org.eclipse.epp.mpc.core/src/org/eclipse/epp/internal/mpc/core/util/TransportFactory.java - mpc/org.eclipse.epp.mpc - Git at Google

 /*******************************************************************************
  * Copyright (c) 2010 The Eclipse Foundation 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:
  *     The Eclipse Foundation - initial API and implementation
  *     Yatta Solutions - bug 432803: public API
  *******************************************************************************/
 package org.eclipse.epp.internal.mpc.core.util;

 import java.io.FileNotFoundException;
 import java.io.InputStream;
 import java.lang.reflect.InvocationTargetException;
 import java.net.URI;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;

 import org.apache.http.NoHttpResponseException;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.MultiStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.epp.internal.mpc.core.MarketplaceClientCore;
 import org.eclipse.epp.internal.mpc.core.MarketplaceClientCorePlugin;
 import org.eclipse.epp.internal.mpc.core.service.ServiceUnavailableException;
 import org.eclipse.epp.mpc.core.service.ITransportFactory;
 import org.eclipse.epp.mpc.core.service.ServiceHelper;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.FrameworkUtil;
 import org.osgi.framework.InvalidSyntaxException;
 import org.osgi.framework.ServiceReference;
 import org.osgi.service.component.ComponentConstants;
 import org.osgi.service.component.ComponentContext;
 import org.osgi.util.tracker.ServiceTracker;
 import org.osgi.util.tracker.ServiceTrackerCustomizer;

 /**
  * Factory to retrieve Transport instances of p2. Will delegate to version-dependent implementations.
  *
  * @author David Green
  * @author Benjamin Muskalla
  * @author Carsten Reckord
  */
 public abstract class TransportFactory implements ITransportFactory {

 	public static final String LEGACY_TRANSPORT_KEY = "org.eclipse.epp.mpc.core.service.transport.legacy"; //$NON-NLS-1$

 	public static final String LEGACY_TRANSPORT_COMPONENT_NAME = "org.eclipse.epp.mpc.core.transportfactory.legacy"; //$NON-NLS-1$

 	public static final String DISABLED_TRANSPORTS_KEY = "org.eclipse.epp.mpc.core.service.transport.disabled"; //$NON-NLS-1$

 	private static final String[] factoryClasses = new String[] { //
 			"org.eclipse.epp.internal.mpc.core.util.P2TransportFactory", // //$NON-NLS-1$
 			"org.eclipse.epp.internal.mpc.core.util.Eclipse36TransportFactory", // //$NON-NLS-1$
 	"org.eclipse.epp.internal.mpc.core.util.JavaPlatformTransportFactory" }; //$NON-NLS-1$

 	private static final String HTTP_TRANSPORT_FACTORY_ID = "org.eclipse.epp.mpc.core.transport.http.factory"; //$NON-NLS-1$

 	private static final String HTTP_TRANSPORT_WRAPPER_ID = "org.eclipse.epp.mpc.core.transport.http.wrapper"; //$NON-NLS-1$

 	private static final String ECF_HTTPCLIENT4_TRANSPORT_ID = "org.eclipse.ecf.provider.filetransfer.httpclient4"; //$NON-NLS-1$

 	private static final String ECF_EXCLUDES_PROPERTY = "org.eclipse.ecf.provider.filetransfer.excludeContributors"; //$NON-NLS-1$

