path: root/plugins/infra/org.eclipse.papyrus.infra.extendedtypes/src/org/eclipse/papyrus/infra/extendedtypes/ExtendedElementTypeSetRegistry.java

/*****************************************************************************
 * Copyright (c) 2013 CEA LIST.
 *    
 * 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:
 *  Remi Schnekenburger (CEA LIST) - Initial API and implementation
 *
 *****************************************************************************/
package org.eclipse.papyrus.infra.extendedtypes;

import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Dictionary;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.StringTokenizer;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.ResourceSet;
import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl;
import org.eclipse.gmf.runtime.emf.type.core.ElementTypeRegistry;
import org.eclipse.gmf.runtime.emf.type.core.IClientContext;
import org.eclipse.papyrus.infra.core.services.ServiceException;
import org.eclipse.papyrus.infra.extendedtypes.preferences.ExtendedTypesPreferences;
import org.eclipse.papyrus.infra.extendedtypes.types.IExtendedHintedElementType;
import org.eclipse.papyrus.infra.services.edit.internal.context.TypeContext;
import org.osgi.framework.Bundle;

/**
 * Registry to manage load/unloaded {@link ExtendedElementTypeSet}.
 */
public class ExtendedElementTypeSetRegistry {

	public static final String LOCAL_CONTRIBUTOR_ID = "local contribution";

	/** private singleton instance */
	private static ExtendedElementTypeSetRegistry registry;

	/** list of retrieved extended type sets */
	protected List<ExtendedElementTypeSet> extendedTypeSets = null;

	/** unique resource set to load all extended types models */
	protected ResourceSet extendedTypesResourceSet = null;

	protected List<ExtendedElementTypeSet> loadedExtendedElementTypeSets = null;

	protected Map<String, IExtendedElementTypeFactory<ElementTypeConfiguration>> configurationTypeToElementTypeFactory = null;

	protected List<String> configurationTypeFactoryExceptions = null;

	/**
	 * returns the singleton instance of this registry
	 * 
	 * @return the singleton instance of this registry
	 */
	public static synchronized ExtendedElementTypeSetRegistry getInstance() {
		if(registry == null) {
			registry = new ExtendedElementTypeSetRegistry();
			registry.init();
		}
		return registry;
	}

	/**
	 * Inits the registry.
	 */
	protected void init() {
		// 0. Resets values
		extendedTypesResourceSet = null;
		extendedTypeSets = null;
		configurationTypeToElementTypeFactory = new HashMap<String, IExtendedElementTypeFactory<ElementTypeConfiguration>>();
		// 1. creates the resource set
		extendedTypesResourceSet = createResourceSet();
		// 2. creates the list only when registry is acceded for the first time, (or on reload?)
		extendedTypeSets = loadExtendedTypeSets();
	}

	/**
	 * Loads the specified extended element type set.
	 * This does not take care to unload a similar set (a set with the same id) before loading. This should be handled before calling this method.
	 * 
	 * @param extendedElementTypeSet
	 *        {@link ExtendedElementTypeSet} to load.
	 */
	public void loadExtendedElementTypeSet(ExtendedElementTypeSet extendedElementTypeSet) {
		IClientContext context;
		try {
			context = TypeContext.getContext();
		} catch (ServiceException e1) {
			Activator.log.error(e1);
			return;
		}
		List<ElementTypeConfiguration> elementTypeConfigurations = extendedElementTypeSet.getElementType();
		for(ElementTypeConfiguration configuration : elementTypeConfigurations) {
			// load class associated to the configuration model => read extension point that defines this kind of configuration. 
			String configurationType = configuration.eClass().getInstanceTypeName();
			// retrieve the factory for a given kind of configuration
			IExtendedElementTypeFactory<ElementTypeConfiguration> factory = configurationTypeToElementTypeFactory.get(configurationType);
			// check factory is not on the exception table
			if(factory == null && isNotInFactoryExceptionList(configurationType)) {
				Class<IExtendedElementTypeFactory<ElementTypeConfiguration>> factoryClass = retrieveFactoryClassFromExtensionPoint(configurationType);
				if(factoryClass != null) {
					try {
						factory = factoryClass.newInstance();
					} catch (InstantiationException e) {
						if(configurationTypeFactoryExceptions == null) {
							configurationTypeFactoryExceptions = new ArrayList<String>();
						}
						configurationTypeFactoryExceptions.add(configurationType);
					} catch (IllegalAccessException e) {
						if(configurationTypeFactoryExceptions == null) {
							configurationTypeFactoryExceptions = new ArrayList<String>();
						}
						configurationTypeFactoryExceptions.add(configurationType);
					}
					configurationTypeToElementTypeFactory.put(configurationType, factory);
				}
			}
			if(factory != null) {
				IExtendedHintedElementType type = factory.createElementType(configuration);
				// register element Type
				ElementTypeRegistry.getInstance().register(type);
				context.bindId(type.getId());
			}
			// TODO handle errors here: no factory, impossible to create element type from configuration, impossible to register, etc.
		}
	}

