org.eclipse.mylyn.reviews.connector/src/org/eclipse/mylyn/reviews/connector/AbstractEmfConnector.java - gerrit/r4e/org.eclipse.mylyn.reviews.r4e - Git at Google

 /*******************************************************************************
  * Copyright (c) 2012, 2013 Ericsson AB 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
  *
  * Description:
  *
  * Contributors:
  *   Miles Parker, Tasktop Technologies - Initial API and Implementation
  *   Others (includes code modified from GerritConnector in org.eclipse.mylyn.gerit, see author annotations.)
  *******************************************************************************/
 package org.eclipse.mylyn.reviews.connector;

 import java.io.File;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;

 import org.apache.commons.lang.ObjectUtils;
 import org.apache.commons.lang.StringUtils;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.emf.common.util.EList;
 import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EEnum;
 import org.eclipse.emf.ecore.EEnumLiteral;
 import org.eclipse.emf.ecore.EFactory;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.emf.ecore.xmi.XMLResource;
 import org.eclipse.mylyn.internal.reviews.connector.EmfCorePlugin;
 import org.eclipse.mylyn.internal.tasks.core.RepositoryTaskHandleUtil;
 import org.eclipse.mylyn.reviews.connector.EmfTaskSchema.FieldFeature;
 import org.eclipse.mylyn.reviews.connector.client.EmfClient;
 import org.eclipse.mylyn.reviews.connector.query.EmfQueryEngine;
 import org.eclipse.mylyn.reviews.connector.query.QueryClause;
 import org.eclipse.mylyn.reviews.connector.query.QueryException;
 import org.eclipse.mylyn.reviews.connector.query.SimpleQueryEngine;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
 import org.eclipse.mylyn.tasks.core.IRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskMapping;
 import org.eclipse.mylyn.tasks.core.RepositoryClientManager;
 import org.eclipse.mylyn.tasks.core.RepositoryResponse;
 import org.eclipse.mylyn.tasks.core.RepositoryResponse.ResponseKind;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskDataHandler;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskSchema.Field;
 import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
 import org.eclipse.mylyn.tasks.core.data.TaskAttributeMapper;
 import org.eclipse.mylyn.tasks.core.data.TaskData;
 import org.eclipse.mylyn.tasks.core.data.TaskDataCollector;
 import org.eclipse.mylyn.tasks.core.data.TaskMapper;
 import org.eclipse.mylyn.tasks.core.sync.ISynchronizationSession;
 import org.osgi.framework.Bundle;

 /**
  * Generic support for connectors to Emf models. Connector implementors should override, providing all meta-data.
  *
  * @author Miles Parker
  */
 @SuppressWarnings("restriction")
 public abstract class AbstractEmfConnector extends AbstractRepositoryConnector {

 	/**
 	 * Unicode en-dash.
 	 */
 	public static final String EN_DASH = "\u2013"; //$NON-NLS-1$

 	public static final String ITEM_DELIM = "#"; //$NON-NLS-1$

 	public enum KeyStrategy {
 		EMF_SCHEMA_FIELD, OBJECT_ID, MEMBER_INDEX, XMI_ID
 	};

 	class EmfClientManager extends RepositoryClientManager<EmfClient, EmfConfiguration> {
 		public EmfClientManager() {
 			super(getCacheFile(), getConfigurationClass());
 		}

 		@Override
 		protected EmfClient createClient(TaskRepository repository, EmfConfiguration configuration) {
 			return AbstractEmfConnector.this.createClient(repository, configuration);
 		}
 	}

 	/**
 	 * By delegating back to the EmfConnector for this case, we can greatly simplify API for consumers.
 	 */
 	class EmfTaskDataHandler extends AbstractTaskDataHandler {

 		@Override
 		public TaskAttributeMapper getAttributeMapper(TaskRepository repository) {
 			return AbstractEmfConnector.this.getAttributeMapper(repository);
 		}

 		@Override
 		public boolean initializeTaskData(TaskRepository repository, TaskData taskData,
 				ITaskMapping initializationData, IProgressMonitor monitor) {
 			return AbstractEmfConnector.this.initializeTaskData(repository, taskData, initializationData, monitor);
 		}

 		@Override
 		public RepositoryResponse postTaskData(TaskRepository repository, TaskData taskData,
 				Set<TaskAttribute> oldAttributes, IProgressMonitor monitor) throws CoreException {
 			return AbstractEmfConnector.this.postTaskData(repository, taskData, oldAttributes, monitor);
 		}
 	}

 	/**
 	 * By delegating back to the EmfConnector for this case, we can greatly simplify API for consumers.
 	 */
 	public class EmfTaskSchemaDelegator extends EmfTaskSchema {

 		@Override
 		protected EClass[] getSchemaEClasses() {
 			return AbstractEmfConnector.this.getTaskClasses();
 		}

 		@Override
 		protected FieldFeature[] getSchemaPairs() {
 			return AbstractEmfConnector.this.getTaskFeatures();
 		}

