1 files changed, 1378 insertions, 1368 deletions
diff --git a/plugins/infra/core/serviceregistry/org.eclipse.papyrus.infra.core.serviceregistry/src/org/eclipse/papyrus/infra/core/serviceregistry/ServicesRegistry.java b/plugins/infra/core/serviceregistry/org.eclipse.papyrus.infra.core.serviceregistry/src/org/eclipse/papyrus/infra/core/serviceregistry/ServicesRegistry.java
index c46bc43eb47..1525420b466 100644
--- a/plugins/infra/core/serviceregistry/org.eclipse.papyrus.infra.core.serviceregistry/src/org/eclipse/papyrus/infra/core/serviceregistry/ServicesRegistry.java
+++ b/plugins/infra/core/serviceregistry/org.eclipse.papyrus.infra.core.serviceregistry/src/org/eclipse/papyrus/infra/core/serviceregistry/ServicesRegistry.java
@@ -1,1368 +1,1378 @@
-/**
- * 
- */
-package org.eclipse.papyrus.infra.core.serviceregistry;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-import org.eclipse.papyrus.infra.core.serviceregistry.ServiceDescriptor.ServiceTypeKind;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.AliasServiceEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.LazyStartupEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.PojoServiceEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceFactoryEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceStartupEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceTypeEntry;
-import org.eclipse.papyrus.infra.core.serviceregistry.internal.StartStartupEntry;
-
-/**
- * A registry of services. This registry allows to get a service by its
- * identifier. The identifier is generally the classname of the service.
- * Services can be added using the Eclipse extension mechanism (if you use {@link ExtensionServicesRegistry}). <br>
- * A Service is a class providing operations. The ServiceRegistry is used to
- * share objects (i.e. services) between nested editors and also the core main
- * editor.
- * 
- * <br>
- * In this implementation, services should be added to the registry before the
- * call to createServices(). If a service is added after the call, it will not
- * be started (except if it is a lazy service). <br>
- * A typical usage is:
- * 
- * <pre>
- * <code>
- *   ServicesRegistry serviceRegistry = new ServiceRegistry();
- *   // Add your services
- *   serviceRegistry.add( ...);
- *   serviceRegistry.add( ...);
- *   
- *   // start the services
- *   serviceRegistry.startRegistry();
- *   
- *   // Retrieve a service
- *   myService = serviceRegistry.getService( serviceKey );
- * </code>
- * </pre>
- * 
- * It is possible to register new services after the serviceRegistry has been
- * started. In this case, you need to start them explicitly if they are of type
- * ServiceStartKind.STARTUP.
- * 
- * <pre>
- * <code>
- *   // Add your new services
- *   serviceRegistry.add( key1, ...);
- *   serviceRegistry.add( key2, ...);
- *   
- *   // start the new services
- *   serviceRegistry.startRegistry(key1, key2);
- * </code>
- * </pre>
- * 
- * <ul>
- * <li></li>
- * <li></li>
- * </ul>
- * 
- * @author cedric dumoulin
- * 
- * 
- */
-public class ServicesRegistry {
-
-	/** Log object */
-	protected Logger log = Logger.getLogger(getClass().getName());
-
-	/**
-	 * Map of existing services.
-	 */
-	// private Map<Object, AbstractServiceEntry> services;
-
-	/**
-	 * A Map of services added to the register (thow the addXxx() methods), but
-	 * not yet registered. They will be registered after a call to startXxx().
-	 */
-	private Map<String, ServiceStartupEntry> addedServices = new HashMap<String, ServiceStartupEntry>();
-
-	/**
-	 * Map of services registered with a name.
-	 */
-	private Map<String, ServiceStartupEntry> namedServices = new HashMap<String, ServiceStartupEntry>();
-
-	/**
-	 * Map of services registered without a name (anonymous). Such services
-	 * can't be retrieved.
-	 */
-	private List<ServiceStartupEntry> anonymousServices = new ArrayList<ServiceStartupEntry>();
-
-	/**
-	 * List of parents used as fallback if the service is not found in this registry.
-	 */
-	private List<ServicesRegistry> parents = new ArrayList<ServicesRegistry>();
-	
-	/**
-	 * Constructor.
-	 */
-	public ServicesRegistry() {
-	}
-
-	/**
-	 * Add a service by its ServiceDescriptor.
-	 * 
-	 * @param serviceDescriptor
-	 *        Descriptor describing the service.
-	 * @throws ServiceException
-	 *         If an error occurs while initializing service.
-	 */
-	public void add(ServiceDescriptor serviceDescriptor) {
-		// Check if the service already exist.
-		ServiceStartupEntry service = addedServices.get(serviceDescriptor.getKey());
-		if(service != null) {
-			if(service.getDescriptor().getPriority() > serviceDescriptor.getPriority())
-				return;
-			else if(service.getDescriptor().getPriority() == serviceDescriptor.getPriority()) {
-				log.warning("Two services with same priority (" + serviceDescriptor.getPriority() + ") are declared under key '" + service.getDescriptor().getKey() + "'. Keep the first encountered only. (bundles: " + service.getDescriptor().getClassBundleID() + ", " + serviceDescriptor.getClassBundleID() + ")");
-			}
-		}
-
-		// Compute the service type entry
-		ServiceTypeEntry serviceTypeEntry;
-		ServiceTypeKind typeKind = serviceDescriptor.getServiceTypeKind();
-		switch( typeKind) {
-		case service:
-			serviceTypeEntry = new ServiceEntry(serviceDescriptor);
-			break;
-		case serviceFactory:
-			serviceTypeEntry = new ServiceFactoryEntry(serviceDescriptor);
-			break;
-		case pojo:
-			serviceTypeEntry = new PojoServiceEntry(serviceDescriptor);
-			break;
-		case alias:
-			serviceTypeEntry = new AliasServiceEntry(serviceDescriptor);
-			break;			
-		default:
-			// Add as pojo
-			// Should better throw an exception. (MalformedDescriptor ?)
-			serviceTypeEntry = new PojoServiceEntry(serviceDescriptor);
-		}
-
-		// Create the entry
-		ServiceStartupEntry serviceEntry;
-		switch(serviceDescriptor.getServiceStartKind()) {
-		case STARTUP:
-			serviceEntry = new StartStartupEntry(serviceTypeEntry);
-			break;
-		case LAZY:
-			serviceEntry = new LazyStartupEntry(serviceTypeEntry, this);
-			break;
-		default:
-			// Add as LAZY
-			// Should better throw an exception. (MalformedDescriptor ?)
-			serviceEntry = new LazyStartupEntry(serviceTypeEntry, this);
-		}
-
-		// Add the entry
-		addedServices.put(serviceDescriptor.getKey(), serviceEntry);
-	}
-
-	/**
-	 * Add a service. The descriptor will be created.
-	 * 
-	 * @param key
-	 *        Service key
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 */
-	public void add(String key, int priority, IService serviceInstance) {
-		add(key, priority, serviceInstance, ServiceStartKind.STARTUP);
-	}
-
-	/**
-	 * Add a service. The descriptor will be created.
-	 * 
-	 * @param key
-	 *        Service key
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 */
-	public void add(Class<?> key, int priority, IService serviceInstance) {
-		add(key.getName(), priority, serviceInstance, ServiceStartKind.STARTUP);
-	}
-
-	/**
-	 * Add a service. The descriptor will be created.
-	 * 
-	 * @param key
-	 *        Service key
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 */
-	public void add(String key, int priority, IService serviceInstance, ServiceStartKind startKind) {
-		// Check if the service already exist.
-		ServiceStartupEntry service = addedServices.get(key);
-		if(service != null) {
-			if(service.getDescriptor().getPriority() > priority)
-				return;
-			else if(service.getDescriptor().getPriority() == priority)
-				log.warning("Two services with same priority (" + priority + ") are declared under key '" + service.getDescriptor().getKey() + "'. Keep the first encountered only.");
-		}
-
-		// Create descriptor and add service.
-		ServiceDescriptor descriptor = new ServiceDescriptor(key, serviceInstance.getClass().getName(), startKind, priority);
-
-		if(startKind == ServiceStartKind.STARTUP)
-			addedServices.put(key, new StartStartupEntry(new ServiceEntry(descriptor, serviceInstance)));
-		else
-			addedServices.put(key, new LazyStartupEntry(new ServiceEntry(descriptor, serviceInstance), this));
-	}
-
-	/**
-	 * Add a service. The descriptor will be created.
-	 * 
-	 * @param key
-	 *        Service key Class used as key. The classname is used as key.
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 */
-	public void add(Class<?> key, int priority, IService serviceInstance, ServiceStartKind startKind) {
-
-		add(key.getName(), priority, serviceInstance, startKind);
-	}
-
-	/**
-	 * Add an already instanciated pojo (Plain Old Java Object) as Service. The
-	 * descriptor will be created. No life cycle methods are called on the
-	 * service.
-	 * 
-	 * @param key
-	 *        Service key
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 */
-	public void add(Class<?> key, int priority, Object serviceInstance) {
-		add(key, priority, serviceInstance, ServiceStartKind.STARTUP);
-	}
-
-	/**
-	 * Add an already instanciated pojo (Plain Old Java Object) as Service. The
-	 * descriptor will be created. No life cycle methods are called on the
-	 * service.
