bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/actions/CommonActionProviderDescriptor.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2003, 2007 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.navigator.actions;

 import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.Set;
 import java.util.TreeSet;

 import org.eclipse.core.expressions.ElementHandler;
 import org.eclipse.core.expressions.EvaluationContext;
 import org.eclipse.core.expressions.EvaluationResult;
 import org.eclipse.core.expressions.Expression;
 import org.eclipse.core.expressions.ExpressionConverter;
 import org.eclipse.core.expressions.IEvaluationContext;
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.ui.internal.navigator.CustomAndExpression;
 import org.eclipse.ui.internal.navigator.NavigatorPlugin;
 import org.eclipse.ui.internal.navigator.extensions.INavigatorContentExtPtConstants;
 import org.eclipse.ui.internal.navigator.extensions.SkeletonActionProvider;
 import org.eclipse.ui.navigator.CommonActionProvider;
 import org.eclipse.ui.navigator.Priority;

 /**
  *
  *
  * @since 3.2
  */
 public class CommonActionProviderDescriptor implements
 		INavigatorContentExtPtConstants {

 	private static final String DEFAULT_ID = "org.eclipse.ui.navigator.actionProvider"; //$NON-NLS-1$

 	private static int count = 0;

 	private final IConfigurationElement configurationElement;

 	private final boolean isNested;

 	private Set dependentDescriptors;

 	private Set overridingDescriptors;

 	private IConfigurationElement enablementElement;

 	private Expression enablement;

 	private boolean hasLoadingFailed;

 	private String definedId;

 	private String visibilityId;

 	private String dependsOnId;

 	private String overridesId;

 	private String toString;

 	private Priority priority;

 	/**
 	 * @param aConfigElement
 	 *            A configuration element with the name "actionProvider" and a
 	 *            "class" attribute which subclasses
 	 *            {@link CommonActionProvider}.
 	 */
 	public CommonActionProviderDescriptor(IConfigurationElement aConfigElement) {
 		super();
 		Assert.isTrue(TAG_ACTION_PROVIDER.equals(aConfigElement.getName()));
 		configurationElement = aConfigElement;
 		isNested = false;
 		init();
 	}

 	/**
 	 * @param aConfigElement
 	 *            A configuration element with the name "actionProvider" and a
 	 *            "class" attribute which subclasses
 	 *            {@link CommonActionProvider}.
 	 * @param anEnablementExpression
 	 *            A configuration element with the name 'enablement' or
 	 *            'triggerPoints' and containing an Eclipse Core Expression
 	 * @param defaultPriority
 	 * @param anOverrideId
 	 *            A unique identifier for this descriptor. Ids can be used as a
 	 *            filtering device for activities or viewer***Bindings.
 	 * @param nestedUnderNavigatorContent
 	 *            A value of <b>true</b> indicates that this
 	 *            CommonActionProvider was declared as a nested
 	 *            &lt;actionProvider /&gt; element under a &lt;navigatorContent
 	 *            /&gt; element.
 	 */
 	public CommonActionProviderDescriptor(IConfigurationElement aConfigElement,
 			IConfigurationElement anEnablementExpression, Priority defaultPriority, String anOverrideId,
 			boolean nestedUnderNavigatorContent) {
 		super();
 		Assert.isTrue(TAG_ACTION_PROVIDER.equals(aConfigElement.getName()));
 		Assert.isTrue(TAG_POSSIBLE_CHILDREN.equals(anEnablementExpression
 				.getName())
 				|| TAG_ENABLEMENT.equals(anEnablementExpression.getName()));
 		configurationElement = aConfigElement;
 		enablementElement = anEnablementExpression;
 		visibilityId = anOverrideId;
 		isNested = nestedUnderNavigatorContent;
 		priority = defaultPriority;
 		init();
 	}

 	private void init() {

 		try {

 			definedId = configurationElement.getAttribute(ATT_ID);

 			// if there was no id attribute, use the default id.
 			if (definedId == null) {
 				definedId = DEFAULT_ID + "." + count++; //$NON-NLS-1$
 			}

 			// we try the id attribute if no override id was supplied.
 			if (visibilityId == null) {
 				visibilityId = definedId;
 			}

 			dependsOnId = configurationElement.getAttribute(ATT_DEPENDS_ON);

 			overridesId = configurationElement.getAttribute(ATT_OVERRIDES);

 			if(priority == null) {
 				String prio = configurationElement.getAttribute(ATT_PRIORITY);
 				if(prio != null)
 					priority = Priority.get(prio);
 				else
 					priority = Priority.NORMAL;
 			}

