| /******************************************************************************* |
| * Copyright (c) 2000, 2005 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.ui.internal.ide.registry; |
| |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.Hashtable; |
| |
| import org.eclipse.core.runtime.IConfigurationElement; |
| import org.eclipse.core.runtime.IExtension; |
| import org.eclipse.core.runtime.IExtensionPoint; |
| import org.eclipse.core.runtime.IExtensionRegistry; |
| import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin; |
| |
| /** |
| * Template implementation of a registry reader that creates objects |
| * representing registry contents. Typically, an extension |
| * contains one element, but this reader handles multiple |
| * elements per extension. |
| * |
| * To start reading the extensions from the registry for an |
| * extension point, call the method <code>readRegistry</code>. |
| * |
| * To read children of an IConfigurationElement, call the |
| * method <code>readElementChildren</code> from your implementation |
| * of the method <code>readElement</code>, as it will not be |
| * done by default. |
| */ |
| public abstract class IDERegistryReader { |
| protected static final String TAG_DESCRIPTION = "description"; //$NON-NLS-1$ |
| |
| protected static Hashtable extensionPoints = new Hashtable(); |
| |
| private static final Comparator comparer = new Comparator() { |
| public int compare(Object arg0, Object arg1) { |
| IExtension i1 = (IExtension) arg0; |
| String s1 = i1.getNamespace(); |
| IExtension i2 = (IExtension) arg1; |
| String s2 = i2.getNamespace(); |
| return s1.compareToIgnoreCase(s2); |
| } |
| }; |
| |
| /** |
| * The constructor. |
| */ |
| protected IDERegistryReader() { |
| } |
| |
| /** |
| * This method extracts description as a subelement of |
| * the given element. |
| * @return description string if defined, or empty string |
| * if not. |
| */ |
| protected String getDescription(IConfigurationElement config) { |
| IConfigurationElement[] children = config.getChildren(TAG_DESCRIPTION); |
| if (children.length >= 1) { |
| return children[0].getValue(); |
| } |
| return "";//$NON-NLS-1$ |
| } |
| |
| /** |
| * Logs the error in the workbench log using the provided |
| * text and the information in the configuration element. |
| */ |
| protected void logError(IConfigurationElement element, String text) { |
| IExtension extension = element.getDeclaringExtension(); |
| String pluginId = extension.getNamespace(); |
| StringBuffer buf = new StringBuffer(); |
| buf.append("Plugin " + pluginId + ", extension " //$NON-NLS-2$//$NON-NLS-1$ |
| + extension.getExtensionPointUniqueIdentifier()); |
| buf.append("\n" + text);//$NON-NLS-1$ |
| IDEWorkbenchPlugin.log(buf.toString()); |
| } |
| |
| /** |
| * Logs a very common registry error when a required attribute is missing. |
| */ |
| protected void logMissingAttribute(IConfigurationElement element, |
| String attributeName) { |
| logError(element, |
| "Required attribute '" + attributeName + "' not defined");//$NON-NLS-2$//$NON-NLS-1$ |
| } |
| |
| /** |
| * Logs a very common registry error when a required child is missing. |
| */ |
| protected void logMissingElement(IConfigurationElement element, |
| String elementName) { |
| logError(element, |
| "Required sub element '" + elementName + "' not defined");//$NON-NLS-2$//$NON-NLS-1$ |
| } |
| |
| /** |
| * Logs a registry error when the configuration element is unknown. |
| */ |
| protected void logUnknownElement(IConfigurationElement element) { |
| logError(element, "Unknown extension tag found: " + element.getName());//$NON-NLS-1$ |
| } |
| |
| /** |
| * Apply a reproducable order to the list of extensions |
| * provided, such that the order will not change as |
| * extensions are added or removed. |
| */ |
| protected IExtension[] orderExtensions(IExtension[] extensions) { |
| // By default, the order is based on plugin id sorted |
| // in ascending order. The order for a plugin providing |
| // more than one extension for an extension point is |
| // dependent in the order listed in the XML file. |
| IExtension[] sortedExtension = new IExtension[extensions.length]; |
| System.arraycopy(extensions, 0, sortedExtension, 0, extensions.length); |
| Collections.sort(Arrays.asList(sortedExtension), comparer); |
| return sortedExtension; |
| } |
| |
| /** |
| * Implement this method to read element's attributes. |
| * If children should also be read, then implementor |
| * is responsible for calling <code>readElementChildren</code>. |
| * Implementor is also responsible for logging missing |
| * attributes. |
| * |
| * @return true if element was recognized, false if not. |
| */ |
| protected abstract boolean readElement(IConfigurationElement element); |
| |
| /** |
| * Read the element's children. This is called by |
| * the subclass' readElement method when it wants |
| * to read the children of the element. |
| */ |
| protected void readElementChildren(IConfigurationElement element) { |
| readElements(element.getChildren()); |
| } |
| |
| /** |
| * Read each element one at a time by calling the |
| * subclass implementation of <code>readElement</code>. |
| * |
| * Logs an error if the element was not recognized. |
| */ |
| protected void readElements(IConfigurationElement[] elements) { |
| for (int i = 0; i < elements.length; i++) { |
| if (!readElement(elements[i])) |
| logUnknownElement(elements[i]); |
| } |
| } |
| |
| /** |
| * Read one extension by looping through its |
| * configuration elements. |
| */ |
| protected void readExtension(IExtension extension) { |
| readElements(extension.getConfigurationElements()); |
| } |
| |
| /** |
| * Start the registry reading process using the |
| * supplied plugin ID and extension point. |
| */ |
| protected void readRegistry(IExtensionRegistry registry, String pluginId, |
| String extensionPoint) { |
| String pointId = pluginId + "-" + extensionPoint; //$NON-NLS-1$ |
| IExtension[] extensions = (IExtension[]) extensionPoints.get(pointId); |
| if (extensions == null) { |
| IExtensionPoint point = registry.getExtensionPoint(pluginId, |
| extensionPoint); |
| if (point == null) |
| return; |
| extensions = point.getExtensions(); |
| extensions = orderExtensions(extensions); |
| extensionPoints.put(pointId, extensions); |
| } |
| for (int i = 0; i < extensions.length; i++) |
| readExtension(extensions[i]); |
| } |
| } |