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

 /*******************************************************************************
  * Copyright (c) 2005, 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.commands;

 import java.util.ArrayList;
 import java.util.List;

 import org.eclipse.core.commands.AbstractParameterValueConverter;
 import org.eclipse.core.commands.Category;
 import org.eclipse.core.commands.Command;
 import org.eclipse.core.commands.ParameterType;
 import org.eclipse.core.commands.State;
 import org.eclipse.core.commands.common.HandleObject;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtensionDelta;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IRegistryChangeEvent;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.commands.ICommandService;
 import org.eclipse.ui.internal.WorkbenchMessages;
 import org.eclipse.ui.internal.registry.IWorkbenchRegistryConstants;
 import org.eclipse.ui.internal.services.RegistryPersistence;
 import org.eclipse.ui.internal.util.PrefUtil;

 /**
  * <p>
  * A static class for accessing the registry and the preference store.
  * </p>
  *
  * @since 3.1
  */
 final class CommandPersistence extends RegistryPersistence {

 	/**
 	 * The index of the category elements in the indexed array.
 	 *
 	 * @see CommandPersistence#read()
 	 */
 	private static final int INDEX_CATEGORY_DEFINITIONS = 0;

 	/**
 	 * The index of the command elements in the indexed array.
 	 *
 	 * @see CommandPersistence#read()
 	 */
 	private static final int INDEX_COMMAND_DEFINITIONS = 1;

 	/**
 	 * The index of the commandParameterType elements in the indexed array.
 	 *
 	 * @see CommandPersistence#read()
 	 * @since 3.2
 	 */
 	private static final int INDEX_PARAMETER_TYPE_DEFINITIONS = 2;

 	/**
 	 * Reads all of the category definitions from the commands extension point.
 	 *
 	 * @param configurationElements
 	 *            The configuration elements in the commands extension point;
 	 *            must not be <code>null</code>, but may be empty.
 	 * @param configurationElementCount
 	 *            The number of configuration elements that are really in the
 	 *            array.
 	 * @param commandService
 	 *            The command service to which the categories should be added;
 	 *            must not be <code>null</code>.
 	 */
 	private static final void readCategoriesFromRegistry(
 			final IConfigurationElement[] configurationElements,
 			final int configurationElementCount,
 			final ICommandService commandService) {
 		// Undefine all the previous handle objects.
 		final HandleObject[] handleObjects = commandService
 				.getDefinedCategories();
 		if (handleObjects != null) {
 			for (int i = 0; i < handleObjects.length; i++) {
 				handleObjects[i].undefine();
 			}
 		}

 		// Define the uncategorized category.
 		commandService
 				.defineUncategorizedCategory(
 						WorkbenchMessages.CommandService_AutogeneratedCategoryName,
 						WorkbenchMessages.CommandService_AutogeneratedCategoryDescription);

 		final List warningsToLog = new ArrayList(1);

 		for (int i = 0; i < configurationElementCount; i++) {
 			final IConfigurationElement configurationElement = configurationElements[i];

 			// Read out the category identifier.
 			final String categoryId = readRequired(configurationElement,
 					ATT_ID, warningsToLog, "Categories need an id"); //$NON-NLS-1$
 			if (categoryId == null) {
 				continue;
 			}

 			// Read out the name.
 			final String name = readRequired(configurationElement, ATT_NAME,
 					warningsToLog, "Categories need a name", //$NON-NLS-1$
 					categoryId);
 			if (name == null) {
 				continue;
 			}

 			// Read out the description.
 			final String description = readOptional(configurationElement,
 					ATT_DESCRIPTION);

 			final Category category = commandService.getCategory(categoryId);
 			category.define(name, description);
 		}

 		// If there were any warnings, then log them now.
 		logWarnings(
 				warningsToLog,
 				"Warnings while parsing the commands from the 'org.eclipse.ui.commands' and 'org.eclipse.ui.actionDefinitions' extension points."); //$NON-NLS-1$
 	}

