plugins/org.eclipse.acceleo.common/src/org/eclipse/acceleo/common/internal/utils/AcceleoPackageRegistry.java - acceleo/org.eclipse.acceleo - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 2015 Obeo.
  * 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:
  *     Obeo - initial API and implementation
  *******************************************************************************/
 package org.eclipse.acceleo.common.internal.utils;

 import java.io.IOException;
 import java.util.AbstractCollection;
 import java.util.AbstractSet;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;

 import org.eclipse.acceleo.common.IAcceleoConstants;
 import org.eclipse.emf.common.EMFPlugin;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EFactory;
 import org.eclipse.emf.ecore.EPackage;
 import org.eclipse.emf.ecore.EPackage.Registry;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.resource.ResourceSet;
 import org.eclipse.emf.ecore.resource.URIConverter;
 import org.eclipse.emf.ecore.resource.impl.ExtensibleURIConverterImpl;

 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;

 /**
  * This registry will act as an extension of the global package registry : dynamic models will be registered
  * and added here, yet they'll never be seen by other plugins.
  * <p>
  * We need to be able to react to changes made to these models : if the user removes or adds a new class, he
  * expects to be able to use this new concept in his generators. Likewise, if the workspace model is deleted,
  * we need to be able to restore the package registry so that the metamodel as installed in the plugins can be
  * used anew without relaunching a new eclipse instance.
  * </p>
  * <p>
  * This registry <b>must be separate from the global registry</b>! We cannot risk adding a model in the global
  * registry and potentially breaking any model the user edits!
  * </p>
  *
  * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
  * @since 3.0
  */
 public final class AcceleoPackageRegistry extends HashMap<String, Object> implements EPackage.Registry {

 	/** Singleton instance of our dynamic registry. */
 	public static final AcceleoPackageRegistry INSTANCE = new AcceleoPackageRegistry();

 	/** Generated SUID. */
 	private static final long serialVersionUID = 5976916017848022583L;

 	/** This is the registry we'll delegate calls to. */
 	private EPackage.Registry delegate = EPackage.Registry.INSTANCE;

 	/**
 	 * For dynamic ecore files only. To get the ecore file path of the registered nsURI. Dynamic packages are
 	 * registered in the EMF Registry by using the {@link #registerEcorePackages(String)} method. The map key
 	 * is the dynamic nsURI of an EPackage and the value is the ecore file path used to register this nsURI.
 	 */
 	private Map<String, String> dynamicEcorePackagePaths = new HashMap<String, String>();

 	/**
 	 * This is a singleton. Access the sole instance through {@link #INSTANCE}.
 	 */
 	private AcceleoPackageRegistry() {
 		// Hides default constructor.
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#clear()
 	 */
 	@Override
 	public void clear() {
 		super.clear();
 		delegate.clear();
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#containsKey(java.lang.Object)
 	 */
 	@Override
 	public boolean containsKey(Object key) {
 		return super.containsKey(key) || delegate.containsKey(key);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#containsValue(java.lang.Object)
 	 */
 	@Override
 	public boolean containsValue(Object value) {
 		return super.containsValue(value) || delegate.containsValue(value);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#entrySet()
 	 */
 	@Override
 	public Set<Map.Entry<String, Object>> entrySet() {
 		Set<Map.Entry<String, Object>> dynamicEntries = super.entrySet();
 		Set<Map.Entry<String, Object>> globalEntries = delegate.entrySet();
 		return new AcceleoMultipleSet<Map.Entry<String, Object>>(dynamicEntries, globalEntries);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#get(java.lang.Object)
 	 */
 	@Override
 	public Object get(Object key) {
 		Object result = super.get(key);
 		if (result == null) {
 			result = delegate.get(key);
 		}
 		return result;
 	}

 	/**
 	 * This will be used by our workspace listener so that it can react to changes on the dynamic ecore
 	 * models.
 	 *
 	 * @return The map of dynamic ecore models.
 	 */
 	public Map<String, String> getDynamicEcorePackagePaths() {
 		return dynamicEcorePackagePaths;
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see org.eclipse.emf.ecore.EPackage.Registry#getEFactory(java.lang.String)
 	 */
 	public EFactory getEFactory(String nsURI) {
 		if (containsKey(nsURI)) {
 			Object ePackage = get(nsURI);
 			if (ePackage instanceof EPackage) {
 				EPackage result = (EPackage)ePackage;
 				return result.getEFactoryInstance();
 			}
 		}
 		return delegate.getEFactory(nsURI);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see org.eclipse.emf.ecore.EPackage.Registry#getEPackage(java.lang.String)
 	 */
 	public EPackage getEPackage(String nsURI) {
 		EPackage found = null;
 		if (containsKey(nsURI)) {
 			Object ePackage = get(nsURI);
 			if (ePackage instanceof EPackage) {
 				found = (EPackage)ePackage;
 			} else if (ePackage instanceof EPackage.Descriptor) {
 				found = ((EPackage.Descriptor)ePackage).getEPackage();
 			}
 		}
 		if (found == null) {
 			found = delegate.getEPackage(nsURI);
 			if (found == null && nsURI != null && !nsURI.startsWith(IAcceleoConstants.LITERAL_BEGIN)) {
 				found = searchInRegisteredEPackageInstances(nsURI);
 			}
 		}
 		return found;
 	}