-	 * 
-	 * @param key
-	 *        Service key
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 * @param startKind
-	 * 
-	 */
-	public void add(String key, int priority, Object serviceInstance, ServiceStartKind startKind) {
-		// Check if the service already exist.
-		ServiceStartupEntry service = addedServices.get(key);
-		if(service != null) {
-			if(service.getDescriptor().getPriority() > priority)
-				return;
-			else if(service.getDescriptor().getPriority() == priority)
-				log.warning("Two services with same priority (" + priority + ") are declared under key '" + service.getDescriptor().getKey() + "'. Keep the first encountered only.");
-		}
-
-		// Create descriptor and add service.
-		ServiceDescriptor descriptor = new ServiceDescriptor(key, serviceInstance.getClass().getName(), startKind, priority);
-
-		if(startKind == ServiceStartKind.STARTUP)
-			addedServices.put(key, new StartStartupEntry(new PojoServiceEntry(descriptor, serviceInstance)));
-		else
-			addedServices.put(key, new LazyStartupEntry(new PojoServiceEntry(descriptor, serviceInstance), this));
-
-	}
-
-	/**
-	 * Add an already instanciated pojo (Plain Old Java Object) as Service. The
-	 * descriptor will be created. No life cycle methods are called on the
-	 * service.
-	 * 
-	 * @param key
-	 *        Service key Class used as key. The classname is used as key.
-	 * @param priority
-	 *        service priority
-	 * @param serviceInstance
-	 *        The instance of the service
-	 * @param startKind
-	 * 
-	 */
-	public void add(Class<?> key, int priority, Object serviceInstance, ServiceStartKind startKind) {
-
-		add(key.getName(), priority, serviceInstance, startKind);
-	}
-
-	/**
-	 * Remove the specified Registry as parent of this registry.
-	 * . 
-	 * @param parentRegistry
-	 */
-	public void addParentRegistry(ServicesRegistry parentRegistry) {
-		
-		if( parentRegistry == null) {
-			return;
-		}
-		parents.add(parentRegistry);
-	}
-	
-	/**
-	 * 
-	 * @param parentRegistry
-	 */
-	public void removeParentRegistry(ServicesRegistry parentRegistry) {
-		
-		if( parentRegistry == null) {
-			return;
-		}
-		parents.remove(parentRegistry);
-	}
-	
-
-	/**
-	 * Remove the specified service from the registry.
-	 * 
-	 * @param key
-	 */
-	public void remove(ServiceDescriptor serviceDescriptor) throws ServiceException {
-		remove(serviceDescriptor.getKey());
-	}
-
-	/**
-	 * Remove the specified service from the registry.
-	 * 
-	 * @param key
-	 */
-	public void remove(Object key) throws ServiceException {
-		ServiceStartupEntry service = namedServices.remove(key);
-		if(service == null) {
-			return;
-		}
-
-		// Stop the service
-		service.disposeService();
-	}
-
-	/**
-	 * Get the requested service by its key. The key is usually the classname of
-	 * the service.
-	 * 
-	 * @param serviceClass
-	 * @return
-	 * @throws ServiceException
-	 *         If servive can't be started
-	 */
-	public Object getService(Object key) throws ServiceException {
-		ServiceStartupEntry serviceEntry = namedServices.get(key);
-		if(serviceEntry == null) {
-			// Check if we can find it in parents
-			Object service = getServiceFromParents(key);
-			if(service != null) {
-				// Found in parent, return it
-				return service;
-			}
-
-			// Not found in parents. Throw an exception
-			// throw an appropriate exception (If added, say it).
-			serviceEntry = addedServices.get(key);
-			if(serviceEntry != null)
-				throw new BadStateException("Registry should be started before.", serviceEntry.getState(), serviceEntry.getDescriptor());
-			else
-				throw new ServiceNotFoundException("No service registered under '" + key + "'");
-		}
-
-		return serviceEntry.getServiceInstance();
-	}
-
-	/**
-	 * Get the requested service by its class (the service has to be registered
-	 * by its class object).
-	 * 
-	 * @param key
-	 *        The service class.
-	 * @return The service.
-	 * @throws ServiceException
-	 *         If service can't be started
-	 */
-	@SuppressWarnings("unchecked")
-	public <S> S getService(Class<S> key) throws ServiceException {
-
-		String realKey = key.getName();
-		ServiceStartupEntry serviceEntry = namedServices.get(realKey);
-
-		// Lookup in parents if not found
-		if( serviceEntry == null) {
-			
-			// Check if we can find it in parents
-			S service = (S)getServiceFromParents(realKey);
-			if(service != null) {
-				// Found in parent, return it
-				return service;
-			}
-
-			// Not found in parents. Throw an exception
-			// throw an appropriate exception (If added, say it).
-			serviceEntry = addedServices.get(realKey);
-			if(serviceEntry != null)
-				throw new BadStateException("Registry should be started before.", serviceEntry.getState(), serviceEntry.getDescriptor());
-			else
-				throw new ServiceNotFoundException("No service registered under '" + key + "'");
-		}
-
-		// Service found, return it.
-		return (S)serviceEntry.getServiceInstance();
-	}
-
-	/**
-	 * Get the requested service by its class (the service has to be registered
-	 * by its class object).
-	 * 
-	 * @param key
-	 *        The service class.
-	 * @return The service.
-	 * @throws ServiceException
-	 *         If service can't be started
-	 */
-	private Object getServiceFromParents(Object key) throws ServiceException {
-	
-		Object foundService;
-		
-		for( ServicesRegistry parent : parents) {
-			foundService = parent.getServiceUnchecked(key);
-			// Check if we have found the service
-			if( foundService != null) {
-				// Found, return it
-				return foundService;
-			}
-		}
-		// Not found
-		return null;
-	}
-	
-	/**
-	 * Get the requested service by its key. The key is usually the classname of
-	 * the service.
-	 * Return the service, or null if not found.
-	 * This is for internal use.
-	 * 
-	 * @param serviceClass
-	 * @return The service, or null if not found.
-	 * @throws ServiceException
-	 *         If servive can't be started
-	 */
-	protected Object getServiceUnchecked(Object key) throws ServiceException {
-		ServiceStartupEntry service = namedServices.get(key);
-		if(service == null) {
-			return null;
-		}
-
-		return service.getServiceInstance();
-	}
-
-	/**
-	 * Try to get the {@link ServiceStartupEntry} of the specified service.
-	 * Search in local namedServices.
-	 * Also lookup in parents. Return null if not found.
-	 * The returned entry should not be modified by caller.
-	 * 
-	 * @param key
-	 * @return The requested entry, or null if not found.
-	 */
-	protected ServiceStartupEntry getServiceStartupEntry( Object key ) {
-		
-		return getServiceStartupEntry(key, true);
-	}
-	
-	/**
-	 * Try to get the {@link ServiceStartupEntry} of the specified service.
-	 * Search in local namedServices.
-	 * Also lookup in parents. Return null if not found.
-	 * The returned entry should not be modified by caller.
-	 * 
-	 * @param key
-	 * @param searchInParent True if we should search in parent, false if search take place in this registry only.
-	 * @return The requested entry, or null if not found.
-	 */
-	protected ServiceStartupEntry getServiceStartupEntry( Object key, boolean searchInParent ) {
-		
-		ServiceStartupEntry service = namedServices.get(key);
-		if( service != null) {
-			return service;
-		}
-
-		// Check in new services
-		service = addedServices.get(key);
-		if( service != null) {
-			return service;
-		}
-		
-		if( searchInParent ) {
-			// Lookup in parents
-			for(ServicesRegistry registry : parents) {
-				service = registry.getServiceStartupEntry(key);
-				if( service != null) {
-					return service;
-				}	
-			}	
-		}
-
-		// Not found
-		return null;
-	}
-	
-	/**
-	 * Return true if the service is instantiated. Return false otherwise.
-	 * 
-	 * @return
-	 */
-	public boolean isStarted(Object key) throws ServiceNotFoundException {
-		return isStarted(key, true);
-	}
-
-	/**
-	 * Return true if the service is instantiated. Return false otherwise.
-	 * 
-	 * @return
-	 */
-	public boolean isStarted(Object key, boolean searchInParents) throws ServiceNotFoundException {
-		ServiceStartupEntry service = getServiceStartupEntry(key, searchInParents);
-		if(service == null) {
-			throw new ServiceNotFoundException("No service registered under '" + key + "'");
-		}
-
-		return service.isStarted();
-	}
-
-	/**
-	 * Return true if the service is instantiated. Return false otherwise.
-	 * The service type is converted to its name, then the method is performed.
-	 * @see #isStarted(Class)
-	 * 
-	 * @return
-	 */
-	public boolean isStarted(Class<?> serviceType) throws ServiceNotFoundException {
-		return isStarted(serviceType.getName(), true);
-	}
-
-	/**
-	 * Return true if the service is instantiated. Return false otherwise.
-	 * The service type is converted to its name, then the method is performed.
-	 * @see #isStarted(Class)
-	 * 
-	 * @return
-	 */
-	public boolean isStarted(Class<?> serviceType, boolean searchInParents) throws ServiceNotFoundException {
-		return isStarted(serviceType.getName(), searchInParents);
-	}
-
-	/**
-	 * Return the state of the specified service.
