org.eclipse.mylyn.oslc.core/src/org/eclipse/mylyn/internal/oslc/core/client/AbstractOslcClient.java - mylyn/org.eclipse.mylyn.tasks - Git at Google

 /*******************************************************************************
  * Copyright (c) 2009 Tasktop Technologies and others.
  *  All rights reserved. This program and the accompanying materials
  *  are made available under the terms of the Eclipse Public License v1.0
  *  which accompanies this distribution, and is available at
  *  http://www.eclipse.org/legal/epl-v10.html
  *
  *  Contributors:
  *      Tasktop Technologies - initial API and implementation
  *******************************************************************************/

 package org.eclipse.mylyn.internal.oslc.core.client;

 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;

 import org.apache.commons.httpclient.HostConfiguration;
 import org.apache.commons.httpclient.HttpClient;
 import org.apache.commons.httpclient.HttpMethodBase;
 import org.apache.commons.httpclient.URIException;
 import org.apache.commons.httpclient.cookie.CookiePolicy;
 import org.apache.commons.httpclient.methods.GetMethod;
 import org.apache.commons.httpclient.methods.PostMethod;
 import org.apache.commons.httpclient.methods.PutMethod;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.net.AbstractWebLocation;
 import org.eclipse.mylyn.commons.net.Policy;
 import org.eclipse.mylyn.commons.net.WebUtil;
 import org.eclipse.mylyn.internal.oslc.core.IOslcCoreConstants;
 import org.eclipse.mylyn.internal.oslc.core.OslcCreationDialogDescriptor;
 import org.eclipse.mylyn.internal.oslc.core.OslcSelectionDialogDescriptor;
 import org.eclipse.mylyn.internal.oslc.core.OslcServiceDescriptor;
 import org.eclipse.mylyn.internal.oslc.core.OslcServiceFactory;
 import org.eclipse.mylyn.internal.oslc.core.OslcServiceProvider;
 import org.eclipse.mylyn.internal.oslc.core.OslcServiceProviderCatalog;
 import org.eclipse.mylyn.internal.oslc.core.ServiceHome;
 import org.eclipse.mylyn.internal.oslc.core.cm.AbstractChangeRequest;
 import org.eclipse.mylyn.tasks.core.RepositoryResponse;
 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.jdom.Attribute;
 import org.jdom.Document;
 import org.jdom.Element;
 import org.jdom.JDOMException;
 import org.jdom.filter.ElementFilter;
 import org.jdom.input.SAXBuilder;

 /**
  * Base class from which to implement an OSLC client
  *
  * @author Robert Elves
  */
 public abstract class AbstractOslcClient {

 	protected final AbstractWebLocation location;

 	protected final HttpClient httpClient;

 	protected final OslcServiceDescriptor configuration;

 	public AbstractOslcClient(AbstractWebLocation location, OslcServiceDescriptor data) {
 		this.location = location;
 		this.httpClient = createHttpClient();
 		this.configuration = data;
 	}

 	protected HttpClient createHttpClient() {
 		HttpClient httpClient = new HttpClient();
 		httpClient.setHttpConnectionManager(WebUtil.getConnectionManager());
 		httpClient.getParams().setCookiePolicy(CookiePolicy.RFC_2109);

 		// See: https://jazz.net/jazz/web/projects/Rational%20Team%20Concert#action=com.ibm.team.workitem.viewWorkItem&id=85127\
 		// Added to support fix session cookie issue when talking to tomcat
 		httpClient.getParams().setParameter("http.protocol.single-cookie-header", true); //$NON-NLS-1$

 		WebUtil.configureHttpClient(httpClient, getUserAgent());
 		return httpClient;
 	}

 	/**
 	 * Return your unique connector identifier i.e. com.mycompany.myconnector
 	 */
 	public abstract String getUserAgent();

 	/**
 	 * Exposed at connector level via IOslcCoreConnector.getAvailableServices()
 	 */
 	public List<OslcServiceProvider> getAvailableServices(String url, IProgressMonitor monitor) throws CoreException {

 		RequestHandler<List<OslcServiceProvider>> handler = new RequestHandler<List<OslcServiceProvider>>(
 				"Requesting Available Services") { //$NON-NLS-1$

 			@Override
 			public List<OslcServiceProvider> run(HttpMethodBase method, IProgressMonitor monitor) throws CoreException {
 				try {
 					final List<OslcServiceProvider> result = new ArrayList<OslcServiceProvider>();
 					parseServices(method.getResponseBodyAsStream(), result, monitor);
 					return result;
 				} catch (IOException e) {
 					throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 							"Network error occurred retrieving available services: " + e.getMessage(), e)); //$NON-NLS-1$
 				}
 			}
 		};

 		return executeMethod(createGetMethod(url), handler, monitor);
 	}

 	protected Document getDocumentFromMethod(HttpMethodBase method) throws CoreException {
 		try {
 			return getDocumentFromStream(method.getResponseBodyAsStream());
 		} catch (IOException e) {
 			throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 					"Network error obtaining response from server: " + e.getMessage(), e)); //$NON-NLS-1$
 		}
 	}

 	protected Document getDocumentFromStream(InputStream inStream) throws CoreException {
 		SAXBuilder builder = new SAXBuilder();
 		builder.setExpandEntities(false);
 		try {
 			return builder.build(inStream);
 		} catch (JDOMException e) {
 			throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 					"Error parsing response: " + e.getMessage(), e)); //$NON-NLS-1$
 		} catch (IOException e) {
 			throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 					"Network error parsing response: " + e.getMessage(), e)); //$NON-NLS-1$
 		}
 	}