 	/**
 	 * Search the nsURI by browsing through the registerd EPackage instances and looking up their nsURI
 	 * attribute. This case might arise when for instance, the plugin.xml registration of the nsURI does not
 	 * match the EPackage nsURI.
 	 *
 	 * @param nsURI
 	 *            the nsURI we are looking for.
 	 * @return a matching {@link EPackage} if found, null otherwise.
 	 */
 	private EPackage searchInRegisteredEPackageInstances(String nsURI) {
 		Collection<Object> values = this.values();
 		for (Object object : values) {
 			if (object instanceof EPackage && ((EPackage)object).eResource() != null) {
 				EPackage ePackage = (EPackage)object;
 				Resource eResource = ePackage.eResource();
 				URI uri = eResource.getURI();
 				if (uri != null && nsURI.equals(uri.toString())) {
 					return ePackage;
 				}
 			}
 		}
 		return null;
 	}

 	/**
 	 * To get the ecore file path of the registered nsURI. Dynamic packages are registered in the EMF EPackage
 	 * Registry by using the 'registerEcorePackages' method. The result is not null when the EPackage has been
 	 * registered in the EMF Registry with the 'registerEcorePackages' method.
 	 *
 	 * @param nsURI
 	 *            the NsURI of an EPackage
 	 * @return the ecore file path that contains the given EPackage, or null if it hasn't been registered in
 	 *         the EMF Registry with the 'registerEcorePackages' method
 	 */
 	public String getRegisteredEcorePackagePath(String nsURI) {
 		return dynamicEcorePackagePaths.get(nsURI);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#isEmpty()
 	 */
 	@Override
 	public boolean isEmpty() {
 		return super.isEmpty() && delegate.isEmpty();
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#keySet()
 	 */
 	@Override
 	public Set<String> keySet() {
 		Set<String> dynamicKeys = super.keySet();
 		Set<String> globalKeys = delegate.keySet();
 		return new AcceleoMultipleSet<String>(dynamicKeys, globalKeys);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#put(java.lang.Object, java.lang.Object)
 	 */
 	@Override
 	public Object put(String key, Object value) {
 		if (dynamicEcorePackagePaths.containsKey(key)) {
 			return super.put(key, value);
 		}
 		return delegate.put(key, value);
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#putAll(java.util.Map)
 	 */
 	@Override
 	public void putAll(Map<? extends String, ? extends Object> m) {
 		for (Map.Entry<? extends String, ? extends Object> entry : m.entrySet()) {
 			// delegation will be taken care of in put(String, Object)
 			put(entry.getKey(), entry.getValue());
 		}
 	}

 	/**
 	 * Register the given ecore file in the EMF Package Registry. It loads the ecore file and browses the
 	 * elements, it means the root EPackage and its descendants.
 	 *
 	 * @param pathName
 	 *            is the path of the ecore file to register
 	 * @param resourceSet
 	 *            The resource set.
 	 * @return the NsURI of the ecore root package, or the given path name if it isn't possible to find the
 	 *         corresponding NsURI
 	 */
 	public List<String> registerEcorePackages(String pathName, ResourceSet resourceSet) {
 		List<String> res = new ArrayList<String>();
 		List<LazyEPackageDescriptor> descriptors = new ArrayList<LazyEPackageDescriptor>();
 		URIConverter converter = resourceSet.getURIConverter();
 		if (converter == null) {
 			converter = new ExtensibleURIConverterImpl();
 		}
 		URI metaURI = null;
 		// Specifically get rid of Ecore.ecore so that we never dynamically register it
 		if (pathName != null && pathName.endsWith(".ecore") && !pathName.startsWith("http://") //$NON-NLS-1$ //$NON-NLS-2$
 				&& !pathName.endsWith("Ecore.ecore")) { //$NON-NLS-1$
 			// Try and load the ecore file with its URI as-is or fall back to platform resource URI.
 			metaURI = URI.createURI(URI.decode(pathName));
 			if (!metaURI.isPlatform()) {
 				metaURI = URI.createPlatformResourceURI(pathName, true);
 			}
 			/*
 			 * If the resourceset already have the EPackage loaded as a model, lets reload it.
 			 */
 			List<Resource> resources = resourceSet.getResources();
 			for (Resource resource : resources) {
 				if (resource.getURI() != null && resource.getURI().equals(metaURI)) {
 					resource.unload();
 					try {
 						resource.load(new HashMap<String, String>());
 					} catch (IOException e) {
 						AcceleoLogger.log(e, false);
 					}
 				}
 			}
 			descriptors.addAll(LazyEPackageDescriptor.create(metaURI, resourceSet, this));

 			// If that failed, try and load the ecore file with a platform:/resource URI
 			if (descriptors.size() == 0) {
 				metaURI = URI.createPlatformResourceURI(pathName, false);
 				descriptors.addAll(LazyEPackageDescriptor.create(metaURI, resourceSet, this));
 			}

