     * @return Image The image stored in the file at the specified path
     */
    public static Image getImage(Class clazz, String path) {
        String key = clazz.getName() + '|' + path;
        Image image = (Image) m_ClassImageMap.get(key);
        if (image == null) {
        	try {
        		if (path.length() > 0 && path.charAt(0) == '/') {
        			String newPath = path.substring(1, path.length());
        			image = getImage(new BufferedInputStream(clazz.getClassLoader().getResourceAsStream(newPath)));
        		} else {
        			image = getImage(clazz.getResourceAsStream(path));
        		}
        		m_ClassImageMap.put(key, image);
        	} catch (Exception e) {
        		image = getMissingImage();
        		m_ClassImageMap.put(key, image);
        	}
        }
        return image;
    }

    private static final int MISSING_IMAGE_SIZE = 10;
	private static Image getMissingImage() {
		Image image = new Image(Display.getCurrent(), MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE);
		//
		GC gc = new GC(image);
		gc.setBackground(getColor(SWT.COLOR_RED));
		gc.fillRectangle(0, 0, MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE);
		gc.dispose();
		//
		return image;
	}

    /**
     * Style constant for placing decorator image in top left corner of base image.
     */
    public static final int TOP_LEFT = 1;
    /**
     * Style constant for placing decorator image in top right corner of base image.
     */
    public static final int TOP_RIGHT = 2;
    /**
     * Style constant for placing decorator image in bottom left corner of base image.
     */
    public static final int BOTTOM_LEFT = 3;
    /**
     * Style constant for placing decorator image in bottom right corner of base image.
     */
    public static final int BOTTOM_RIGHT = 4;
    
    /**
     * Returns an image composed of a base image decorated by another image
     * @param baseImage Image The base image that should be decorated
     * @param decorator Image The image to decorate the base image
     * @return Image The resulting decorated image
     */