 	/**
 	 * Reads all of the command definitions from the commands extension point.
 	 *
 	 * @param configurationElements
 	 *            The configuration elements in the commands extension point;
 	 *            must not be <code>null</code>, but may be empty.
 	 * @param configurationElementCount
 	 *            The number of configuration elements that are really in the
 	 *            array.
 	 * @param commandService
 	 *            The command service to which the commands should be added;
 	 *            must not be <code>null</code>.
 	 */
 	private static final void readCommandsFromRegistry(
 			final IConfigurationElement[] configurationElements,
 			final int configurationElementCount,
 			final ICommandService commandService) {
 		// Undefine all the previous handle objects.
 		final HandleObject[] handleObjects = commandService
 				.getDefinedCommands();
 		if (handleObjects != null) {
 			for (int i = 0; i < handleObjects.length; i++) {
 				handleObjects[i].undefine();
 			}
 		}

 		final List warningsToLog = new ArrayList(1);

 		for (int i = 0; i < configurationElementCount; i++) {
 			final IConfigurationElement configurationElement = configurationElements[i];

 			// Read out the command identifier.
 			final String commandId = readRequired(configurationElement, ATT_ID,
 					warningsToLog, "Commands need an id"); //$NON-NLS-1$
 			if (commandId == null) {
 				continue;
 			}

 			// Read out the name.
 			final String name = readRequired(configurationElement, ATT_NAME,
 					warningsToLog, "Commands need a name"); //$NON-NLS-1$
 			if (name == null) {
 				continue;
 			}

 			// Read out the description.
 			final String description = readOptional(configurationElement,
 					ATT_DESCRIPTION);

 			// Read out the category id.
 			String categoryId = configurationElement
 					.getAttribute(ATT_CATEGORY_ID);
 			if ((categoryId == null) || (categoryId.length() == 0)) {
 				categoryId = configurationElement.getAttribute(ATT_CATEGORY);
 				if ((categoryId != null) && (categoryId.length() == 0)) {
 					categoryId = null;
 				}
 			}

 			// Read out the parameters.
 			final Parameter[] parameters = readParameters(configurationElement,
 					warningsToLog, commandService);

 			// Read out the returnTypeId.
 			final String returnTypeId = readOptional(configurationElement,
 					ATT_RETURN_TYPE_ID);

 			// Read out the help context identifier.
 			final String helpContextId = readOptional(configurationElement,
 					ATT_HELP_CONTEXT_ID);

 			final Command command = commandService.getCommand(commandId);
 			final Category category = commandService.getCategory(categoryId);
 			if (!category.isDefined()) {
 				addWarning(
 						warningsToLog,
 						"Commands should really have a category", //$NON-NLS-1$
 						configurationElement, commandId,
 						"categoryId", categoryId); //$NON-NLS-1$
 			}

 			final ParameterType returnType;
 			if (returnTypeId == null) {
 				returnType = null;
 			} else {
 				returnType = commandService.getParameterType(returnTypeId);
 			}

 			command.define(name, description, category, parameters, returnType,
 					helpContextId);
 			readState(configurationElement, warningsToLog, command);
 		}

 		// If there were any warnings, then log them now.
 		logWarnings(
 				warningsToLog,
 				"Warnings while parsing the commands from the 'org.eclipse.ui.commands' and 'org.eclipse.ui.actionDefinitions' extension points."); //$NON-NLS-1$
 	}

 	/**
 	 * Reads the parameters from a parent configuration element. This is used to
 	 * read the parameter sub-elements from a command element. Each parameter is
 	 * guaranteed to be valid. If invalid parameters are found, then a warning
 	 * status will be appended to the <code>warningsToLog</code> list.
 	 *
 	 * @param configurationElement
 	 *            The configuration element from which the parameters should be
 	 *            read; must not be <code>null</code>.
 	 * @param warningsToLog
 	 *            The list of warnings found during parsing. Warnings found
 	 *            while parsing the parameters will be appended to this list.
 	 *            This value must not be <code>null</code>.
 	 * @param commandService
 	 *            The command service from which the parameter can get parameter
 	 *            types; must not be <code>null</code>.
 	 * @return The array of parameters found for this configuration element;
 	 *         <code>null</code> if none can be found.
 	 */
 	private static final Parameter[] readParameters(
 			final IConfigurationElement configurationElement,
 			final List warningsToLog, final ICommandService commandService) {
 		final IConfigurationElement[] parameterElements = configurationElement
 				.getChildren(TAG_COMMAND_PARAMETER);
 		if ((parameterElements == null) || (parameterElements.length == 0)) {
 			return null;
 		}

 		int insertionIndex = 0;
 		Parameter[] parameters = new Parameter[parameterElements.length];
 		for (int i = 0; i < parameterElements.length; i++) {
 			final IConfigurationElement parameterElement = parameterElements[i];
 			// Read out the id
 			final String id = readRequired(parameterElement, ATT_ID,
 					warningsToLog, "Parameters need an id"); //$NON-NLS-1$
 			if (id == null) {
 				continue;
 			}