 			IConfigurationElement[] children = configurationElement
 					.getChildren(TAG_ENABLEMENT);
 			// if no child enablement is specified, and we have an override, use
 			// it
 			if (children.length == 0 && enablementElement != null) {
 				enablement = new CustomAndExpression(enablementElement);
 				// otherwise the child enablement takes priority
 			} else if (children.length == 1) {
 				enablement = ElementHandler.getDefault().create(
 						ExpressionConverter.getDefault(), children[0]);

 			} else {
 				System.err.println("Incorrect number of expressions: " + //$NON-NLS-1$
 						TAG_ENABLEMENT
 						+ " in navigator extension: " + //$NON-NLS-1$
 						configurationElement.getDeclaringExtension()
 								.getUniqueIdentifier() + " in plugin " + //$NON-NLS-1$
 								configurationElement.getDeclaringExtension().getNamespaceIdentifier());
 			}
 		} catch (CoreException e) {
 			NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
 		}
 	}

 	/**
 	 *
 	 * @return The instantiated CommonActionProvider for this descriptor as
 	 *         declared in the ATT_CLASS attribute or
 	 *         {@link SkeletonActionProvider} if a problem occurs while loading
 	 *         the instance.
 	 */
 	public CommonActionProvider createActionProvider() {
 		if (hasLoadingFailed) {
 			return SkeletonActionProvider.INSTANCE;
 		}
 		CommonActionProvider provider = null;
 		try {
 			provider = (CommonActionProvider) configurationElement
 					.createExecutableExtension(ATT_CLASS);
 		} catch (CoreException exception) {
 			NavigatorPlugin.log(exception.getStatus());
 			hasLoadingFailed = true;
 			provider = SkeletonActionProvider.INSTANCE;
 		} catch (Exception e) {
 			NavigatorPlugin.log(new Status(IStatus.ERROR,
 					NavigatorPlugin.PLUGIN_ID, 0, e.getMessage(), e));
 			hasLoadingFailed = true;
 			provider = SkeletonActionProvider.INSTANCE;
 		}

 		return provider;
 	}

 	/**
 	 * Determine if this content extension is enabled for the given selection.
 	 * The content extension is enabled for the selection if and only if it is
 	 * enabled for each element in the selection.
 	 *
 	 * @param aStructuredSelection
 	 *            The selection from the viewer
 	 * @return True if and only if the extension is enabled for each element in
 	 *         the selection.
 	 */
 	public boolean isEnabledFor(IStructuredSelection aStructuredSelection) {
 		if (enablement == null) {
 			return false;
 		}

 		if(aStructuredSelection.isEmpty()) {
 			IEvaluationContext context = null;
 			context = new EvaluationContext(null, Collections.EMPTY_LIST);
 			context.setAllowPluginActivation(true);
 			try {
 				if (enablement.evaluate(context) != EvaluationResult.TRUE) {
 					return false;
 				}
 			} catch (CoreException e) {
 				NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
 				return false;
 			}
 		} else {

 			IEvaluationContext context = null;
 			Iterator elements = aStructuredSelection.iterator();
 			while (elements.hasNext()) {
 				context = new EvaluationContext(null, elements.next());
 				context.setAllowPluginActivation(true);
 				try {
 					if (enablement.evaluate(context) != EvaluationResult.TRUE) {
 						return false;
 					}
 				} catch (CoreException e) {
 					NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
 					return false;
 				}
 			}
 		}
 		return true;
 	}

 	/**
 	 * Determine if this content extension is enabled for the given element.
 	 *
 	 * @param anElement
 	 *            The element that should be used for the evaluation.
 	 * @return True if and only if the extension is enabled for the element.
 	 */
 	public boolean isEnabledFor(Object anElement) {
 		if (enablement == null || anElement == null) {
 			return false;
 		}

 		try {
 			EvaluationContext context = new EvaluationContext(null, anElement);
 			context.setAllowPluginActivation(true);
 			return (enablement.evaluate(context) == EvaluationResult.TRUE);
 		} catch (CoreException e) {
 			NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
 		}
 		return false;
 	}

 	/**
 	 *
 	 * @return An identifier for this ICommonActionProvider. Defaults to
 	 *         "org.eclipse.ui.navigator.actionProvider". May not be unique.
 	 *         Used to filter the actionProvider using the visibility state
 	 *         information.
 	 */
 	public String getId() {
 		return visibilityId;
 	}

