examples/org.eclipse.ocl.examples.pivot/src/org/eclipse/ocl/examples/pivot/utilities/EnvironmentRegistryImpl.java - ocl/org.eclipse.ocl - Git at Google

 /**
  * <copyright>
  *
  * Copyright (c) 2006, 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 - Initial API and implementation
  *
  * </copyright>
  *
  * $Id: EnvironmentRegistryImpl.java,v 1.2 2011/04/25 09:49:15 ewillink Exp $
  */

 package org.eclipse.ocl.examples.pivot.utilities;

 import java.util.Map;
 import java.util.Set;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtension;
 import org.eclipse.core.runtime.IExtensionDelta;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IRegistryChangeEvent;
 import org.eclipse.core.runtime.IRegistryChangeListener;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.emf.common.util.BasicEList;
 import org.eclipse.emf.common.util.Diagnostic;
 import org.eclipse.emf.common.util.EList;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EPackage;
 import org.eclipse.ocl.examples.pivot.Environment;
 import org.eclipse.ocl.examples.pivot.EnvironmentFactory;
 import org.eclipse.ocl.examples.pivot.OclExpression;
 import org.eclipse.ocl.examples.pivot.Operation;
 import org.eclipse.ocl.examples.pivot.Property;
 import org.eclipse.ocl.examples.pivot.Type;
 import org.eclipse.ocl.examples.pivot.TypedElement;
 import org.eclipse.ocl.examples.pivot.messages.OCLMessages;
 import org.eclipse.ocl.examples.pivot.util.PivotPlugin;
 import org.eclipse.osgi.util.NLS;

 /**
  * Implementation of the environment registry.
  *
  * @author cdamus
  */
 public class EnvironmentRegistryImpl implements Environment.Registry {
 	private final EList<Object> environments = new BasicEList<Object>();

     private static final String PT_ENVIRONMENTS = "environments"; //$NON-NLS-1$
     private static final String E_ENVIRONMENT_FACTORY = "environmentFactory"; //$NON-NLS-1$
     private static final String A_CLASS = "class"; //$NON-NLS-1$
     private static final String E_PACKAGE = "package"; //$NON-NLS-1$
     private static final String A_NS_URI = "nsURI"; //$NON-NLS-1$

 	public Environment getEnvironmentFor(OclExpression expression) {
 		return getEnvironmentFor(expression.getType());
 	}

 	public Environment getEnvironmentFor(Object abstractSyntaxElement) {

 		if (abstractSyntaxElement instanceof TypedElement) {
 			return getEnvironmentFor(((TypedElement) abstractSyntaxElement).getType());
 		}

 		for (int i = 0; i < environments.size(); i++) {
 			Object next = environments.get(i);

 			if (next instanceof EnvironmentDescriptor) {
 				EnvironmentDescriptor descriptor = (EnvironmentDescriptor) next;

 				if (descriptor.matches(abstractSyntaxElement)) {
 					// instantiate the descriptor now
 					next = descriptor.instantiate();
 					environments.set(i, next);
 				}
 			}

 			if (next instanceof Environment) {
 				if ((abstractSyntaxElement instanceof Type)
 						|| (abstractSyntaxElement instanceof Operation)
 						|| (abstractSyntaxElement instanceof Property)) {

 					return (Environment) next;
 				}
 			}
 		}

 		return null;
 	}

 	public void registerEnvironment(Environment environment) {

 		if (!environments.contains(environment)) {
 			environments.add(environment);
 		}
 	}

     public void deregisterEnvironment(Environment environment) {
         environments.remove(environment);
     }

 	/**
 	 * Utility class that reads the Eclipse extension registry to find registered
 	 * OCL environments.
 	 *
 	 * @author cdamus
 	 */
 	class RegistryReader implements IRegistryChangeListener {
 		private final String namespace;
 		private IExtensionRegistry extensionRegistry;
 		private final Map<String, EnvironmentDescriptor> descriptors =
 			new java.util.HashMap<String, EnvironmentDescriptor>();

 		RegistryReader(PivotPlugin plugin) {
 			// FIXME
 			namespace = "org.eclipse.ocl"; //$NON-NLS-1$ //plugin.getSymbolicName();
 		}

 		void readRegistry() {
 			if (extensionRegistry == null) {
 				extensionRegistry = Platform.getExtensionRegistry();
 				readRegistryImpl();
 			}
 		}

 		private void readRegistryImpl() {
 			extensionRegistry.addRegistryChangeListener(this, namespace);