-	 * 
-	 * @return
-	 */
-	public ServiceState serviceState(Object key) throws ServiceNotFoundException {
-		return serviceState(key, true);
-	}
-
-	/**
-	 * Return the state of the specified service.
-	 * @param key
-	 * @param searchInParents
-	 * @return
-	 * @throws ServiceNotFoundException
-	 */
-	public ServiceState serviceState(Object key, boolean searchInParents ) throws ServiceNotFoundException {
-		ServiceStartupEntry service = getServiceStartupEntry(key, searchInParents);
-		if(service == null) {
-			throw new ServiceNotFoundException("No service registered under '" + key + "'");
-		}
-
-		return service.getState();
-	}
-
-	/**
-	 * Return the state of the specified service.
-	 * 
-	 * @return
-	 */
-	public ServiceState serviceState(Class<?> serviceType) throws ServiceNotFoundException {
-		return serviceState(serviceType.getName(), true);
-	}
-
-	/**
-	 * Return the state of the specified service.
-	 * 
-	 * @return
-	 */
-	public ServiceState serviceState(Class<?> serviceType, boolean searchInParents) throws ServiceNotFoundException {
-		return serviceState(serviceType.getName(), searchInParents);
-	}
-
-	/**
-	 * Start services newly added.
-	 * Start all services marked as start = STARTUP. 
-	 * All services are first created, then initialized and finally
-	 * started. If an error occur on a service during one of this step, the
-	 * service is removed from the registry and and the error is logged.
-
-	 * @throws ServiceMultiException
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 * 
-	 */
-	public void startNewServices() throws ServiceMultiException {
-		// Build the lookup maps
-		LookupMap localSpace = new LookupMap(addedServices, namedServices);
-		// search space including parents
-		LookupMap fullSpace = new LookupMap(addedServices, namedServices, parents);
-
-		// Check if all dependencies exist.
-		checkDependencies(addedServices.values(), fullSpace);
-
-		// Get all roots : LAZY and START
-		Collection<ServiceStartupEntry> roots = getServiceRoots(addedServices.values(), localSpace);
-		// showServices(" Roots:", roots);
-		// Detect cycles
-		checkCycle(roots, localSpace);
-		
-		// Order services in the order we should start them.
-		// Lazy services are taken into account, as they can be in a chain of start.
-		List<ServiceStartupEntry> toStart = buildTopologicalListOfServicesToStart(roots, localSpace);
-		
-		// Retain only services with startupkind == START
-		// 
-		roots = retainsToStartServices(roots);
-
-		if(Activator.log.isDebugEnabled()) {
-			showServices(" Services to start:", toStart);
-		}
-
-		// Create an object to collect errors if any.
-		ServiceMultiException errors = new ServiceMultiException();
-
-		createServices(toStart, errors);
-		// Register all new services : lazy and start
-		registerServices(addedServices.values());
-		initServices(toStart, errors);
-		startServices(toStart, errors);
-
-		// Report errors if any
-		if(errors.getExceptions().size() > 0)
-			throw errors;
-
-		
-	}
-
-	/**
-	 * Start the registry. Start all services marked as start = STARTUP are
-	 * started. All services are first created, then initialized and finally
-	 * started. If an error occur on a service during one of this step, the
-	 * service is removed from the registry and and the error is logged.
-	 * 
-	 * @throws ServiceMultiException
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 *         
-	 * @deprecated Use {@link #startNewServices()}        
-	 */
-	protected void startRegistry() throws ServiceMultiException {
-
-		startNewServices();
-	}
-
-	/**
-	 * Start the specified services, and their required services. The specifies
-	 * services should be in the addServices or already registered. Start all
-	 * services marked as start = STARTUP . All eligible services are first
-	 * created, then initialized and finally started. If an error occur on a
-	 * service during one of this step, the service is removed from the registry
-	 * and and the error is logged.
-	 * 
-	 * @param serviceKeys
-	 *        Keys of services to start.
-	 * @throws ServiceMultiException
-	 * @throws ServiceNotFoundException
-	 *         If a service can't be retrieved by its key.
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	public void startServices(List<String> serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
-
-		// Build the lookup maps
-		LookupMap map = new LookupMap(addedServices, namedServices);
-
-		// Get the services
-		List<ServiceStartupEntry> services = keysToServices(serviceKeys, map);
-
-		// Start them
-		startServices(services, map);
-	}
-
-	/**
-	 * Same as {@link #startServices(List)}, but with an array as input.
-	 * 
-	 * @see #startServices(List)
-	 * 
-	 * @param serviceKeys
-	 *        Keys of services to start.
-	 * @throws ServiceMultiException
-	 * @throws ServiceNotFoundException
-	 *         If a service can't be retrieved by its key.
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	public void startServices(String... serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
-
-		List<String> serviceKeysList = Arrays.asList(serviceKeys);
-		startServices(serviceKeysList);
-	}
-
-	/**
-	 * Start the specified services, and their required services. The specifies
-	 * services should be in the addServices or already registered. Start all
-	 * services marked as start = STARTUP . All eligible services are first
-	 * created, then initialized and finally started. If an error occur on a
-	 * service during one of this step, the service is removed from the registry
-	 * and and the error is logged.
-	 * 
-	 * @param serviceKeys
-	 *        Keys of services to start. Keys will be translated to the
-	 *        classname.
-	 * @throws ServiceMultiException
-	 * @throws ServiceNotFoundException
-	 *         If a service can't be retrieved by its key.
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	public void startServicesByClassKeys(List<Class<?>> serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
-
-		// Build the lookup maps
-		LookupMap map = new LookupMap(addedServices, namedServices);
-
-		// Get the services
-		List<ServiceStartupEntry> services = classKeysToServices(serviceKeys, map);
-
-		// Start them
-		startServices(services, map);
-	}
-
-	/**
-	 * Same as {@link #startServicesByClassKeys(List)}, but with an array as
-	 * input.
-	 * 
-	 * @see #startServices(List)
-	 * 
-	 * @param serviceKeys
-	 *        Keys of services to start.
-	 * @throws ServiceMultiException
-	 * @throws ServiceNotFoundException
-	 *         If a service can't be retrieved by its key.
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	public void startServicesByClassKeys(Class<?>... serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
-
-		List<Class<?>> serviceKeysList = Arrays.asList(serviceKeys);
-		startServicesByClassKeys(serviceKeysList);
-	}
-
-	/**
-	 * Start the specified services, and their required services. The specifies
-	 * services should be in the specified map. The map is also used to resolves
-	 * dependencies. Start all services marked as start = STARTUP . All eligible
-	 * services are first created, then initialized and finally started. If an
-	 * error occur on a service during one of this step, the service is removed
-	 * from the registry and and the error is logged.
-	 * 
-	 * @param services
-	 *        Services to start
-	 * @param map
-	 *        a table of (key, service) used to get a service by its key.
-	 * @throws ServiceMultiException
-	 *         If a service can't be started.
-	 */
-	private void startServices(List<ServiceStartupEntry> services, LookupMap map) throws ServiceMultiException {
-		// Check if all dependencies exist.
-		checkDependencies(services, map);
-
-		// Get all roots : LAZY and START
-		Collection<ServiceStartupEntry> roots = getServiceRoots(services, map);
-		if(Activator.log.isDebugEnabled()) {
-			showServices(" Roots:", roots);
-		}
-		// Detect cycles
-		checkCycle(roots, map);
-		// Retain only services with startupkind == START and state ==
-		// REGISTERED
-		roots = retainsToStartServices(roots);
-		//
-		List<ServiceStartupEntry> toStart = buildTopologicalListOfServicesToStart(roots, map);
-
-		// Remove already started services
-		toStart = retainsToStartServices(toStart);
-
-		// if( log.isLoggable(Level.FINE))
-		// {
-		showServices(" Services to start:", toStart);
-		// }
-
-		// Create an object to collect errors if any.
-		ServiceMultiException errors = new ServiceMultiException();
-
-		createServices(toStart, errors);
-		// Register all started services
-		registerServices(toStart);
-		initServices(toStart, errors);
-		startServices(toStart, errors);
-
-		// Report errors if any
-		if(errors.getExceptions().size() > 0)
-			throw errors;
-	}
-
-	/**
-	 * Return a list of services from a list of services keys.
-	 * 
-	 * @param serviceKeys
-	 * @param map
-	 * @return
-	 * @throws ServiceNotFoundException
-	 *         If a service can't be retrieved by its key.
-	 */
-	private List<ServiceStartupEntry> keysToServices(List<String> serviceKeys, LookupMap map) throws ServiceNotFoundException {
-
-		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>(serviceKeys.size());
-
-		for(String key : serviceKeys) {
-			result.add(map.getChecked(key));
-		}
-		return result;
-	}
-
-	/**
-	 * Return a list of services from a list of services keys.
-	 * 
-	 * @param serviceKeys
-	 * @param map
-	 * @return
-	 * @throws ServiceNotFoundException
-	 *         If a service can't be retrieved by its key.