 	/**
 	 *
 	 * @return An identifier for this ICommonActionProvider. Defaults to
 	 *         'org.eclipse.ui.navigator.actionProvider'. May not be unique.
 	 *         Used to determine override or depends on cases.
 	 */
 	public String getDefinedId() {
 		return definedId;
 	}

 	/**
 	 *
 	 * @return True if this is a nested &lt;actionProvider /&gt; element.
 	 */
 	public boolean isNested() {
 		return isNested;
 	}

 	/**
 	 *
 	 * @return The value specified by the <i>dependsOn</i> attribute of the
 	 *         &lt;actionProvider /&gt; element.
 	 */
 	public String getDependsOnId() {
 		return dependsOnId;
 	}

 	/**
 	 *
 	 * @return The value specified by the <i>overridesId</i> attribute of the
 	 *         &lt;actionProvider /&gt; element.
 	 */
 	public String getOverridesId() {
 		return overridesId;
 	}

 	/**
 	 * Only nested Action Providers have priority (as of 3.2.1).
 	 *
 	 * @return The priority associated with this Action Provider Descriptor.
 	 */
 	public Priority getPriority() {
 		return priority;
 	}


 	public int hashCode() {
 		final int PRIME = 31;
 		int result = 1;
 		result = PRIME * result + ((definedId == null) ? 0 : definedId.hashCode());
 		result = PRIME * result + ((visibilityId == null) ? 0 : visibilityId.hashCode());
 		return result;
 	}

 	public boolean equals(Object obj) {
 		if (this == obj)
 			return true;
 		if (!super.equals(obj))
 			return false;
 		if (getClass() != obj.getClass())
 			return false;
 		final CommonActionProviderDescriptor other = (CommonActionProviderDescriptor) obj;
 		if (definedId == null) {
 			if (other.definedId != null)
 				return false;
 		} else if (!definedId.equals(other.definedId))
 			return false;
 		if (visibilityId == null) {
 			if (other.visibilityId != null)
 				return false;
 		} else if (!visibilityId.equals(other.visibilityId))
 			return false;
 		return true;
 	}


 	protected void addDependentDescriptor(
 			CommonActionProviderDescriptor dependentDescriptor) {
 		Assert.isTrue(this != dependentDescriptor);
 		if (dependentDescriptors == null) {
 			dependentDescriptors = new LinkedHashSet();
 		}
 		dependentDescriptors.add(dependentDescriptor);
 	}

 	protected void addOverridingDescriptor(
 			CommonActionProviderDescriptor overridingDescriptor) {
 		Assert.isTrue(this != overridingDescriptor);
 		if (overridingDescriptors == null) {
 			overridingDescriptors = new TreeSet(CommonActionProviderDescriptorCompator.INSTANCE);
 		}
 		overridingDescriptors.add(overridingDescriptor);
 	}

 	protected boolean hasDependentDescriptors() {
 		return dependentDescriptors != null && !dependentDescriptors.isEmpty();
 	}

 	protected boolean hasOverridingDescriptors() {
 		return overridingDescriptors != null
 				&& !overridingDescriptors.isEmpty();
 	}

 	protected Iterator dependentDescriptors() {
 		return dependentDescriptors.iterator();
 	}

 	protected Iterator overridingDescriptors() {
 		return overridingDescriptors.iterator();
 	}

 	public String toString() {
 		if (toString == null) {
 			toString = "CommonActionProviderDescriptor[definedId=" + getDefinedId() + ", visibilityId=" + getId() + ", dependsOn=" + getDependsOnId() + ", overrides=" + getOverridesId() + "]"; //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$
 		}
 		return toString;
 	}


 	/**
 	 * Sorts CommonActionProviderDescriptors by priority, and then by defined id.
 	 * @since 3.2
 	 *
 	 */
 	public static class CommonActionProviderDescriptorCompator implements Comparator {

 		/**
 		 * The singleton instance.
 		 */
 		public static final CommonActionProviderDescriptorCompator INSTANCE = new CommonActionProviderDescriptorCompator();

 		private static final int LESS_THAN = -1;
 		private static final int EQUALS = 0;