 			// Read out the name.
 			final String name = readRequired(parameterElement, ATT_NAME,
 					warningsToLog, "Parameters need a name"); //$NON-NLS-1$
 			if (name == null) {
 				continue;
 			}

 			/*
 			 * The IParameterValues will be initialized lazily as an
 			 * IExecutableExtension.
 			 */

 			// Read out the typeId attribute, if present.
 			final String typeId = readOptional(parameterElement, ATT_TYPE_ID);

 			// Read out the optional attribute, if present.
 			final boolean optional = readBoolean(parameterElement,
 					ATT_OPTIONAL, true);

 			final ParameterType type;
 			if (typeId == null) {
 				type = null;
 			} else {
 				type = commandService.getParameterType(typeId);
 			}

 			final Parameter parameter = new Parameter(id, name,
 					parameterElement, type, optional);
 			parameters[insertionIndex++] = parameter;
 		}

 		if (insertionIndex != parameters.length) {
 			final Parameter[] compactedParameters = new Parameter[insertionIndex];
 			System.arraycopy(parameters, 0, compactedParameters, 0,
 					insertionIndex);
 			parameters = compactedParameters;
 		}

 		return parameters;
 	}

 	/**
 	 * Reads all of the commandParameterType definitions from the commands
 	 * extension point.
 	 *
 	 * @param configurationElements
 	 *            The configuration elements in the commands extension point;
 	 *            must not be <code>null</code>, but may be empty.
 	 * @param configurationElementCount
 	 *            The number of configuration elements that are really in the
 	 *            array.
 	 * @param commandService
 	 *            The command service to which the commands should be added;
 	 *            must not be <code>null</code>.
 	 * @since 3.2
 	 */
 	private static final void readParameterTypesFromRegistry(
 			final IConfigurationElement[] configurationElements,
 			final int configurationElementCount,
 			final ICommandService commandService) {

 		// Undefine all the previous handle objects.
 		final HandleObject[] handleObjects = commandService
 				.getDefinedParameterTypes();
 		if (handleObjects != null) {
 			for (int i = 0; i < handleObjects.length; i++) {
 				handleObjects[i].undefine();
 			}
 		}

 		final List warningsToLog = new ArrayList(1);

 		for (int i = 0; i < configurationElementCount; i++) {
 			final IConfigurationElement configurationElement = configurationElements[i];

 			// Read out the commandParameterType identifier.
 			final String parameterTypeId = readRequired(configurationElement,
 					ATT_ID, warningsToLog, "Command parameter types need an id"); //$NON-NLS-1$
 			if (parameterTypeId == null) {
 				continue;
 			}

 			// Read out the type.
 			final String type = readOptional(configurationElement, ATT_TYPE);

 			// Read out the converter.
 			final String converter = readOptional(configurationElement,
 					ATT_CONVERTER);

 			/*
 			 * if the converter attribute was given, create a proxy
 			 * AbstractParameterValueConverter for the ParameterType, otherwise
 			 * null indicates there is no converter
 			 */
 			final AbstractParameterValueConverter parameterValueConverter = (converter == null) ? null
 					: new ParameterValueConverterProxy(configurationElement);

 			final ParameterType parameterType = commandService
 					.getParameterType(parameterTypeId);
 			parameterType.define(type, parameterValueConverter);
 		}

 		// If there were any warnings, then log them now.
 		logWarnings(
 				warningsToLog,
 				"Warnings while parsing the commandParameterTypes from the 'org.eclipse.ui.commands' extension point."); //$NON-NLS-1$

 	}

 	/**
 	 * Reads the states from a parent configuration element. This is used to
 	 * read the state sub-elements from a command element. Each state is
 	 * guaranteed to be valid. If invalid states are found, then a warning
 	 * status will be appended to the <code>warningsToLog</code> list.
 	 *
 	 * @param configurationElement
 	 *            The configuration element from which the states should be
 	 *            read; must not be <code>null</code>.
 	 * @param warningsToLog
 	 *            The list of warnings found during parsing. Warnings found
 	 *            while parsing the parameters will be appended to this list.
 	 *            This value must not be <code>null</code>.
 	 * @param command
 	 *            The command for which the state is being read; may be
 	 *            <code>null</code>.
 	 */
 	private static final void readState(
 			final IConfigurationElement configurationElement,
 			final List warningsToLog, final Command command) {
 		final IConfigurationElement[] stateElements = configurationElement
 				.getChildren(TAG_STATE);
 		if ((stateElements == null) || (stateElements.length == 0)) {
 			return;
 		}