 	public static String computeDisabledTransportsFilter() {
 		BundleContext bundleContext = FrameworkUtil.getBundle(TransportFactory.class).getBundleContext();
 		String disabledTransportsStr = bundleContext.getProperty(DISABLED_TRANSPORTS_KEY);
 		if (disabledTransportsStr == null) {
 			disabledTransportsStr = ""; //$NON-NLS-1$
 		}
 		String excludeContributors = bundleContext
 				.getProperty(ECF_EXCLUDES_PROPERTY);
 		if (excludeContributors != null && excludeContributors.contains(ECF_HTTPCLIENT4_TRANSPORT_ID)) {
 			disabledTransportsStr += "," + HTTP_TRANSPORT_WRAPPER_ID + "," + HTTP_TRANSPORT_FACTORY_ID; //$NON-NLS-1$//$NON-NLS-2$
 		}
 		Set<String> disabledTransports = new HashSet<String>();
 		StringBuilder bldr = new StringBuilder("(&"); //$NON-NLS-1$
 		for (String transportName : disabledTransportsStr.split(",")) { //$NON-NLS-1$
 			transportName = transportName.trim();
 			if (!"".equals(transportName) && disabledTransports.add(transportName)) { //$NON-NLS-1$
 				bldr.append("(!(") //$NON-NLS-1$
 				.append(ComponentConstants.COMPONENT_NAME)
 				.append("=") //$NON-NLS-1$
 				.append(transportName)
 				.append("))"); //$NON-NLS-1$
 			}
 		}
 		bldr.append(")"); //$NON-NLS-1$
 		String disabledTransportsFilter = disabledTransports.isEmpty() ? "" : bldr.toString(); //$NON-NLS-1$
 		return disabledTransportsFilter;
 	}

 	public static final class LegacyFactory implements ITransportFactory {
 		private ITransportFactory delegate;

 		private ServiceReference<ITransportFactory> delegateReference;

 		public LegacyFactory() {
 		}

 		public ITransportFactory getDelegate() {
 			return delegate;
 		}

 		@Override
 		public org.eclipse.epp.mpc.core.service.ITransport getTransport() {
 			return delegate.getTransport();
 		}

 		public void activate(ComponentContext context) throws InvalidSyntaxException {
 			BundleContext bundleContext = context.getBundleContext();
 			Collection<ServiceReference<ITransportFactory>> serviceReferences = bundleContext.getServiceReferences(
 					ITransportFactory.class,
 					"(&" //$NON-NLS-1$
 					+ "(" + LEGACY_TRANSPORT_KEY + "=true)" //$NON-NLS-1$//$NON-NLS-2$
 					+ "(!(" + ComponentConstants.COMPONENT_NAME + "=" + LEGACY_TRANSPORT_COMPONENT_NAME + "))" //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
 					+ computeDisabledTransportsFilter()
 					+ ")"); //$NON-NLS-1$
 			if (!serviceReferences.isEmpty()) {
 				for (ServiceReference<ITransportFactory> serviceReference : serviceReferences) {
 					ITransportFactory service = bundleContext.getService(serviceReference);
 					if (service instanceof TransportFactory) {
 						delegate = service;
 						delegateReference = serviceReference;
 						return;
 					} else {
 						bundleContext.ungetService(serviceReference);
 					}
 				}
 			}
 			List<ITransportFactory> availableFactories = listAvailableFactories();
 			if (availableFactories.isEmpty()) {
 				context.disableComponent(LEGACY_TRANSPORT_COMPONENT_NAME);
 				throw new IllegalStateException(Messages.TransportFactory_NoLegacyTransportFactoriesError);
 			}
 			delegate = availableFactories.get(0);
 			delegateReference = null;
 		}

 		public void deactivate(ComponentContext context) {
 			delegate = null;
 			if (delegateReference != null) {
 				context.getBundleContext().ungetService(delegateReference);
 				delegateReference = null;
 			}
 		}
 	}

 	public static class LegacyTransportFactoryTracker extends ServiceTracker<ITransportFactory, TransportFactory> {

 		public LegacyTransportFactoryTracker(final BundleContext context) {
 			super(context, ITransportFactory.class, new LegacyTransportFactoryTrackerCustomizer(context));
 		}
 	}

 	public static class LegacyTransportFactoryTrackerCustomizer
 	implements ServiceTrackerCustomizer<ITransportFactory, TransportFactory> {
 		private final BundleContext context;

 		private final Map<ServiceReference<ITransportFactory>, TransportFactory> trackedServices = new HashMap<ServiceReference<ITransportFactory>, TransportFactory>();

 		private LegacyTransportFactoryTrackerCustomizer(BundleContext context) {
 			this.context = context;
 		}

