resources.java

j2me设计的界面包

/*
 * Copyright 2008 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */
package com.sun.lwuit.util;

import com.sun.lwuit.Font;
import com.sun.lwuit.Image;
import com.sun.lwuit.IndexedImage;
import com.sun.lwuit.StaticAnimation;
import com.sun.lwuit.plaf.Border;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

/**
 * Loads resources from the binary resource file generated during the build process.
 * A resource is loaded entirely into memory since random file access is not supported
 * in Java ME, any other approach would be inefficient. This means that memory must
 * be made available to accomodate the resource file. 
 * 
 * @author Shai Almog
 */
public class Resources {
    /**
     * Magic numbers to prevent data corruption
     */
    static final byte MAGIC_IMAGE = (byte)0xF3;
    static final byte MAGIC_PACKED_IMAGE8 = (byte)0xF4;
    static final byte MAGIC_FONT = (byte)0xF6;
    static final byte MAGIC_THEME = (byte)0xF7;
    static final byte MAGIC_ANIMATION = (byte)0xF8;
    static final byte MAGIC_L10N = (byte)0xF9;
    static final byte MAGIC_DATA = (byte)0xFA;
    static final byte MAGIC_PACKED_FONT = (byte)0xFB;
    
    /**
     * Temporary member for compatibility with older versions, in future versions
     * this will superceed the MAGIC_THEME property
     */
    static final byte MAGIC_THEME_2 = (byte)0xF2;
    
    static final int BORDER_TYPE_EMPTY = 0;
    static final int BORDER_TYPE_LINE = 1;
    static final int BORDER_TYPE_ROUNDED = 2;
    static final int BORDER_TYPE_ETCHED_LOWERED = 4;
    static final int BORDER_TYPE_ETCHED_RAISED = 5;
    static final int BORDER_TYPE_BEVEL_RAISED = 6;
    static final int BORDER_TYPE_BEVEL_LOWERED = 7;
    static final int BORDER_TYPE_IMAGE = 8;

    // for use by the resource editor
    private static Class classLoader = Resources.class;
    
    static void setClassLoader(Class cls) {
        classLoader = cls;
    }
    
    /**
     * Hashtable containing the mapping between element types and their names in the
     * resource hashtable
     */
    private Hashtable resourceTypes = new Hashtable();
    
    /**
     * A cache within the resource allowing us to preserve some resources in memory
     * so they can be utilized by a theme when it is loaded
     */
    private Hashtable resources = new Hashtable();
    
    private DataInputStream input; 
    
    // for internal use by the resource editor, creates an empty resource
    Resources() {
    }
    
    Resources(InputStream input) throws IOException {
        openFile(input);
    }
    
    void clear() {
        resourceTypes.clear();
        resources.clear();
        input = null;
    }
    
    void openFile(InputStream input) throws IOException {
        clear();
        this.input = new DataInputStream(input);
        int resourceCount = this.input.readShort();
        for(int iter = 0 ; iter < resourceCount ; iter++) {
            byte magic = this.input.readByte();
            String id = this.input.readUTF();
            switch(magic) {
                case MAGIC_IMAGE:
                    setResource(id, magic, createImage());
                    continue;
                case MAGIC_PACKED_IMAGE8:
                    setResource(id, magic, createPackedImage8());
                    continue;
                case MAGIC_THEME:
                case MAGIC_THEME_2: 
                    setResource(id, MAGIC_THEME_2, loadTheme(id, magic == MAGIC_THEME_2));
                    continue;
                case MAGIC_FONT:
                    setResource(id, magic, loadFont(id, false));
                    continue;
                case MAGIC_PACKED_FONT:
                    setResource(id, magic, loadFont(id, true));
                    continue;
                case MAGIC_ANIMATION:
                    setResource(id, magic, loadAnimation(id, this.input));
                    continue;
                case MAGIC_DATA:
                    setResource(id, magic, createData());
                    continue;
                case MAGIC_L10N:
                    setResource(id, magic, loadL10N());
                    continue;
                default:
                    throw new IOException("Corrupt theme file unrecognized magic number: " + Integer.toHexString(magic & 0xff));
            }
        }
    }
    
    /**
     * Returns the names of the resources within this bundle
     * 
     * @return array of names of all the resources in this bundle
     */
    public String[] getResourceNames() {
        String[] arr = new String[resourceTypes.size()];
        Enumeration e = resourceTypes.keys();
        for(int iter = 0 ; iter < arr.length ; iter++) {
            arr[iter] = (String)e.nextElement();
        }
        return arr;
    }

    /**
     * Returns the names of the data resources within this bundle
     * 
     * @return array of names of the data resources in this bundle
     */
    public String[] getDataResourceNames() {
        return getResourceTypeNames(MAGIC_DATA);
    }

    /**
     * For internal use only
     */
    void setResource(String id, byte type, Object value) {
        if(value == null) {
            resources.remove(id);
            resourceTypes.remove(id);
        } else {
            resources.put(id, value);
            resourceTypes.put(id, new Byte(type));
        }
    }
    

    /**
     * Returns the names of the localization bundles within this bundle
     * 
     * @return array of names of the localization resources in this bundle
     */
    public String[] getL10NResourceNames() {
        return getResourceTypeNames(MAGIC_L10N);
    }