 			IExtension[] extensions = extensionRegistry.getExtensionPoint(
 					namespace, PT_ENVIRONMENTS).getExtensions();

 			for (IExtension extension : extensions) {
 				read(extension);
 			}
 		}

 		private void read(IExtension extension) {
 			IConfigurationElement[] elements = extension.getConfigurationElements();

 			for (IConfigurationElement element : elements) {
 				if (E_ENVIRONMENT_FACTORY.equals(element.getName())) {
 					readEnvironmentFactory(element);
 				} else {
 				    PivotPlugin.log(Diagnostic.ERROR, 1,
 				    	NLS.bind(
                             OCLMessages.EnvRegistry_unknownElement_ERROR_,
                             getExtensionID(extension),
                             element.getName()),
                         null);
                 }
 			}
 		}

 		private void readEnvironmentFactory(final IConfigurationElement element) {
 			String className = element.getAttribute(A_CLASS);

 			if (className != null) {
 				EnvironmentDescriptor descriptor = new EnvironmentDescriptor() {
 					@Override
 					EnvironmentFactory createFactory() {
 						try {
 							return (EnvironmentFactory)
 								element.createExecutableExtension(A_CLASS);
 						} catch (CoreException e) {
                             PivotPlugin.getPlugin().log(e);
 							return null;
 						}
 					}};
 				descriptors.put(className, descriptor);
 				environments.add(descriptor);

 				for (IConfigurationElement pkg : element.getChildren(E_PACKAGE)) {
 					readPackage(descriptor, pkg);
 				}
             } else {
                 PivotPlugin.log(Diagnostic.ERROR, 1,
                 	NLS.bind(
                         OCLMessages.EnvRegistry_missingClass_ERROR_,
                         getExtensionID(element)),
                     null);
 			}
 		}

 		private void readPackage(EnvironmentDescriptor descriptor,
 				IConfigurationElement element) {

 			String nsURI = element.getAttribute(A_NS_URI);
 			if (nsURI != null) {
 				descriptor.addPackageURI(nsURI);
             } else {
                 PivotPlugin.log(Diagnostic.ERROR, 1,
                 	NLS.bind(
                         OCLMessages.EnvRegistry_missingNsURI_ERROR_,
                         getExtensionID(element)),
                     null);
 			}
 		}

 		private void remove(IExtension extension) {
 			IConfigurationElement[] elements = extension.getConfigurationElements();

 			for (IConfigurationElement element : elements) {
 				if (E_ENVIRONMENT_FACTORY.equals(element.getName())) {
 					removeEnvironmentFactory(element);
 				}
 			}
 		}

 		private void removeEnvironmentFactory(IConfigurationElement element) {
 			String className = element.getAttribute(A_CLASS);

 			if (className != null) {
 				EnvironmentDescriptor descriptor = descriptors.get(className);

 				if (descriptor != null) {
 					descriptor.dispose();
 				}
 			}
 		}

 		public void registryChanged(IRegistryChangeEvent event) {
 			for (IExtensionDelta delta : event.getExtensionDeltas(
                     namespace, PT_ENVIRONMENTS)) {
 				switch (delta.getKind()) {
 				case IExtensionDelta.ADDED:
 					read(delta.getExtension());
 					break;
 				case IExtensionDelta.REMOVED:
 					remove(delta.getExtension());
 					break;
 				}
 			}
 		}
 	}

 	/**
 	 * Descriptor for a lazily-instantiated OCL environment, loaded from the
 	 * Eclipse extension registry.
 	 *
 	 * @author cdamus
 	 */
 	private abstract class EnvironmentDescriptor {
 		private final Set<String> packageURIs = new java.util.HashSet<String>();
 		private Environment env;

 		EnvironmentDescriptor() {
 			super();
 		}

 		void addPackageURI(String packageURI) {
 			packageURIs.add(packageURI);
 		}

 		boolean matches(Object object) {
 			boolean result = object instanceof EObject;

 			if (result) {
 				EPackage epackage = ((EObject) object).eClass().getEPackage();

 				result = (epackage != null) && packageURIs.contains(epackage.getNsURI());
 			}

 			return result;
 		}

 		Environment instantiate() {
 			if (env == null) {
 				EnvironmentFactory factory = createFactory();

 				env = factory.createEnvironment();
 			}

 			return env;
 		}

 		void dispose() {
 			if (env != null) {
 				// I have been instantiated, so remove my environment from
 				//    the list
 				environments.remove(env);
 			}

 			// make sure that I'm not in the environments list, either
 			environments.remove(this);
 		}

 		abstract EnvironmentFactory createFactory();
 	}

     /**
      * Obtains the ID of the extension defining the specified element,
      * or the defining plug-in ID if the extension has none.
      *
      * @param element an element
      * @return an identifier for the extension
      */
     private String getExtensionID(IConfigurationElement element) {
         return getExtensionID(element.getDeclaringExtension());
     }