 			// If all failed, try and load the model with a platform:/plugin URI
 			if (descriptors.size() == 0) {
 				metaURI = URI.createPlatformPluginURI(pathName, false);
 				descriptors.addAll(LazyEPackageDescriptor.create(metaURI, resourceSet, this));
 			}
 		}

 		final List<LazyEPackageDescriptor> toRemove = new ArrayList<LazyEPackageDescriptor>();
 		for (LazyEPackageDescriptor descriptor : descriptors) {
 			if ("".equals(descriptor.getNsURI())) { //$NON-NLS-1$
 				toRemove.add(descriptor);
 			}
 		}
 		descriptors.removeAll(toRemove);

 		if (descriptors.size() != 0) {
 			/*
 			 * If there is already a LazyEPackageDescriptor for this uri, lets start by removing it.
 			 */
 			registerOrReplaceInRegistry(this, metaURI, descriptors);
 			for (LazyEPackageDescriptor descriptor : descriptors) {
 				res.add(descriptor.getNsURI());
 			}
 			return res;
 		}
 		res.add(pathName);
 		return res;
 	}

 	/**
 	 * Register the given descriptor in the registry but first de-registering any instance which might have
 	 * been previously registered with an equivalent resource URI. This is done to support cases where for
 	 * instance, the end user changed the nsURI of an {@link EPackage} in its workspace. We don't want the old
 	 * nsURI to stay around.
 	 *
 	 * @param registry
 	 *            registry to update.
 	 * @param resourceURI
 	 *            the resource URI
 	 * @param descriptors
 	 *            descriptors to register.
 	 */
 	private void registerOrReplaceInRegistry(Registry registry, URI resourceURI,
 			List<LazyEPackageDescriptor> descriptors) {

 		List<String> toRemove = Lists.newArrayList();
 		Set<LazyEPackageDescriptor> toUnload = Sets.newLinkedHashSet();
 		for (Map.Entry<String, Object> entry : registry.entrySet()) {
 			/*
 			 * I only take care of my own instances to avoid unpredictable side effects on other tools.
 			 */
 			if (entry.getValue() instanceof LazyEPackageDescriptor) {
 				LazyEPackageDescriptor registered = (LazyEPackageDescriptor)entry.getValue();
 				if (registered.getResourceURI().equals(resourceURI)) {
 					toRemove.add(entry.getKey());
 				}
 				toUnload.add(registered);
 			}
 		}
 		for (String nsURI : toRemove) {
 			registry.remove(nsURI);
 		}
 		for (LazyEPackageDescriptor descriptor : descriptors) {
 			registerDescriptorsHierarchy(registry, descriptor);
 		}

 	}

 	/**
 	 * Register the given descriptor and its sub descriptors in the given registry.
 	 *
 	 * @param registry
 	 *            registry to update.
 	 * @param descriptor
 	 *            the descriptor to register.
 	 */
 	private void registerDescriptorsHierarchy(Registry registry, LazyEPackageDescriptor descriptor) {
 		if (descriptor.getNsURI() != null) {
 			// The MTL ecore file mustn't be dynamic!!!
 			// TODO JMU we should use an extension point for the dynamic ecore files we would like to exclude
 			if (!"mtl".equals(descriptor.getNsPrefix()) && !"mtlnonstdlib".equals(descriptor.getNsPrefix()) //$NON-NLS-1$ //$NON-NLS-2$
 					&& !"mtlstdlib".equals(descriptor.getNsPrefix()) && !"oclstdlib".equals(descriptor.getNsPrefix())) { //$NON-NLS-1$ //$NON-NLS-2$
 				dynamicEcorePackagePaths.put(descriptor.getNsURI(), descriptor.getResourceURI().toString());

 				registry.put(descriptor.getNsURI(), descriptor);
 			}
 		}

 		for (LazyEPackageDescriptor child : descriptor.getESubpackages()) {
 			registerDescriptorsHierarchy(registry, child);
 		}

 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#remove(java.lang.Object)
 	 */
 	@Override
 	public Object remove(Object key) {
 		boolean hasBeenRemoved = false;
 		if (dynamicEcorePackagePaths.containsKey(key) && EMFPlugin.IS_ECLIPSE_RUNNING) {
 			List<Resource> resources = AcceleoDynamicMetamodelResourceSetImpl.DYNAMIC_METAMODEL_RESOURCE_SET
 					.getResources();
 			Iterator<Resource> iterator = resources.iterator();
 			while (iterator.hasNext()) {
 				Resource resource = iterator.next();
 				if (key instanceof String && key.equals(resource.getURI().toString())) {
 					iterator.remove();
 					super.remove(key);
 					hasBeenRemoved = true;
 				} else {
 					String value = dynamicEcorePackagePaths.get(key);
 					if (value.equals(resource.getURI().toString())) {
 						iterator.remove();
 						super.remove(key);
 						hasBeenRemoved = true;
 					}
 				}
 			}
 		}
 		Object value = get(key);
 		if (value instanceof LazyEPackageDescriptor) {
 			super.remove(key);
 			hasBeenRemoved = true;
 		}
 		if (!hasBeenRemoved) {
 			// if we found it in this package registry, it means that it was in the workspace.
 			// no need to delete another version in the plugin.
 			return delegate.remove(key);
 		}
 		return null;
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#size()
 	 */
 	@Override
 	public int size() {
 		return super.size() + delegate.size();
 	}