	/**
	 * check this configuration type has not already caused issues du
	 * 
	 * @param configurationType
	 * @return
	 */
	protected boolean isNotInFactoryExceptionList(String configurationType) {
		if(configurationTypeFactoryExceptions == null) {
			return true;
		}
		// this is not null, check the configuration type is not in the list
		return !configurationTypeFactoryExceptions.contains(configurationType);
	}

	/**
	 * Returns the {@link IExtendedElementTypeFactory} class used to instantiate element type for the given configuration
	 * 
	 * @return the {@link IExtendedElementTypeFactory} found or <code>null</code> if none was found
	 */
	@SuppressWarnings("unchecked")
	protected Class<IExtendedElementTypeFactory<ElementTypeConfiguration>> retrieveFactoryClassFromExtensionPoint(String configurationType) {
		IConfigurationElement[] elements = Platform.getExtensionRegistry().getConfigurationElementsFor(IExtendedTypeConfigurationExtensionPoint.EXTENSION_POINT_ID);
		for(IConfigurationElement configurationElement : elements) {
			String eCoreClassName = configurationElement.getAttribute(IExtendedTypeConfigurationExtensionPoint.CONFIGURATION_CLASS);
			if(configurationType.equals(eCoreClassName)) {
				// retrieve factory to load
				String factoryClassName = configurationElement.getAttribute(IExtendedTypeConfigurationExtensionPoint.FACTORY_CLASS);
				return (Class<IExtendedElementTypeFactory<ElementTypeConfiguration>>)loadClass(factoryClassName, configurationElement.getContributor().getName());
			}
		}
		return null;
	}

	/**
	 * Retrieves and loads extended type sets registered in the platform. It should also load configuration sets from the workspace.
	 */
	protected List<ExtendedElementTypeSet> loadExtendedTypeSets() {
		List<ExtendedElementTypeSet> extendedElementTypeSets = new ArrayList<ExtendedElementTypeSet>();
		// 1. retrieve from the workspace
		Map<String, ExtendedElementTypeSet> localSets = loadExtendedTypeSetsFromWorkspace();
		if(localSets != null && !localSets.isEmpty()) {
			extendedElementTypeSets.addAll(localSets.values());
		}
		
		// 2. retrieve from the platform. If already in workspace (id), do not load the platform ones
		Map<String, ExtendedElementTypeSet> registeredSets = loadExtendedTypeSetsFromPlatform(localSets.keySet());
		if(registeredSets != null && !registeredSets.isEmpty()) {
			extendedElementTypeSets.addAll(registeredSets.values());
		}
		// load each extended element type set
		for(ExtendedElementTypeSet extendedElementTypeSet : extendedElementTypeSets) {
			loadExtendedElementTypeSet(extendedElementTypeSet);
		}
		return extendedElementTypeSets;
	}

	/**
	 * @return
	 */
	protected Map<String, ExtendedElementTypeSet> loadExtendedTypeSetsFromWorkspace() {
		Map<String, String> localFilesPath = ExtendedTypesPreferences.getLocalExtendedTypesDefinitions();
		Map<String, ExtendedElementTypeSet> workspaceElementTypeSets = new HashMap<String, ExtendedElementTypeSet>();
		if(localFilesPath != null && !localFilesPath.isEmpty()) {
			for(Entry<String, String> idToPath : localFilesPath.entrySet()) {
				String filePath = idToPath.getValue();
				String id = idToPath.getKey();
				
				URI localURI = URI.createPlatformResourceURI(filePath, true);
				Resource resource = extendedTypesResourceSet.createResource(localURI);
				try {
					resource.load(null);
					EObject content = resource.getContents().get(0);
					if(content instanceof ExtendedElementTypeSet) {
						workspaceElementTypeSets.put(id, (ExtendedElementTypeSet)content);
					}
				} catch (IOException e) {
					Activator.log.error(e);
				}
			}
		}
		return workspaceElementTypeSets;
	}