 		@Override
 		public TransportFactory addingService(ServiceReference<ITransportFactory> reference) {
 			Object legacyProperty = reference.getProperty(TransportFactory.LEGACY_TRANSPORT_KEY);
 			if (!Boolean.parseBoolean(String.valueOf(legacyProperty))) {
 				return null;
 			}
 			ITransportFactory service = context.getService(reference);
 			if (service instanceof TransportFactory.LegacyFactory) {
 				TransportFactory.LegacyFactory legacyFactory = (TransportFactory.LegacyFactory) service;
 				service = legacyFactory.getDelegate();
 			}
 			if (service instanceof TransportFactory) {
 				TransportFactory transportFactory = (TransportFactory) service;
 				if (!trackedServices.containsValue(transportFactory)) {
 					trackedServices.put(reference, transportFactory);
 					return transportFactory;
 				}
 			}
 			return null;
 		}

 		@Override
 		public void modifiedService(ServiceReference<ITransportFactory> reference, TransportFactory service) {
 			// ignore
 		}

 		@Override
 		public void removedService(ServiceReference<ITransportFactory> reference, TransportFactory service) {
 			trackedServices.remove(reference);
 		}
 	}

 	/**
 	 * @deprecated use registered {@link ITransportFactory} OSGi service
 	 * @see ServiceHelper#getTransportFactory()
 	 */
 	@Deprecated
 	public static synchronized TransportFactory instance() {
 		TransportFactory legacyTransportFactory = MarketplaceClientCorePlugin.getDefault()
 				.getServiceHelper()
 				.getLegacyTransportFactory();
 		if (legacyTransportFactory == null) {
 			throw new IllegalStateException();
 		}
 		return legacyTransportFactory;
 	}

 	public static org.eclipse.epp.mpc.core.service.ITransport createTransport() {
 		//search for registered factory service
 		BundleContext context = MarketplaceClientCorePlugin.getBundle().getBundleContext();
 		ServiceReference<ITransportFactory> serviceReference = getTransportServiceReference(context);
 		if (serviceReference != null) {
 			ITransportFactory transportService = context.getService(serviceReference);
 			if (transportService != null) {
 				try {
 					return transportService.getTransport();
 				} finally {
 					transportService = null;
 					context.ungetService(serviceReference);
 				}
 			}
 		}
 		IStatus serviceError = diagnoseTransportServiceRegistration(context, serviceReference);
 		throw new IllegalStateException(new CoreException(serviceError));
 	}

 	private static IStatus diagnoseTransportServiceRegistration(BundleContext context,
 			ServiceReference<ITransportFactory> serviceReference) {
 		MultiStatus serviceError = null;
 		if (serviceReference != null) {
 			serviceError = new MultiStatus(MarketplaceClientCore.BUNDLE_ID, 0,
 					Messages.TransportFactory_ServiceErrorUnregistered, null);
 			serviceError.add(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
 					Messages.TransportFactory_ServiceErrorServiceReference + serviceReference));
 		} else {
 			serviceError = new MultiStatus(MarketplaceClientCore.BUNDLE_ID, 0,
 					Messages.TransportFactory_ServiceErrorNotFound, null);
 			try {
 				Collection<ServiceReference<ITransportFactory>> allServiceReferences = context
 						.getServiceReferences(ITransportFactory.class, null);
 				if (allServiceReferences.isEmpty()) {
 					serviceError.add(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
 							Messages.TransportFactory_ServiceErrorNoneAvailable));
 				} else {
 					String filter = computeDisabledTransportsFilter();
 					serviceError.add(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
 							Messages.TransportFactory_ServiceErrorAppliedFilter + filter));
 				}
 				for (ServiceReference<ITransportFactory> availableReference : allServiceReferences) {
 					serviceError.add(new Status(IStatus.INFO, MarketplaceClientCore.BUNDLE_ID,
 							Messages.TransportFactory_ServiceErrorFilteredService + availableReference.toString()));
 				}
 			} catch (InvalidSyntaxException e) {
 				//Unreachable
 				serviceError.add(
 						new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
 								Messages.TransportFactory_ServiceErrorDetails, e));
 			}
 		}
 		return serviceError;
 	}

