bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/registry/RegistryReader.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2006 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.registry;

 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;

 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.WorkbenchPlugin;

 /**
  *	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 RegistryReader {

     // for dynamic UI - remove this cache to avoid inconsistency
     //protected static Hashtable extensionPoints = new Hashtable();
     /**
      * The constructor.
      */
     protected RegistryReader() {
     }

     /**
      * Logs the error in the workbench log using the provided
      * text and the information in the configuration element.
      */
     protected static void logError(IConfigurationElement element, String text) {
         IExtension extension = element.getDeclaringExtension();
         StringBuffer buf = new StringBuffer();
         buf
                 .append("Plugin " + extension.getNamespace() + ", extension " + extension.getExtensionPointUniqueIdentifier());//$NON-NLS-2$//$NON-NLS-1$
         buf.append("\n" + text);//$NON-NLS-1$
         WorkbenchPlugin.log(buf.toString());
     }

     /**
      * Logs a very common registry error when a required attribute is missing.
      */
     protected static 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 static 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 static 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.
      * @param extensions the extensions to order
      * @return ordered extensions
      */
     public static 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);
         Comparator comparer = new Comparator() {
             public int compare(Object arg0, Object arg1) {
                 String s1 = ((IExtension) arg0).getNamespace();
                 String s2 = ((IExtension) arg1).getNamespace();
                 return s1.compareToIgnoreCase(s2);
             }
         };
         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.
      *
      * @param registry the registry to read from
      * @param pluginId the plugin id of the extenion point
      * @param extensionPoint the extension point id
      */
     public void readRegistry(IExtensionRegistry registry, String pluginId,
             String extensionPoint) {
         IExtensionPoint point = registry.getExtensionPoint(pluginId,
                 extensionPoint);
         if (point == null) {
 			return;
 		}
         IExtension[] extensions = point.getExtensions();
         extensions = orderExtensions(extensions);
         for (int i = 0; i < extensions.length; i++) {
 			readExtension(extensions[i]);
 		}
     }

     /**
      * Utility for extracting the description child of an element.
      *
      * @param configElement the element
      * @return the description
      * @since 3.1
      */
     public static String getDescription(IConfigurationElement configElement) {
 		IConfigurationElement[] children = configElement.getChildren(IWorkbenchRegistryConstants.TAG_DESCRIPTION);
 	    if (children.length >= 1) {
 	        return children[0].getValue();
 	    }
 	    return "";//$NON-NLS-1$
     }

     /**
 	 * Utility for extracting the value of a class attribute or a nested class
 	 * element that follows the pattern set forth by
 	 * {@link org.eclipse.core.runtime.IExecutableExtension}.
 	 *
 	 * @param configElement
 	 *            the element
 	 * @param classAttributeName
 	 *            the name of the class attribute to check
 	 * @return the value of the attribute or nested class element
 	 * @since 3.1
 	 */
     public static String getClassValue(IConfigurationElement configElement, String classAttributeName) {
     	String className = configElement.getAttribute(classAttributeName);
     	if (className != null) {
 			return className;
 		}
 		IConfigurationElement [] candidateChildren = configElement.getChildren(classAttributeName);
 		if (candidateChildren.length == 0) {
 			return null;
 		}

 		return candidateChildren[0].getAttribute(IWorkbenchRegistryConstants.ATT_CLASS);
     }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2006 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.registry;

	import java.util.Arrays;
	import java.util.Collections;
	import java.util.Comparator;

	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.WorkbenchPlugin;

	/**
	* 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 RegistryReader {

	// for dynamic UI - remove this cache to avoid inconsistency
	//protected static Hashtable extensionPoints = new Hashtable();
	/**
	* The constructor.
	*/
	protected RegistryReader() {
	}

	/**
	* Logs the error in the workbench log using the provided
	* text and the information in the configuration element.
	*/
	protected static void logError(IConfigurationElement element, String text) {
	IExtension extension = element.getDeclaringExtension();
	StringBuffer buf = new StringBuffer();
	buf
	.append("Plugin " + extension.getNamespace() + ", extension " + extension.getExtensionPointUniqueIdentifier());//$NON-NLS-2$//$NON-NLS-1$
	buf.append("\n" + text);//$NON-NLS-1$
	WorkbenchPlugin.log(buf.toString());
	}

	/**
	* Logs a very common registry error when a required attribute is missing.
	*/
	protected static 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 static 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 static 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.
	* @param extensions the extensions to order
	* @return ordered extensions
	*/
	public static 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);
	Comparator comparer = new Comparator() {
	public int compare(Object arg0, Object arg1) {
	String s1 = ((IExtension) arg0).getNamespace();
	String s2 = ((IExtension) arg1).getNamespace();
	return s1.compareToIgnoreCase(s2);
	}
	};
	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.
	*
	* @param registry the registry to read from
	* @param pluginId the plugin id of the extenion point
	* @param extensionPoint the extension point id
	*/
	public void readRegistry(IExtensionRegistry registry, String pluginId,
	String extensionPoint) {
	IExtensionPoint point = registry.getExtensionPoint(pluginId,
	extensionPoint);
	if (point == null) {
	return;
	}
	IExtension[] extensions = point.getExtensions();
	extensions = orderExtensions(extensions);
	for (int i = 0; i < extensions.length; i++) {
	readExtension(extensions[i]);
	}
	}

	/**
	* Utility for extracting the description child of an element.
	*
	* @param configElement the element
	* @return the description
	* @since 3.1
	*/
	public static String getDescription(IConfigurationElement configElement) {
	IConfigurationElement[] children = configElement.getChildren(IWorkbenchRegistryConstants.TAG_DESCRIPTION);
	if (children.length >= 1) {
	return children[0].getValue();
	}
	return "";//$NON-NLS-1$
	}

	/**
	* Utility for extracting the value of a class attribute or a nested class
	* element that follows the pattern set forth by
	* {@link org.eclipse.core.runtime.IExecutableExtension}.
	*
	* @param configElement
	* the element
	* @param classAttributeName
	* the name of the class attribute to check
	* @return the value of the attribute or nested class element
	* @since 3.1
	*/
	public static String getClassValue(IConfigurationElement configElement, String classAttributeName) {
	String className = configElement.getAttribute(classAttributeName);
	if (className != null) {
	return className;
	}
	IConfigurationElement [] candidateChildren = configElement.getChildren(classAttributeName);
	if (candidateChildren.length == 0) {
	return null;
	}

	return candidateChildren[0].getAttribute(IWorkbenchRegistryConstants.ATT_CLASS);
	}
	}