 		/* (non-Javadoc)
 		 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
 		 */
 		public int compare(Object o1, Object o2) {
 			CommonActionProviderDescriptor lvalue= null, rvalue= null;

 			if(o1 instanceof CommonActionProviderDescriptor)
 				lvalue = (CommonActionProviderDescriptor) o1;

 			if(o2 instanceof CommonActionProviderDescriptor)
 				rvalue = (CommonActionProviderDescriptor) o2;

 			if(lvalue == null || rvalue == null)
 				return LESS_THAN;
 			if(lvalue.equals(rvalue))
 				return EQUALS;
 			int comparison = lvalue.getPriority().getValue() - rvalue.getPriority().getValue();
 			if(comparison == 0)
 				return lvalue.getDefinedId().compareTo(rvalue.getDefinedId());
 			return comparison;

 		}


 	}

 }
	/*******************************************************************************
	* Copyright (c) 2003, 2007 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.navigator.actions;

	import java.util.Collections;
	import java.util.Comparator;
	import java.util.Iterator;
	import java.util.LinkedHashSet;
	import java.util.Set;
	import java.util.TreeSet;

	import org.eclipse.core.expressions.ElementHandler;
	import org.eclipse.core.expressions.EvaluationContext;
	import org.eclipse.core.expressions.EvaluationResult;
	import org.eclipse.core.expressions.Expression;
	import org.eclipse.core.expressions.ExpressionConverter;
	import org.eclipse.core.expressions.IEvaluationContext;
	import org.eclipse.core.runtime.Assert;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.ui.internal.navigator.CustomAndExpression;
	import org.eclipse.ui.internal.navigator.NavigatorPlugin;
	import org.eclipse.ui.internal.navigator.extensions.INavigatorContentExtPtConstants;
	import org.eclipse.ui.internal.navigator.extensions.SkeletonActionProvider;
	import org.eclipse.ui.navigator.CommonActionProvider;
	import org.eclipse.ui.navigator.Priority;

	/**
	*
	*
	* @since 3.2
	*/
	public class CommonActionProviderDescriptor implements
	INavigatorContentExtPtConstants {

	private static final String DEFAULT_ID = "org.eclipse.ui.navigator.actionProvider"; //$NON-NLS-1$

	private static int count = 0;

	private final IConfigurationElement configurationElement;

	private final boolean isNested;

	private Set dependentDescriptors;

	private Set overridingDescriptors;

	private IConfigurationElement enablementElement;

	private Expression enablement;

	private boolean hasLoadingFailed;

	private String definedId;

	private String visibilityId;

	private String dependsOnId;

	private String overridesId;

	private String toString;

	private Priority priority;

	/**
	* @param aConfigElement
	* A configuration element with the name "actionProvider" and a
	* "class" attribute which subclasses
	* {@link CommonActionProvider}.
	*/
	public CommonActionProviderDescriptor(IConfigurationElement aConfigElement) {
	super();
	Assert.isTrue(TAG_ACTION_PROVIDER.equals(aConfigElement.getName()));
	configurationElement = aConfigElement;
	isNested = false;
	init();
	}

	/**
	* @param aConfigElement
	* A configuration element with the name "actionProvider" and a
	* "class" attribute which subclasses
	* {@link CommonActionProvider}.
	* @param anEnablementExpression
	* A configuration element with the name 'enablement' or
	* 'triggerPoints' and containing an Eclipse Core Expression
	* @param defaultPriority
	* @param anOverrideId
	* A unique identifier for this descriptor. Ids can be used as a
	* filtering device for activities or viewer***Bindings.
	* @param nestedUnderNavigatorContent
	* A value of <b>true</b> indicates that this
	* CommonActionProvider was declared as a nested
	* <actionProvider /> element under a <navigatorContent
	* /> element.
	*/
	public CommonActionProviderDescriptor(IConfigurationElement aConfigElement,
	IConfigurationElement anEnablementExpression, Priority defaultPriority, String anOverrideId,
	boolean nestedUnderNavigatorContent) {
	super();
	Assert.isTrue(TAG_ACTION_PROVIDER.equals(aConfigElement.getName()));
	Assert.isTrue(TAG_POSSIBLE_CHILDREN.equals(anEnablementExpression
	.getName())
	\|\| TAG_ENABLEMENT.equals(anEnablementExpression.getName()));
	configurationElement = aConfigElement;
	enablementElement = anEnablementExpression;
	visibilityId = anOverrideId;
	isNested = nestedUnderNavigatorContent;
	priority = defaultPriority;
	init();
	}

	private void init() {

	try {

	definedId = configurationElement.getAttribute(ATT_ID);

	// if there was no id attribute, use the default id.
	if (definedId == null) {
	definedId = DEFAULT_ID + "." + count++; //$NON-NLS-1$
	}