 		for (int i = 0; i < stateElements.length; i++) {
 			final IConfigurationElement stateElement = stateElements[i];

 			final String id = readRequired(stateElement, ATT_ID, warningsToLog,
 					"State needs an id"); //$NON-NLS-1$
 			if (id == null) {
 				continue;
 			}

 			if (checkClass(stateElement, warningsToLog,
 					"State must have an associated class", id)) { //$NON-NLS-1$
 				final State state = new CommandStateProxy(stateElement,
 						ATT_CLASS, PrefUtil.getInternalPreferenceStore(),
 						CommandService.createPreferenceKey(command, id));
 				command.addState(id, state);
 			}
 		}
 	}

 	/**
 	 * The command service with which this persistence class is associated;
 	 * never <code>null</code>.
 	 */
 	private final ICommandService commandService;

 	/**
 	 * Constructs a new instance of <code>CommandPersistence</code>.
 	 *
 	 * @param commandService
 	 *            The command service which should be populated with the values
 	 *            from the registry; must not be <code>null</code>.
 	 */
 	CommandPersistence(final ICommandService commandService) {
 		if (commandService == null) {
 			throw new NullPointerException("The command service cannot be null"); //$NON-NLS-1$
 		}
 		this.commandService = commandService;
 	}

 	protected final boolean isChangeImportant(final IRegistryChangeEvent event) {
 		final IExtensionDelta[] commandDeltas = event.getExtensionDeltas(
 				PlatformUI.PLUGIN_ID, IWorkbenchRegistryConstants.PL_COMMANDS);
 		if (commandDeltas.length == 0) {
 			final IExtensionDelta[] actionDefinitionDeltas = event
 					.getExtensionDeltas(PlatformUI.PLUGIN_ID,
 							IWorkbenchRegistryConstants.PL_ACTION_DEFINITIONS);
 			if (actionDefinitionDeltas.length == 0) {
 				return false;
 			}
 		}

 		return true;
 	}

 	/**
 	 * Reads all of the commands and categories from the registry,
 	 *
 	 * @param commandService
 	 *            The command service which should be populated with the values
 	 *            from the registry; must not be <code>null</code>.
 	 */
 	protected final void read() {
 		super.read();

 		// Create the extension registry mementos.
 		final IExtensionRegistry registry = Platform.getExtensionRegistry();
 		int commandDefinitionCount = 0;
 		int categoryDefinitionCount = 0;
 		int parameterTypeDefinitionCount = 0;
 		final IConfigurationElement[][] indexedConfigurationElements = new IConfigurationElement[3][];

 		// Sort the commands extension point based on element name.
 		final IConfigurationElement[] commandsExtensionPoint = registry
 				.getConfigurationElementsFor(EXTENSION_COMMANDS);
 		for (int i = 0; i < commandsExtensionPoint.length; i++) {
 			final IConfigurationElement configurationElement = commandsExtensionPoint[i];
 			final String name = configurationElement.getName();

 			// Check if it is a binding definition.
 			if (TAG_COMMAND.equals(name)) {
 				addElementToIndexedArray(configurationElement,
 						indexedConfigurationElements,
 						INDEX_COMMAND_DEFINITIONS, commandDefinitionCount++);
 			} else if (TAG_CATEGORY.equals(name)) {
 				addElementToIndexedArray(configurationElement,
 						indexedConfigurationElements,
 						INDEX_CATEGORY_DEFINITIONS, categoryDefinitionCount++);
 			} else if (TAG_COMMAND_PARAMETER_TYPE.equals(name)) {
 				addElementToIndexedArray(configurationElement,
 						indexedConfigurationElements,
 						INDEX_PARAMETER_TYPE_DEFINITIONS,
 						parameterTypeDefinitionCount++);
 			}
 		}

 		final IConfigurationElement[] actionDefinitionsExtensionPoint = registry
 				.getConfigurationElementsFor(EXTENSION_ACTION_DEFINITIONS);
 		for (int i = 0; i < actionDefinitionsExtensionPoint.length; i++) {
 			final IConfigurationElement configurationElement = actionDefinitionsExtensionPoint[i];
 			final String name = configurationElement.getName();

 			if (TAG_ACTION_DEFINITION.equals(name)) {
 				addElementToIndexedArray(configurationElement,
 						indexedConfigurationElements,
 						INDEX_COMMAND_DEFINITIONS, commandDefinitionCount++);
 			}
 		}

 		readCategoriesFromRegistry(
 				indexedConfigurationElements[INDEX_CATEGORY_DEFINITIONS],
 				categoryDefinitionCount, commandService);
 		readCommandsFromRegistry(
 				indexedConfigurationElements[INDEX_COMMAND_DEFINITIONS],
 				commandDefinitionCount, commandService);
 		readParameterTypesFromRegistry(
 				indexedConfigurationElements[INDEX_PARAMETER_TYPE_DEFINITIONS],
 				parameterTypeDefinitionCount, commandService);