 	}

 	public static final String EMF_ITEM_DELIM = "#"; //$NON-NLS-1$

 	private final EmfTaskDataHandler taskDataHandler = new EmfTaskDataHandler();

 	private RepositoryClientManager<EmfClient, EmfConfiguration> clientManager;

 	private EmfTaskSchema taskSchema;

 	private final File configurationCacheFile;

 	private final Set<QueryClause> queryClauses = new HashSet<QueryClause>();

 	public AbstractEmfConnector() {
 		IPath stateLocation = Platform.getStateLocation(EmfCorePlugin.getDefault().getBundle());
 		IPath cache = stateLocation.append("repositoryConfigurations"); //$NON-NLS-1$
 		configurationCacheFile = cache.toFile();
 	}

 	public Class<EmfConfiguration> getConfigurationClass() {
 		return EmfConfiguration.class;
 	}

 	/**
 	 * Not supported yet.
 	 */
 	@Override
 	public boolean canCreateNewTask(TaskRepository arg0) {
 		return true;
 	}

 	@Override
 	public boolean canCreateTaskFromKey(TaskRepository arg0) {
 		return true;
 	}

 	public EmfClient getClient(TaskRepository repository) {
 		return getClientManager().getClient(repository);
 	}

 	public TaskAttributeMapper getAttributeMapper(TaskRepository repository) {
 		return getSchema().getAttributeMapper(repository);
 	}

 	public EmfAttributeMapper getEmfMapper(TaskRepository repository) {
 		return (EmfAttributeMapper) getAttributeMapper(repository);
 	}

 	public EmfQueryEngine getQueryEngine(TaskRepository repository) {
 		return new SimpleQueryEngine(this, repository);
 	}

 	public boolean initializeTaskData(TaskRepository repository, TaskData data, ITaskMapping initializationData,
 			IProgressMonitor monitor) {
 		getSchema().initialize(data);
 		String taskId = data.getTaskId();
 		data.getRoot()
 				.createAttribute(TaskAttribute.TASK_URL)
 				.setValue(getTaskUrl(repository.getRepositoryUrl(), taskId));
 		data.getRoot().createAttribute(TaskAttribute.TASK_KEY).setValue(encodeTaskKey(taskId));
 		return true;
 	}

 	public RepositoryResponse postTaskData(TaskRepository repository, TaskData taskData,
 			Set<TaskAttribute> oldAttributes, IProgressMonitor monitor) throws CoreException {
 		EmfClient client = getClient(repository);
 		client.open();
 		String taskId = taskData.getTaskId();
 		EObject emfTask;
 		if (taskId.equals("")) { //$NON-NLS-1$
 			EClass containedClass = getTaskClasses()[0];
 			@SuppressWarnings("unchecked")
 			EList<? super EObject> taskContainment = (EList<? super EObject>) client.getRootContainer().eGet(
 					getContainmentReference());
 			emfTask = client.create(containedClass, taskData);
 			taskContainment.add(emfTask);
 			//Emf implementation may create a key at model save time (e.g. XMLResource uuid implementation)
 			client.save();
 			taskId = getTaskKey(repository, emfTask);
 			if (StringUtils.isEmpty(taskId) || taskId.equals("0")) { //$NON-NLS-1$
 				taskId = getNextTaskId(client.getRootContainer());
 				if (taskId != null) {
 					TaskAttribute keyAttribute = taskData.getRoot().getAttribute(TaskAttribute.TASK_KEY);
 					keyAttribute.setValue(taskId);
 					oldAttributes.add(keyAttribute);
 				}
 			}
 			for (Field field : getSchema().getFields()) {
 				oldAttributes.add(taskData.getRoot().getAttribute(field.getKey()));
 			}
 		} else {
 			emfTask = getTaskObjectChecked(repository, taskId, monitor);
 		}
 		boolean emfDirty = false;
 		for (TaskAttribute staleAttribute : oldAttributes) {
 			String id = staleAttribute.getId();
 			TaskAttribute newAttribute = taskData.getRoot().getAttribute(id);
 			boolean isSet = newAttribute.getValues().size() > 0;
 			if (isSet) {
 				boolean setValueForKey = getEmfMapper(repository).copyTaskToEmf(newAttribute, emfTask);
 				emfDirty |= setValueForKey;
 			}
 		}
 		if (emfDirty) {
 			Date time = Calendar.getInstance().getTime();
 			EStructuralFeature dateModificationFeature = getSchema().getFeature(TaskAttribute.DATE_MODIFICATION);
 			emfTask.eSet(dateModificationFeature, time);
 			client.notifyChanged(emfTask);
 		}
 		return new RepositoryResponse(ResponseKind.TASK_UPDATED, taskId);
 	}

 	public TaskData createTaskData(TaskRepository repository, String taskId, IProgressMonitor monitor) {
 		TaskData data = new TaskData(getAttributeMapper(repository), getConnectorKind(), repository.getRepositoryUrl(),
 				taskId);
 		initializeTaskData(repository, data, null, monitor);
 		return data;
 	}

 	public TaskData createPartialTaskData(TaskRepository repository, String taskId, IProgressMonitor monitor) {
 		TaskData data = new TaskData(getAttributeMapper(repository), getConnectorKind(), repository.getRepositoryUrl(),
 				taskId);
 		//Only create summary and other mapped attributes now
 		getSchema().initialize(data);
 		data.setPartial(true);
 		return data;
 	}