 	/**
 	 * Removes the given ecore file from the EMF Package Registry.
 	 *
 	 * @param pathName
 	 *            is the path of the ecore file to remove
 	 */
 	public void unregisterEcorePackages(String pathName) {
 		Iterator<Map.Entry<String, String>> entryIterator = dynamicEcorePackagePaths.entrySet().iterator();
 		while (entryIterator.hasNext()) {
 			Map.Entry<String, String> dynamicEcore = entryIterator.next();
 			if (dynamicEcore.getValue().endsWith(pathName)) {
 				remove(dynamicEcore.getKey());
 				entryIterator.remove();
 			}
 		}
 	}

 	/**
 	 * {@inheritDoc}
 	 *
 	 * @see java.util.HashMap#values()
 	 */
 	@Override
 	public Collection<Object> values() {
 		Collection<Object> dynamicValues = super.values();
 		Collection<Object> globalValues = delegate.values();
 		return new AcceleoMultipleCollection<Object>(dynamicValues, globalValues);
 	}

 	/**
 	 * Utility operation to register Ecore packages for dynamic metamodel already loaded by EMF.
 	 *
 	 * @param loadedEPackage
 	 *            The EPackage to register.
 	 */
 	public void registerEcorePackage(EPackage loadedEPackage) {
 		this.registerDescriptorsHierarchy(this, LazyEPackageDescriptor.create(loadedEPackage, this));
 	}

 	/**
 	 * This custom implementation of a Set will simply allow us to "wrap" around two sets so that iterating
 	 * over one switches to the second once all entries have been browsed.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class AcceleoMultipleSet<K> extends AbstractSet<K> {
 		/** First of the two sets to iterate over. */
 		private final Set<K> firstSet;

 		/** Second of the two sets to iterate over. */
 		private final Set<K> secondSet;

 		/**
 		 * This default constructor initializes the two sets this instance will wrap.
 		 *
 		 * @param set1
 		 *            First of the two sets to iterate over.
 		 * @param set2
 		 *            Second of the two sets to iterate over.
 		 */
 		public AcceleoMultipleSet(Set<K> set1, Set<K> set2) {
 			firstSet = set1;
 			secondSet = set2;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.AbstractCollection#iterator()
 		 */
 		@Override
 		public Iterator<K> iterator() {
 			return new AcceleoMultipleIterator<K>(firstSet.iterator(), secondSet.iterator());
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.AbstractCollection#size()
 		 */
 		@Override
 		public int size() {
 			return firstSet.size() + secondSet.size();
 		}
 	}

 	/**
 	 * This custom implementation of a Collection will simply allow us to "wrap" around two Collections so
 	 * that iterating over one switches to the second once all entries have been browsed.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class AcceleoMultipleCollection<V> extends AbstractCollection<V> {
 		/** First of the two collections to iterate over. */
 		private final Collection<V> firstCollection;

 		/** Second of the two collections to iterate over. */
 		private final Collection<V> secondCollection;

 		/**
 		 * This default constructor initializes the two collections this instance will wrap.
 		 *
 		 * @param collection1
 		 *            First of the two collections to iterate over.
 		 * @param collection2
 		 *            Second of the two collections to iterate over.
 		 */
 		public AcceleoMultipleCollection(Collection<V> collection1, Collection<V> collection2) {
 			firstCollection = collection1;
 			secondCollection = collection2;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.AbstractCollection#iterator()
 		 */
 		@Override
 		public Iterator<V> iterator() {
 			return new AcceleoMultipleIterator<V>(firstCollection.iterator(), secondCollection.iterator());
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.AbstractCollection#size()
 		 */
 		@Override
 		public int size() {
 			return firstCollection.size() + secondCollection.size();
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.AbstractCollection#contains(java.lang.Object)
 		 */
 		@Override
 		public boolean contains(Object o) {
 			return firstCollection.contains(o) || secondCollection.contains(o);
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.AbstractCollection#clear()
 		 */
 		@Override
 		public void clear() {
 			firstCollection.clear();
 			secondCollection.clear();
 		}
 	}

 	/**
 	 * This custom implementation of an Iterator will simply allow us to "wrap" around two Iterators so that
 	 * iterating over one switches to the second once all entries have been browsed.
 	 *
 	 * @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
 	 */
 	private class AcceleoMultipleIterator<E> implements Iterator<E> {
 		/** First of the two iterators to iterate over. */
 		private final Iterator<E> firstIterator;

 		/** Second of the two iterators to iterate over. */
 		private final Iterator<E> secondIterator;

 		/** Keeps track of the current iterator. */
 		private Iterator<E> current;