 	public static ServiceReference<ITransportFactory> getTransportServiceReference(BundleContext context) {
 		ServiceReference<ITransportFactory> serviceReference = null;
 		String disabledTransportsFilter = computeDisabledTransportsFilter();
 		if ("".equals(disabledTransportsFilter)) { //$NON-NLS-1$
 			serviceReference = context.getServiceReference(ITransportFactory.class);
 		} else {
 			try {
 				Collection<ServiceReference<ITransportFactory>> serviceReferences = context
 						.getServiceReferences(ITransportFactory.class, disabledTransportsFilter);
 				if (!serviceReferences.isEmpty()) {
 					serviceReference = serviceReferences.iterator().next();
 				}
 			} catch (InvalidSyntaxException e) {
 				MarketplaceClientCore.error(e);
 				serviceReference = context.getServiceReference(ITransportFactory.class);
 			}
 		}
 		return serviceReference;
 	}

 	public static List<ITransportFactory> listAvailableFactories() {
 		List<ITransportFactory> factories = new ArrayList<ITransportFactory>();
 		for (String factoryClass : factoryClasses) {
 			TransportFactory factory;
 			try {
 				factory = (TransportFactory) Class.forName(factoryClass, true, TransportFactory.class.getClassLoader())
 						.newInstance();
 			} catch (Throwable t) {
 				// ignore
 				continue;
 			}
 			try {
 				if (factory.isAvailable()) {
 					factories.add(factory);
 				}
 			} catch (Throwable t) {
 				MarketplaceClientCore.getLog().log(new Status(IStatus.WARNING, MarketplaceClientCore.BUNDLE_ID,
 						Messages.TransportFactory_transportAvailabilityError, t));
 			}
 		}
 		return factories;
 	}

 	@Override
 	@SuppressWarnings("deprecation")
 	public ITransport getTransport() {
 		return new ITransport() {

 			@Override
 			public InputStream stream(URI location, IProgressMonitor monitor) throws FileNotFoundException,
 			org.eclipse.epp.mpc.core.service.ServiceUnavailableException, CoreException {
 				try {
 					return invokeStream(location, monitor);
 				} catch (Exception e) {
 					handleStreamExceptions(e);
 				}
 				return null;
 			}

 		};
 	}

 	protected abstract boolean isAvailable();

 	protected abstract InputStream invokeStream(URI location, IProgressMonitor monitor) throws Exception;

 	@SuppressWarnings("deprecation")
 	protected void handleStreamExceptions(Exception e) throws ServiceUnavailableException, CoreException,
 	FileNotFoundException {
 		if (e instanceof InvocationTargetException) {
 			InvocationTargetException targetException = (InvocationTargetException) e;
 			Throwable cause = targetException.getCause();
 			if (cause instanceof CoreException) {
 				CoreException coreCause = (CoreException) cause;
 				handleServiceUnavailable(coreCause);
 				throw coreCause;
 			} else if (cause instanceof FileNotFoundException) {
 				throw (FileNotFoundException) cause;
 			}

 		} else {
 			throw new CoreException(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID, e.getMessage(), e));
 		}
 	}