-	 */
-	private List<ServiceStartupEntry> classKeysToServices(List<Class<?>> serviceKeys, LookupMap map) throws ServiceNotFoundException {
-
-		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>(serviceKeys.size());
-
-		for(Class<?> key : serviceKeys) {
-			result.add(map.getChecked(key.getName()));
-		}
-		return result;
-	}
-
-	/**
-	 * Print the services. For debug purpose
-	 * 
-	 * @param roots
-	 */
-	private void showServices(String message, Collection<ServiceStartupEntry> roots) {
-		StringBuffer buffer = new StringBuffer();
-		buffer.append("--------------------------\n");
-		buffer.append(message);
-		buffer.append("\n");
-		for(ServiceStartupEntry service : roots) {
-			buffer.append("  ");
-			buffer.append(service.getDescriptor().toString());
-			buffer.append("\n");
-		}
-		buffer.append("--------- done -----------\n");
-		Activator.log.debug(buffer.toString());
-	}
-
-	/**
-	 * Check if all dependencies exist. Throw an error if a declared dependency
-	 * has no corresponding service.
-	 * 
-	 * @param services
-	 *        Services to check
-	 * @param map
-	 *        Map of services by keys.
-	 * @throws ServiceMultiException
-	 */
-	private void checkDependencies(Collection<ServiceStartupEntry> services, LookupMap map) throws ServiceMultiException {
-
-		ServiceMultiException errors = new ServiceMultiException();
-
-		// Walk each service and check if its required services exist.
-		for(ServiceStartupEntry service : services) {
-			ServiceDescriptor desc = service.getDescriptor();
-
-			// Check each required service
-			for(String key : desc.getRequiredServiceKeys()) {
-
-				// Check if service can be found
-				try {
-					map.getChecked(key);
-				} catch (ServiceNotFoundException e) {
-					errors.addException(desc.getKey(), e);
-				}
-			}
-		}
-
-		// Throw errors if any
-		if(errors.getExceptions().size() > 0)
-			throw errors;
-	}
-
-	/**
-	 * Retains only the services that should be started. Retains only services
-	 * with startupkind = START and state == REGISTERED
-	 * 
-	 * @param services
-	 *        Collection to filter
-	 * @return a new Collection containing the services to start.
-	 */
-	private List<ServiceStartupEntry> retainsToStartServices(Collection<ServiceStartupEntry> services) {
-
-		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>();
-		for(ServiceStartupEntry service : services) {
-			ServiceDescriptor desc = service.getDescriptor();
-			if(service.getState() == ServiceState.registered && desc.isStartAtStartup()) {
-				result.add(service);
-			}
-		}
-
-		return result;
-	}
-
-	/**
-	 * Check for cycles. Throws an exception if a cycle is discovered. Each root
-	 * is checked to see if it contains a cycle.
-	 * 
-	 * @param roots
-	 * @param map
-	 */
-	private void checkCycle(Collection<ServiceStartupEntry> roots, LookupMap map) {
-		// TODO Auto-generated method stub
-
-	}
-
-	/**
-	 * Build a list of services to start, in the topological order (right
-	 * order). The required services are placed before the dependent services in
-	 * the list. Services already started are disguarded.
-	 * 
-	 * @param roots
-	 * @param map
-	 *        Map used to resolve the entry by their key.
-	 * @return
-	 */
-	private List<ServiceStartupEntry> buildTopologicalListOfServicesToStart(Collection<ServiceStartupEntry> roots, LookupMap map) {
-
-		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>();
-
-		// Each root represent a graph. Walk the root and its child in the list,
-		// in the right order.
-		for(ServiceStartupEntry root : roots) {
-			walkGraphDepthFirst(result, root, map);
-		}
-
-		return result;
-	}
-
-	/**
-	 * Add recursively the provided node, and then its direct children.
-	 * 
-	 * @param result
-	 *        The list where the node are added
-	 * @param node
-	 *        The node to add
-	 * @param map
-	 */
-	private void walkGraphDepthFirst(List<ServiceStartupEntry> result, ServiceStartupEntry node, LookupMap map) {
-
-		// Do not add already added or started node.
-		if(result.contains(node) || node.isStarted())
-			return;
-
-		// add direct child
-		for(String serviceKey : node.getDescriptor().getRequiredServiceKeys()) {
-			try {
-				ServiceStartupEntry child = map.getChecked(serviceKey);
-				walkGraphDepthFirst(result, child, map);
-			} catch (ServiceNotFoundException e) {
-				// Do nothing, we have already reported the problems with
-				// checkServices;
-			}
-		}
-
-		// Now add the node
-		result.add(node);
-	}
-
-	/**
-	 * Create a List of the root services. The roots are services that are not
-	 * required by any service.
-	 * 
-	 * @param addedServices
-	 *        A collection from which roots are required. The collection is
-	 *        unmodified.
-	 * @param map
-	 * @return
-	 */
-	private Collection<ServiceStartupEntry> getServiceRoots(Collection<ServiceStartupEntry> addedServices, LookupMap keyServiceMap) {
-
-		// Create a copy of the list of services
-		Collection<ServiceStartupEntry> services = new ArrayList<ServiceStartupEntry>(addedServices);
-
-		List<ServiceStartupEntry> allRequired = new ArrayList<ServiceStartupEntry>();
-
-		// The roots are services that are not required by any service.
-		// Build a list of the services required by all other services.
-		for(ServiceStartupEntry service : services) {
-			// Add each child to the list of required
-			for(String serviceKey : service.getDescriptor().getRequiredServiceKeys()) {
-				try {
-
-					ServiceStartupEntry child = keyServiceMap.getChecked(serviceKey);
-					allRequired.add(child);
-				} catch (ServiceNotFoundException e) {
-					// Do nothing, we have already reported the problems with
-					// checkServices;
-				}
-			}
-
-		}
-
-		// Roots are those that are not required.
-		// So it is the original list minus the required.
-		services.removeAll(allRequired);
-
-		return services;
-	}
-
-	/**
-	 * Dispose all services for this registry and its parents.
-	 * 
-	 * @throws ServiceMultiException
-	 */
-	public void disposeRegistry() throws ServiceMultiException {
-
-		disposeRegistry(true);
-	}
-
-	/**
-	 * Dispose all services, and parent registries if any.
-	 * 
-	 * @throws ServiceMultiException
-	 */
-	public void disposeRegistry(boolean isRecursive) throws ServiceMultiException {
-
-		// List of keys of service in error.
-		ServiceMultiException errors = new ServiceMultiException();
-		disposeRegistry(errors, isRecursive);
-		// Report errors if any
-		if(errors.getExceptions().size() > 0)
-			throw errors;
-	}
-
-	/**
-	 * Dispose all services, and parent registries if any.
-	 * 
-	 * @throws ServiceMultiException
-	 */
-	protected void disposeRegistry(ServiceMultiException errors, boolean isRecursive) throws ServiceMultiException {
-
-		// List of keys of service in error.
-		disposeServices(namedServices.values(), errors);
-		disposeServices(anonymousServices, errors);
-
-		// Clean up properties to help GC
-		addedServices.clear();
-		addedServices = null;
-		anonymousServices.clear();
-		anonymousServices = null;
-		namedServices.clear();
-		namedServices = null;
-		
-		// Do parents
-		if( isRecursive ) {
-			for( ServicesRegistry parent : parents) {
-				parent.disposeRegistry( errors, true);
-			}
-		}
-	}
-
-	/**
-	 * Create all services provided in the list
-	 * 
-	 * @param toStart
-	 *        List of services to create.
-	 * @param errors
-	 *        Exception to collect errors.
-	 * 
-	 * @throws ServiceMultiException
-	 *         If an error occure during the creation
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	private void createServices(List<ServiceStartupEntry> toStart, ServiceMultiException errors) throws ServiceMultiException {
-
-		// Loop on all services
-		for(ServiceStartupEntry serviceEntry : toStart) {
-			try {
-
-				serviceEntry.createService();
-			} catch (ServiceException e) {
-				log.log(Level.SEVERE, "Can't create service '" + serviceEntry + "'", e);
-
-				errors.addException(serviceEntry.getDescriptor().getKey(), e);
-			}
-		}
-
-	}
-
-	/**
-	 * Register all services provided in the list. After this operation,
-	 * services are available thru {@link #getService(Class)}.
-	 * 
-	 * @param toStart
-	 *        List of services to register.
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	private void registerServices(Collection<ServiceStartupEntry> toStart) {
-
-		// Loop on all services
-		for(ServiceStartupEntry serviceEntry : toStart) {
-			ServiceDescriptor desc = serviceEntry.getDescriptor();
-			if(desc.isAnonymous()) {
-				anonymousServices.add(serviceEntry);
-			} else {
-				namedServices.put(desc.getKey(), serviceEntry);
-			}
-		}
-	}
-
-	/**
-	 * Init all services provided in the list
-	 * 
-	 * @param toStart
-	 *        List of services to init.
-	 * @param errors
-	 * 
-	 * @throws ServiceMultiException
-	 *         If an error occure during the process
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	private void initServices(List<ServiceStartupEntry> toStart, ServiceMultiException errors) throws ServiceMultiException {
-
-		// Loop on all services
-		for(ServiceStartupEntry serviceEntry : toStart) {
-			try {
-
-				serviceEntry.initService(this);
-			} catch (ServiceException e) {
-				log.log(Level.SEVERE, "Can't initialize service '" + serviceEntry + "'", e);
-				errors.addException(serviceEntry.getDescriptor().getKey(), e);
-			}
-		}
-
-	}
-
-	/**
-	 * Init all services provided in the list
-	 * 
-	 * @param toStart
-	 *        List of services to init.