 		/**
 		 * This default constructor initializes the two iterators this instance will wrap.
 		 *
 		 * @param iterator1
 		 *            First of the two iterators to iterate over.
 		 * @param iterator2
 		 *            Second of the two iterators to iterate over.
 		 */
 		public AcceleoMultipleIterator(Iterator<E> iterator1, Iterator<E> iterator2) {
 			firstIterator = iterator1;
 			secondIterator = iterator2;
 			current = firstIterator;
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.Iterator#hasNext()
 		 */
 		public boolean hasNext() {
 			return firstIterator.hasNext() || secondIterator.hasNext();
 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.Iterator#next()
 		 */
 		public E next() {
 			if (firstIterator.hasNext()) {
 				return firstIterator.next();
 			}
 			current = secondIterator;
 			return secondIterator.next();

 		}

 		/**
 		 * {@inheritDoc}
 		 *
 		 * @see java.util.Iterator#remove()
 		 */
 		public void remove() {
 			current.remove();
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2008, 2015 Obeo.
	* 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:
	* Obeo - initial API and implementation
	*******************************************************************************/
	package org.eclipse.acceleo.common.internal.utils;

	import java.io.IOException;
	import java.util.AbstractCollection;
	import java.util.AbstractSet;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;

	import org.eclipse.acceleo.common.IAcceleoConstants;
	import org.eclipse.emf.common.EMFPlugin;
	import org.eclipse.emf.common.util.URI;
	import org.eclipse.emf.ecore.EFactory;
	import org.eclipse.emf.ecore.EPackage;
	import org.eclipse.emf.ecore.EPackage.Registry;
	import org.eclipse.emf.ecore.resource.Resource;
	import org.eclipse.emf.ecore.resource.ResourceSet;
	import org.eclipse.emf.ecore.resource.URIConverter;
	import org.eclipse.emf.ecore.resource.impl.ExtensibleURIConverterImpl;

	import com.google.common.collect.Lists;
	import com.google.common.collect.Sets;

	/**
	* This registry will act as an extension of the global package registry : dynamic models will be registered
	* and added here, yet they'll never be seen by other plugins.
	* <p>
	* We need to be able to react to changes made to these models : if the user removes or adds a new class, he
	* expects to be able to use this new concept in his generators. Likewise, if the workspace model is deleted,
	* we need to be able to restore the package registry so that the metamodel as installed in the plugins can be
	* used anew without relaunching a new eclipse instance.
	* </p>
	* <p>
	* This registry <b>must be separate from the global registry</b>! We cannot risk adding a model in the global
	* registry and potentially breaking any model the user edits!
	* </p>
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	* @since 3.0
	*/
	public final class AcceleoPackageRegistry extends HashMap<String, Object> implements EPackage.Registry {

	/** Singleton instance of our dynamic registry. */
	public static final AcceleoPackageRegistry INSTANCE = new AcceleoPackageRegistry();

	/** Generated SUID. */
	private static final long serialVersionUID = 5976916017848022583L;

	/** This is the registry we'll delegate calls to. */
	private EPackage.Registry delegate = EPackage.Registry.INSTANCE;

	/**
	* For dynamic ecore files only. To get the ecore file path of the registered nsURI. Dynamic packages are
	* registered in the EMF Registry by using the {@link #registerEcorePackages(String)} method. The map key
	* is the dynamic nsURI of an EPackage and the value is the ecore file path used to register this nsURI.
	*/
	private Map<String, String> dynamicEcorePackagePaths = new HashMap<String, String>();

	/**
	* This is a singleton. Access the sole instance through {@link #INSTANCE}.
	*/
	private AcceleoPackageRegistry() {
	// Hides default constructor.
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#clear()
	*/
	@Override
	public void clear() {
	super.clear();
	delegate.clear();
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#containsKey(java.lang.Object)
	*/
	@Override
	public boolean containsKey(Object key) {
	return super.containsKey(key) \|\| delegate.containsKey(key);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#containsValue(java.lang.Object)
	*/
	@Override
	public boolean containsValue(Object value) {
	return super.containsValue(value) \|\| delegate.containsValue(value);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#entrySet()
	*/
	@Override
	public Set<Map.Entry<String, Object>> entrySet() {
	Set<Map.Entry<String, Object>> dynamicEntries = super.entrySet();
	Set<Map.Entry<String, Object>> globalEntries = delegate.entrySet();
	return new AcceleoMultipleSet<Map.Entry<String, Object>>(dynamicEntries, globalEntries);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#get(java.lang.Object)
	*/
	@Override
	public Object get(Object key) {
	Object result = super.get(key);
	if (result == null) {
	result = delegate.get(key);
	}
	return result;
	}

	/**
	* This will be used by our workspace listener so that it can react to changes on the dynamic ecore
	* models.
	*
	* @return The map of dynamic ecore models.
	*/
	public Map<String, String> getDynamicEcorePackagePaths() {
	return dynamicEcorePackagePaths;
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.emf.ecore.EPackage.Registry#getEFactory(java.lang.String)
	*/
	public EFactory getEFactory(String nsURI) {
	if (containsKey(nsURI)) {
	Object ePackage = get(nsURI);
	if (ePackage instanceof EPackage) {
	EPackage result = (EPackage)ePackage;
	return result.getEFactoryInstance();
	}
	}
	return delegate.getEFactory(nsURI);
	}