 	}
 }
	/*******************************************************************************
	* Copyright (c) 2005, 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.commands;

	import java.util.ArrayList;
	import java.util.List;

	import org.eclipse.core.commands.AbstractParameterValueConverter;
	import org.eclipse.core.commands.Category;
	import org.eclipse.core.commands.Command;
	import org.eclipse.core.commands.ParameterType;
	import org.eclipse.core.commands.State;
	import org.eclipse.core.commands.common.HandleObject;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExtensionDelta;
	import org.eclipse.core.runtime.IExtensionRegistry;
	import org.eclipse.core.runtime.IRegistryChangeEvent;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.ui.PlatformUI;
	import org.eclipse.ui.commands.ICommandService;
	import org.eclipse.ui.internal.WorkbenchMessages;
	import org.eclipse.ui.internal.registry.IWorkbenchRegistryConstants;
	import org.eclipse.ui.internal.services.RegistryPersistence;
	import org.eclipse.ui.internal.util.PrefUtil;

	/**
	* <p>
	* A static class for accessing the registry and the preference store.
	* </p>
	*
	* @since 3.1
	*/
	final class CommandPersistence extends RegistryPersistence {

	/**
	* The index of the category elements in the indexed array.
	*
	* @see CommandPersistence#read()
	*/
	private static final int INDEX_CATEGORY_DEFINITIONS = 0;

	/**
	* The index of the command elements in the indexed array.
	*
	* @see CommandPersistence#read()
	*/
	private static final int INDEX_COMMAND_DEFINITIONS = 1;

	/**
	* The index of the commandParameterType elements in the indexed array.
	*
	* @see CommandPersistence#read()
	* @since 3.2
	*/
	private static final int INDEX_PARAMETER_TYPE_DEFINITIONS = 2;

	/**
	* Reads all of the category definitions from the commands extension point.
	*
	* @param configurationElements
	* The configuration elements in the commands extension point;
	* must not be <code>null</code>, but may be empty.
	* @param configurationElementCount
	* The number of configuration elements that are really in the
	* array.
	* @param commandService
	* The command service to which the categories should be added;
	* must not be <code>null</code>.
	*/
	private static final void readCategoriesFromRegistry(
	final IConfigurationElement[] configurationElements,
	final int configurationElementCount,
	final ICommandService commandService) {
	// Undefine all the previous handle objects.
	final HandleObject[] handleObjects = commandService
	.getDefinedCategories();
	if (handleObjects != null) {
	for (int i = 0; i < handleObjects.length; i++) {
	handleObjects[i].undefine();
	}
	}

	// Define the uncategorized category.
	commandService
	.defineUncategorizedCategory(
	WorkbenchMessages.CommandService_AutogeneratedCategoryName,
	WorkbenchMessages.CommandService_AutogeneratedCategoryDescription);

	final List warningsToLog = new ArrayList(1);

	for (int i = 0; i < configurationElementCount; i++) {
	final IConfigurationElement configurationElement = configurationElements[i];

	// Read out the category identifier.
	final String categoryId = readRequired(configurationElement,
	ATT_ID, warningsToLog, "Categories need an id"); //$NON-NLS-1$
	if (categoryId == null) {
	continue;
	}

	// Read out the name.
	final String name = readRequired(configurationElement, ATT_NAME,
	warningsToLog, "Categories need a name", //$NON-NLS-1$
	categoryId);
	if (name == null) {
	continue;
	}

	// Read out the description.
	final String description = readOptional(configurationElement,
	ATT_DESCRIPTION);

	final Category category = commandService.getCategory(categoryId);
	category.define(name, description);
	}

	// If there were any warnings, then log them now.
	logWarnings(
	warningsToLog,
	"Warnings while parsing the commands from the 'org.eclipse.ui.commands' and 'org.eclipse.ui.actionDefinitions' extension points."); //$NON-NLS-1$
	}