 	/**
 	 * public for testing
 	 */
 	public void parseServices(InputStream inStream, Collection<OslcServiceProvider> providers, IProgressMonitor monitor)
 			throws CoreException {

 		Document doc = getDocumentFromStream(inStream);

 		Iterator<?> itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SERVICE_PROVIDER_CATALOG));
 		while (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			if (element != doc.getRootElement()) {
 				Attribute attrAbout = element.getAttribute(IOslcCoreConstants.ATTRIBUTE_ABOUT,
 						IOslcCoreConstants.NAMESPACE_RDF);
 				String title = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
 						.getText();
 				if (attrAbout != null && attrAbout.getValue().length() > 0) {
 					providers.add(new OslcServiceProviderCatalog(title, attrAbout.getValue()));
 				}
 			}
 		}
 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SERVICE_PROVIDER));
 		while (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			String title = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
 					.getText();
 			Element service = element.getChild(IOslcCoreConstants.ELEMENT_SERVICES,
 					IOslcCoreConstants.NAMESPACE_OSLC_DISCOVERY_1_0);
 			if (service != null) {
 				String resource = service.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_RESOURCE,
 						IOslcCoreConstants.NAMESPACE_RDF);
 				providers.add(new OslcServiceProvider(title, resource));
 			}
 		}
 	}

 	/**
 	 * Retrieve a service descriptor for the given service provider. Exposed at connector level by
 	 * IOslcConnector.getServiceDescriptor()
 	 *
 	 * @throws CoreException
 	 */
 	public OslcServiceDescriptor getServiceDescriptor(OslcServiceProvider provider, IProgressMonitor monitor)
 			throws CoreException {
 		OslcServiceDescriptor configuration = new OslcServiceDescriptor(provider.getUrl());
 		downloadServiceDescriptor(configuration, monitor);
 		return configuration;
 	}

 	/**
 	 * Populate the provided configuration with new data from the remote repository.
 	 */
 	protected void downloadServiceDescriptor(final OslcServiceDescriptor config, IProgressMonitor monitor)
 			throws CoreException {

 		RequestHandler<OslcServiceDescriptor> handler = new RequestHandler<OslcServiceDescriptor>(
 				"Retrieving Service Descriptor") { //$NON-NLS-1$

 			@Override
 			public OslcServiceDescriptor run(HttpMethodBase method, IProgressMonitor monitor) throws CoreException,
 					IOException {
 				config.clear();
 				parseServiceDescriptor(method.getResponseBodyAsStream(), config, monitor);
 				return config;
 			}
 		};

 		executeMethod(createGetMethod(config.getAboutUrl()), handler, monitor);

 	}

 	/**
 	 * public for testing
 	 */
 	public void parseServiceDescriptor(InputStream inStream, OslcServiceDescriptor config, IProgressMonitor monitor)
 			throws CoreException {
 		Document doc = getDocumentFromStream(inStream);

 		Iterator<?> itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_TITLE,
 				IOslcCoreConstants.NAMESPACE_DC));
 		if (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			config.setTitle(element.getText());
 		}

 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_DESCRIPTION,
 				IOslcCoreConstants.NAMESPACE_DC));
 		if (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			config.setDescription(element.getText());
 		}

 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_CREATIONDIALOG,
 				IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0));
 		while (itr.hasNext()) {
 			boolean isDefault = false;
 			Element element = (Element) itr.next();
 			String label = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
 					.getText();
 			String url = element.getChild(IOslcCoreConstants.ELEMENT_URL, IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0)
 					.getText();
 			Attribute attrDefault = element.getAttribute(IOslcCoreConstants.ATTRIBUTE_DEFAULT,
 					IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 			if (attrDefault != null && attrDefault.getValue().equals("true")) { //$NON-NLS-1$
 				isDefault = true;
 			}
 			OslcCreationDialogDescriptor recordType = new OslcCreationDialogDescriptor(label, url);
 			config.addCreationDialog(recordType);
 			if (isDefault) {
 				config.setDefaultCreationDialog(recordType);
 			}
 		}

 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SIMPLEQUERY));
 		if (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			String url = element.getChild(IOslcCoreConstants.ELEMENT_URL, IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0)
 					.getText();
 			if (url != null) {
 				config.setSimpleQueryUrl(url);
 			}
 		}