	/**
	* {@inheritDoc}
	*
	* @see org.eclipse.emf.ecore.EPackage.Registry#getEPackage(java.lang.String)
	*/
	public EPackage getEPackage(String nsURI) {
	EPackage found = null;
	if (containsKey(nsURI)) {
	Object ePackage = get(nsURI);
	if (ePackage instanceof EPackage) {
	found = (EPackage)ePackage;
	} else if (ePackage instanceof EPackage.Descriptor) {
	found = ((EPackage.Descriptor)ePackage).getEPackage();
	}
	}
	if (found == null) {
	found = delegate.getEPackage(nsURI);
	if (found == null && nsURI != null && !nsURI.startsWith(IAcceleoConstants.LITERAL_BEGIN)) {
	found = searchInRegisteredEPackageInstances(nsURI);
	}
	}
	return found;
	}

	/**
	* Search the nsURI by browsing through the registerd EPackage instances and looking up their nsURI
	* attribute. This case might arise when for instance, the plugin.xml registration of the nsURI does not
	* match the EPackage nsURI.
	*
	* @param nsURI
	* the nsURI we are looking for.
	* @return a matching {@link EPackage} if found, null otherwise.
	*/
	private EPackage searchInRegisteredEPackageInstances(String nsURI) {
	Collection<Object> values = this.values();
	for (Object object : values) {
	if (object instanceof EPackage && ((EPackage)object).eResource() != null) {
	EPackage ePackage = (EPackage)object;
	Resource eResource = ePackage.eResource();
	URI uri = eResource.getURI();
	if (uri != null && nsURI.equals(uri.toString())) {
	return ePackage;
	}
	}
	}
	return null;
	}

	/**
	* To get the ecore file path of the registered nsURI. Dynamic packages are registered in the EMF EPackage
	* Registry by using the 'registerEcorePackages' method. The result is not null when the EPackage has been
	* registered in the EMF Registry with the 'registerEcorePackages' method.
	*
	* @param nsURI
	* the NsURI of an EPackage
	* @return the ecore file path that contains the given EPackage, or null if it hasn't been registered in
	* the EMF Registry with the 'registerEcorePackages' method
	*/
	public String getRegisteredEcorePackagePath(String nsURI) {
	return dynamicEcorePackagePaths.get(nsURI);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#isEmpty()
	*/
	@Override
	public boolean isEmpty() {
	return super.isEmpty() && delegate.isEmpty();
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#keySet()
	*/
	@Override
	public Set<String> keySet() {
	Set<String> dynamicKeys = super.keySet();
	Set<String> globalKeys = delegate.keySet();
	return new AcceleoMultipleSet<String>(dynamicKeys, globalKeys);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#put(java.lang.Object, java.lang.Object)
	*/
	@Override
	public Object put(String key, Object value) {
	if (dynamicEcorePackagePaths.containsKey(key)) {
	return super.put(key, value);
	}
	return delegate.put(key, value);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#putAll(java.util.Map)
	*/
	@Override
	public void putAll(Map<? extends String, ? extends Object> m) {
	for (Map.Entry<? extends String, ? extends Object> entry : m.entrySet()) {
	// delegation will be taken care of in put(String, Object)
	put(entry.getKey(), entry.getValue());
	}
	}

	/**
	* Register the given ecore file in the EMF Package Registry. It loads the ecore file and browses the
	* elements, it means the root EPackage and its descendants.
	*
	* @param pathName
	* is the path of the ecore file to register
	* @param resourceSet
	* The resource set.
	* @return the NsURI of the ecore root package, or the given path name if it isn't possible to find the
	* corresponding NsURI
	*/
	public List<String> registerEcorePackages(String pathName, ResourceSet resourceSet) {
	List<String> res = new ArrayList<String>();
	List<LazyEPackageDescriptor> descriptors = new ArrayList<LazyEPackageDescriptor>();
	URIConverter converter = resourceSet.getURIConverter();
	if (converter == null) {
	converter = new ExtensibleURIConverterImpl();
	}
	URI metaURI = null;
	// Specifically get rid of Ecore.ecore so that we never dynamically register it
	if (pathName != null && pathName.endsWith(".ecore") && !pathName.startsWith("http://") //$NON-NLS-1$ //$NON-NLS-2$
	&& !pathName.endsWith("Ecore.ecore")) { //$NON-NLS-1$
	// Try and load the ecore file with its URI as-is or fall back to platform resource URI.
	metaURI = URI.createURI(URI.decode(pathName));
	if (!metaURI.isPlatform()) {
	metaURI = URI.createPlatformResourceURI(pathName, true);
	}
	/*
	* If the resourceset already have the EPackage loaded as a model, lets reload it.
	*/
	List<Resource> resources = resourceSet.getResources();
	for (Resource resource : resources) {
	if (resource.getURI() != null && resource.getURI().equals(metaURI)) {
	resource.unload();
	try {
	resource.load(new HashMap<String, String>());
	} catch (IOException e) {
	AcceleoLogger.log(e, false);
	}
	}
	}
	descriptors.addAll(LazyEPackageDescriptor.create(metaURI, resourceSet, this));

	// If that failed, try and load the ecore file with a platform:/resource URI
	if (descriptors.size() == 0) {
	metaURI = URI.createPlatformResourceURI(pathName, false);
	descriptors.addAll(LazyEPackageDescriptor.create(metaURI, resourceSet, this));
	}