     /**
      * Obtains the ID of the specified extension,
      * or the defining plug-in ID if the extension has none.
      *
      * @param extension an extension
      * @return an identifier for the extension
      */
     private String getExtensionID(IExtension extension) {
         String result = extension.getUniqueIdentifier();

         if (result == null) {
             result = extension.getNamespaceIdentifier();
         }

         return result;
     }
 }
	/**
	* <copyright>
	*
	* Copyright (c) 2006, 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 - Initial API and implementation
	*
	* </copyright>
	*
	* $Id: EnvironmentRegistryImpl.java,v 1.2 2011/04/25 09:49:15 ewillink Exp $
	*/

	package org.eclipse.ocl.examples.pivot.utilities;

	import java.util.Map;
	import java.util.Set;

	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExtension;
	import org.eclipse.core.runtime.IExtensionDelta;
	import org.eclipse.core.runtime.IExtensionRegistry;
	import org.eclipse.core.runtime.IRegistryChangeEvent;
	import org.eclipse.core.runtime.IRegistryChangeListener;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.emf.common.util.BasicEList;
	import org.eclipse.emf.common.util.Diagnostic;
	import org.eclipse.emf.common.util.EList;
	import org.eclipse.emf.ecore.EObject;
	import org.eclipse.emf.ecore.EPackage;
	import org.eclipse.ocl.examples.pivot.Environment;
	import org.eclipse.ocl.examples.pivot.EnvironmentFactory;
	import org.eclipse.ocl.examples.pivot.OclExpression;
	import org.eclipse.ocl.examples.pivot.Operation;
	import org.eclipse.ocl.examples.pivot.Property;
	import org.eclipse.ocl.examples.pivot.Type;
	import org.eclipse.ocl.examples.pivot.TypedElement;
	import org.eclipse.ocl.examples.pivot.messages.OCLMessages;
	import org.eclipse.ocl.examples.pivot.util.PivotPlugin;
	import org.eclipse.osgi.util.NLS;

	/**
	* Implementation of the environment registry.
	*
	* @author cdamus
	*/
	public class EnvironmentRegistryImpl implements Environment.Registry {
	private final EList<Object> environments = new BasicEList<Object>();

	private static final String PT_ENVIRONMENTS = "environments"; //$NON-NLS-1$
	private static final String E_ENVIRONMENT_FACTORY = "environmentFactory"; //$NON-NLS-1$
	private static final String A_CLASS = "class"; //$NON-NLS-1$
	private static final String E_PACKAGE = "package"; //$NON-NLS-1$
	private static final String A_NS_URI = "nsURI"; //$NON-NLS-1$

	public Environment getEnvironmentFor(OclExpression expression) {
	return getEnvironmentFor(expression.getType());
	}

	public Environment getEnvironmentFor(Object abstractSyntaxElement) {

	if (abstractSyntaxElement instanceof TypedElement) {
	return getEnvironmentFor(((TypedElement) abstractSyntaxElement).getType());
	}

	for (int i = 0; i < environments.size(); i++) {
	Object next = environments.get(i);

	if (next instanceof EnvironmentDescriptor) {
	EnvironmentDescriptor descriptor = (EnvironmentDescriptor) next;

	if (descriptor.matches(abstractSyntaxElement)) {
	// instantiate the descriptor now
	next = descriptor.instantiate();
	environments.set(i, next);
	}
	}

	if (next instanceof Environment) {
	if ((abstractSyntaxElement instanceof Type)
	\|\| (abstractSyntaxElement instanceof Operation)
	\|\| (abstractSyntaxElement instanceof Property)) {

	return (Environment) next;
	}
	}
	}

	return null;
	}

	public void registerEnvironment(Environment environment) {

	if (!environments.contains(environment)) {
	environments.add(environment);
	}
	}

	public void deregisterEnvironment(Environment environment) {
	environments.remove(environment);
	}

	/**
	* Utility class that reads the Eclipse extension registry to find registered
	* OCL environments.
	*
	* @author cdamus
	*/
	class RegistryReader implements IRegistryChangeListener {
	private final String namespace;
	private IExtensionRegistry extensionRegistry;
	private final Map<String, EnvironmentDescriptor> descriptors =
	new java.util.HashMap<String, EnvironmentDescriptor>();

	RegistryReader(PivotPlugin plugin) {
	// FIXME
	namespace = "org.eclipse.ocl"; //$NON-NLS-1$ //plugin.getSymbolicName();
	}

	void readRegistry() {
	if (extensionRegistry == null) {
	extensionRegistry = Platform.getExtensionRegistry();
	readRegistryImpl();
	}
	}

	private void readRegistryImpl() {
	extensionRegistry.addRegistryChangeListener(this, namespace);