 	@SuppressWarnings("deprecation")
 	protected static void handleServiceUnavailable(CoreException e) throws ServiceUnavailableException {
 		if (e.getStatus().getCode() == 1002) { //failed to read
 			Throwable cause = e.getCause();
 			if (cause != null) {
 				if (cause instanceof NoHttpResponseException || cause.getMessage() != null
 						&& cause.getMessage().indexOf("503") != -1) { //$NON-NLS-1$
 					throw new ServiceUnavailableException(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
 							503, Messages.DefaultMarketplaceService_serviceUnavailable503, e));
 				}
 			}
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2010 The Eclipse Foundation 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:
	* The Eclipse Foundation - initial API and implementation
	* Yatta Solutions - bug 432803: public API
	*******************************************************************************/
	package org.eclipse.epp.internal.mpc.core.util;

	import java.io.FileNotFoundException;
	import java.io.InputStream;
	import java.lang.reflect.InvocationTargetException;
	import java.net.URI;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;

	import org.apache.http.NoHttpResponseException;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.MultiStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.epp.internal.mpc.core.MarketplaceClientCore;
	import org.eclipse.epp.internal.mpc.core.MarketplaceClientCorePlugin;
	import org.eclipse.epp.internal.mpc.core.service.ServiceUnavailableException;
	import org.eclipse.epp.mpc.core.service.ITransportFactory;
	import org.eclipse.epp.mpc.core.service.ServiceHelper;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.FrameworkUtil;
	import org.osgi.framework.InvalidSyntaxException;
	import org.osgi.framework.ServiceReference;
	import org.osgi.service.component.ComponentConstants;
	import org.osgi.service.component.ComponentContext;
	import org.osgi.util.tracker.ServiceTracker;
	import org.osgi.util.tracker.ServiceTrackerCustomizer;

	/**
	* Factory to retrieve Transport instances of p2. Will delegate to version-dependent implementations.
	*
	* @author David Green
	* @author Benjamin Muskalla
	* @author Carsten Reckord
	*/
	public abstract class TransportFactory implements ITransportFactory {

	public static final String LEGACY_TRANSPORT_KEY = "org.eclipse.epp.mpc.core.service.transport.legacy"; //$NON-NLS-1$

	public static final String LEGACY_TRANSPORT_COMPONENT_NAME = "org.eclipse.epp.mpc.core.transportfactory.legacy"; //$NON-NLS-1$

	public static final String DISABLED_TRANSPORTS_KEY = "org.eclipse.epp.mpc.core.service.transport.disabled"; //$NON-NLS-1$

	private static final String[] factoryClasses = new String[] { //
	"org.eclipse.epp.internal.mpc.core.util.P2TransportFactory", // //$NON-NLS-1$
	"org.eclipse.epp.internal.mpc.core.util.Eclipse36TransportFactory", // //$NON-NLS-1$
	"org.eclipse.epp.internal.mpc.core.util.JavaPlatformTransportFactory" }; //$NON-NLS-1$

	private static final String HTTP_TRANSPORT_FACTORY_ID = "org.eclipse.epp.mpc.core.transport.http.factory"; //$NON-NLS-1$

	private static final String HTTP_TRANSPORT_WRAPPER_ID = "org.eclipse.epp.mpc.core.transport.http.wrapper"; //$NON-NLS-1$

	private static final String ECF_HTTPCLIENT4_TRANSPORT_ID = "org.eclipse.ecf.provider.filetransfer.httpclient4"; //$NON-NLS-1$

	private static final String ECF_EXCLUDES_PROPERTY = "org.eclipse.ecf.provider.filetransfer.excludeContributors"; //$NON-NLS-1$

