jbt.tools.bteditor.ApplicationIcons.java Source code

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Here is the source code for jbt.tools.bteditor.ApplicationIcons.java

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/*******************************************************************************
 * Copyright (c) 2010 Ricardo Juan Palma Durn.
 * 
 * This source file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, version 3 of
 * the License. The text of the GNU Lesser General Public License 
 * is included with this application in the file LICENSE.TXT.
 * 
 * This source file 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.
 ******************************************************************************/
package jbt.tools.bteditor;

import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import java.util.Collection;
import java.util.Collections;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import java.util.Vector;

import jbt.tools.bteditor.util.IconsPaths;

import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.Path;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;

/**
 * Class used to manage common icons in the application. These include icons
 * for standard nodes (those read form the
 * {@link NodesLoader#STANDARD_NODES_FILE} file), as well for "actions",
 * "conditions", "categories" and "guards" (whose path can be accessed via
 * {@link IconsPaths}).
 * <p>
 * They can be retrieved by their path in the plugin, and they are
 * automatically disposed by the application.
 * 
 * @author Ricardo Juan Palma Durn
 * 
 */
public class ApplicationIcons {
    /** List of the icons. Can be retrieved by their path in the plugin. */
    private static Map<String, Image> applicationIcons = new Hashtable<String, Image>();

    /**
     * Returns an icon by its path in the plugin, or null if it cannot be
     * found.
     * <p>
     * The returned image does not have to be disposed. It is automatically
     * managed by the application.
     * <p>
     * This function should be called after loading the icons (
     * {@link #loadIcons()}).
     */
    public static Image getIcon(String iconLocation) {
        return applicationIcons.get(iconLocation);
    }

    /**
     * Loads all the common standard icons.
     * 
     * @throws IOException
     *             in case there is an error while loading the icons.
     */
    public static void loadIcons() throws IOException {
        URL url = FileLocator.find(Activator.getDefault().getBundle(), new Path(NodesLoader.STANDARD_NODES_FILE),
                Collections.EMPTY_MAP);

        URL fileUrl = null;
        fileUrl = FileLocator.toFileURL(url);
        FileInputStream file = new FileInputStream(fileUrl.getPath());

        /* First get icons from the standard nodes file. */
        parseStandardNodesFile(file);

        /* Then non standard icons. */
        loadNonStandardIcons();
    }

    private static List<Exception> parseStandardNodesFile(FileInputStream file) {
        List<Exception> exceptions = new Vector<Exception>();

        SAXBuilder builder = new SAXBuilder();
        try {
            Document doc = builder.build(file);

            Element root = doc.getRootElement();

            parseElement(root);
        } catch (Exception e) {
            exceptions.add(e);
        }

        return exceptions;
    }

    private static void parseElement(Element e) {
        String nodeType = e.getName();

        if (nodeType.equals("Category")) {
            List<Element> children = e.getChildren();

            for (Element child : children) {
                parseElement(child);
            }
        } else if (nodeType.equals("Node")) {
            String path = e.getChildText("Icon");
            loadIcon(path);
        }
    }

    private static void loadNonStandardIcons() {
        loadIcon(IconsPaths.ACTION);
        loadIcon(IconsPaths.CONDITION);
        loadIcon(IconsPaths.ROOT);
        loadIcon(IconsPaths.CATEGORY);
        loadIcon(IconsPaths.GUARD);
        loadIcon(IconsPaths.BT);
    }

    /**
     * Loads an icon into {@link #applicationIcons} from an icon path.
     */
    private static void loadIcon(String iconPath) {
        ImageDescriptor imageDescriptor = AbstractUIPlugin.imageDescriptorFromPlugin(Activator.PLUGIN_ID, iconPath);
        Image icon = imageDescriptor == null ? null : imageDescriptor.createImage();

        applicationIcons.put(iconPath, icon);
    }

    /**
     * Disposes all the icons stored by the ApplicationIcons.
     */
    public static void disposeIcons() {
        Collection<Image> icons = applicationIcons.values();
        for (Image icon : icons) {
            if (icon != null) {
                icon.dispose();
            }
        }
    }

    private ApplicationIcons() {
    };
}