 	/**
 	 * Retrieves task data for the given review from repository.
 	 */
 	@Override
 	public TaskData getTaskData(TaskRepository repository, String taskId, IProgressMonitor monitor)
 			throws CoreException {
 		EmfClient client = getClient(repository);
 		client.updateConfiguration(monitor);
 		EObject emfObject = getTaskObjectChecked(repository, taskId, monitor);
 		String id = getTaskKey(repository, emfObject);
 		TaskData data = createTaskData(repository, id, monitor);
 		EmfTaskSchema schema = getSchema();
 		for (Field field : schema.getFields()) {
 			EStructuralFeature feature = schema.getFeature(field.getKey());
 			//TODO support object references
 			if (feature instanceof EAttribute && !((EAttribute) feature).isMany()) {
 				EAttribute emfAttribute = (EAttribute) feature;
 				Object emfValue = emfObject.eGet(feature);
 				TaskAttribute taskAttribute = field.createAttribute(data.getRoot());
 				if (emfAttribute.getEAttributeType() instanceof EEnum) {
 					EEnum enumerator = (EEnum) emfAttribute.getEAttributeType();
 					for (EEnumLiteral literal : enumerator.getELiterals()) {
 						taskAttribute.putOption(literal.getLiteral(), literal.getName());
 					}
 				}
 				getEmfMapper(repository).copyEmfToTask(emfObject, taskAttribute);
 				if (emfValue != null) {
 					EFactory factory = emfAttribute.getEAttributeType().getEPackage().getEFactoryInstance();
 					String stringValue = factory.convertToString(emfAttribute.getEAttributeType(), emfValue);
 					taskAttribute.setValue(stringValue);
 				} else if (!emfObject.eIsSet(feature)) {
 					taskAttribute.clearValues();
 				} else {
 					taskAttribute.setValue(""); //$NON-NLS-1$
 				}
 			}
 		}
 		return data;
 	}

 	protected KeyStrategy getKeyStrategy() {
 		return KeyStrategy.EMF_SCHEMA_FIELD;
 	}

 	protected String getTaskKey(TaskRepository repository, EObject emfObject) {
 		String key = null;
 		switch (getKeyStrategy()) {
 		case EMF_SCHEMA_FIELD:
 			key = getEmfMapper(repository).getEmfString(emfObject, TaskAttribute.TASK_KEY);
 			break;
 		case OBJECT_ID:
 			key = EcoreUtil.getID(emfObject);
 			break;
 		case XMI_ID:
 			Resource resource = emfObject.eResource();
 			if (resource instanceof XMLResource) {
 				XMLResource xmlResource = (XMLResource) resource;
 				key = xmlResource.getID(emfObject);
 			}
 			break;
 		case MEMBER_INDEX:
 			EObject rootContainer = EcoreUtil.getRootContainer(emfObject);
 			String uriFragment = rootContainer.eResource().getURIFragment(emfObject);
 			key = uriFragment;
 			int dotIndex = key.indexOf('.');
 			if (dotIndex >= 0) {
 				key = key.substring(dotIndex + 1);
 			}
 			break;
 		}
 		return encodeTaskKey(key);
 	}

 	public EObject getTaskObject(TaskRepository repository, String taskId, IProgressMonitor monitor)
 			throws CoreException {
 		taskId = encodeTaskKey(taskId);
 		EmfClient client = getClient(repository);
 		client.open();
 		EObject container = client.getRootContainer();
 		EObject rootContainer = EcoreUtil.getRootContainer(container);
 		EObject referencedObject = rootContainer.eResource().getEObject(taskId);
 		taskId = encodeTaskKey(taskId);
 		if (referencedObject == null) {
 			for (Object object : ((List<?>) container.eGet(getContainmentReference()))) {
 				if (object instanceof EObject) {
 					EObject eObject = (EObject) object;
 					String stringValueForKey = getTaskKey(repository, eObject);
 					if (ObjectUtils.equals(stringValueForKey, taskId)) {
 						referencedObject = eObject;
 						break;
 					}
 				}
 			}
 		}
 		return referencedObject;
 	}

 	public EObject getTaskObjectChecked(TaskRepository repository, String taskId, IProgressMonitor monitor)
 			throws CoreException {
 		EObject emfObject = getTaskObject(repository, taskId, monitor);
 		if (emfObject == null) {
 			throw new CoreException(new Status(IStatus.WARNING, EmfCorePlugin.PLUGIN_ID,
 					"Couldn't locate task object for taskId: " + taskId //$NON-NLS-1$
 			));
 		}
 		return emfObject;
 	}

 	@Override
 	public AbstractTaskDataHandler getTaskDataHandler() {
 		return taskDataHandler;
 	}

 	/**
 	 * Encode a task id to prevent use of handle delimiters.
 	 *
 	 * @param taskId
 	 * @return
 	 */
 	public String encodeTaskKey(String taskId) {
 		return StringUtils.replace(taskId, RepositoryTaskHandleUtil.HANDLE_DELIM, EN_DASH);
 	}

 	/**
 	 * Decode a task id to restore any handle delimiters.
 	 *
 	 * @param taskId
 	 * @return
 	 */
 	public String decodeTaskKey(String taskId) {
 		return StringUtils.replace(taskId, EN_DASH, RepositoryTaskHandleUtil.HANDLE_DELIM);
 	}

 	@Override
 	public String getRepositoryUrlFromTaskUrl(String url) {
 		if (url == null) {
 			return null;
 		}

 		int i = url.indexOf(ITEM_DELIM);
 		if (i != -1) {
 			return url.substring(0, i);
 		}
 		return null;
 	}