	public static String computeDisabledTransportsFilter() {
	BundleContext bundleContext = FrameworkUtil.getBundle(TransportFactory.class).getBundleContext();
	String disabledTransportsStr = bundleContext.getProperty(DISABLED_TRANSPORTS_KEY);
	if (disabledTransportsStr == null) {
	disabledTransportsStr = ""; //$NON-NLS-1$
	}
	String excludeContributors = bundleContext
	.getProperty(ECF_EXCLUDES_PROPERTY);
	if (excludeContributors != null && excludeContributors.contains(ECF_HTTPCLIENT4_TRANSPORT_ID)) {
	disabledTransportsStr += "," + HTTP_TRANSPORT_WRAPPER_ID + "," + HTTP_TRANSPORT_FACTORY_ID; //$NON-NLS-1$//$NON-NLS-2$
	}
	Set<String> disabledTransports = new HashSet<String>();
	StringBuilder bldr = new StringBuilder("(&"); //$NON-NLS-1$
	for (String transportName : disabledTransportsStr.split(",")) { //$NON-NLS-1$
	transportName = transportName.trim();
	if (!"".equals(transportName) && disabledTransports.add(transportName)) { //$NON-NLS-1$
	bldr.append("(!(") //$NON-NLS-1$
	.append(ComponentConstants.COMPONENT_NAME)
	.append("=") //$NON-NLS-1$
	.append(transportName)
	.append("))"); //$NON-NLS-1$
	}
	}
	bldr.append(")"); //$NON-NLS-1$
	String disabledTransportsFilter = disabledTransports.isEmpty() ? "" : bldr.toString(); //$NON-NLS-1$
	return disabledTransportsFilter;
	}

	public static final class LegacyFactory implements ITransportFactory {
	private ITransportFactory delegate;

	private ServiceReference<ITransportFactory> delegateReference;

	public LegacyFactory() {
	}

	public ITransportFactory getDelegate() {
	return delegate;
	}

	@Override
	public org.eclipse.epp.mpc.core.service.ITransport getTransport() {
	return delegate.getTransport();
	}

	public void activate(ComponentContext context) throws InvalidSyntaxException {
	BundleContext bundleContext = context.getBundleContext();
	Collection<ServiceReference<ITransportFactory>> serviceReferences = bundleContext.getServiceReferences(
	ITransportFactory.class,
	"(&" //$NON-NLS-1$
	+ "(" + LEGACY_TRANSPORT_KEY + "=true)" //$NON-NLS-1$//$NON-NLS-2$
	+ "(!(" + ComponentConstants.COMPONENT_NAME + "=" + LEGACY_TRANSPORT_COMPONENT_NAME + "))" //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
	+ computeDisabledTransportsFilter()
	+ ")"); //$NON-NLS-1$
	if (!serviceReferences.isEmpty()) {
	for (ServiceReference<ITransportFactory> serviceReference : serviceReferences) {
	ITransportFactory service = bundleContext.getService(serviceReference);
	if (service instanceof TransportFactory) {
	delegate = service;
	delegateReference = serviceReference;
	return;
	} else {
	bundleContext.ungetService(serviceReference);
	}
	}
	}
	List<ITransportFactory> availableFactories = listAvailableFactories();
	if (availableFactories.isEmpty()) {
	context.disableComponent(LEGACY_TRANSPORT_COMPONENT_NAME);
	throw new IllegalStateException(Messages.TransportFactory_NoLegacyTransportFactoriesError);
	}
	delegate = availableFactories.get(0);
	delegateReference = null;
	}

	public void deactivate(ComponentContext context) {
	delegate = null;
	if (delegateReference != null) {
	context.getBundleContext().ungetService(delegateReference);
	delegateReference = null;
	}
	}
	}

	public static class LegacyTransportFactoryTracker extends ServiceTracker<ITransportFactory, TransportFactory> {

	public LegacyTransportFactoryTracker(final BundleContext context) {
	super(context, ITransportFactory.class, new LegacyTransportFactoryTrackerCustomizer(context));
	}
	}

	public static class LegacyTransportFactoryTrackerCustomizer
	implements ServiceTrackerCustomizer<ITransportFactory, TransportFactory> {
	private final BundleContext context;

	private final Map<ServiceReference<ITransportFactory>, TransportFactory> trackedServices = new HashMap<ServiceReference<ITransportFactory>, TransportFactory>();

	private LegacyTransportFactoryTrackerCustomizer(BundleContext context) {
	this.context = context;
	}