 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_FACTORY));
 		while (itr.hasNext()) {
 			boolean isDefault = false;
 			Element element = (Element) itr.next();
 			String title = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
 					.getText();
 			String url = element.getChild(IOslcCoreConstants.ELEMENT_URL, IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0)
 					.getText();
 			if (element.getAttribute(IOslcCoreConstants.ATTRIBUTE_DEFAULT) != null
 					&& element.getAttribute(IOslcCoreConstants.ATTRIBUTE_DEFAULT).getValue().equals("true")) { //$NON-NLS-1$
 				isDefault = true;
 			}
 			OslcServiceFactory factory = new OslcServiceFactory(title, url);
 			if (isDefault) {
 				config.setDefaultFactory(factory);
 			}
 			config.addServiceFactory(factory);
 		}

 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_HOME));
 		if (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			Element childTitle = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC);
 			Element childUrl = element.getChild(IOslcCoreConstants.ELEMENT_URL,
 					IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 			if (childTitle != null && childTitle.getText().length() > 0 && childUrl != null
 					&& childUrl.getText().length() > 0) {
 				ServiceHome home = new ServiceHome(childTitle.getText(), childUrl.getText());
 				config.setHome(home);
 			}
 		}

 		itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SELECTIONDIALOG));
 		if (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			Element childTitle = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC);
 			Element childUrl = element.getChild(IOslcCoreConstants.ELEMENT_URL,
 					IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 			if (childTitle != null && childTitle.getText().length() > 0 && childUrl != null
 					&& childUrl.getText().length() > 0) {

 				OslcSelectionDialogDescriptor selection = new OslcSelectionDialogDescriptor(childTitle.getText(),
 						childUrl.getText());

 				String isDefault = element.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_DEFAULT,
 						IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 				if (isDefault != null) {
 					selection.setDefault(isDefault.equals("true")); //$NON-NLS-1$
 				}

 				String hintHeight = element.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_HINTHEIGHT,
 						IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 				if (hintHeight != null) {
 					selection.setHintHeight(hintHeight);
 				}

 				String hintWidth = element.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_HINTWIDTH,
 						IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 				if (hintWidth != null) {
 					selection.setHintWidth(hintWidth);
 				}

 				String label = element.getChildText(IOslcCoreConstants.ELEMENT_LABEL,
 						IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
 				if (label != null) {
 					selection.setLabel(label);
 				}

 				config.addSelectionDialog(selection);
 			}
 		}

 	}

 	public Collection<AbstractChangeRequest> performQuery(String queryUrl, IProgressMonitor monitor)
 			throws CoreException {

 		RequestHandler<Collection<AbstractChangeRequest>> handler = new RequestHandler<Collection<AbstractChangeRequest>>(
 				"Performing Query") { //$NON-NLS-1$

 			@Override
 			public Collection<AbstractChangeRequest> run(HttpMethodBase method, IProgressMonitor monitor)
 					throws CoreException, IOException {
 				Collection<AbstractChangeRequest> result = new ArrayList<AbstractChangeRequest>();
 				parseQueryResponse(method.getResponseBodyAsStream(), result, monitor);
 				return result;
 			}
 		};

 		return executeMethod(createGetMethod(queryUrl), handler, monitor);

 	}

 	// TODO: Handle pagination
 	public void parseQueryResponse(InputStream inStream, Collection<AbstractChangeRequest> requests,
 			IProgressMonitor monitor) throws CoreException {
 		Document doc = getDocumentFromStream(inStream);

 		Iterator<?> itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_CHANGEREQUEST,
 				IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0));
 		while (itr.hasNext()) {
 			Element element = (Element) itr.next();
 			String title = element.getChildText(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC);
 			String id = element.getChildText(IOslcCoreConstants.ELEMENT_IDENTIFIER, IOslcCoreConstants.NAMESPACE_DC);

 			if (title != null && id != null) {
 				AbstractChangeRequest request = createChangeRequest(id, title);
 				request.setType(element.getChildText(IOslcCoreConstants.ELEMENT_TYPE, IOslcCoreConstants.NAMESPACE_DC));
 				request.setDescription(element.getChildText(IOslcCoreConstants.ELEMENT_DESCRIPTION,
 						IOslcCoreConstants.NAMESPACE_DC));
 				request.setSubject(element.getChildText(IOslcCoreConstants.ELEMENT_SUBJECT,
 						IOslcCoreConstants.NAMESPACE_DC));
 				request.setCreator(element.getChildText(IOslcCoreConstants.ELEMENT_CREATOR,
 						IOslcCoreConstants.NAMESPACE_DC));
 				request.setModified(element.getChildText(IOslcCoreConstants.ELEMENT_MODIFIED,
 						IOslcCoreConstants.NAMESPACE_DC));
 				requests.add(request);
 			}

 		}
 	}

 	protected abstract AbstractChangeRequest createChangeRequest(String id, String title);