	/**
	* Reads all of the command definitions from the commands extension point.
	*
	* @param configurationElements
	* The configuration elements in the commands extension point;
	* must not be <code>null</code>, but may be empty.
	* @param configurationElementCount
	* The number of configuration elements that are really in the
	* array.
	* @param commandService
	* The command service to which the commands should be added;
	* must not be <code>null</code>.
	*/
	private static final void readCommandsFromRegistry(
	final IConfigurationElement[] configurationElements,
	final int configurationElementCount,
	final ICommandService commandService) {
	// Undefine all the previous handle objects.
	final HandleObject[] handleObjects = commandService
	.getDefinedCommands();
	if (handleObjects != null) {
	for (int i = 0; i < handleObjects.length; i++) {
	handleObjects[i].undefine();
	}
	}

	final List warningsToLog = new ArrayList(1);

	for (int i = 0; i < configurationElementCount; i++) {
	final IConfigurationElement configurationElement = configurationElements[i];

	// Read out the command identifier.
	final String commandId = readRequired(configurationElement, ATT_ID,
	warningsToLog, "Commands need an id"); //$NON-NLS-1$
	if (commandId == null) {
	continue;
	}

	// Read out the name.
	final String name = readRequired(configurationElement, ATT_NAME,
	warningsToLog, "Commands need a name"); //$NON-NLS-1$
	if (name == null) {
	continue;
	}

	// Read out the description.
	final String description = readOptional(configurationElement,
	ATT_DESCRIPTION);

	// Read out the category id.
	String categoryId = configurationElement
	.getAttribute(ATT_CATEGORY_ID);
	if ((categoryId == null) \|\| (categoryId.length() == 0)) {
	categoryId = configurationElement.getAttribute(ATT_CATEGORY);
	if ((categoryId != null) && (categoryId.length() == 0)) {
	categoryId = null;
	}
	}

	// Read out the parameters.
	final Parameter[] parameters = readParameters(configurationElement,
	warningsToLog, commandService);

	// Read out the returnTypeId.
	final String returnTypeId = readOptional(configurationElement,
	ATT_RETURN_TYPE_ID);

	// Read out the help context identifier.
	final String helpContextId = readOptional(configurationElement,
	ATT_HELP_CONTEXT_ID);

	final Command command = commandService.getCommand(commandId);
	final Category category = commandService.getCategory(categoryId);
	if (!category.isDefined()) {
	addWarning(
	warningsToLog,
	"Commands should really have a category", //$NON-NLS-1$
	configurationElement, commandId,
	"categoryId", categoryId); //$NON-NLS-1$
	}

	final ParameterType returnType;
	if (returnTypeId == null) {
	returnType = null;
	} else {
	returnType = commandService.getParameterType(returnTypeId);
	}

	command.define(name, description, category, parameters, returnType,
	helpContextId);
	readState(configurationElement, warningsToLog, command);
	}

	// If there were any warnings, then log them now.
	logWarnings(
	warningsToLog,
	"Warnings while parsing the commands from the 'org.eclipse.ui.commands' and 'org.eclipse.ui.actionDefinitions' extension points."); //$NON-NLS-1$
	}

	/**
	* Reads the parameters from a parent configuration element. This is used to
	* read the parameter sub-elements from a command element. Each parameter is
	* guaranteed to be valid. If invalid parameters are found, then a warning
	* status will be appended to the <code>warningsToLog</code> list.
	*
	* @param configurationElement
	* The configuration element from which the parameters should be
	* read; must not be <code>null</code>.
	* @param warningsToLog
	* The list of warnings found during parsing. Warnings found
	* while parsing the parameters will be appended to this list.
	* This value must not be <code>null</code>.
	* @param commandService
	* The command service from which the parameter can get parameter
	* types; must not be <code>null</code>.
	* @return The array of parameters found for this configuration element;
	* <code>null</code> if none can be found.
	*/
	private static final Parameter[] readParameters(
	final IConfigurationElement configurationElement,
	final List warningsToLog, final ICommandService commandService) {
	final IConfigurationElement[] parameterElements = configurationElement
	.getChildren(TAG_COMMAND_PARAMETER);
	if ((parameterElements == null) \|\| (parameterElements.length == 0)) {
	return null;
	}

	int insertionIndex = 0;
	Parameter[] parameters = new Parameter[parameterElements.length];
	for (int i = 0; i < parameterElements.length; i++) {
	final IConfigurationElement parameterElement = parameterElements[i];
	// Read out the id
	final String id = readRequired(parameterElement, ATT_ID,
	warningsToLog, "Parameters need an id"); //$NON-NLS-1$
	if (id == null) {
	continue;
	}