 	@Override
 	public String getTaskIdFromTaskUrl(String url) {
 		if (url == null) {
 			return null;
 		}
 		int index = url.indexOf(ITEM_DELIM);
 		if (index > 0) {
 			String taskId = url.substring(index + ITEM_DELIM.length());
 			try {
 				taskId = URLDecoder.decode(taskId, "utf-8"); //$NON-NLS-1$
 			} catch (UnsupportedEncodingException e) {
 				throw new RuntimeException(e);
 			}
 			return taskId;
 		}
 		return null;
 	}

 	@Override
 	public String getTaskUrl(String repositoryUrl, String taskId) {
 		String encodedId = taskId;
 		try {
 			encodedId = URLEncoder.encode(taskId, "utf-8"); //$NON-NLS-1$
 		} catch (UnsupportedEncodingException e) {
 			throw new RuntimeException(e);
 		}
 		return repositoryUrl + ITEM_DELIM + encodedId;
 	}

 	@Override
 	public ITaskMapping getTaskMapping(TaskData taskData) {
 		return new TaskMapper(taskData);
 	}

 	@Override
 	public boolean hasTaskChanged(TaskRepository repository, ITask task, TaskData taskData) {
 		ITaskMapping taskMapping = getTaskMapping(taskData);
 		if (taskData.isPartial() && task.getModificationDate() != null) {
 			return false;
 		}
 		Date repositoryDate = taskMapping.getModificationDate();
 		Date localDate = task.getModificationDate();
 		boolean hasChanged = repositoryDate != null && repositoryDate.equals(localDate);
 		return hasChanged;
 	}

 	@Override
 	public IStatus performQuery(TaskRepository repository, IRepositoryQuery query, TaskDataCollector resultCollector,
 			ISynchronizationSession session, IProgressMonitor monitor) {
 		try {
 			EmfClient client = getClient(repository);
 			client.open();
 			List<EObject> results;
 			try {
 				results = getQueryEngine(repository).performQuery(query, monitor);
 				for (EObject taskObject : results) {
 					String id = encodeTaskKey(getTaskKey(repository, taskObject));
 					if (!StringUtils.isEmpty(id)) {
 						TaskData taskData = createPartialTaskData(repository, id, monitor);
 						resultCollector.accept(taskData);
 					}
 				}
 				return Status.OK_STATUS;
 			} catch (QueryException e) {
 				return new Status(IStatus.ERROR, EmfCorePlugin.PLUGIN_ID, "Problem occurred while executing query.", e); //$NON-NLS-1$
 			}
 		} catch (CoreException e) {
 			return e.getStatus();
 		} finally {
 			monitor.done();
 		}
 	}

 	@Override
 	public void updateRepositoryConfiguration(TaskRepository repository, IProgressMonitor monitor) throws CoreException {
 		getClient(repository).updateConfiguration(monitor);
 	}

 	@Override
 	public void updateTaskFromTaskData(TaskRepository taskRepository, ITask task, TaskData taskData) {
 		Date oldModificationDate = task.getModificationDate();

 		TaskMapper mapper = (TaskMapper) getTaskMapping(taskData);
 		// retain modification date to force an update when full task data is received
 		if (taskData.isPartial()) {
 			task.setModificationDate(oldModificationDate);
 		} else {
 			mapper.applyTo(task);
 		}
 	}

 	public IStatus validate(TaskRepository repository, IProgressMonitor monitor) throws CoreException {
 		return Status.OK_STATUS;
 	}

 	public RepositoryClientManager<EmfClient, EmfConfiguration> getClientManager() {
 		if (clientManager == null) {
 			clientManager = new EmfClientManager();
 		}
 		return clientManager;
 	}

 	public final EmfTaskSchema getSchema() {
 		if (taskSchema == null) {
 			taskSchema = createTaskSchema();
 			taskSchema.initialize();
 		}
 		return taskSchema;
 	}

 	/**
 	 * Override to provide a custom task schema implementation. (The default Schema will provide values based on the
 	 * connector meta-data .)
 	 *
 	 * @return
 	 */
 	public EmfTaskSchema createTaskSchema() {
 		return new EmfTaskSchemaDelegator();
 	}

 	public File getCacheFile() {
 		return configurationCacheFile;
 	}

 	/**
 	 * Override to implement a custom EMF client. In most cases this should not be necessary.
 	 *
 	 * @param repository
 	 * @param configuration
 	 * @return
 	 */
 	protected EmfClient createClient(TaskRepository repository, EmfConfiguration configuration) {
 		return new EmfClient(repository, configuration) {
 			@Override
 			public AbstractEmfConnector getConnector() {
 				return AbstractEmfConnector.this;
 			}

 		};
 	}

 	public Set<QueryClause> getQueryClauses() {
 		return queryClauses;
 	}

 	public abstract String getNextTaskId(EObject taskContainer);

 	public abstract EAttribute getContentsNameAttribute();

 	public abstract EReference getContainmentReference();