 	/**
 	 * Updates this clients 'repository configuration'. If old types were in use (locally cached) and still exist they
 	 * are re-read from repository.
 	 */
 	public void updateRepositoryConfiguration(IProgressMonitor monitor) throws CoreException {
 		configuration.clear();
 		downloadServiceDescriptor(configuration, monitor);
 	}

 	public abstract TaskData getTaskData(final String encodedTaskId, TaskAttributeMapper mapper,
 			IProgressMonitor monitor) throws CoreException;

 	public abstract RepositoryResponse putTaskData(TaskData taskData, Set<TaskAttribute> oldValues,
 			IProgressMonitor monitor) throws CoreException;

 	protected GetMethod createGetMethod(String requestPath) {
 		GetMethod method = new GetMethod(getRequestPath(requestPath));
 		method.setFollowRedirects(true);
 		method.setDoAuthentication(true);
 		// application/xml is returned by oslc servers by default
 		//method.setRequestHeader("Accept", "application/xml");
 		return method;
 	}

 	protected PostMethod createPostMethod(String requestPath) {
 		PostMethod method = new PostMethod(getRequestPath(requestPath));
 		method.setFollowRedirects(false);
 		method.setDoAuthentication(true);
 //		this.entity = getRequestEntity(method);
 //		if (pairs != null) {
 //			method.setRequestBody(pairs);
 //		} else if (entity != null) {
 //			method.setRequestEntity(entity);
 //		} else {
 //			StatusHandler.log(new Status(IStatus.WARNING, IOslcCoreConstants.ID_PLUGIN,
 //					"Request body or entity missing upon post.")); //$NON-NLS-1$
 //		}
 		return method;
 	}

 	protected PutMethod createPutMethod(String requestPath) {
 		PutMethod method = new PutMethod(getRequestPath(requestPath));
 		method.setFollowRedirects(false);
 		method.setDoAuthentication(true);
 		return method;
 	}

 	protected <T> T executeMethod(HttpMethodBase method, RequestHandler<T> handler, IProgressMonitor monitor)
 			throws CoreException {
 		monitor = Policy.monitorFor(monitor);
 		try {
 			monitor.beginTask(handler.getRequestName(), IProgressMonitor.UNKNOWN);

 			HostConfiguration hostConfiguration = WebUtil.createHostConfiguration(httpClient, location, monitor);
 			int code = WebUtil.execute(httpClient, hostConfiguration, method, monitor);

 			handler.handleReturnCode(code, method);

 			return handler.run(method, monitor);
 		} catch (IOException e) {
 			throw new CoreException(new Status(IStatus.WARNING, IOslcCoreConstants.ID_PLUGIN,
 					"An unexpected network error has occurred: " + e.getMessage(), e)); //$NON-NLS-1$
 		} finally {
 			if (method != null) {
 				method.releaseConnection();
 			}
 			monitor.done();
 		}

 	}

 	public String getRequestPath(String repositoryUrl) {
 		if (repositoryUrl.startsWith("./")) { //$NON-NLS-1$
 			return WebUtil.getRequestPath(location.getUrl()) + repositoryUrl.substring(1);
 		} else if (repositoryUrl.startsWith("/")) { //$NON-NLS-1$
 			return WebUtil.getRequestPath(location.getUrl()) + repositoryUrl;
 		}
 		return WebUtil.getRequestPath(repositoryUrl);
 	}

 	public abstract class RequestHandler<T> {

 		private final String requestName;

 		public RequestHandler(String requestName) {
 			this.requestName = requestName;
 		}

 		public abstract T run(HttpMethodBase method, IProgressMonitor monitor) throws CoreException, IOException;

 		public String getRequestName() {
 			return requestName;
 		}

 		protected void handleReturnCode(int code, HttpMethodBase method) throws CoreException {
 			try {
 				if (code == java.net.HttpURLConnection.HTTP_OK) {
 					return;// Status.OK_STATUS;
 				} else if (code == java.net.HttpURLConnection.HTTP_MOVED_TEMP
 						|| code == java.net.HttpURLConnection.HTTP_CREATED) {
 					// A new resource created...
 					return;// Status.OK_STATUS;
 				} else if (code == java.net.HttpURLConnection.HTTP_UNAUTHORIZED
 						|| code == java.net.HttpURLConnection.HTTP_FORBIDDEN) {
 					throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 							"Unable to log into server, ensure repository credentials are correct.")); //$NON-NLS-1$
 				} else if (code == java.net.HttpURLConnection.HTTP_PRECON_FAILED) {
 					// Mid-air collision
 					throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 							"Mid-air collision occurred.")); //$NON-NLS-1$
 				} else if (code == java.net.HttpURLConnection.HTTP_CONFLICT) {
 					throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
 							"A conflict occurred.")); //$NON-NLS-1$
 				} else {
 					throw new CoreException(
 							new Status(
 									IStatus.ERROR,
 									IOslcCoreConstants.ID_PLUGIN,
 									"Unknown error occurred. Http Code: " + code + " Request: " + method.getURI() + " Response: " //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 											+ method.getResponseBodyAsString()));
 				}
 			} catch (URIException e) {
 				throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN, "Network Error: " //$NON-NLS-1$
 						+ e.getMessage()));
 			} catch (IOException e) {
 				throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN, "Network Error: " //$NON-NLS-1$
 						+ e.getMessage()));
 			}
 		}