	// we try the id attribute if no override id was supplied.
	if (visibilityId == null) {
	visibilityId = definedId;
	}

	dependsOnId = configurationElement.getAttribute(ATT_DEPENDS_ON);

	overridesId = configurationElement.getAttribute(ATT_OVERRIDES);

	if(priority == null) {
	String prio = configurationElement.getAttribute(ATT_PRIORITY);
	if(prio != null)
	priority = Priority.get(prio);
	else
	priority = Priority.NORMAL;
	}

	IConfigurationElement[] children = configurationElement
	.getChildren(TAG_ENABLEMENT);
	// if no child enablement is specified, and we have an override, use
	// it
	if (children.length == 0 && enablementElement != null) {
	enablement = new CustomAndExpression(enablementElement);
	// otherwise the child enablement takes priority
	} else if (children.length == 1) {
	enablement = ElementHandler.getDefault().create(
	ExpressionConverter.getDefault(), children[0]);

	} else {
	System.err.println("Incorrect number of expressions: " + //$NON-NLS-1$
	TAG_ENABLEMENT
	+ " in navigator extension: " + //$NON-NLS-1$
	configurationElement.getDeclaringExtension()
	.getUniqueIdentifier() + " in plugin " + //$NON-NLS-1$
	configurationElement.getDeclaringExtension().getNamespaceIdentifier());
	}
	} catch (CoreException e) {
	NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
	}
	}

	/**
	*
	* @return The instantiated CommonActionProvider for this descriptor as
	* declared in the ATT_CLASS attribute or
	* {@link SkeletonActionProvider} if a problem occurs while loading
	* the instance.
	*/
	public CommonActionProvider createActionProvider() {
	if (hasLoadingFailed) {
	return SkeletonActionProvider.INSTANCE;
	}
	CommonActionProvider provider = null;
	try {
	provider = (CommonActionProvider) configurationElement
	.createExecutableExtension(ATT_CLASS);
	} catch (CoreException exception) {
	NavigatorPlugin.log(exception.getStatus());
	hasLoadingFailed = true;
	provider = SkeletonActionProvider.INSTANCE;
	} catch (Exception e) {
	NavigatorPlugin.log(new Status(IStatus.ERROR,
	NavigatorPlugin.PLUGIN_ID, 0, e.getMessage(), e));
	hasLoadingFailed = true;
	provider = SkeletonActionProvider.INSTANCE;
	}

	return provider;
	}

	/**
	* Determine if this content extension is enabled for the given selection.
	* The content extension is enabled for the selection if and only if it is
	* enabled for each element in the selection.
	*
	* @param aStructuredSelection
	* The selection from the viewer
	* @return True if and only if the extension is enabled for each element in
	* the selection.
	*/
	public boolean isEnabledFor(IStructuredSelection aStructuredSelection) {
	if (enablement == null) {
	return false;
	}

	if(aStructuredSelection.isEmpty()) {
	IEvaluationContext context = null;
	context = new EvaluationContext(null, Collections.EMPTY_LIST);
	context.setAllowPluginActivation(true);
	try {
	if (enablement.evaluate(context) != EvaluationResult.TRUE) {
	return false;
	}
	} catch (CoreException e) {
	NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
	return false;
	}
	} else {

	IEvaluationContext context = null;
	Iterator elements = aStructuredSelection.iterator();
	while (elements.hasNext()) {
	context = new EvaluationContext(null, elements.next());
	context.setAllowPluginActivation(true);
	try {
	if (enablement.evaluate(context) != EvaluationResult.TRUE) {
	return false;
	}
	} catch (CoreException e) {
	NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
	return false;
	}
	}
	}
	return true;
	}

	/**
	* Determine if this content extension is enabled for the given element.
	*
	* @param anElement
	* The element that should be used for the evaluation.
	* @return True if and only if the extension is enabled for the element.
	*/
	public boolean isEnabledFor(Object anElement) {
	if (enablement == null \|\| anElement == null) {
	return false;
	}

	try {
	EvaluationContext context = new EvaluationContext(null, anElement);
	context.setAllowPluginActivation(true);
	return (enablement.evaluate(context) == EvaluationResult.TRUE);
	} catch (CoreException e) {
	NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
	}
	return false;
	}

	/**
	*
	* @return An identifier for this ICommonActionProvider. Defaults to
	* "org.eclipse.ui.navigator.actionProvider". May not be unique.
	* Used to filter the actionProvider using the visibility state
	* information.
	*/
	public String getId() {
	return visibilityId;
	}