-	 * @param errors
-	 * 
-	 * @throws ServiceMultiException
-	 *         If an error occure during the process
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	private void startServices(List<ServiceStartupEntry> toStart, ServiceMultiException errors) throws ServiceMultiException {
-
-		// Loop on all services
-		for(ServiceStartupEntry serviceEntry : toStart) {
-			try {
-
-				serviceEntry.startService();
-			} catch (ServiceException e) {
-				log.log(Level.SEVERE, "Can't start service '" + serviceEntry + "'", e);
-
-				errors.addException(serviceEntry.getDescriptor().getKey(), e);
-			}
-		}
-
-	}
-
-	/**
-	 * Dispose all started services.
-	 * Services are disposed in creation reverse order
-	 * 
-	 * @throws ServiceMultiException
-	 * 
-	 * @throws ServiceException
-	 *         If a service can't be started.
-	 */
-	private void disposeServices(Collection<ServiceStartupEntry> services, ServiceMultiException errors) {
-
-		// Dispose services
-		for(ServiceStartupEntry serviceEntry : services) {
-			try {
-				serviceEntry.disposeService();
-			} catch (ServiceException e) {
-				log.log(Level.SEVERE, "Can't dispose service '" + serviceEntry.getDescriptor().getKey() + "'", e);
-				errors.addException(serviceEntry.getDescriptor(), e);
-			}
-		}
-	}
-
-	/**
-	 * This class represents a union of two maps of <String,
-	 * ServiceStartupEntry>. It provide specific methods to retrieve a {@link ServiceStartupEntry} by its key.
-	 * <br>
-	 * This class is used to lookup {@link ServiceStartupEntry} in multiple namespaces (2 maps, and then registries).
-	 * 
-	 * 
-	 * @author cedric dumoulin
-	 * 
-	 */
-	private class LookupMap {
-
-		Map<String, ServiceStartupEntry> map1;
-
-		Map<String, ServiceStartupEntry> map2;
-		
-		// additional service registries into which we should search
-		List<ServicesRegistry> registries;
-
-		/**
-		 * 
-		 * Constructor. Build a union of two maps.
-		 * 
-		 * @param map1
-		 * @param map2
-		 */
-		public LookupMap(Map<String, ServiceStartupEntry> map1, Map<String, ServiceStartupEntry> map2) {
-			this.map1 = map1;
-			this.map2 = map2;
-		}
-
-		public LookupMap(Map<String, ServiceStartupEntry> space1, Map<String, ServiceStartupEntry> space2, List<ServicesRegistry> registries) {
-			this( space1, space2);
-			this.registries = registries;
-		}
-
-		/**
-		 * 
-		 * Constructor. Build a union of one map (sic).
-		 * 
-		 * @param map
-		 */
-		@SuppressWarnings("unused")
-		public LookupMap(Map<String, ServiceStartupEntry> map) {
-			this(map, null);
-		}
-
-		/**
-		 * Get a service by its key.
-		 * 
-		 * @param key
-		 * @return the service or null if not found.
-		 */
-		@SuppressWarnings("unused")
-		public ServiceStartupEntry get(String key) {
-
-			ServiceStartupEntry res = map1.get(key);
-			if(res != null)
-				return res;
-			if(map2 != null) {
-				res = map2.get(key);
-			}
-			if( res == null && registries != null) {
-				// lookup in registries
-				res = getFromRegistries(key);
-			}
-
-			return res;
-		}
-
-		/**
-		 * Get a service by its key.
-		 * 
-		 * @param key
-		 * @return The requested service.
-		 * @throws ServiceNotFoundException
-		 *         if the service can't be found.
-		 */
-		public ServiceStartupEntry getChecked(String key) throws ServiceNotFoundException {
-
-			ServiceStartupEntry res = map1.get(key);
-			if(res != null)
-				return res;
-			if(map2 != null)
-				res = map2.get(key);
-			if( res == null && registries != null) {
-				// lookup in registries
-				res = getFromRegistries(key);
-			}
-			if(res != null)
-				return res;
-
-			throw new ServiceNotFoundException("No service found under key '" + key.toString() + "'");
-		}
-		
-		/**
-		 * Try to get the entry from the registries.
-		 * @param key
-		 * @return
-		 */
-		private ServiceStartupEntry getFromRegistries(String key) {
-			
-			ServiceStartupEntry service;
-			// Lookup in parents
-			for(ServicesRegistry registry : registries) {
-				service = registry.getServiceStartupEntry(key);
-				if( service != null) {
-					return service;
-				}	
-			}
-
-			return null;
-		}
-	}
-
-}
+/*****************************************************************************
+ * Copyright (c) 2011, 2014 LIFL 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:
+ *  LIFL - Initial API and implementation
+ *
+ *****************************************************************************/
+package org.eclipse.papyrus.infra.core.serviceregistry;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.eclipse.papyrus.infra.core.serviceregistry.ServiceDescriptor.ServiceTypeKind;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.AliasServiceEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.LazyStartupEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.PojoServiceEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceFactoryEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceStartupEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.ServiceTypeEntry;
+import org.eclipse.papyrus.infra.core.serviceregistry.internal.StartStartupEntry;
+
+/**
+ * A registry of services. This registry allows to get a service by its
+ * identifier. The identifier is generally the classname of the service.
+ * Services can be added using the Eclipse extension mechanism (if you use {@link ExtensionServicesRegistry}). <br>
+ * A Service is a class providing operations. The ServiceRegistry is used to
+ * share objects (i.e. services) between nested editors and also the core main
+ * editor.
+ * 
+ * <br>
+ * In this implementation, services should be added to the registry before the
+ * call to createServices(). If a service is added after the call, it will not
+ * be started (except if it is a lazy service). <br>
+ * A typical usage is:
+ * 
+ * <pre>
+ * <code>
+ *   ServicesRegistry serviceRegistry = new ServiceRegistry();
+ *   // Add your services
+ *   serviceRegistry.add( ...);
+ *   serviceRegistry.add( ...);
+ *   
+ *   // start the services
+ *   serviceRegistry.startRegistry();
+ *   
+ *   // Retrieve a service
+ *   myService = serviceRegistry.getService( serviceKey );
+ * </code>
+ * </pre>
+ * 
+ * It is possible to register new services after the serviceRegistry has been
+ * started. In this case, you need to start them explicitly if they are of type
+ * ServiceStartKind.STARTUP.
+ * 
+ * <pre>
+ * <code>
+ *   // Add your new services
+ *   serviceRegistry.add( key1, ...);
+ *   serviceRegistry.add( key2, ...);
+ *   
+ *   // start the new services
+ *   serviceRegistry.startRegistry(key1, key2);
+ * </code>
+ * </pre>
+ * 
+ * <ul>
+ * <li></li>
+ * <li></li>
+ * </ul>
+ * 
+ * @author cedric dumoulin
+ * 
+ * 
+ */
+public class ServicesRegistry {
+
+	/** Log object */
+	protected Logger log = Logger.getLogger(getClass().getName());
+
+	/**
+	 * Map of existing services.
+	 */
+	// private Map<Object, AbstractServiceEntry> services;
+
+	/**
+	 * A Map of services added to the register (thow the addXxx() methods), but
+	 * not yet registered. They will be registered after a call to startXxx().
+	 */
+	private Map<String, ServiceStartupEntry> addedServices = new HashMap<String, ServiceStartupEntry>();
+
+	/**
+	 * Map of services registered with a name.
+	 */
+	private Map<String, ServiceStartupEntry> namedServices = new HashMap<String, ServiceStartupEntry>();
+
+	/**
+	 * Map of services registered without a name (anonymous). Such services
+	 * can't be retrieved.
+	 */
+	private List<ServiceStartupEntry> anonymousServices = new ArrayList<ServiceStartupEntry>();
+
+	/**
+	 * List of parents used as fallback if the service is not found in this registry.
+	 */
+	private List<ServicesRegistry> parents = new ArrayList<ServicesRegistry>();
+	
+	/**
+	 * Constructor.
+	 */
+	public ServicesRegistry() {
+	}
+
+	/**
+	 * Add a service by its ServiceDescriptor.
+	 * 
+	 * @param serviceDescriptor
+	 *        Descriptor describing the service.
+	 * @throws ServiceException
+	 *         If an error occurs while initializing service.
+	 */
+	public void add(ServiceDescriptor serviceDescriptor) {
+		// Check if the service already exist.