    /**
     * Returns the names of the fonts within this bundle
     * 
     * @return array of names of the font resources in this bundle
     */
    public String[] getFontResourceNames() {
        Vector vec = new Vector();
        Enumeration e = resourceTypes.keys();
        while(e.hasMoreElements()) {
            String c = (String)e.nextElement();
            if(isFont(c)) {
                vec.addElement(c);
            }
        }
        return toStringArray(vec);
    }

    /**
     * Returns the names of the images within this bundle
     * 
     * @return array of names of the image resources in this bundle
     */
    public String[] getThemeResourceNames() {
        Vector vec = new Vector();
        Enumeration e = resourceTypes.keys();
        while(e.hasMoreElements()) {
            String c = (String)e.nextElement();
            if(isTheme(c)) {
                vec.addElement(c);
            }
        }
        return toStringArray(vec);
    }

    /**
     * Returns the names of the images within this bundle
     * 
     * @return array of names of the image resources in this bundle
     */
    public String[] getImageResourceNames() {
        Vector vec = new Vector();
        Enumeration e = resourceTypes.keys();
        while(e.hasMoreElements()) {
            String c = (String)e.nextElement();
            if(isImage(c)) {
                vec.addElement(c);
            }
        }
        return toStringArray(vec);
    }

    /**
     * Returns the names of the animations within this bundle
     * 
     * @return array of names of the animation resources in this bundle
     */
    public String[] getAnimationResourceNames() {
        return getResourceTypeNames(MAGIC_ANIMATION);
    }
    
    /**
     * For internal use only
     */
    byte getResourceType(String name) {
        return ((Byte)resourceTypes.get(name)).byteValue();
    }
    
    private String[] getResourceTypeNames(byte b) {
        Vector vec = new Vector();
        Enumeration e = resourceTypes.keys();
        while(e.hasMoreElements()) {
            String c = (String)e.nextElement();
            if(((Byte)resourceTypes.get(c)).byteValue() == b) {
                vec.addElement(c);
            }
        }
        return toStringArray(vec);
    }

    private static String[] toStringArray(Vector v) {
        String[] s = new String[v.size()];
        for(int iter = 0 ; iter < s.length ; iter++) {
            s[iter] = (String)v.elementAt(iter);
        }
        return s;
    }

    /**
     * Returns true if this is a generic data resource
     * 
     * @param name the name of the resource
     * @return true if the resource is a data resource
     * @throws NullPointerException if the resource doesn't exist
     */
    public boolean isL10N(String name) {
        byte b = ((Byte)resourceTypes.get(name)).byteValue();
        return b == MAGIC_L10N;
    }
    
    /**
     * Returns true if this is a theme resource
     * 
     * @param name the name of the resource
     * @return true if the resource is a theme
     * @throws NullPointerException if the resource doesn't exist
     */
    public boolean isTheme(String name) {
        byte b = ((Byte)resourceTypes.get(name)).byteValue();
        return b == MAGIC_THEME || b == MAGIC_THEME_2;
    }

    /**
     * Returns true if this is a font resource
     * 
     * @param name the name of the resource
     * @return true if the resource is a font
     * @throws NullPointerException if the resource doesn't exist
     */
    public boolean isFont(String name) {
        byte b = ((Byte)resourceTypes.get(name)).byteValue();
        return b == MAGIC_FONT || b == MAGIC_PACKED_FONT;
    }

    /**
     * Returns true if this is an animation resource
     * 
     * @param name the name of the resource
     * @return true if the resource is an animation
     * @throws NullPointerException if the resource doesn't exist
     */
    public boolean isAnimation(String name) {
        byte b = ((Byte)resourceTypes.get(name)).byteValue();
        return b == MAGIC_ANIMATION;
    }

    /**
     * Returns true if this is a data resource
     * 
     * @param name the name of the resource
     * @return true if the resource is a data resource
     * @throws NullPointerException if the resource doesn't exist
     */
    public boolean isData(String name) {
        byte b = ((Byte)resourceTypes.get(name)).byteValue();
        return b == MAGIC_DATA;
    }

    /**
     * Returns true if this is an image resource
     * 
     * @param name the name of the resource
     * @return true if the resource is an image
     * @throws NullPointerException if the resource doesn't exist
     */
    public boolean isImage(String name) {
        byte b = ((Byte)resourceTypes.get(name)).byteValue();
        return b == MAGIC_IMAGE || b == MAGIC_PACKED_IMAGE8;
    }
    
    /**
     * Creates a resource object from the local JAR resource identifier
     * 
     * @param resource a local reference to a resource using the syntax of Class.getResourceAsStream(String)
     * @return a resource object
     * @throws java.io.IOException if opening/reading the resource fails
     */
    public static Resources open(String resource) throws IOException {
        try {
            return new Resources(classLoader.getResourceAsStream(resource));
        } catch(RuntimeException err) {
            // intercept exceptions since user code might not deal well with runtime exceptions 
            err.printStackTrace();
            throw new IOException(err.getMessage());
        }
    }

    StaticAnimation loadAnimation(String name, DataInputStream input) throws IOException {
        return StaticAnimation.createAnimation(input);
    }
    
    /**
     * Creates a resource object from the given input stream
     * 
     * @param resource stream from which to read the resource
     * @return a resource object
     * @throws java.io.IOException if opening/reading the resource fails
     */