	/**
	 * Loads the extensions in the platform
	 * 
	 * @return the list of extension registered in the platform
	 */
	protected Map<String, ExtendedElementTypeSet> loadExtendedTypeSetsFromPlatform(Set<String> workspaceDefinitions) {
		Map<String, ExtendedElementTypeSet> platformElementTypeSets = new HashMap<String, ExtendedElementTypeSet>();
		IConfigurationElement[] elements = Platform.getExtensionRegistry().getConfigurationElementsFor(IExtendedElementTypeSetExtensionPoint.EXTENSION_POINT_ID);
		// for each element, parses and retrieve the model file. then loads it and returns the root element 
		for(IConfigurationElement element : elements) {
			String modelPath = element.getAttribute(IExtendedElementTypeSetExtensionPoint.PATH);
			String extendedTypeSetId = element.getAttribute(IExtendedElementTypeSetExtensionPoint.ID);
			String contributorID = element.getContributor().getName();
			if(Platform.inDebugMode()) {
				Activator.log.debug("[Reading extension point]");
				Activator.log.debug("-  Path to the model: " + modelPath);
				Activator.log.debug("-  id of the container bundle: " + contributorID);
				Activator.log.debug("-  id of the extended type set: " + extendedTypeSetId);
			}
			ExtendedElementTypeSet set = getExtendedElementTypeSet(extendedTypeSetId, modelPath, contributorID);
			if(set != null && !workspaceDefinitions.contains(extendedTypeSetId)) { // do not add if it is locally redefined
				platformElementTypeSets.put(extendedTypeSetId, set);
			}
		}
		return platformElementTypeSets;
	}

	/**
	 * <p>
	 * Loads the resource containing the extended element type set model.
	 * </p>
	 * <p>
	 * It looks the model file in the fragments first, then in the plugin itself.<BR>
	 * If this is already a fragment, it should look in the fragment only
	 * </p>
	 * 
	 * @param extendedTypesID
	 *        id of the extended type set to load
	 * @param modelPath
	 *        path of the model in the bundle
	 * @param bundleId
	 *        id of the bundle containing the model file
	 * @return the loaded file or <code>null</code> if some problem occured during loading
	 */
	protected ExtendedElementTypeSet getExtendedElementTypeSet(String extendedTypesID, String modelPath, String bundleId) {
		// 1. look in preferences.
		String filePath = ExtendedTypesPreferences.getExtendedTypesRedefinition(extendedTypesID);
		if(filePath != null) {
			getExtendedElementTypeSetInPluginStateArea(extendedTypesID);
		}
		// 2. no local redefinition. Load extended type set from plugin definition
		Bundle bundle = Platform.getBundle(bundleId);
		if(Platform.isFragment(bundle)) {
			return getExtendedElementTypeSetInBundle(modelPath, bundleId);
		} else { // this is a plugin. Search in sub fragments, then in the plugin
			Bundle[] fragments = Platform.getFragments(bundle);
			// no fragment, so the file should be in the plugin itself
			if(fragments == null) {
				return getExtendedElementTypeSetInBundle(modelPath, bundleId);
			} else {
				for(Bundle fragment : fragments) {
					ExtendedElementTypeSet extendedElementTypeSet = getExtendedElementTypeSetInBundle(modelPath, fragment.getSymbolicName());
					if(extendedElementTypeSet != null) {
						return extendedElementTypeSet;
					}
				}
				// not found in fragments. Look in the plugin itself
				return getExtendedElementTypeSetInBundle(modelPath, bundleId);
			}
		}
	}

	/**
	 * Retrieves the contribution in the plugin area
	 * 
	 * @param path
	 *        the path of the element type set to load in the plugin area
	 */
	protected ExtendedElementTypeSet getExtendedElementTypeSetInPluginStateArea(String path) {
		// read in preferences area
		IPath resourcePath = Activator.getDefault().getStateLocation().append(path);
		URI uri = URI.createFileURI(resourcePath.toOSString());
		if(uri != null && uri.isFile()) {
			Resource resource = extendedTypesResourceSet.createResource(uri);
			try {
				resource.load(null);
			} catch (IOException e) {
				return null;
			}
			EObject content = resource.getContents().get(0);
			if(content instanceof ExtendedElementTypeSet) {
				return (ExtendedElementTypeSet)content;
			}
			Activator.log.error("Impossible to cast the object into an ExtendedElementTypeSet: " + content, null);
			return null;
		}
		return null;
	}

	/**
	 * 
	 * @param modelPath
	 *        path of the model in the bundle
	 * @param bundleId
	 *        id of the bundle containing the model file
	 * @return the loaded file or <code>null</code> if some problem occured during loading
	 */
	protected ExtendedElementTypeSet getExtendedElementTypeSetInBundle(String modelPath, String bundleID) {
		Resource resource = extendedTypesResourceSet.createResource(URI.createPlatformPluginURI(bundleID + Path.SEPARATOR + modelPath, true));
		try {
			resource.load(null);
		} catch (IOException e) {
			return null;
		}
		EObject content = resource.getContents().get(0);
		if(content instanceof ExtendedElementTypeSet) {
			return (ExtendedElementTypeSet)content;
		}
		Activator.log.error("Impossible to cast the object into an ExtendedElementTypeSet: " + content, null);
		return null;
	}