+		ServiceStartupEntry service = addedServices.get(serviceDescriptor.getKey());
+		if(service != null) {
+			if(service.getDescriptor().getPriority() > serviceDescriptor.getPriority())
+				return;
+			else if(service.getDescriptor().getPriority() == serviceDescriptor.getPriority()) {
+				log.warning("Two services with same priority (" + serviceDescriptor.getPriority() + ") are declared under key '" + service.getDescriptor().getKey() + "'. Keep the first encountered only. (bundles: " + service.getDescriptor().getClassBundleID() + ", " + serviceDescriptor.getClassBundleID() + ")");
+			}
+		}
+
+		// Compute the service type entry
+		ServiceTypeEntry serviceTypeEntry;
+		ServiceTypeKind typeKind = serviceDescriptor.getServiceTypeKind();
+		switch( typeKind) {
+		case service:
+			serviceTypeEntry = new ServiceEntry(serviceDescriptor);
+			break;
+		case serviceFactory:
+			serviceTypeEntry = new ServiceFactoryEntry(serviceDescriptor);
+			break;
+		case pojo:
+			serviceTypeEntry = new PojoServiceEntry(serviceDescriptor);
+			break;
+		case alias:
+			serviceTypeEntry = new AliasServiceEntry(serviceDescriptor);
+			break;			
+		default:
+			// Add as pojo
+			// Should better throw an exception. (MalformedDescriptor ?)
+			serviceTypeEntry = new PojoServiceEntry(serviceDescriptor);
+		}
+
+		// Create the entry
+		ServiceStartupEntry serviceEntry;
+		switch(serviceDescriptor.getServiceStartKind()) {
+		case STARTUP:
+			serviceEntry = new StartStartupEntry(serviceTypeEntry);
+			break;
+		case LAZY:
+			serviceEntry = new LazyStartupEntry(serviceTypeEntry, this);
+			break;
+		default:
+			// Add as LAZY
+			// Should better throw an exception. (MalformedDescriptor ?)
+			serviceEntry = new LazyStartupEntry(serviceTypeEntry, this);
+		}
+
+		// Add the entry
+		addedServices.put(serviceDescriptor.getKey(), serviceEntry);
+	}
+
+	/**
+	 * Add a service. The descriptor will be created.
+	 * 
+	 * @param key
+	 *        Service key
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 */
+	public void add(String key, int priority, IService serviceInstance) {
+		add(key, priority, serviceInstance, ServiceStartKind.STARTUP);
+	}
+
+	/**
+	 * Add a service. The descriptor will be created.
+	 * 
+	 * @param key
+	 *        Service key
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 */
+	public void add(Class<?> key, int priority, IService serviceInstance) {
+		add(key.getName(), priority, serviceInstance, ServiceStartKind.STARTUP);
+	}
+
+	/**
+	 * Add a service. The descriptor will be created.
+	 * 
+	 * @param key
+	 *        Service key
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 */
+	public void add(String key, int priority, IService serviceInstance, ServiceStartKind startKind) {
+		// Check if the service already exist.
+		ServiceStartupEntry service = addedServices.get(key);
+		if(service != null) {
+			if(service.getDescriptor().getPriority() > priority)
+				return;
+			else if(service.getDescriptor().getPriority() == priority)
+				log.warning("Two services with same priority (" + priority + ") are declared under key '" + service.getDescriptor().getKey() + "'. Keep the first encountered only."); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+		}
+
+		// Create descriptor and add service.
+		ServiceDescriptor descriptor = new ServiceDescriptor(key, serviceInstance.getClass().getName(), startKind, priority);
+
+		if(startKind == ServiceStartKind.STARTUP)
+			addedServices.put(key, new StartStartupEntry(new ServiceEntry(descriptor, serviceInstance)));
+		else
+			addedServices.put(key, new LazyStartupEntry(new ServiceEntry(descriptor, serviceInstance), this));
+	}
+
+	/**
+	 * Add a service. The descriptor will be created.
+	 * 
+	 * @param key
+	 *        Service key Class used as key. The classname is used as key.
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 */
+	public void add(Class<?> key, int priority, IService serviceInstance, ServiceStartKind startKind) {
+
+		add(key.getName(), priority, serviceInstance, startKind);
+	}
+
+	/**
+	 * Add an already instanciated pojo (Plain Old Java Object) as Service. The
+	 * descriptor will be created. No life cycle methods are called on the
+	 * service.
+	 * 
+	 * @param key
+	 *        Service key
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 */
+	public void add(Class<?> key, int priority, Object serviceInstance) {
+		add(key, priority, serviceInstance, ServiceStartKind.STARTUP);
+	}
+
+	/**
+	 * Add an already instanciated pojo (Plain Old Java Object) as Service. The
+	 * descriptor will be created. No life cycle methods are called on the
+	 * service.
+	 * 
+	 * @param key
+	 *        Service key
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 * @param startKind
+	 * 
+	 */
+	public void add(String key, int priority, Object serviceInstance, ServiceStartKind startKind) {
+		// Check if the service already exist.
+		ServiceStartupEntry service = addedServices.get(key);
+		if(service != null) {
+			if(service.getDescriptor().getPriority() > priority)
+				return;
+			else if(service.getDescriptor().getPriority() == priority)
+				log.warning("Two services with same priority (" + priority + ") are declared under key '" + service.getDescriptor().getKey() + "'. Keep the first encountered only."); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+		}
+
+		// Create descriptor and add service.
+		ServiceDescriptor descriptor = new ServiceDescriptor(key, serviceInstance.getClass().getName(), startKind, priority);
+
+		if(startKind == ServiceStartKind.STARTUP)
+			addedServices.put(key, new StartStartupEntry(new PojoServiceEntry(descriptor, serviceInstance)));
+		else
+			addedServices.put(key, new LazyStartupEntry(new PojoServiceEntry(descriptor, serviceInstance), this));
+
+	}
+
+	/**
+	 * Add an already instanciated pojo (Plain Old Java Object) as Service. The
+	 * descriptor will be created. No life cycle methods are called on the
+	 * service.
+	 * 
+	 * @param key
+	 *        Service key Class used as key. The classname is used as key.
+	 * @param priority
+	 *        service priority
+	 * @param serviceInstance
+	 *        The instance of the service
+	 * @param startKind
+	 * 
+	 */
+	public void add(Class<?> key, int priority, Object serviceInstance, ServiceStartKind startKind) {
+
+		add(key.getName(), priority, serviceInstance, startKind);
+	}
+
+	/**
+	 * Remove the specified Registry as parent of this registry.
+	 * . 
+	 * @param parentRegistry
+	 */
+	public void addParentRegistry(ServicesRegistry parentRegistry) {
+		
+		if( parentRegistry == null) {
+			return;
+		}
+		parents.add(parentRegistry);
+	}
+	
+	/**
+	 * 
+	 * @param parentRegistry
+	 */
+	public void removeParentRegistry(ServicesRegistry parentRegistry) {
+		
+		if( parentRegistry == null) {
+			return;
+		}
+		parents.remove(parentRegistry);
+	}
+	
+
+	/**
+	 * Remove the specified service from the registry.
+	 * 
+	 * @param key
+	 */
+	public void remove(ServiceDescriptor serviceDescriptor) throws ServiceException {
+		remove(serviceDescriptor.getKey());
+	}
+
+	/**
+	 * Remove the specified service from the registry.
+	 * 
+	 * @param key
+	 */
+	public void remove(Object key) throws ServiceException {
+		ServiceStartupEntry service = namedServices.remove(key);
+		if(service == null) {
+			return;
+		}
+
+		// Stop the service
+		service.disposeService();
+	}
+
+	/**
+	 * Get the requested service by its key. The key is usually the classname of
+	 * the service.
+	 * 
+	 * @param serviceClass
+	 * @return
+	 * @throws ServiceException
+	 *         If servive can't be started
+	 */
+	public Object getService(Object key) throws ServiceException {
+		ServiceStartupEntry serviceEntry = namedServices.get(key);
+		if(serviceEntry == null) {
+			// Check if we can find it in parents
+			Object service = getServiceFromParents(key);
+			if(service != null) {
+				// Found in parent, return it
+				return service;
+			}
+
+			// Not found in parents. Throw an exception
+			// throw an appropriate exception (If added, say it).
+			serviceEntry = addedServices.get(key);
+			if(serviceEntry != null)
+				throw new BadStateException("Registry should be started before.", serviceEntry.getState(), serviceEntry.getDescriptor()); //$NON-NLS-1$
+			else
+				throw new ServiceNotFoundException("No service registered under '" + key + "'"); //$NON-NLS-1$ //$NON-NLS-2$
+		}
+
+		return serviceEntry.getServiceInstance();
+	}
+
+	/**
+	 * Get the requested service by its class (the service has to be registered
+	 * by its class object).
+	 * 
+	 * @param key
+	 *        The service class.
+	 * @return The service.
+	 * @throws ServiceException
+	 *         If service can't be started
+	 */
+	@SuppressWarnings("unchecked")
+	public <S> S getService(Class<S> key) throws ServiceException {
+
+		String realKey = key.getName();
+		ServiceStartupEntry serviceEntry = namedServices.get(realKey);
+
+		// Lookup in parents if not found
+		if( serviceEntry == null) {
+			
+			// Check if we can find it in parents
+			S service = (S)getServiceFromParents(realKey);
+			if(service != null) {
+				// Found in parent, return it
+				return service;
+			}
+
+			// Not found in parents. Throw an exception
+			// throw an appropriate exception (If added, say it).
+			serviceEntry = addedServices.get(realKey);
+			if(serviceEntry != null)
+				throw new BadStateException("Registry should be started before.", serviceEntry.getState(), serviceEntry.getDescriptor()); //$NON-NLS-1$
+			else
+				throw new ServiceNotFoundException("No service registered under '" + key + "'"); //$NON-NLS-1$ //$NON-NLS-2$
+		}
+
+		// Service found, return it.