 	/**
 	 * The class to be used for task container. By default this is the clss defined by the containment reference.
 	 *
 	 * @return
 	 */
 	public EClass getContainerClass() {
 		return getContainmentReference().getEContainingClass();
 	}

 	public abstract EAttribute[] getSearchAttributes();

 	public abstract Bundle getConnectorBundle();

 	public abstract EClass[] getTaskClasses();

 	public abstract FieldFeature[] getTaskFeatures();
 }
	/*******************************************************************************
	* Copyright (c) 2012, 2013 Ericsson AB 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
	*
	* Description:
	*
	* Contributors:
	* Miles Parker, Tasktop Technologies - Initial API and Implementation
	* Others (includes code modified from GerritConnector in org.eclipse.mylyn.gerit, see author annotations.)
	*******************************************************************************/
	package org.eclipse.mylyn.reviews.connector;

	import java.io.File;
	import java.io.UnsupportedEncodingException;
	import java.net.URLDecoder;
	import java.net.URLEncoder;
	import java.util.Calendar;
	import java.util.Date;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Set;

	import org.apache.commons.lang.ObjectUtils;
	import org.apache.commons.lang.StringUtils;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.emf.common.util.EList;
	import org.eclipse.emf.ecore.EAttribute;
	import org.eclipse.emf.ecore.EClass;
	import org.eclipse.emf.ecore.EEnum;
	import org.eclipse.emf.ecore.EEnumLiteral;
	import org.eclipse.emf.ecore.EFactory;
	import org.eclipse.emf.ecore.EObject;
	import org.eclipse.emf.ecore.EReference;
	import org.eclipse.emf.ecore.EStructuralFeature;
	import org.eclipse.emf.ecore.resource.Resource;
	import org.eclipse.emf.ecore.util.EcoreUtil;
	import org.eclipse.emf.ecore.xmi.XMLResource;
	import org.eclipse.mylyn.internal.reviews.connector.EmfCorePlugin;
	import org.eclipse.mylyn.internal.tasks.core.RepositoryTaskHandleUtil;
	import org.eclipse.mylyn.reviews.connector.EmfTaskSchema.FieldFeature;
	import org.eclipse.mylyn.reviews.connector.client.EmfClient;
	import org.eclipse.mylyn.reviews.connector.query.EmfQueryEngine;
	import org.eclipse.mylyn.reviews.connector.query.QueryClause;
	import org.eclipse.mylyn.reviews.connector.query.QueryException;
	import org.eclipse.mylyn.reviews.connector.query.SimpleQueryEngine;
	import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
	import org.eclipse.mylyn.tasks.core.IRepositoryQuery;
	import org.eclipse.mylyn.tasks.core.ITask;
	import org.eclipse.mylyn.tasks.core.ITaskMapping;
	import org.eclipse.mylyn.tasks.core.RepositoryClientManager;
	import org.eclipse.mylyn.tasks.core.RepositoryResponse;
	import org.eclipse.mylyn.tasks.core.RepositoryResponse.ResponseKind;
	import org.eclipse.mylyn.tasks.core.TaskRepository;
	import org.eclipse.mylyn.tasks.core.data.AbstractTaskDataHandler;
	import org.eclipse.mylyn.tasks.core.data.AbstractTaskSchema.Field;
	import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
	import org.eclipse.mylyn.tasks.core.data.TaskAttributeMapper;
	import org.eclipse.mylyn.tasks.core.data.TaskData;
	import org.eclipse.mylyn.tasks.core.data.TaskDataCollector;
	import org.eclipse.mylyn.tasks.core.data.TaskMapper;
	import org.eclipse.mylyn.tasks.core.sync.ISynchronizationSession;
	import org.osgi.framework.Bundle;

	/**
	* Generic support for connectors to Emf models. Connector implementors should override, providing all meta-data.
	*
	* @author Miles Parker
	*/
	@SuppressWarnings("restriction")
	public abstract class AbstractEmfConnector extends AbstractRepositoryConnector {

	/**
	* Unicode en-dash.
	*/
	public static final String EN_DASH = "\u2013"; //$NON-NLS-1$

	public static final String ITEM_DELIM = "#"; //$NON-NLS-1$

	public enum KeyStrategy {
	EMF_SCHEMA_FIELD, OBJECT_ID, MEMBER_INDEX, XMI_ID
	};

	class EmfClientManager extends RepositoryClientManager<EmfClient, EmfConfiguration> {
	public EmfClientManager() {
	super(getCacheFile(), getConfigurationClass());
	}

	@Override
	protected EmfClient createClient(TaskRepository repository, EmfConfiguration configuration) {
	return AbstractEmfConnector.this.createClient(repository, configuration);
	}
	}

	/**
	* By delegating back to the EmfConnector for this case, we can greatly simplify API for consumers.
	*/
	class EmfTaskDataHandler extends AbstractTaskDataHandler {

	@Override
	public TaskAttributeMapper getAttributeMapper(TaskRepository repository) {
	return AbstractEmfConnector.this.getAttributeMapper(repository);
	}

	@Override
	public boolean initializeTaskData(TaskRepository repository, TaskData taskData,
	ITaskMapping initializationData, IProgressMonitor monitor) {
	return AbstractEmfConnector.this.initializeTaskData(repository, taskData, initializationData, monitor);
	}

	@Override
	public RepositoryResponse postTaskData(TaskRepository repository, TaskData taskData,
	Set<TaskAttribute> oldAttributes, IProgressMonitor monitor) throws CoreException {
	return AbstractEmfConnector.this.postTaskData(repository, taskData, oldAttributes, monitor);
	}
	}