	IExtension[] extensions = extensionRegistry.getExtensionPoint(
	namespace, PT_ENVIRONMENTS).getExtensions();

	for (IExtension extension : extensions) {
	read(extension);
	}
	}

	private void read(IExtension extension) {
	IConfigurationElement[] elements = extension.getConfigurationElements();

	for (IConfigurationElement element : elements) {
	if (E_ENVIRONMENT_FACTORY.equals(element.getName())) {
	readEnvironmentFactory(element);
	} else {
	PivotPlugin.log(Diagnostic.ERROR, 1,
	NLS.bind(
	OCLMessages.EnvRegistry_unknownElement_ERROR_,
	getExtensionID(extension),
	element.getName()),
	null);
	}
	}
	}

	private void readEnvironmentFactory(final IConfigurationElement element) {
	String className = element.getAttribute(A_CLASS);

	if (className != null) {
	EnvironmentDescriptor descriptor = new EnvironmentDescriptor() {
	@Override
	EnvironmentFactory createFactory() {
	try {
	return (EnvironmentFactory)
	element.createExecutableExtension(A_CLASS);
	} catch (CoreException e) {
	PivotPlugin.getPlugin().log(e);
	return null;
	}
	}};
	descriptors.put(className, descriptor);
	environments.add(descriptor);

	for (IConfigurationElement pkg : element.getChildren(E_PACKAGE)) {
	readPackage(descriptor, pkg);
	}
	} else {
	PivotPlugin.log(Diagnostic.ERROR, 1,
	NLS.bind(
	OCLMessages.EnvRegistry_missingClass_ERROR_,
	getExtensionID(element)),
	null);
	}
	}

	private void readPackage(EnvironmentDescriptor descriptor,
	IConfigurationElement element) {

	String nsURI = element.getAttribute(A_NS_URI);
	if (nsURI != null) {
	descriptor.addPackageURI(nsURI);
	} else {
	PivotPlugin.log(Diagnostic.ERROR, 1,
	NLS.bind(
	OCLMessages.EnvRegistry_missingNsURI_ERROR_,
	getExtensionID(element)),
	null);
	}
	}

	private void remove(IExtension extension) {
	IConfigurationElement[] elements = extension.getConfigurationElements();

	for (IConfigurationElement element : elements) {
	if (E_ENVIRONMENT_FACTORY.equals(element.getName())) {
	removeEnvironmentFactory(element);
	}
	}
	}

	private void removeEnvironmentFactory(IConfigurationElement element) {
	String className = element.getAttribute(A_CLASS);

	if (className != null) {
	EnvironmentDescriptor descriptor = descriptors.get(className);

	if (descriptor != null) {
	descriptor.dispose();
	}
	}
	}

	public void registryChanged(IRegistryChangeEvent event) {
	for (IExtensionDelta delta : event.getExtensionDeltas(
	namespace, PT_ENVIRONMENTS)) {
	switch (delta.getKind()) {
	case IExtensionDelta.ADDED:
	read(delta.getExtension());
	break;
	case IExtensionDelta.REMOVED:
	remove(delta.getExtension());
	break;
	}
	}
	}
	}

	/**
	* Descriptor for a lazily-instantiated OCL environment, loaded from the
	* Eclipse extension registry.
	*
	* @author cdamus
	*/
	private abstract class EnvironmentDescriptor {
	private final Set<String> packageURIs = new java.util.HashSet<String>();
	private Environment env;

	EnvironmentDescriptor() {
	super();
	}

	void addPackageURI(String packageURI) {
	packageURIs.add(packageURI);
	}

	boolean matches(Object object) {
	boolean result = object instanceof EObject;

	if (result) {
	EPackage epackage = ((EObject) object).eClass().getEPackage();

	result = (epackage != null) && packageURIs.contains(epackage.getNsURI());
	}

	return result;
	}

	Environment instantiate() {
	if (env == null) {
	EnvironmentFactory factory = createFactory();

	env = factory.createEnvironment();
	}

	return env;
	}

	void dispose() {
	if (env != null) {
	// I have been instantiated, so remove my environment from
	// the list
	environments.remove(env);
	}

	// make sure that I'm not in the environments list, either
	environments.remove(this);
	}

	abstract EnvironmentFactory createFactory();
	}

	/**
	* Obtains the ID of the extension defining the specified element,
	* or the defining plug-in ID if the extension has none.
	*
	* @param element an element
	* @return an identifier for the extension
	*/
	private String getExtensionID(IConfigurationElement element) {
	return getExtensionID(element.getDeclaringExtension());
	}

	/**
	* Obtains the ID of the specified extension,
	* or the defining plug-in ID if the extension has none.
	*
	* @param extension an extension
	* @return an identifier for the extension
	*/
	private String getExtensionID(IExtension extension) {
	String result = extension.getUniqueIdentifier();

	if (result == null) {
	result = extension.getNamespaceIdentifier();
	}

	return result;
	}
	}