+		return (S)serviceEntry.getServiceInstance();
+	}
+
+	/**
+	 * Get the requested service by its class (the service has to be registered
+	 * by its class object).
+	 * 
+	 * @param key
+	 *        The service class.
+	 * @return The service.
+	 * @throws ServiceException
+	 *         If service can't be started
+	 */
+	private Object getServiceFromParents(Object key) throws ServiceException {
+	
+		Object foundService;
+		
+		for( ServicesRegistry parent : parents) {
+			foundService = parent.getServiceUnchecked(key);
+			// Check if we have found the service
+			if( foundService != null) {
+				// Found, return it
+				return foundService;
+			}
+		}
+		// Not found
+		return null;
+	}
+	
+	/**
+	 * Get the requested service by its key. The key is usually the classname of
+	 * the service.
+	 * Return the service, or null if not found.
+	 * This is for internal use.
+	 * 
+	 * @param serviceClass
+	 * @return The service, or null if not found.
+	 * @throws ServiceException
+	 *         If servive can't be started
+	 */
+	protected Object getServiceUnchecked(Object key) throws ServiceException {
+		ServiceStartupEntry service = namedServices.get(key);
+		if(service == null) {
+			return null;
+		}
+
+		return service.getServiceInstance();
+	}
+
+	/**
+	 * Try to get the {@link ServiceStartupEntry} of the specified service.
+	 * Search in local namedServices.
+	 * Also lookup in parents. Return null if not found.
+	 * The returned entry should not be modified by caller.
+	 * 
+	 * @param key
+	 * @return The requested entry, or null if not found.
+	 */
+	protected ServiceStartupEntry getServiceStartupEntry( Object key ) {
+		
+		return getServiceStartupEntry(key, true);
+	}
+	
+	/**
+	 * Try to get the {@link ServiceStartupEntry} of the specified service.
+	 * Search in local namedServices.
+	 * Also lookup in parents. Return null if not found.
+	 * The returned entry should not be modified by caller.
+	 * 
+	 * @param key
+	 * @param searchInParent True if we should search in parent, false if search take place in this registry only.
+	 * @return The requested entry, or null if not found.
+	 */
+	protected ServiceStartupEntry getServiceStartupEntry( Object key, boolean searchInParent ) {
+		
+		ServiceStartupEntry service = namedServices.get(key);
+		if( service != null) {
+			return service;
+		}
+
+		// Check in new services
+		service = addedServices.get(key);
+		if( service != null) {
+			return service;
+		}
+		
+		if( searchInParent ) {
+			// Lookup in parents
+			for(ServicesRegistry registry : parents) {
+				service = registry.getServiceStartupEntry(key);
+				if( service != null) {
+					return service;
+				}	
+			}	
+		}
+
+		// Not found
+		return null;
+	}
+	
+	/**
+	 * Return true if the service is instantiated. Return false otherwise.
+	 * 
+	 * @return
+	 */
+	public boolean isStarted(Object key) throws ServiceNotFoundException {
+		return isStarted(key, true);
+	}
+
+	/**
+	 * Return true if the service is instantiated. Return false otherwise.
+	 * 
+	 * @return
+	 */
+	public boolean isStarted(Object key, boolean searchInParents) throws ServiceNotFoundException {
+		ServiceStartupEntry service = getServiceStartupEntry(key, searchInParents);
+		if(service == null) {
+			throw new ServiceNotFoundException("No service registered under '" + key + "'"); //$NON-NLS-1$ //$NON-NLS-2$
+		}
+
+		return service.isStarted();
+	}
+
+	/**
+	 * Return true if the service is instantiated. Return false otherwise.
+	 * The service type is converted to its name, then the method is performed.
+	 * @see #isStarted(Class)
+	 * 
+	 * @return
+	 */
+	public boolean isStarted(Class<?> serviceType) throws ServiceNotFoundException {
+		return isStarted(serviceType.getName(), true);
+	}
+
+	/**
+	 * Return true if the service is instantiated. Return false otherwise.
+	 * The service type is converted to its name, then the method is performed.
+	 * @see #isStarted(Class)
+	 * 
+	 * @return
+	 */
+	public boolean isStarted(Class<?> serviceType, boolean searchInParents) throws ServiceNotFoundException {
+		return isStarted(serviceType.getName(), searchInParents);
+	}
+
+	/**
+	 * Return the state of the specified service.
+	 * 
+	 * @return
+	 */
+	public ServiceState serviceState(Object key) throws ServiceNotFoundException {
+		return serviceState(key, true);
+	}
+
+	/**
+	 * Return the state of the specified service.
+	 * @param key
+	 * @param searchInParents
+	 * @return
+	 * @throws ServiceNotFoundException
+	 */
+	public ServiceState serviceState(Object key, boolean searchInParents ) throws ServiceNotFoundException {
+		ServiceStartupEntry service = getServiceStartupEntry(key, searchInParents);
+		if(service == null) {
+			throw new ServiceNotFoundException("No service registered under '" + key + "'"); //$NON-NLS-1$ //$NON-NLS-2$
+		}
+
+		return service.getState();
+	}
+
+	/**
+	 * Return the state of the specified service.
+	 * 
+	 * @return
+	 */
+	public ServiceState serviceState(Class<?> serviceType) throws ServiceNotFoundException {
+		return serviceState(serviceType.getName(), true);
+	}
+
+	/**
+	 * Return the state of the specified service.
+	 * 
+	 * @return
+	 */
+	public ServiceState serviceState(Class<?> serviceType, boolean searchInParents) throws ServiceNotFoundException {
+		return serviceState(serviceType.getName(), searchInParents);
+	}
+
+	/**
+	 * Start services newly added.
+	 * Start all services marked as start = STARTUP. 
+	 * All services are first created, then initialized and finally
+	 * started. If an error occur on a service during one of this step, the
+	 * service is removed from the registry and and the error is logged.
+
+	 * @throws ServiceMultiException
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 * 
+	 */
+	public void startNewServices() throws ServiceMultiException {
+		// Build the lookup maps
+		LookupMap localSpace = new LookupMap(addedServices, namedServices);
+		// search space including parents
+		LookupMap fullSpace = new LookupMap(addedServices, namedServices, parents);
+
+		// Check if all dependencies exist.
+		checkDependencies(addedServices.values(), fullSpace);
+
+		// Get all roots : LAZY and START
+		Collection<ServiceStartupEntry> roots = getServiceRoots(addedServices.values(), localSpace);
+		// showServices(" Roots:", roots);
+		// Detect cycles
+		checkCycle(roots, localSpace);
+		
+		// Order services in the order we should start them.
+		// Lazy services are taken into account, as they can be in a chain of start.
+		List<ServiceStartupEntry> toStart = buildTopologicalListOfServicesToStart(roots, localSpace);
+		
+		// Retain only services with startupkind == START
+		// 
+		roots = retainsToStartServices(roots);
+
+		if(Activator.log.isDebugEnabled()) {
+			showServices(" Services to start:", toStart);
+		}
+
+		// Create an object to collect errors if any.
+		ServiceMultiException errors = new ServiceMultiException();
+
+		createServices(toStart, errors);
+		// Register all new services : lazy and start
+		registerServices(addedServices.values());
+		initServices(toStart, errors);
+		startServices(toStart, errors);
+
+		// Report errors if any
+		if(errors.getExceptions().size() > 0)
+			throw errors;
+
+		
+	}
+
+	/**
+	 * Start the registry. Start all services marked as start = STARTUP are
+	 * started. All services are first created, then initialized and finally
+	 * started. If an error occur on a service during one of this step, the
+	 * service is removed from the registry and and the error is logged.
+	 * 
+	 * @throws ServiceMultiException
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 *         
+	 * @deprecated Use {@link #startNewServices()}        
+	 */
+	protected void startRegistry() throws ServiceMultiException {
+
+		startNewServices();
+	}
+
+	/**
+	 * Start the specified services, and their required services. The specifies
+	 * services should be in the addServices or already registered. Start all
+	 * services marked as start = STARTUP . All eligible services are first
+	 * created, then initialized and finally started. If an error occur on a
+	 * service during one of this step, the service is removed from the registry
+	 * and and the error is logged.
+	 * 
+	 * @param serviceKeys
+	 *        Keys of services to start.
+	 * @throws ServiceMultiException
+	 * @throws ServiceNotFoundException
+	 *         If a service can't be retrieved by its key.
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	public void startServices(List<String> serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
+
+		// Build the lookup maps
+		LookupMap map = new LookupMap(addedServices, namedServices);
+
+		// Get the services
+		List<ServiceStartupEntry> services = keysToServices(serviceKeys, map);
+
+		// Start them
+		startServices(services, map);
+	}
+
+	/**
+	 * Same as {@link #startServices(List)}, but with an array as input.
+	 * 
+	 * @see #startServices(List)
+	 * 
+	 * @param serviceKeys
+	 *        Keys of services to start.
+	 * @throws ServiceMultiException
+	 * @throws ServiceNotFoundException
+	 *         If a service can't be retrieved by its key.