	/**
	* By delegating back to the EmfConnector for this case, we can greatly simplify API for consumers.
	*/
	public class EmfTaskSchemaDelegator extends EmfTaskSchema {

	@Override
	protected EClass[] getSchemaEClasses() {
	return AbstractEmfConnector.this.getTaskClasses();
	}

	@Override
	protected FieldFeature[] getSchemaPairs() {
	return AbstractEmfConnector.this.getTaskFeatures();
	}

	}

	public static final String EMF_ITEM_DELIM = "#"; //$NON-NLS-1$

	private final EmfTaskDataHandler taskDataHandler = new EmfTaskDataHandler();

	private RepositoryClientManager<EmfClient, EmfConfiguration> clientManager;

	private EmfTaskSchema taskSchema;

	private final File configurationCacheFile;

	private final Set<QueryClause> queryClauses = new HashSet<QueryClause>();

	public AbstractEmfConnector() {
	IPath stateLocation = Platform.getStateLocation(EmfCorePlugin.getDefault().getBundle());
	IPath cache = stateLocation.append("repositoryConfigurations"); //$NON-NLS-1$
	configurationCacheFile = cache.toFile();
	}

	public Class<EmfConfiguration> getConfigurationClass() {
	return EmfConfiguration.class;
	}

	/**
	* Not supported yet.
	*/
	@Override
	public boolean canCreateNewTask(TaskRepository arg0) {
	return true;
	}

	@Override
	public boolean canCreateTaskFromKey(TaskRepository arg0) {
	return true;
	}

	public EmfClient getClient(TaskRepository repository) {
	return getClientManager().getClient(repository);
	}

	public TaskAttributeMapper getAttributeMapper(TaskRepository repository) {
	return getSchema().getAttributeMapper(repository);
	}

	public EmfAttributeMapper getEmfMapper(TaskRepository repository) {
	return (EmfAttributeMapper) getAttributeMapper(repository);
	}

	public EmfQueryEngine getQueryEngine(TaskRepository repository) {
	return new SimpleQueryEngine(this, repository);
	}

	public boolean initializeTaskData(TaskRepository repository, TaskData data, ITaskMapping initializationData,
	IProgressMonitor monitor) {
	getSchema().initialize(data);
	String taskId = data.getTaskId();
	data.getRoot()
	.createAttribute(TaskAttribute.TASK_URL)
	.setValue(getTaskUrl(repository.getRepositoryUrl(), taskId));
	data.getRoot().createAttribute(TaskAttribute.TASK_KEY).setValue(encodeTaskKey(taskId));
	return true;
	}

	public RepositoryResponse postTaskData(TaskRepository repository, TaskData taskData,
	Set<TaskAttribute> oldAttributes, IProgressMonitor monitor) throws CoreException {
	EmfClient client = getClient(repository);
	client.open();
	String taskId = taskData.getTaskId();
	EObject emfTask;
	if (taskId.equals("")) { //$NON-NLS-1$
	EClass containedClass = getTaskClasses()[0];
	@SuppressWarnings("unchecked")
	EList<? super EObject> taskContainment = (EList<? super EObject>) client.getRootContainer().eGet(
	getContainmentReference());
	emfTask = client.create(containedClass, taskData);
	taskContainment.add(emfTask);
	//Emf implementation may create a key at model save time (e.g. XMLResource uuid implementation)
	client.save();
	taskId = getTaskKey(repository, emfTask);
	if (StringUtils.isEmpty(taskId) \|\| taskId.equals("0")) { //$NON-NLS-1$
	taskId = getNextTaskId(client.getRootContainer());
	if (taskId != null) {
	TaskAttribute keyAttribute = taskData.getRoot().getAttribute(TaskAttribute.TASK_KEY);
	keyAttribute.setValue(taskId);
	oldAttributes.add(keyAttribute);
	}
	}
	for (Field field : getSchema().getFields()) {
	oldAttributes.add(taskData.getRoot().getAttribute(field.getKey()));
	}
	} else {
	emfTask = getTaskObjectChecked(repository, taskId, monitor);
	}
	boolean emfDirty = false;
	for (TaskAttribute staleAttribute : oldAttributes) {
	String id = staleAttribute.getId();
	TaskAttribute newAttribute = taskData.getRoot().getAttribute(id);
	boolean isSet = newAttribute.getValues().size() > 0;
	if (isSet) {
	boolean setValueForKey = getEmfMapper(repository).copyTaskToEmf(newAttribute, emfTask);
	emfDirty \|= setValueForKey;
	}
	}
	if (emfDirty) {
	Date time = Calendar.getInstance().getTime();
	EStructuralFeature dateModificationFeature = getSchema().getFeature(TaskAttribute.DATE_MODIFICATION);
	emfTask.eSet(dateModificationFeature, time);
	client.notifyChanged(emfTask);
	}
	return new RepositoryResponse(ResponseKind.TASK_UPDATED, taskId);
	}

	public TaskData createTaskData(TaskRepository repository, String taskId, IProgressMonitor monitor) {
	TaskData data = new TaskData(getAttributeMapper(repository), getConnectorKind(), repository.getRepositoryUrl(),
	taskId);
	initializeTaskData(repository, data, null, monitor);
	return data;
	}

	public TaskData createPartialTaskData(TaskRepository repository, String taskId, IProgressMonitor monitor) {
	TaskData data = new TaskData(getAttributeMapper(repository), getConnectorKind(), repository.getRepositoryUrl(),
	taskId);
	//Only create summary and other mapped attributes now
	getSchema().initialize(data);
	data.setPartial(true);
	return data;
	}