	/**
	*
	* @return An identifier for this ICommonActionProvider. Defaults to
	* 'org.eclipse.ui.navigator.actionProvider'. May not be unique.
	* Used to determine override or depends on cases.
	*/
	public String getDefinedId() {
	return definedId;
	}

	/**
	*
	* @return True if this is a nested <actionProvider /> element.
	*/
	public boolean isNested() {
	return isNested;
	}

	/**
	*
	* @return The value specified by the <i>dependsOn</i> attribute of the
	* <actionProvider /> element.
	*/
	public String getDependsOnId() {
	return dependsOnId;
	}

	/**
	*
	* @return The value specified by the <i>overridesId</i> attribute of the
	* <actionProvider /> element.
	*/
	public String getOverridesId() {
	return overridesId;
	}

	/**
	* Only nested Action Providers have priority (as of 3.2.1).
	*
	* @return The priority associated with this Action Provider Descriptor.
	*/
	public Priority getPriority() {
	return priority;
	}


	public int hashCode() {
	final int PRIME = 31;
	int result = 1;
	result = PRIME * result + ((definedId == null) ? 0 : definedId.hashCode());
	result = PRIME * result + ((visibilityId == null) ? 0 : visibilityId.hashCode());
	return result;
	}

	public boolean equals(Object obj) {
	if (this == obj)
	return true;
	if (!super.equals(obj))
	return false;
	if (getClass() != obj.getClass())
	return false;
	final CommonActionProviderDescriptor other = (CommonActionProviderDescriptor) obj;
	if (definedId == null) {
	if (other.definedId != null)
	return false;
	} else if (!definedId.equals(other.definedId))
	return false;
	if (visibilityId == null) {
	if (other.visibilityId != null)
	return false;
	} else if (!visibilityId.equals(other.visibilityId))
	return false;
	return true;
	}



	protected void addDependentDescriptor(
	CommonActionProviderDescriptor dependentDescriptor) {
	Assert.isTrue(this != dependentDescriptor);
	if (dependentDescriptors == null) {
	dependentDescriptors = new LinkedHashSet();
	}
	dependentDescriptors.add(dependentDescriptor);
	}

	protected void addOverridingDescriptor(
	CommonActionProviderDescriptor overridingDescriptor) {
	Assert.isTrue(this != overridingDescriptor);
	if (overridingDescriptors == null) {
	overridingDescriptors = new TreeSet(CommonActionProviderDescriptorCompator.INSTANCE);
	}
	overridingDescriptors.add(overridingDescriptor);
	}

	protected boolean hasDependentDescriptors() {
	return dependentDescriptors != null && !dependentDescriptors.isEmpty();
	}

	protected boolean hasOverridingDescriptors() {
	return overridingDescriptors != null
	&& !overridingDescriptors.isEmpty();
	}

	protected Iterator dependentDescriptors() {
	return dependentDescriptors.iterator();
	}

	protected Iterator overridingDescriptors() {
	return overridingDescriptors.iterator();
	}

	public String toString() {
	if (toString == null) {
	toString = "CommonActionProviderDescriptor[definedId=" + getDefinedId() + ", visibilityId=" + getId() + ", dependsOn=" + getDependsOnId() + ", overrides=" + getOverridesId() + "]"; //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$
	}
	return toString;
	}


	/**
	* Sorts CommonActionProviderDescriptors by priority, and then by defined id.
	* @since 3.2
	*
	*/
	public static class CommonActionProviderDescriptorCompator implements Comparator {

	/**
	* The singleton instance.
	*/
	public static final CommonActionProviderDescriptorCompator INSTANCE = new CommonActionProviderDescriptorCompator();

	private static final int LESS_THAN = -1;
	private static final int EQUALS = 0;

	/* (non-Javadoc)
	* @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
	*/
	public int compare(Object o1, Object o2) {
	CommonActionProviderDescriptor lvalue= null, rvalue= null;

	if(o1 instanceof CommonActionProviderDescriptor)
	lvalue = (CommonActionProviderDescriptor) o1;

	if(o2 instanceof CommonActionProviderDescriptor)
	rvalue = (CommonActionProviderDescriptor) o2;

	if(lvalue == null \|\| rvalue == null)
	return LESS_THAN;
	if(lvalue.equals(rvalue))
	return EQUALS;
	int comparison = lvalue.getPriority().getValue() - rvalue.getPriority().getValue();
	if(comparison == 0)
	return lvalue.getDefinedId().compareTo(rvalue.getDefinedId());
	return comparison;

	}


	}

	}