	// If all failed, try and load the model with a platform:/plugin URI
	if (descriptors.size() == 0) {
	metaURI = URI.createPlatformPluginURI(pathName, false);
	descriptors.addAll(LazyEPackageDescriptor.create(metaURI, resourceSet, this));
	}
	}

	final List<LazyEPackageDescriptor> toRemove = new ArrayList<LazyEPackageDescriptor>();
	for (LazyEPackageDescriptor descriptor : descriptors) {
	if ("".equals(descriptor.getNsURI())) { //$NON-NLS-1$
	toRemove.add(descriptor);
	}
	}
	descriptors.removeAll(toRemove);

	if (descriptors.size() != 0) {
	/*
	* If there is already a LazyEPackageDescriptor for this uri, lets start by removing it.
	*/
	registerOrReplaceInRegistry(this, metaURI, descriptors);
	for (LazyEPackageDescriptor descriptor : descriptors) {
	res.add(descriptor.getNsURI());
	}
	return res;
	}
	res.add(pathName);
	return res;
	}

	/**
	* Register the given descriptor in the registry but first de-registering any instance which might have
	* been previously registered with an equivalent resource URI. This is done to support cases where for
	* instance, the end user changed the nsURI of an {@link EPackage} in its workspace. We don't want the old
	* nsURI to stay around.
	*
	* @param registry
	* registry to update.
	* @param resourceURI
	* the resource URI
	* @param descriptors
	* descriptors to register.
	*/
	private void registerOrReplaceInRegistry(Registry registry, URI resourceURI,
	List<LazyEPackageDescriptor> descriptors) {

	List<String> toRemove = Lists.newArrayList();
	Set<LazyEPackageDescriptor> toUnload = Sets.newLinkedHashSet();
	for (Map.Entry<String, Object> entry : registry.entrySet()) {
	/*
	* I only take care of my own instances to avoid unpredictable side effects on other tools.
	*/
	if (entry.getValue() instanceof LazyEPackageDescriptor) {
	LazyEPackageDescriptor registered = (LazyEPackageDescriptor)entry.getValue();
	if (registered.getResourceURI().equals(resourceURI)) {
	toRemove.add(entry.getKey());
	}
	toUnload.add(registered);
	}
	}
	for (String nsURI : toRemove) {
	registry.remove(nsURI);
	}
	for (LazyEPackageDescriptor descriptor : descriptors) {
	registerDescriptorsHierarchy(registry, descriptor);
	}

	}

	/**
	* Register the given descriptor and its sub descriptors in the given registry.
	*
	* @param registry
	* registry to update.
	* @param descriptor
	* the descriptor to register.
	*/
	private void registerDescriptorsHierarchy(Registry registry, LazyEPackageDescriptor descriptor) {
	if (descriptor.getNsURI() != null) {
	// The MTL ecore file mustn't be dynamic!!!
	// TODO JMU we should use an extension point for the dynamic ecore files we would like to exclude
	if (!"mtl".equals(descriptor.getNsPrefix()) && !"mtlnonstdlib".equals(descriptor.getNsPrefix()) //$NON-NLS-1$ //$NON-NLS-2$
	&& !"mtlstdlib".equals(descriptor.getNsPrefix()) && !"oclstdlib".equals(descriptor.getNsPrefix())) { //$NON-NLS-1$ //$NON-NLS-2$
	dynamicEcorePackagePaths.put(descriptor.getNsURI(), descriptor.getResourceURI().toString());

	registry.put(descriptor.getNsURI(), descriptor);
	}
	}

	for (LazyEPackageDescriptor child : descriptor.getESubpackages()) {
	registerDescriptorsHierarchy(registry, child);
	}

	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#remove(java.lang.Object)
	*/
	@Override
	public Object remove(Object key) {
	boolean hasBeenRemoved = false;
	if (dynamicEcorePackagePaths.containsKey(key) && EMFPlugin.IS_ECLIPSE_RUNNING) {
	List<Resource> resources = AcceleoDynamicMetamodelResourceSetImpl.DYNAMIC_METAMODEL_RESOURCE_SET
	.getResources();
	Iterator<Resource> iterator = resources.iterator();
	while (iterator.hasNext()) {
	Resource resource = iterator.next();
	if (key instanceof String && key.equals(resource.getURI().toString())) {
	iterator.remove();
	super.remove(key);
	hasBeenRemoved = true;
	} else {
	String value = dynamicEcorePackagePaths.get(key);
	if (value.equals(resource.getURI().toString())) {
	iterator.remove();
	super.remove(key);
	hasBeenRemoved = true;
	}
	}
	}
	}
	Object value = get(key);
	if (value instanceof LazyEPackageDescriptor) {
	super.remove(key);
	hasBeenRemoved = true;
	}
	if (!hasBeenRemoved) {
	// if we found it in this package registry, it means that it was in the workspace.
	// no need to delete another version in the plugin.
	return delegate.remove(key);
	}
	return null;
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#size()
	*/
	@Override
	public int size() {
	return super.size() + delegate.size();
	}

