Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2007 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.examples.launcher; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.text.MessageFormat; import java.util.HashMap; import java.util.HashSet; import java.util.MissingResourceException; import java.util.ResourceBundle; import java.util.Set; import org.eclipse.core.runtime.IConfigurationElement; import org.eclipse.core.runtime.IExtensionRegistry; import org.eclipse.core.runtime.IStatus; import org.eclipse.core.runtime.Platform; import org.eclipse.core.runtime.Status; import org.eclipse.swt.graphics.Image; import org.eclipse.swt.graphics.ImageData; import org.eclipse.ui.plugin.AbstractUIPlugin; import org.osgi.framework.Bundle; import org.osgi.framework.BundleContext; /** * The main plugin class to be used in the desktop. */ public class LauncherPlugin extends AbstractUIPlugin { //The shared instance. private static LauncherPlugin plugin; private static ResourceBundle resourceBundle; public static final String LAUNCH_ITEMS_POINT_ID = "org.eclipse.swt.examples.launcher.launchItems", LAUNCH_ITEMS_XML_CATEGORY = "category", LAUNCH_ITEMS_XML_ITEM = "item", LAUNCH_ITEMS_XML_ITEM_ICON = "icon", LAUNCH_ITEMS_XML_ITEM_DESCRIPTION = "description", LAUNCH_ITEMS_XML_PROGRAM = "program", LAUNCH_ITEMS_XML_PROGRAM_PLUGIN = "pluginId", LAUNCH_ITEMS_XML_PROGRAM_CLASS = "mainClass", LAUNCH_ITEMS_XML_VIEW = "view", LAUNCH_ITEMS_XML_VIEW_VIEWID = "viewId", LAUNCH_ITEMS_XML_ATTRIB_ID = "id", LAUNCH_ITEMS_XML_ATTRIB_NAME = "name", LAUNCH_ITEMS_XML_ATTRIB_ENABLED = "enabled", LAUNCH_ITEMS_XML_ATTRIB_CATEGORY = "category", LAUNCH_ITEMS_XML_VALUE_TRUE = "true", LAUNCH_ITEMS_XML_VALUE_FALSE = "false"; static final int liClosedFolder = 0, liOpenFolder = 1, liGenericExample = 2; static final String[] imageLocations = { "icons/closedFolder.gif", "icons/openFolder.gif", "icons/generic_example.gif" }; static Image images[]; /** * Constructs the LauncherPlugin. */ public LauncherPlugin() { super(); plugin = this; } @Override public void start(BundleContext context) throws Exception { super.start(context); resourceBundle = Platform.getResourceBundle(getBundle()); } /** * Clean up */ @Override public void stop(BundleContext context) throws Exception { freeResources(); super.stop(context); } /** * Returns the shared instance. */ public static LauncherPlugin getDefault() { return plugin; } /** * Loads the resources */ public static void initResources() { if (images == null) { images = new Image[imageLocations.length]; for (int i = 0; i < imageLocations.length; ++i) { images[i] = getImageFromPlugin(plugin.getBundle(), imageLocations[i]); if (images[i] == null) { freeResources(); logError(getResourceString("error.CouldNotLoadResources"), null); throw new IllegalStateException(); } } } } /** * Frees the resources */ public static void freeResources() { if (images != null) { for (Image image : images) { if (image != null) image.dispose(); } images = null; } } /** * Log an error to the ILog for this plugin * * @param message the localized error message text * @param exception the associated exception, or null */ public static void logError(String message, Throwable exception) { plugin.getLog().log(new Status(IStatus.ERROR, plugin.getBundle().getSymbolicName(), 0, message, exception)); } /** * Returns a string from the resource bundle. * We don't want to crash because of a missing String. * Returns the key if not found. */ public static String getResourceString(String key) { try { return resourceBundle.getString(key); } catch (MissingResourceException e) { return key; } catch (NullPointerException e) { return "!" + key + "!"; } } /** * Returns a string from the resource bundle and binds it * with the given arguments. If the key is not found, * return the key. */ public static String getResourceString(String key, Object[] args) { try { return MessageFormat.format(getResourceString(key), args); } catch (MissingResourceException e) { return key; } catch (NullPointerException e) { return "!" + key + "!"; } } /** * Constructs a list of available programs from registered extensions. * * @return an ItemTreeNode representing the root of a tree of items (the root is not to be displayed) */ public static ItemTreeNode getLaunchItemTree() { ItemTreeNode categoryTree = new ItemTreeNode( new ItemDescriptor("<<Root>>", "<<Root>>", null, null, null, null, null, null)); // get the platform's public plugin registry IExtensionRegistry extensionRegistry = Platform.getExtensionRegistry(); // retrieve all configuration elements registered at our launchItems extension-point IConfigurationElement[] configurationElements = extensionRegistry .getConfigurationElementsFor(LAUNCH_ITEMS_POINT_ID); if (configurationElements == null || configurationElements.length == 0) { logError(getResourceString("error.CouldNotFindRegisteredExtensions"), null); return categoryTree; } /* Collect all launch categories -- coalesce those with same ID */ HashMap<String, ItemTreeNode> idMap = new HashMap<>(); for (IConfigurationElement ce : configurationElements) { final String ceName = ce.getName(); final String attribId = getItemAttribute(ce, LAUNCH_ITEMS_XML_ATTRIB_ID, null); if (idMap.containsKey(attribId)) continue; if (ceName.equalsIgnoreCase(LAUNCH_ITEMS_XML_CATEGORY)) { final String attribName = getItemName(ce); ItemDescriptor theDescriptor = new ItemDescriptor(attribId, attribName, getItemDescription(ce), null, null, null, null, ce); idMap.put(attribId, new ItemTreeNode(theDescriptor)); } } /* Generate launch category hierarchy */ Set<String> tempIdSet = new HashSet<>(); // used to prevent duplicates from being entered into the tree for (IConfigurationElement ce : configurationElements) { final String ceName = ce.getName(); final String attribId = getItemAttribute(ce, LAUNCH_ITEMS_XML_ATTRIB_ID, null); if (tempIdSet.contains(attribId)) continue; if (ceName.equalsIgnoreCase(LAUNCH_ITEMS_XML_CATEGORY)) { final ItemTreeNode theNode = idMap.get(attribId); addItemByCategory(ce, categoryTree, theNode, idMap); tempIdSet.add(attribId); } } /* Generate program tree */ for (IConfigurationElement ce : configurationElements) { final String ceName = ce.getName(); final String attribId = getItemAttribute(ce, LAUNCH_ITEMS_XML_ATTRIB_ID, null); if (idMap.containsKey(attribId)) continue; if (ceName.equalsIgnoreCase(LAUNCH_ITEMS_XML_CATEGORY)) { // ignore } else if (ceName.equalsIgnoreCase(LAUNCH_ITEMS_XML_ITEM)) { final String enabled = getItemAttribute(ce, LAUNCH_ITEMS_XML_ATTRIB_ENABLED, LAUNCH_ITEMS_XML_VALUE_TRUE); if (enabled.equalsIgnoreCase(LAUNCH_ITEMS_XML_VALUE_FALSE)) continue; ItemDescriptor theDescriptor = createItemDescriptor(ce, attribId); if (theDescriptor != null) { final ItemTreeNode theNode = new ItemTreeNode(theDescriptor); addItemByCategory(ce, categoryTree, theNode, idMap); idMap.put(attribId, theNode); } } } return categoryTree; } /** * Adds an item to the category tree. */ private static void addItemByCategory(IConfigurationElement ce, ItemTreeNode root, ItemTreeNode theNode, HashMap<String, ItemTreeNode> idMap) { final String attribCategory = getItemAttribute(ce, LAUNCH_ITEMS_XML_ATTRIB_CATEGORY, null); // locate the parent node ItemTreeNode parentNode = null; if (attribCategory != null) { parentNode = idMap.get(attribCategory); } if (parentNode == null) parentNode = root; // add the item parentNode.addSortedNode(theNode); } /** * Creates an ItemDescriptor from an XML definition. * * @param ce the IConfigurationElement describing the item * @param attribId the attribute id * @return a new ItemDescriptor, or null if an error occurs */ private static ItemDescriptor createItemDescriptor(IConfigurationElement ce, String attribId) { final String attribName = getItemName(ce); final Image attribIcon = getItemIcon(ce); final String attribDescription = getItemDescription(ce); IConfigurationElement viewCE = getItemElement(ce, LAUNCH_ITEMS_XML_VIEW); if (viewCE != null) { //Item is a view final String attribView = getItemAttribute(viewCE, LAUNCH_ITEMS_XML_VIEW_VIEWID, null); if (attribView == null) { logError(getResourceString("error.IncompleteViewLaunchItem", new Object[] { attribId }), null); return null; } return new ItemDescriptor(attribId, attribName, attribDescription, attribIcon, attribView, null, null, viewCE); } else { //Item is a standalone IConfigurationElement programCE = getItemElement(ce, LAUNCH_ITEMS_XML_PROGRAM); if (programCE != null) { final String attribPluginId = getItemAttribute(programCE, LAUNCH_ITEMS_XML_PROGRAM_PLUGIN, null); final String attribClass = getItemAttribute(programCE, LAUNCH_ITEMS_XML_PROGRAM_CLASS, null); if (attribClass == null || attribPluginId == null) { logError(getResourceString("error.IncompleteProgramLaunchItem", new Object[] { attribId }), null); return null; } return new ItemDescriptor(attribId, attribName, attribDescription, attribIcon, null, attribClass, attribPluginId, programCE); } else { logError(getResourceString("error.IncompleteLaunchItem", new Object[] { attribId }), null); return null; } } } /** * Returns the first instance of a particular child XML element. * * @param ce the IConfigurationElement parent * @param element the name of the element to fetch * @return the element's IConfigurationElement, or null if not found */ private static IConfigurationElement getItemElement(IConfigurationElement ce, String element) { IConfigurationElement[] elementCEs = ce.getChildren(element); return (elementCEs != null && elementCEs.length != 0) ? elementCEs[0] : null; } /** * Returns the value of an XML attribute for an item. * * @param ce the IConfigurationElement describing the item * @param attribute the attribute to fetch * @param defaultValue the value to return if the attribute is not found * @return the attribute value */ private static String getItemAttribute(IConfigurationElement ce, String attribute, String defaultValue) { String value = ce.getAttribute(attribute); return (value != null) ? value : defaultValue; } /** * Returns the description string given the IConfigurationElement for an item. * * @param ce the IConfigurationElement describing the item * @return a newline-delimited string that describes this item, or null if none */ private static String getItemDescription(IConfigurationElement ce) { String description = getItemAttribute(ce, LAUNCH_ITEMS_XML_ITEM_DESCRIPTION, ""); return (description.length() == 0) ? null : description; } /** * Returns the name of an item. * * @param ce the IConfigurationElement describing the item * @return the attribute value */ private static String getItemName(IConfigurationElement ce) { return getItemAttribute(ce, LAUNCH_ITEMS_XML_ATTRIB_NAME, getResourceString("launchitem.Missing.name")); } /** * Returns the icon for an item. * * @param ce the IConfigurationElement describing the item * @return an icon */ private static Image getItemIcon(IConfigurationElement ce) { String iconPath = getItemAttribute(ce, LAUNCH_ITEMS_XML_ITEM_ICON, ""); if (iconPath.length() != 0) { String symbolicName = ce.getDeclaringExtension().getContributor().getName(); Bundle bundle = Platform.getBundle(symbolicName); Image icon = getImageFromPlugin(bundle, iconPath); if (icon != null) { Image[] newImages = new Image[images.length + 1]; System.arraycopy(images, 0, newImages, 0, images.length); newImages[images.length] = icon; images = newImages; return icon; } } return images[liGenericExample]; } /** * Gets an image from a path relative to the plugin install directory. * * @param bundle the plugin descriptor for the plugin with the image * @param iconPath the path relative to the install directory * @return the image, or null if not found */ private static Image getImageFromPlugin(Bundle bundle, String iconPath) { InputStream is = null; try { URL installUrl = bundle.getEntry("/"); URL url = new URL(installUrl, iconPath); is = url.openConnection().getInputStream(); ImageData source = new ImageData(is); ImageData mask = source.getTransparencyMask(); Image image = new Image(null, source, mask); return image; } catch (Throwable ex) { return null; } finally { try { if (is != null) is.close(); } catch (IOException e) { } } } }