	/**
	* Retrieves task data for the given review from repository.
	*/
	@Override
	public TaskData getTaskData(TaskRepository repository, String taskId, IProgressMonitor monitor)
	throws CoreException {
	EmfClient client = getClient(repository);
	client.updateConfiguration(monitor);
	EObject emfObject = getTaskObjectChecked(repository, taskId, monitor);
	String id = getTaskKey(repository, emfObject);
	TaskData data = createTaskData(repository, id, monitor);
	EmfTaskSchema schema = getSchema();
	for (Field field : schema.getFields()) {
	EStructuralFeature feature = schema.getFeature(field.getKey());
	//TODO support object references
	if (feature instanceof EAttribute && !((EAttribute) feature).isMany()) {
	EAttribute emfAttribute = (EAttribute) feature;
	Object emfValue = emfObject.eGet(feature);
	TaskAttribute taskAttribute = field.createAttribute(data.getRoot());
	if (emfAttribute.getEAttributeType() instanceof EEnum) {
	EEnum enumerator = (EEnum) emfAttribute.getEAttributeType();
	for (EEnumLiteral literal : enumerator.getELiterals()) {
	taskAttribute.putOption(literal.getLiteral(), literal.getName());
	}
	}
	getEmfMapper(repository).copyEmfToTask(emfObject, taskAttribute);
	if (emfValue != null) {
	EFactory factory = emfAttribute.getEAttributeType().getEPackage().getEFactoryInstance();
	String stringValue = factory.convertToString(emfAttribute.getEAttributeType(), emfValue);
	taskAttribute.setValue(stringValue);
	} else if (!emfObject.eIsSet(feature)) {
	taskAttribute.clearValues();
	} else {
	taskAttribute.setValue(""); //$NON-NLS-1$
	}
	}
	}
	return data;
	}

	protected KeyStrategy getKeyStrategy() {
	return KeyStrategy.EMF_SCHEMA_FIELD;
	}

	protected String getTaskKey(TaskRepository repository, EObject emfObject) {
	String key = null;
	switch (getKeyStrategy()) {
	case EMF_SCHEMA_FIELD:
	key = getEmfMapper(repository).getEmfString(emfObject, TaskAttribute.TASK_KEY);
	break;
	case OBJECT_ID:
	key = EcoreUtil.getID(emfObject);
	break;
	case XMI_ID:
	Resource resource = emfObject.eResource();
	if (resource instanceof XMLResource) {
	XMLResource xmlResource = (XMLResource) resource;
	key = xmlResource.getID(emfObject);
	}
	break;
	case MEMBER_INDEX:
	EObject rootContainer = EcoreUtil.getRootContainer(emfObject);
	String uriFragment = rootContainer.eResource().getURIFragment(emfObject);
	key = uriFragment;
	int dotIndex = key.indexOf('.');
	if (dotIndex >= 0) {
	key = key.substring(dotIndex + 1);
	}
	break;
	}
	return encodeTaskKey(key);
	}

	public EObject getTaskObject(TaskRepository repository, String taskId, IProgressMonitor monitor)
	throws CoreException {
	taskId = encodeTaskKey(taskId);
	EmfClient client = getClient(repository);
	client.open();
	EObject container = client.getRootContainer();
	EObject rootContainer = EcoreUtil.getRootContainer(container);
	EObject referencedObject = rootContainer.eResource().getEObject(taskId);
	taskId = encodeTaskKey(taskId);
	if (referencedObject == null) {
	for (Object object : ((List<?>) container.eGet(getContainmentReference()))) {
	if (object instanceof EObject) {
	EObject eObject = (EObject) object;
	String stringValueForKey = getTaskKey(repository, eObject);
	if (ObjectUtils.equals(stringValueForKey, taskId)) {
	referencedObject = eObject;
	break;
	}
	}
	}
	}
	return referencedObject;
	}

	public EObject getTaskObjectChecked(TaskRepository repository, String taskId, IProgressMonitor monitor)
	throws CoreException {
	EObject emfObject = getTaskObject(repository, taskId, monitor);
	if (emfObject == null) {
	throw new CoreException(new Status(IStatus.WARNING, EmfCorePlugin.PLUGIN_ID,
	"Couldn't locate task object for taskId: " + taskId //$NON-NLS-1$
	));
	}
	return emfObject;
	}

	@Override
	public AbstractTaskDataHandler getTaskDataHandler() {
	return taskDataHandler;
	}

	/**
	* Encode a task id to prevent use of handle delimiters.
	*
	* @param taskId
	* @return
	*/
	public String encodeTaskKey(String taskId) {
	return StringUtils.replace(taskId, RepositoryTaskHandleUtil.HANDLE_DELIM, EN_DASH);
	}

	/**
	* Decode a task id to restore any handle delimiters.
	*
	* @param taskId
	* @return
	*/
	public String decodeTaskKey(String taskId) {
	return StringUtils.replace(taskId, EN_DASH, RepositoryTaskHandleUtil.HANDLE_DELIM);
	}