	/**
	* Removes the given ecore file from the EMF Package Registry.
	*
	* @param pathName
	* is the path of the ecore file to remove
	*/
	public void unregisterEcorePackages(String pathName) {
	Iterator<Map.Entry<String, String>> entryIterator = dynamicEcorePackagePaths.entrySet().iterator();
	while (entryIterator.hasNext()) {
	Map.Entry<String, String> dynamicEcore = entryIterator.next();
	if (dynamicEcore.getValue().endsWith(pathName)) {
	remove(dynamicEcore.getKey());
	entryIterator.remove();
	}
	}
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.HashMap#values()
	*/
	@Override
	public Collection<Object> values() {
	Collection<Object> dynamicValues = super.values();
	Collection<Object> globalValues = delegate.values();
	return new AcceleoMultipleCollection<Object>(dynamicValues, globalValues);
	}

	/**
	* Utility operation to register Ecore packages for dynamic metamodel already loaded by EMF.
	*
	* @param loadedEPackage
	* The EPackage to register.
	*/
	public void registerEcorePackage(EPackage loadedEPackage) {
	this.registerDescriptorsHierarchy(this, LazyEPackageDescriptor.create(loadedEPackage, this));
	}

	/**
	* This custom implementation of a Set will simply allow us to "wrap" around two sets so that iterating
	* over one switches to the second once all entries have been browsed.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class AcceleoMultipleSet<K> extends AbstractSet<K> {
	/** First of the two sets to iterate over. */
	private final Set<K> firstSet;

	/** Second of the two sets to iterate over. */
	private final Set<K> secondSet;

	/**
	* This default constructor initializes the two sets this instance will wrap.
	*
	* @param set1
	* First of the two sets to iterate over.
	* @param set2
	* Second of the two sets to iterate over.
	*/
	public AcceleoMultipleSet(Set<K> set1, Set<K> set2) {
	firstSet = set1;
	secondSet = set2;
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.AbstractCollection#iterator()
	*/
	@Override
	public Iterator<K> iterator() {
	return new AcceleoMultipleIterator<K>(firstSet.iterator(), secondSet.iterator());
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.AbstractCollection#size()
	*/
	@Override
	public int size() {
	return firstSet.size() + secondSet.size();
	}
	}

	/**
	* This custom implementation of a Collection will simply allow us to "wrap" around two Collections so
	* that iterating over one switches to the second once all entries have been browsed.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class AcceleoMultipleCollection<V> extends AbstractCollection<V> {
	/** First of the two collections to iterate over. */
	private final Collection<V> firstCollection;

	/** Second of the two collections to iterate over. */
	private final Collection<V> secondCollection;

	/**
	* This default constructor initializes the two collections this instance will wrap.
	*
	* @param collection1
	* First of the two collections to iterate over.
	* @param collection2
	* Second of the two collections to iterate over.
	*/
	public AcceleoMultipleCollection(Collection<V> collection1, Collection<V> collection2) {
	firstCollection = collection1;
	secondCollection = collection2;
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.AbstractCollection#iterator()
	*/
	@Override
	public Iterator<V> iterator() {
	return new AcceleoMultipleIterator<V>(firstCollection.iterator(), secondCollection.iterator());
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.AbstractCollection#size()
	*/
	@Override
	public int size() {
	return firstCollection.size() + secondCollection.size();
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.AbstractCollection#contains(java.lang.Object)
	*/
	@Override
	public boolean contains(Object o) {
	return firstCollection.contains(o) \|\| secondCollection.contains(o);
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.AbstractCollection#clear()
	*/
	@Override
	public void clear() {
	firstCollection.clear();
	secondCollection.clear();
	}
	}

	/**
	* This custom implementation of an Iterator will simply allow us to "wrap" around two Iterators so that
	* iterating over one switches to the second once all entries have been browsed.
	*
	* @author <a href="mailto:laurent.goubet@obeo.fr">Laurent Goubet</a>
	*/
	private class AcceleoMultipleIterator<E> implements Iterator<E> {
	/** First of the two iterators to iterate over. */
	private final Iterator<E> firstIterator;

	/** Second of the two iterators to iterate over. */
	private final Iterator<E> secondIterator;

	/** Keeps track of the current iterator. */
	private Iterator<E> current;

	/**
	* This default constructor initializes the two iterators this instance will wrap.
	*
	* @param iterator1
	* First of the two iterators to iterate over.
	* @param iterator2
	* Second of the two iterators to iterate over.
	*/
	public AcceleoMultipleIterator(Iterator<E> iterator1, Iterator<E> iterator2) {
	firstIterator = iterator1;
	secondIterator = iterator2;
	current = firstIterator;
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.Iterator#hasNext()
	*/
	public boolean hasNext() {
	return firstIterator.hasNext() \|\| secondIterator.hasNext();
	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.Iterator#next()
	*/
	public E next() {
	if (firstIterator.hasNext()) {
	return firstIterator.next();
	}
	current = secondIterator;
	return secondIterator.next();

	}

	/**
	* {@inheritDoc}
	*
	* @see java.util.Iterator#remove()
	*/
	public void remove() {
	current.remove();
	}
	}

	}