 	}
 }
	/*******************************************************************************
	* Copyright (c) 2009 Tasktop Technologies and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* Tasktop Technologies - initial API and implementation
	*******************************************************************************/

	package org.eclipse.mylyn.internal.oslc.core.client;

	import java.io.IOException;
	import java.io.InputStream;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Set;

	import org.apache.commons.httpclient.HostConfiguration;
	import org.apache.commons.httpclient.HttpClient;
	import org.apache.commons.httpclient.HttpMethodBase;
	import org.apache.commons.httpclient.URIException;
	import org.apache.commons.httpclient.cookie.CookiePolicy;
	import org.apache.commons.httpclient.methods.GetMethod;
	import org.apache.commons.httpclient.methods.PostMethod;
	import org.apache.commons.httpclient.methods.PutMethod;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.mylyn.commons.net.AbstractWebLocation;
	import org.eclipse.mylyn.commons.net.Policy;
	import org.eclipse.mylyn.commons.net.WebUtil;
	import org.eclipse.mylyn.internal.oslc.core.IOslcCoreConstants;
	import org.eclipse.mylyn.internal.oslc.core.OslcCreationDialogDescriptor;
	import org.eclipse.mylyn.internal.oslc.core.OslcSelectionDialogDescriptor;
	import org.eclipse.mylyn.internal.oslc.core.OslcServiceDescriptor;
	import org.eclipse.mylyn.internal.oslc.core.OslcServiceFactory;
	import org.eclipse.mylyn.internal.oslc.core.OslcServiceProvider;
	import org.eclipse.mylyn.internal.oslc.core.OslcServiceProviderCatalog;
	import org.eclipse.mylyn.internal.oslc.core.ServiceHome;
	import org.eclipse.mylyn.internal.oslc.core.cm.AbstractChangeRequest;
	import org.eclipse.mylyn.tasks.core.RepositoryResponse;
	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.jdom.Attribute;
	import org.jdom.Document;
	import org.jdom.Element;
	import org.jdom.JDOMException;
	import org.jdom.filter.ElementFilter;
	import org.jdom.input.SAXBuilder;

	/**
	* Base class from which to implement an OSLC client
	*
	* @author Robert Elves
	*/
	public abstract class AbstractOslcClient {

	protected final AbstractWebLocation location;

	protected final HttpClient httpClient;

	protected final OslcServiceDescriptor configuration;

	public AbstractOslcClient(AbstractWebLocation location, OslcServiceDescriptor data) {
	this.location = location;
	this.httpClient = createHttpClient();
	this.configuration = data;
	}

	protected HttpClient createHttpClient() {
	HttpClient httpClient = new HttpClient();
	httpClient.setHttpConnectionManager(WebUtil.getConnectionManager());
	httpClient.getParams().setCookiePolicy(CookiePolicy.RFC_2109);

	// See: https://jazz.net/jazz/web/projects/Rational%20Team%20Concert#action=com.ibm.team.workitem.viewWorkItem&id=85127\
	// Added to support fix session cookie issue when talking to tomcat
	httpClient.getParams().setParameter("http.protocol.single-cookie-header", true); //$NON-NLS-1$

	WebUtil.configureHttpClient(httpClient, getUserAgent());
	return httpClient;
	}

	/**
	* Return your unique connector identifier i.e. com.mycompany.myconnector
	*/
	public abstract String getUserAgent();

	/**
	* Exposed at connector level via IOslcCoreConnector.getAvailableServices()
	*/
	public List<OslcServiceProvider> getAvailableServices(String url, IProgressMonitor monitor) throws CoreException {

	RequestHandler<List<OslcServiceProvider>> handler = new RequestHandler<List<OslcServiceProvider>>(
	"Requesting Available Services") { //$NON-NLS-1$

	@Override
	public List<OslcServiceProvider> run(HttpMethodBase method, IProgressMonitor monitor) throws CoreException {
	try {
	final List<OslcServiceProvider> result = new ArrayList<OslcServiceProvider>();
	parseServices(method.getResponseBodyAsStream(), result, monitor);
	return result;
	} catch (IOException e) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"Network error occurred retrieving available services: " + e.getMessage(), e)); //$NON-NLS-1$
	}
	}
	};

	return executeMethod(createGetMethod(url), handler, monitor);
	}

	protected Document getDocumentFromMethod(HttpMethodBase method) throws CoreException {
	try {
	return getDocumentFromStream(method.getResponseBodyAsStream());
	} catch (IOException e) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"Network error obtaining response from server: " + e.getMessage(), e)); //$NON-NLS-1$
	}
	}

	protected Document getDocumentFromStream(InputStream inStream) throws CoreException {
	SAXBuilder builder = new SAXBuilder();
	builder.setExpandEntities(false);
	try {
	return builder.build(inStream);
	} catch (JDOMException e) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"Error parsing response: " + e.getMessage(), e)); //$NON-NLS-1$
	} catch (IOException e) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"Network error parsing response: " + e.getMessage(), e)); //$NON-NLS-1$
	}
	}