	// Read out the name.
	final String name = readRequired(parameterElement, ATT_NAME,
	warningsToLog, "Parameters need a name"); //$NON-NLS-1$
	if (name == null) {
	continue;
	}

	/*
	* The IParameterValues will be initialized lazily as an
	* IExecutableExtension.
	*/

	// Read out the typeId attribute, if present.
	final String typeId = readOptional(parameterElement, ATT_TYPE_ID);

	// Read out the optional attribute, if present.
	final boolean optional = readBoolean(parameterElement,
	ATT_OPTIONAL, true);

	final ParameterType type;
	if (typeId == null) {
	type = null;
	} else {
	type = commandService.getParameterType(typeId);
	}

	final Parameter parameter = new Parameter(id, name,
	parameterElement, type, optional);
	parameters[insertionIndex++] = parameter;
	}

	if (insertionIndex != parameters.length) {
	final Parameter[] compactedParameters = new Parameter[insertionIndex];
	System.arraycopy(parameters, 0, compactedParameters, 0,
	insertionIndex);
	parameters = compactedParameters;
	}

	return parameters;
	}

	/**
	* Reads all of the commandParameterType definitions from the commands
	* extension point.
	*
	* @param configurationElements
	* The configuration elements in the commands extension point;
	* must not be <code>null</code>, but may be empty.
	* @param configurationElementCount
	* The number of configuration elements that are really in the
	* array.
	* @param commandService
	* The command service to which the commands should be added;
	* must not be <code>null</code>.
	* @since 3.2
	*/
	private static final void readParameterTypesFromRegistry(
	final IConfigurationElement[] configurationElements,
	final int configurationElementCount,
	final ICommandService commandService) {

	// Undefine all the previous handle objects.
	final HandleObject[] handleObjects = commandService
	.getDefinedParameterTypes();
	if (handleObjects != null) {
	for (int i = 0; i < handleObjects.length; i++) {
	handleObjects[i].undefine();
	}
	}

	final List warningsToLog = new ArrayList(1);

	for (int i = 0; i < configurationElementCount; i++) {
	final IConfigurationElement configurationElement = configurationElements[i];

	// Read out the commandParameterType identifier.
	final String parameterTypeId = readRequired(configurationElement,
	ATT_ID, warningsToLog, "Command parameter types need an id"); //$NON-NLS-1$
	if (parameterTypeId == null) {
	continue;
	}

	// Read out the type.
	final String type = readOptional(configurationElement, ATT_TYPE);

	// Read out the converter.
	final String converter = readOptional(configurationElement,
	ATT_CONVERTER);

	/*
	* if the converter attribute was given, create a proxy
	* AbstractParameterValueConverter for the ParameterType, otherwise
	* null indicates there is no converter
	*/
	final AbstractParameterValueConverter parameterValueConverter = (converter == null) ? null
	: new ParameterValueConverterProxy(configurationElement);

	final ParameterType parameterType = commandService
	.getParameterType(parameterTypeId);
	parameterType.define(type, parameterValueConverter);
	}

	// If there were any warnings, then log them now.
	logWarnings(
	warningsToLog,
	"Warnings while parsing the commandParameterTypes from the 'org.eclipse.ui.commands' extension point."); //$NON-NLS-1$

	}

	/**
	* Reads the states from a parent configuration element. This is used to
	* read the state sub-elements from a command element. Each state is
	* guaranteed to be valid. If invalid states are found, then a warning
	* status will be appended to the <code>warningsToLog</code> list.
	*
	* @param configurationElement
	* The configuration element from which the states should be
	* read; must not be <code>null</code>.
	* @param warningsToLog
	* The list of warnings found during parsing. Warnings found
	* while parsing the parameters will be appended to this list.
	* This value must not be <code>null</code>.
	* @param command
	* The command for which the state is being read; may be
	* <code>null</code>.
	*/
	private static final void readState(
	final IConfigurationElement configurationElement,
	final List warningsToLog, final Command command) {
	final IConfigurationElement[] stateElements = configurationElement
	.getChildren(TAG_STATE);
	if ((stateElements == null) \|\| (stateElements.length == 0)) {
	return;
	}

	for (int i = 0; i < stateElements.length; i++) {
	final IConfigurationElement stateElement = stateElements[i];

	final String id = readRequired(stateElement, ATT_ID, warningsToLog,
	"State needs an id"); //$NON-NLS-1$
	if (id == null) {
	continue;
	}

	if (checkClass(stateElement, warningsToLog,
	"State must have an associated class", id)) { //$NON-NLS-1$
	final State state = new CommandStateProxy(stateElement,
	ATT_CLASS, PrefUtil.getInternalPreferenceStore(),
	CommandService.createPreferenceKey(command, id));
	command.addState(id, state);
	}
	}
	}