	@Override
	public TransportFactory addingService(ServiceReference<ITransportFactory> reference) {
	Object legacyProperty = reference.getProperty(TransportFactory.LEGACY_TRANSPORT_KEY);
	if (!Boolean.parseBoolean(String.valueOf(legacyProperty))) {
	return null;
	}
	ITransportFactory service = context.getService(reference);
	if (service instanceof TransportFactory.LegacyFactory) {
	TransportFactory.LegacyFactory legacyFactory = (TransportFactory.LegacyFactory) service;
	service = legacyFactory.getDelegate();
	}
	if (service instanceof TransportFactory) {
	TransportFactory transportFactory = (TransportFactory) service;
	if (!trackedServices.containsValue(transportFactory)) {
	trackedServices.put(reference, transportFactory);
	return transportFactory;
	}
	}
	return null;
	}

	@Override
	public void modifiedService(ServiceReference<ITransportFactory> reference, TransportFactory service) {
	// ignore
	}

	@Override
	public void removedService(ServiceReference<ITransportFactory> reference, TransportFactory service) {
	trackedServices.remove(reference);
	}
	}

	/**
	* @deprecated use registered {@link ITransportFactory} OSGi service
	* @see ServiceHelper#getTransportFactory()
	*/
	@Deprecated
	public static synchronized TransportFactory instance() {
	TransportFactory legacyTransportFactory = MarketplaceClientCorePlugin.getDefault()
	.getServiceHelper()
	.getLegacyTransportFactory();
	if (legacyTransportFactory == null) {
	throw new IllegalStateException();
	}
	return legacyTransportFactory;
	}

	public static org.eclipse.epp.mpc.core.service.ITransport createTransport() {
	//search for registered factory service
	BundleContext context = MarketplaceClientCorePlugin.getBundle().getBundleContext();
	ServiceReference<ITransportFactory> serviceReference = getTransportServiceReference(context);
	if (serviceReference != null) {
	ITransportFactory transportService = context.getService(serviceReference);
	if (transportService != null) {
	try {
	return transportService.getTransport();
	} finally {
	transportService = null;
	context.ungetService(serviceReference);
	}
	}
	}
	IStatus serviceError = diagnoseTransportServiceRegistration(context, serviceReference);
	throw new IllegalStateException(new CoreException(serviceError));
	}

	private static IStatus diagnoseTransportServiceRegistration(BundleContext context,
	ServiceReference<ITransportFactory> serviceReference) {
	MultiStatus serviceError = null;
	if (serviceReference != null) {
	serviceError = new MultiStatus(MarketplaceClientCore.BUNDLE_ID, 0,
	Messages.TransportFactory_ServiceErrorUnregistered, null);
	serviceError.add(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
	Messages.TransportFactory_ServiceErrorServiceReference + serviceReference));
	} else {
	serviceError = new MultiStatus(MarketplaceClientCore.BUNDLE_ID, 0,
	Messages.TransportFactory_ServiceErrorNotFound, null);
	try {
	Collection<ServiceReference<ITransportFactory>> allServiceReferences = context
	.getServiceReferences(ITransportFactory.class, null);
	if (allServiceReferences.isEmpty()) {
	serviceError.add(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
	Messages.TransportFactory_ServiceErrorNoneAvailable));
	} else {
	String filter = computeDisabledTransportsFilter();
	serviceError.add(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
	Messages.TransportFactory_ServiceErrorAppliedFilter + filter));
	}
	for (ServiceReference<ITransportFactory> availableReference : allServiceReferences) {
	serviceError.add(new Status(IStatus.INFO, MarketplaceClientCore.BUNDLE_ID,
	Messages.TransportFactory_ServiceErrorFilteredService + availableReference.toString()));
	}
	} catch (InvalidSyntaxException e) {
	//Unreachable
	serviceError.add(
	new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
	Messages.TransportFactory_ServiceErrorDetails, e));
	}
	}
	return serviceError;
	}