	/**
	* public for testing
	*/
	public void parseServices(InputStream inStream, Collection<OslcServiceProvider> providers, IProgressMonitor monitor)
	throws CoreException {

	Document doc = getDocumentFromStream(inStream);

	Iterator<?> itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SERVICE_PROVIDER_CATALOG));
	while (itr.hasNext()) {
	Element element = (Element) itr.next();
	if (element != doc.getRootElement()) {
	Attribute attrAbout = element.getAttribute(IOslcCoreConstants.ATTRIBUTE_ABOUT,
	IOslcCoreConstants.NAMESPACE_RDF);
	String title = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
	.getText();
	if (attrAbout != null && attrAbout.getValue().length() > 0) {
	providers.add(new OslcServiceProviderCatalog(title, attrAbout.getValue()));
	}
	}
	}
	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SERVICE_PROVIDER));
	while (itr.hasNext()) {
	Element element = (Element) itr.next();
	String title = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
	.getText();
	Element service = element.getChild(IOslcCoreConstants.ELEMENT_SERVICES,
	IOslcCoreConstants.NAMESPACE_OSLC_DISCOVERY_1_0);
	if (service != null) {
	String resource = service.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_RESOURCE,
	IOslcCoreConstants.NAMESPACE_RDF);
	providers.add(new OslcServiceProvider(title, resource));
	}
	}
	}

	/**
	* Retrieve a service descriptor for the given service provider. Exposed at connector level by
	* IOslcConnector.getServiceDescriptor()
	*
	* @throws CoreException
	*/
	public OslcServiceDescriptor getServiceDescriptor(OslcServiceProvider provider, IProgressMonitor monitor)
	throws CoreException {
	OslcServiceDescriptor configuration = new OslcServiceDescriptor(provider.getUrl());
	downloadServiceDescriptor(configuration, monitor);
	return configuration;
	}

	/**
	* Populate the provided configuration with new data from the remote repository.
	*/
	protected void downloadServiceDescriptor(final OslcServiceDescriptor config, IProgressMonitor monitor)
	throws CoreException {

	RequestHandler<OslcServiceDescriptor> handler = new RequestHandler<OslcServiceDescriptor>(
	"Retrieving Service Descriptor") { //$NON-NLS-1$

	@Override
	public OslcServiceDescriptor run(HttpMethodBase method, IProgressMonitor monitor) throws CoreException,
	IOException {
	config.clear();
	parseServiceDescriptor(method.getResponseBodyAsStream(), config, monitor);
	return config;
	}
	};

	executeMethod(createGetMethod(config.getAboutUrl()), handler, monitor);

	}

	/**
	* public for testing
	*/
	public void parseServiceDescriptor(InputStream inStream, OslcServiceDescriptor config, IProgressMonitor monitor)
	throws CoreException {
	Document doc = getDocumentFromStream(inStream);

	Iterator<?> itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_TITLE,
	IOslcCoreConstants.NAMESPACE_DC));
	if (itr.hasNext()) {
	Element element = (Element) itr.next();
	config.setTitle(element.getText());
	}

	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_DESCRIPTION,
	IOslcCoreConstants.NAMESPACE_DC));
	if (itr.hasNext()) {
	Element element = (Element) itr.next();
	config.setDescription(element.getText());
	}

	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_CREATIONDIALOG,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0));
	while (itr.hasNext()) {
	boolean isDefault = false;
	Element element = (Element) itr.next();
	String label = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
	.getText();
	String url = element.getChild(IOslcCoreConstants.ELEMENT_URL, IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0)
	.getText();
	Attribute attrDefault = element.getAttribute(IOslcCoreConstants.ATTRIBUTE_DEFAULT,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (attrDefault != null && attrDefault.getValue().equals("true")) { //$NON-NLS-1$
	isDefault = true;
	}
	OslcCreationDialogDescriptor recordType = new OslcCreationDialogDescriptor(label, url);
	config.addCreationDialog(recordType);
	if (isDefault) {
	config.setDefaultCreationDialog(recordType);
	}
	}

	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SIMPLEQUERY));
	if (itr.hasNext()) {
	Element element = (Element) itr.next();
	String url = element.getChild(IOslcCoreConstants.ELEMENT_URL, IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0)
	.getText();
	if (url != null) {
	config.setSimpleQueryUrl(url);
	}
	}