	/**
	* The command service with which this persistence class is associated;
	* never <code>null</code>.
	*/
	private final ICommandService commandService;

	/**
	* Constructs a new instance of <code>CommandPersistence</code>.
	*
	* @param commandService
	* The command service which should be populated with the values
	* from the registry; must not be <code>null</code>.
	*/
	CommandPersistence(final ICommandService commandService) {
	if (commandService == null) {
	throw new NullPointerException("The command service cannot be null"); //$NON-NLS-1$
	}
	this.commandService = commandService;
	}

	protected final boolean isChangeImportant(final IRegistryChangeEvent event) {
	final IExtensionDelta[] commandDeltas = event.getExtensionDeltas(
	PlatformUI.PLUGIN_ID, IWorkbenchRegistryConstants.PL_COMMANDS);
	if (commandDeltas.length == 0) {
	final IExtensionDelta[] actionDefinitionDeltas = event
	.getExtensionDeltas(PlatformUI.PLUGIN_ID,
	IWorkbenchRegistryConstants.PL_ACTION_DEFINITIONS);
	if (actionDefinitionDeltas.length == 0) {
	return false;
	}
	}

	return true;
	}

	/**
	* Reads all of the commands and categories from the registry,
	*
	* @param commandService
	* The command service which should be populated with the values
	* from the registry; must not be <code>null</code>.
	*/
	protected final void read() {
	super.read();

	// Create the extension registry mementos.
	final IExtensionRegistry registry = Platform.getExtensionRegistry();
	int commandDefinitionCount = 0;
	int categoryDefinitionCount = 0;
	int parameterTypeDefinitionCount = 0;
	final IConfigurationElement[][] indexedConfigurationElements = new IConfigurationElement[3][];

	// Sort the commands extension point based on element name.
	final IConfigurationElement[] commandsExtensionPoint = registry
	.getConfigurationElementsFor(EXTENSION_COMMANDS);
	for (int i = 0; i < commandsExtensionPoint.length; i++) {
	final IConfigurationElement configurationElement = commandsExtensionPoint[i];
	final String name = configurationElement.getName();

	// Check if it is a binding definition.
	if (TAG_COMMAND.equals(name)) {
	addElementToIndexedArray(configurationElement,
	indexedConfigurationElements,
	INDEX_COMMAND_DEFINITIONS, commandDefinitionCount++);
	} else if (TAG_CATEGORY.equals(name)) {
	addElementToIndexedArray(configurationElement,
	indexedConfigurationElements,
	INDEX_CATEGORY_DEFINITIONS, categoryDefinitionCount++);
	} else if (TAG_COMMAND_PARAMETER_TYPE.equals(name)) {
	addElementToIndexedArray(configurationElement,
	indexedConfigurationElements,
	INDEX_PARAMETER_TYPE_DEFINITIONS,
	parameterTypeDefinitionCount++);
	}
	}

	final IConfigurationElement[] actionDefinitionsExtensionPoint = registry
	.getConfigurationElementsFor(EXTENSION_ACTION_DEFINITIONS);
	for (int i = 0; i < actionDefinitionsExtensionPoint.length; i++) {
	final IConfigurationElement configurationElement = actionDefinitionsExtensionPoint[i];
	final String name = configurationElement.getName();

	if (TAG_ACTION_DEFINITION.equals(name)) {
	addElementToIndexedArray(configurationElement,
	indexedConfigurationElements,
	INDEX_COMMAND_DEFINITIONS, commandDefinitionCount++);
	}
	}

	readCategoriesFromRegistry(
	indexedConfigurationElements[INDEX_CATEGORY_DEFINITIONS],
	categoryDefinitionCount, commandService);
	readCommandsFromRegistry(
	indexedConfigurationElements[INDEX_COMMAND_DEFINITIONS],
	commandDefinitionCount, commandService);
	readParameterTypesFromRegistry(
	indexedConfigurationElements[INDEX_PARAMETER_TYPE_DEFINITIONS],
	parameterTypeDefinitionCount, commandService);

	}
	}