	@Override
	public String getRepositoryUrlFromTaskUrl(String url) {
	if (url == null) {
	return null;
	}

	int i = url.indexOf(ITEM_DELIM);
	if (i != -1) {
	return url.substring(0, i);
	}
	return null;
	}

	@Override
	public String getTaskIdFromTaskUrl(String url) {
	if (url == null) {
	return null;
	}
	int index = url.indexOf(ITEM_DELIM);
	if (index > 0) {
	String taskId = url.substring(index + ITEM_DELIM.length());
	try {
	taskId = URLDecoder.decode(taskId, "utf-8"); //$NON-NLS-1$
	} catch (UnsupportedEncodingException e) {
	throw new RuntimeException(e);
	}
	return taskId;
	}
	return null;
	}

	@Override
	public String getTaskUrl(String repositoryUrl, String taskId) {
	String encodedId = taskId;
	try {
	encodedId = URLEncoder.encode(taskId, "utf-8"); //$NON-NLS-1$
	} catch (UnsupportedEncodingException e) {
	throw new RuntimeException(e);
	}
	return repositoryUrl + ITEM_DELIM + encodedId;
	}

	@Override
	public ITaskMapping getTaskMapping(TaskData taskData) {
	return new TaskMapper(taskData);
	}

	@Override
	public boolean hasTaskChanged(TaskRepository repository, ITask task, TaskData taskData) {
	ITaskMapping taskMapping = getTaskMapping(taskData);
	if (taskData.isPartial() && task.getModificationDate() != null) {
	return false;
	}
	Date repositoryDate = taskMapping.getModificationDate();
	Date localDate = task.getModificationDate();
	boolean hasChanged = repositoryDate != null && repositoryDate.equals(localDate);
	return hasChanged;
	}

	@Override
	public IStatus performQuery(TaskRepository repository, IRepositoryQuery query, TaskDataCollector resultCollector,
	ISynchronizationSession session, IProgressMonitor monitor) {
	try {
	EmfClient client = getClient(repository);
	client.open();
	List<EObject> results;
	try {
	results = getQueryEngine(repository).performQuery(query, monitor);
	for (EObject taskObject : results) {
	String id = encodeTaskKey(getTaskKey(repository, taskObject));
	if (!StringUtils.isEmpty(id)) {
	TaskData taskData = createPartialTaskData(repository, id, monitor);
	resultCollector.accept(taskData);
	}
	}
	return Status.OK_STATUS;
	} catch (QueryException e) {
	return new Status(IStatus.ERROR, EmfCorePlugin.PLUGIN_ID, "Problem occurred while executing query.", e); //$NON-NLS-1$
	}
	} catch (CoreException e) {
	return e.getStatus();
	} finally {
	monitor.done();
	}
	}

	@Override
	public void updateRepositoryConfiguration(TaskRepository repository, IProgressMonitor monitor) throws CoreException {
	getClient(repository).updateConfiguration(monitor);
	}

	@Override
	public void updateTaskFromTaskData(TaskRepository taskRepository, ITask task, TaskData taskData) {
	Date oldModificationDate = task.getModificationDate();

	TaskMapper mapper = (TaskMapper) getTaskMapping(taskData);
	// retain modification date to force an update when full task data is received
	if (taskData.isPartial()) {
	task.setModificationDate(oldModificationDate);
	} else {
	mapper.applyTo(task);
	}
	}

	public IStatus validate(TaskRepository repository, IProgressMonitor monitor) throws CoreException {
	return Status.OK_STATUS;
	}

	public RepositoryClientManager<EmfClient, EmfConfiguration> getClientManager() {
	if (clientManager == null) {
	clientManager = new EmfClientManager();
	}
	return clientManager;
	}

	public final EmfTaskSchema getSchema() {
	if (taskSchema == null) {
	taskSchema = createTaskSchema();
	taskSchema.initialize();
	}
	return taskSchema;
	}

	/**
	* Override to provide a custom task schema implementation. (The default Schema will provide values based on the
	* connector meta-data .)
	*
	* @return
	*/
	public EmfTaskSchema createTaskSchema() {
	return new EmfTaskSchemaDelegator();
	}

	public File getCacheFile() {
	return configurationCacheFile;
	}

	/**
	* Override to implement a custom EMF client. In most cases this should not be necessary.
	*
	* @param repository
	* @param configuration
	* @return
	*/
	protected EmfClient createClient(TaskRepository repository, EmfConfiguration configuration) {
	return new EmfClient(repository, configuration) {
	@Override
	public AbstractEmfConnector getConnector() {
	return AbstractEmfConnector.this;
	}

	};
	}

	public Set<QueryClause> getQueryClauses() {
	return queryClauses;
	}

	public abstract String getNextTaskId(EObject taskContainer);

	public abstract EAttribute getContentsNameAttribute();

	public abstract EReference getContainmentReference();

	/**
	* The class to be used for task container. By default this is the clss defined by the containment reference.
	*
	* @return
	*/
	public EClass getContainerClass() {
	return getContainmentReference().getEContainingClass();
	}

	public abstract EAttribute[] getSearchAttributes();

	public abstract Bundle getConnectorBundle();

	public abstract EClass[] getTaskClasses();

	public abstract FieldFeature[] getTaskFeatures();
	}