	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_FACTORY));
	while (itr.hasNext()) {
	boolean isDefault = false;
	Element element = (Element) itr.next();
	String title = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC)
	.getText();
	String url = element.getChild(IOslcCoreConstants.ELEMENT_URL, IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0)
	.getText();
	if (element.getAttribute(IOslcCoreConstants.ATTRIBUTE_DEFAULT) != null
	&& element.getAttribute(IOslcCoreConstants.ATTRIBUTE_DEFAULT).getValue().equals("true")) { //$NON-NLS-1$
	isDefault = true;
	}
	OslcServiceFactory factory = new OslcServiceFactory(title, url);
	if (isDefault) {
	config.setDefaultFactory(factory);
	}
	config.addServiceFactory(factory);
	}

	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_HOME));
	if (itr.hasNext()) {
	Element element = (Element) itr.next();
	Element childTitle = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC);
	Element childUrl = element.getChild(IOslcCoreConstants.ELEMENT_URL,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (childTitle != null && childTitle.getText().length() > 0 && childUrl != null
	&& childUrl.getText().length() > 0) {
	ServiceHome home = new ServiceHome(childTitle.getText(), childUrl.getText());
	config.setHome(home);
	}
	}

	itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_SELECTIONDIALOG));
	if (itr.hasNext()) {
	Element element = (Element) itr.next();
	Element childTitle = element.getChild(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC);
	Element childUrl = element.getChild(IOslcCoreConstants.ELEMENT_URL,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (childTitle != null && childTitle.getText().length() > 0 && childUrl != null
	&& childUrl.getText().length() > 0) {

	OslcSelectionDialogDescriptor selection = new OslcSelectionDialogDescriptor(childTitle.getText(),
	childUrl.getText());

	String isDefault = element.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_DEFAULT,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (isDefault != null) {
	selection.setDefault(isDefault.equals("true")); //$NON-NLS-1$
	}

	String hintHeight = element.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_HINTHEIGHT,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (hintHeight != null) {
	selection.setHintHeight(hintHeight);
	}

	String hintWidth = element.getAttributeValue(IOslcCoreConstants.ATTRIBUTE_HINTWIDTH,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (hintWidth != null) {
	selection.setHintWidth(hintWidth);
	}

	String label = element.getChildText(IOslcCoreConstants.ELEMENT_LABEL,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0);
	if (label != null) {
	selection.setLabel(label);
	}

	config.addSelectionDialog(selection);
	}
	}

	}

	public Collection<AbstractChangeRequest> performQuery(String queryUrl, IProgressMonitor monitor)
	throws CoreException {

	RequestHandler<Collection<AbstractChangeRequest>> handler = new RequestHandler<Collection<AbstractChangeRequest>>(
	"Performing Query") { //$NON-NLS-1$

	@Override
	public Collection<AbstractChangeRequest> run(HttpMethodBase method, IProgressMonitor monitor)
	throws CoreException, IOException {
	Collection<AbstractChangeRequest> result = new ArrayList<AbstractChangeRequest>();
	parseQueryResponse(method.getResponseBodyAsStream(), result, monitor);
	return result;
	}
	};

	return executeMethod(createGetMethod(queryUrl), handler, monitor);

	}

	// TODO: Handle pagination
	public void parseQueryResponse(InputStream inStream, Collection<AbstractChangeRequest> requests,
	IProgressMonitor monitor) throws CoreException {
	Document doc = getDocumentFromStream(inStream);

	Iterator<?> itr = doc.getDescendants(new ElementFilter(IOslcCoreConstants.ELEMENT_CHANGEREQUEST,
	IOslcCoreConstants.NAMESPACE_OSLC_CM_1_0));
	while (itr.hasNext()) {
	Element element = (Element) itr.next();
	String title = element.getChildText(IOslcCoreConstants.ELEMENT_TITLE, IOslcCoreConstants.NAMESPACE_DC);
	String id = element.getChildText(IOslcCoreConstants.ELEMENT_IDENTIFIER, IOslcCoreConstants.NAMESPACE_DC);

	if (title != null && id != null) {
	AbstractChangeRequest request = createChangeRequest(id, title);
	request.setType(element.getChildText(IOslcCoreConstants.ELEMENT_TYPE, IOslcCoreConstants.NAMESPACE_DC));
	request.setDescription(element.getChildText(IOslcCoreConstants.ELEMENT_DESCRIPTION,
	IOslcCoreConstants.NAMESPACE_DC));
	request.setSubject(element.getChildText(IOslcCoreConstants.ELEMENT_SUBJECT,
	IOslcCoreConstants.NAMESPACE_DC));
	request.setCreator(element.getChildText(IOslcCoreConstants.ELEMENT_CREATOR,
	IOslcCoreConstants.NAMESPACE_DC));
	request.setModified(element.getChildText(IOslcCoreConstants.ELEMENT_MODIFIED,
	IOslcCoreConstants.NAMESPACE_DC));
	requests.add(request);
	}

	}
	}

	protected abstract AbstractChangeRequest createChangeRequest(String id, String title);