	/**
	 * Creates the resource set that contains all models for extended types
	 * 
	 * @return the resource set newly created.
	 */
	protected ResourceSet createResourceSet() {
		ResourceSet set = new ResourceSetImpl();
		return set;
	}

	///////////////////////////////////////////////////////////////////////////
	// loading resource
	///////////////////////////////////////////////////////////////////////////
	/** A map of classes that have been successfully loaded, keyed on the class name optionally prepended by the plugin ID, if specified. */
	private static Map<String, WeakReference<Class<?>>> successLookupTable = new HashMap<String, WeakReference<Class<?>>>();

	/** A map of classes that could not be loaded, keyed on the class name, optionally prepended by the plugin ID if specified. */
	private static Set<String> failureLookupTable = new HashSet<String>();

	/** A map to hold the bundle to exception list */
	private static Map<Bundle, Set<String>> bundleToExceptionsSetMap = new HashMap<Bundle, Set<String>>();

	/**
	 * A utility method to load a class using its name and a given class loader.
	 * 
	 * @param className
	 *        The class name
	 * @param bundle
	 *        The class loader
	 * @return The loaded class or <code>null</code> if could not be loaded
	 */
	protected static Class<?> loadClass(String className, String pluginId) {
		StringBuffer keyStringBuf = new StringBuffer(className.length() + pluginId.length() + 2); // 2 is for . and extra.
		keyStringBuf.append(pluginId);
		keyStringBuf.append('.');
		keyStringBuf.append(className);
		String keyString = keyStringBuf.toString();
		WeakReference<Class<?>> ref = successLookupTable.get(keyString);
		Class<?> found = (ref != null) ? ref.get() : null;
		if(found == null) {
			if(ref != null)
				successLookupTable.remove(keyString);
			if(!failureLookupTable.contains(keyString)) {
				try {
					Bundle bundle = basicGetPluginBundle(pluginId);
					if(bundle != null) {
						// never load the class if the bundle is not active other wise
						// we will cause the plugin to load
						// unless the class is in the exception list
						int state = bundle.getState();
						if(state == org.osgi.framework.Bundle.ACTIVE || isInExceptionList(bundle, className)) {
							found = bundle.loadClass(className);
							successLookupTable.put(keyString, new WeakReference<Class<?>>(found));
							if(state == org.osgi.framework.Bundle.ACTIVE) {
								bundleToExceptionsSetMap.remove(bundle);
							}
						}
					} else {
						failureLookupTable.add(keyString);
					}
				} catch (ClassNotFoundException e) {
					failureLookupTable.add(keyString);
				}
			}
		}
		return found;
	}

	/**
	 * Given a bundle id, it checks if the bundle is found and activated. If it
	 * is, the method returns the bundle, otherwise it returns <code>null</code>.
	 * 
	 * @param pluginId
	 *        the bundle ID
	 * @return the bundle, if found
	 */
	protected static Bundle getPluginBundle(String pluginId) {
		Bundle bundle = basicGetPluginBundle(pluginId);
		if(null != bundle && bundle.getState() == org.osgi.framework.Bundle.ACTIVE)
			return bundle;
		return null;
	}

	private static Bundle basicGetPluginBundle(String pluginId) {
		return Platform.getBundle(pluginId);
	}

	private static boolean isInExceptionList(Bundle bundle, String className) {
		String packageName = className.substring(0, className.lastIndexOf('.'));
		Set<String> exceptionSet = bundleToExceptionsSetMap.get(bundle);
		if(exceptionSet == null) {
			Dictionary<String, String> dict = bundle.getHeaders();
			String value = dict.get("Eclipse-LazyStart"); //$NON-NLS-1$
			if(value != null) {
				int index = value.indexOf("exceptions"); //$NON-NLS-1$
				if(index != -1) {
					try {
						int start = value.indexOf('"', index + 1);
						int end = value.indexOf('"', start + 1);
						String exceptions = value.substring(start + 1, end);
						exceptionSet = new HashSet<String>(2);
						StringTokenizer tokenizer = new StringTokenizer(exceptions, ","); //$NON-NLS-1$
						while(tokenizer.hasMoreTokens()) {
							exceptionSet.add(tokenizer.nextToken().trim());
						}
					} catch (IndexOutOfBoundsException exception) {
						// this means the MF did not follow the documented format for the exceptions list  so i'll consider it empty
						exceptionSet = Collections.emptySet();
					}
				} else {
					exceptionSet = Collections.emptySet();
				}
			} else {
				exceptionSet = Collections.emptySet();
			}
			bundleToExceptionsSetMap.put(bundle, exceptionSet);
		}
		return exceptionSet.contains(packageName);
	}

	/**
	 * 
	 */
	public void reset() {
		init();
		
	}
}