	public static ServiceReference<ITransportFactory> getTransportServiceReference(BundleContext context) {
	ServiceReference<ITransportFactory> serviceReference = null;
	String disabledTransportsFilter = computeDisabledTransportsFilter();
	if ("".equals(disabledTransportsFilter)) { //$NON-NLS-1$
	serviceReference = context.getServiceReference(ITransportFactory.class);
	} else {
	try {
	Collection<ServiceReference<ITransportFactory>> serviceReferences = context
	.getServiceReferences(ITransportFactory.class, disabledTransportsFilter);
	if (!serviceReferences.isEmpty()) {
	serviceReference = serviceReferences.iterator().next();
	}
	} catch (InvalidSyntaxException e) {
	MarketplaceClientCore.error(e);
	serviceReference = context.getServiceReference(ITransportFactory.class);
	}
	}
	return serviceReference;
	}

	public static List<ITransportFactory> listAvailableFactories() {
	List<ITransportFactory> factories = new ArrayList<ITransportFactory>();
	for (String factoryClass : factoryClasses) {
	TransportFactory factory;
	try {
	factory = (TransportFactory) Class.forName(factoryClass, true, TransportFactory.class.getClassLoader())
	.newInstance();
	} catch (Throwable t) {
	// ignore
	continue;
	}
	try {
	if (factory.isAvailable()) {
	factories.add(factory);
	}
	} catch (Throwable t) {
	MarketplaceClientCore.getLog().log(new Status(IStatus.WARNING, MarketplaceClientCore.BUNDLE_ID,
	Messages.TransportFactory_transportAvailabilityError, t));
	}
	}
	return factories;
	}

	@Override
	@SuppressWarnings("deprecation")
	public ITransport getTransport() {
	return new ITransport() {

	@Override
	public InputStream stream(URI location, IProgressMonitor monitor) throws FileNotFoundException,
	org.eclipse.epp.mpc.core.service.ServiceUnavailableException, CoreException {
	try {
	return invokeStream(location, monitor);
	} catch (Exception e) {
	handleStreamExceptions(e);
	}
	return null;
	}

	};
	}

	protected abstract boolean isAvailable();

	protected abstract InputStream invokeStream(URI location, IProgressMonitor monitor) throws Exception;

	@SuppressWarnings("deprecation")
	protected void handleStreamExceptions(Exception e) throws ServiceUnavailableException, CoreException,
	FileNotFoundException {
	if (e instanceof InvocationTargetException) {
	InvocationTargetException targetException = (InvocationTargetException) e;
	Throwable cause = targetException.getCause();
	if (cause instanceof CoreException) {
	CoreException coreCause = (CoreException) cause;
	handleServiceUnavailable(coreCause);
	throw coreCause;
	} else if (cause instanceof FileNotFoundException) {
	throw (FileNotFoundException) cause;
	}

	} else {
	throw new CoreException(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID, e.getMessage(), e));
	}
	}


	@SuppressWarnings("deprecation")
	protected static void handleServiceUnavailable(CoreException e) throws ServiceUnavailableException {
	if (e.getStatus().getCode() == 1002) { //failed to read
	Throwable cause = e.getCause();
	if (cause != null) {
	if (cause instanceof NoHttpResponseException \|\| cause.getMessage() != null
	&& cause.getMessage().indexOf("503") != -1) { //$NON-NLS-1$
	throw new ServiceUnavailableException(new Status(IStatus.ERROR, MarketplaceClientCore.BUNDLE_ID,
	503, Messages.DefaultMarketplaceService_serviceUnavailable503, e));
	}
	}
	}
	}
	}