	/**
	* Updates this clients 'repository configuration'. If old types were in use (locally cached) and still exist they
	* are re-read from repository.
	*/
	public void updateRepositoryConfiguration(IProgressMonitor monitor) throws CoreException {
	configuration.clear();
	downloadServiceDescriptor(configuration, monitor);
	}

	public abstract TaskData getTaskData(final String encodedTaskId, TaskAttributeMapper mapper,
	IProgressMonitor monitor) throws CoreException;

	public abstract RepositoryResponse putTaskData(TaskData taskData, Set<TaskAttribute> oldValues,
	IProgressMonitor monitor) throws CoreException;

	protected GetMethod createGetMethod(String requestPath) {
	GetMethod method = new GetMethod(getRequestPath(requestPath));
	method.setFollowRedirects(true);
	method.setDoAuthentication(true);
	// application/xml is returned by oslc servers by default
	//method.setRequestHeader("Accept", "application/xml");
	return method;
	}

	protected PostMethod createPostMethod(String requestPath) {
	PostMethod method = new PostMethod(getRequestPath(requestPath));
	method.setFollowRedirects(false);
	method.setDoAuthentication(true);
	// this.entity = getRequestEntity(method);
	// if (pairs != null) {
	// method.setRequestBody(pairs);
	// } else if (entity != null) {
	// method.setRequestEntity(entity);
	// } else {
	// StatusHandler.log(new Status(IStatus.WARNING, IOslcCoreConstants.ID_PLUGIN,
	// "Request body or entity missing upon post.")); //$NON-NLS-1$
	// }
	return method;
	}

	protected PutMethod createPutMethod(String requestPath) {
	PutMethod method = new PutMethod(getRequestPath(requestPath));
	method.setFollowRedirects(false);
	method.setDoAuthentication(true);
	return method;
	}

	protected <T> T executeMethod(HttpMethodBase method, RequestHandler<T> handler, IProgressMonitor monitor)
	throws CoreException {
	monitor = Policy.monitorFor(monitor);
	try {
	monitor.beginTask(handler.getRequestName(), IProgressMonitor.UNKNOWN);

	HostConfiguration hostConfiguration = WebUtil.createHostConfiguration(httpClient, location, monitor);
	int code = WebUtil.execute(httpClient, hostConfiguration, method, monitor);

	handler.handleReturnCode(code, method);

	return handler.run(method, monitor);
	} catch (IOException e) {
	throw new CoreException(new Status(IStatus.WARNING, IOslcCoreConstants.ID_PLUGIN,
	"An unexpected network error has occurred: " + e.getMessage(), e)); //$NON-NLS-1$
	} finally {
	if (method != null) {
	method.releaseConnection();
	}
	monitor.done();
	}

	}

	public String getRequestPath(String repositoryUrl) {
	if (repositoryUrl.startsWith("./")) { //$NON-NLS-1$
	return WebUtil.getRequestPath(location.getUrl()) + repositoryUrl.substring(1);
	} else if (repositoryUrl.startsWith("/")) { //$NON-NLS-1$
	return WebUtil.getRequestPath(location.getUrl()) + repositoryUrl;
	}
	return WebUtil.getRequestPath(repositoryUrl);
	}

	public abstract class RequestHandler<T> {

	private final String requestName;

	public RequestHandler(String requestName) {
	this.requestName = requestName;
	}

	public abstract T run(HttpMethodBase method, IProgressMonitor monitor) throws CoreException, IOException;

	public String getRequestName() {
	return requestName;
	}

	protected void handleReturnCode(int code, HttpMethodBase method) throws CoreException {
	try {
	if (code == java.net.HttpURLConnection.HTTP_OK) {
	return;// Status.OK_STATUS;
	} else if (code == java.net.HttpURLConnection.HTTP_MOVED_TEMP
	\|\| code == java.net.HttpURLConnection.HTTP_CREATED) {
	// A new resource created...
	return;// Status.OK_STATUS;
	} else if (code == java.net.HttpURLConnection.HTTP_UNAUTHORIZED
	\|\| code == java.net.HttpURLConnection.HTTP_FORBIDDEN) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"Unable to log into server, ensure repository credentials are correct.")); //$NON-NLS-1$
	} else if (code == java.net.HttpURLConnection.HTTP_PRECON_FAILED) {
	// Mid-air collision
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"Mid-air collision occurred.")); //$NON-NLS-1$
	} else if (code == java.net.HttpURLConnection.HTTP_CONFLICT) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN,
	"A conflict occurred.")); //$NON-NLS-1$
	} else {
	throw new CoreException(
	new Status(
	IStatus.ERROR,
	IOslcCoreConstants.ID_PLUGIN,
	"Unknown error occurred. Http Code: " + code + " Request: " + method.getURI() + " Response: " //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	+ method.getResponseBodyAsString()));
	}
	} catch (URIException e) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN, "Network Error: " //$NON-NLS-1$
	+ e.getMessage()));
	} catch (IOException e) {
	throw new CoreException(new Status(IStatus.ERROR, IOslcCoreConstants.ID_PLUGIN, "Network Error: " //$NON-NLS-1$
	+ e.getMessage()));
	}
	}

	}
	}