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	public void startServices(String... serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
+
+		List<String> serviceKeysList = Arrays.asList(serviceKeys);
+		startServices(serviceKeysList);
+	}
+
+	/**
+	 * Start the specified services, and their required services. The specifies
+	 * services should be in the addServices or already registered. Start all
+	 * services marked as start = STARTUP . All eligible services are first
+	 * created, then initialized and finally started. If an error occur on a
+	 * service during one of this step, the service is removed from the registry
+	 * and and the error is logged.
+	 * 
+	 * @param serviceKeys
+	 *        Keys of services to start. Keys will be translated to the
+	 *        classname.
+	 * @throws ServiceMultiException
+	 * @throws ServiceNotFoundException
+	 *         If a service can't be retrieved by its key.
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	public void startServicesByClassKeys(List<Class<?>> serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
+
+		// Build the lookup maps
+		LookupMap map = new LookupMap(addedServices, namedServices);
+
+		// Get the services
+		List<ServiceStartupEntry> services = classKeysToServices(serviceKeys, map);
+
+		// Start them
+		startServices(services, map);
+	}
+
+	/**
+	 * Same as {@link #startServicesByClassKeys(List)}, but with an array as
+	 * input.
+	 * 
+	 * @see #startServices(List)
+	 * 
+	 * @param serviceKeys
+	 *        Keys of services to start.
+	 * @throws ServiceMultiException
+	 * @throws ServiceNotFoundException
+	 *         If a service can't be retrieved by its key.
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	public void startServicesByClassKeys(Class<?>... serviceKeys) throws ServiceMultiException, ServiceNotFoundException {
+
+		List<Class<?>> serviceKeysList = Arrays.asList(serviceKeys);
+		startServicesByClassKeys(serviceKeysList);
+	}
+
+	/**
+	 * Start the specified services, and their required services. The specifies
+	 * services should be in the specified map. The map is also used to resolves
+	 * dependencies. Start all services marked as start = STARTUP . All eligible
+	 * services are first created, then initialized and finally started. If an
+	 * error occur on a service during one of this step, the service is removed
+	 * from the registry and and the error is logged.
+	 * 
+	 * @param services
+	 *        Services to start
+	 * @param map
+	 *        a table of (key, service) used to get a service by its key.
+	 * @throws ServiceMultiException
+	 *         If a service can't be started.
+	 */
+	private void startServices(List<ServiceStartupEntry> services, LookupMap map) throws ServiceMultiException {
+		// Check if all dependencies exist.
+		checkDependencies(services, map);
+
+		// Get all roots : LAZY and START
+		Collection<ServiceStartupEntry> roots = getServiceRoots(services, map);
+		if(Activator.log.isDebugEnabled()) {
+			showServices(" Roots:", roots);
+		}
+		// Detect cycles
+		checkCycle(roots, map);
+		// Retain only services with startupkind == START and state ==
+		// REGISTERED
+		roots = retainsToStartServices(roots);
+		//
+		List<ServiceStartupEntry> toStart = buildTopologicalListOfServicesToStart(roots, map);
+
+		// Remove already started services
+		toStart = retainsToStartServices(toStart);
+
+		// if( log.isLoggable(Level.FINE))
+		// {
+		showServices(" Services to start:", toStart);
+		// }
+
+		// Create an object to collect errors if any.
+		ServiceMultiException errors = new ServiceMultiException();
+
+		createServices(toStart, errors);
+		// Register all started services
+		registerServices(toStart);
+		initServices(toStart, errors);
+		startServices(toStart, errors);
+
+		// Report errors if any
+		if(errors.getExceptions().size() > 0)
+			throw errors;
+	}
+
+	/**
+	 * Return a list of services from a list of services keys.
+	 * 
+	 * @param serviceKeys
+	 * @param map
+	 * @return
+	 * @throws ServiceNotFoundException
+	 *         If a service can't be retrieved by its key.
+	 */
+	private List<ServiceStartupEntry> keysToServices(List<String> serviceKeys, LookupMap map) throws ServiceNotFoundException {
+
+		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>(serviceKeys.size());
+
+		for(String key : serviceKeys) {
+			result.add(map.getChecked(key));
+		}
+		return result;
+	}
+
+	/**
+	 * Return a list of services from a list of services keys.
+	 * 
+	 * @param serviceKeys
+	 * @param map
+	 * @return
+	 * @throws ServiceNotFoundException
+	 *         If a service can't be retrieved by its key.
+	 */
+	private List<ServiceStartupEntry> classKeysToServices(List<Class<?>> serviceKeys, LookupMap map) throws ServiceNotFoundException {
+
+		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>(serviceKeys.size());
+
+		for(Class<?> key : serviceKeys) {
+			result.add(map.getChecked(key.getName()));
+		}
+		return result;
+	}
+
+	/**
+	 * Print the services. For debug purpose
+	 * 
+	 * @param roots
+	 */
+	private void showServices(String message, Collection<ServiceStartupEntry> roots) {
+		StringBuffer buffer = new StringBuffer();
+		buffer.append("--------------------------\n");
+		buffer.append(message);
+		buffer.append("\n");
+		for(ServiceStartupEntry service : roots) {
+			buffer.append("  ");
+			buffer.append(service.getDescriptor().toString());
+			buffer.append("\n");
+		}
+		buffer.append("--------- done -----------\n");
+		Activator.log.debug(buffer.toString());
+	}
+
+	/**
+	 * Check if all dependencies exist. Throw an error if a declared dependency
+	 * has no corresponding service.
+	 * 
+	 * @param services
+	 *        Services to check
+	 * @param map
+	 *        Map of services by keys.
+	 * @throws ServiceMultiException
+	 */
+	private void checkDependencies(Collection<ServiceStartupEntry> services, LookupMap map) throws ServiceMultiException {
+
+		ServiceMultiException errors = new ServiceMultiException();
+
+		// Walk each service and check if its required services exist.
+		for(ServiceStartupEntry service : services) {
+			ServiceDescriptor desc = service.getDescriptor();
+
+			// Check each required service
+			for(String key : desc.getRequiredServiceKeys()) {
+
+				// Check if service can be found
+				try {
+					map.getChecked(key);
+				} catch (ServiceNotFoundException e) {
+					errors.addException(desc.getKey(), e);
+				}
+			}
+		}
+
+		// Throw errors if any
+		if(errors.getExceptions().size() > 0)
+			throw errors;
+	}
+
+	/**
+	 * Retains only the services that should be started. Retains only services
+	 * with startupkind = START and state == REGISTERED
+	 * 
+	 * @param services
+	 *        Collection to filter
+	 * @return a new Collection containing the services to start.
+	 */
+	private List<ServiceStartupEntry> retainsToStartServices(Collection<ServiceStartupEntry> services) {
+
+		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>();
+		for(ServiceStartupEntry service : services) {
+			ServiceDescriptor desc = service.getDescriptor();
+			if(service.getState() == ServiceState.registered && desc.isStartAtStartup()) {
+				result.add(service);
+			}
+		}
+
+		return result;
+	}
+
+	/**
+	 * Check for cycles. Throws an exception if a cycle is discovered. Each root
+	 * is checked to see if it contains a cycle.
+	 * 
+	 * @param roots
+	 * @param map
+	 */
+	private void checkCycle(Collection<ServiceStartupEntry> roots, LookupMap map) {
+		// TODO Auto-generated method stub
+
+	}
+
+	/**
+	 * Build a list of services to start, in the topological order (right
+	 * order). The required services are placed before the dependent services in
+	 * the list. Services already started are disguarded.
+	 * 
+	 * @param roots
+	 * @param map
+	 *        Map used to resolve the entry by their key.
+	 * @return
+	 */
+	private List<ServiceStartupEntry> buildTopologicalListOfServicesToStart(Collection<ServiceStartupEntry> roots, LookupMap map) {
+
+		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>();
+
+		// Each root represent a graph. Walk the root and its child in the list,
+		// in the right order.
+		for(ServiceStartupEntry root : roots) {
+			walkGraphDepthFirst(result, root, map);
+		}
+
+		return result;
+	}
+
+	/**
+	 * Add recursively the provided node, and then its direct children.
+	 * 
+	 * @param result
+	 *        The list where the node are added
+	 * @param node
+	 *        The node to add
+	 * @param map
+	 */
+	private void walkGraphDepthFirst(List<ServiceStartupEntry> result, ServiceStartupEntry node, LookupMap map) {
+
+		// Do not add already added or started node.
+		if(result.contains(node) || node.isStarted())
+			return;
+
+		// add direct child
+		for(String serviceKey : node.getDescriptor().getRequiredServiceKeys()) {
+			try {
+				ServiceStartupEntry child = map.getChecked(serviceKey);
+				walkGraphDepthFirst(result, child, map);
+			} catch (ServiceNotFoundException e) {
+				// Do nothing, we have already reported the problems with
+				// checkServices;
+			}
+		}
+
+		// Now add the node
+		result.add(node);
+	}
+
+	/**
+	 * Create a List of the root services. The roots are services that are not
+	 * required by any service.
+	 * 
+	 * @param addedServices
+	 *        A collection from which roots are required. The collection is
+	 *        unmodified.
+	 * @param map
+	 * @return
+	 */
+	private Collection<ServiceStartupEntry> getServiceRoots(Collection<ServiceStartupEntry> addedServices, LookupMap keyServiceMap) {
+
+		// Create a copy of the list of services
+		Collection<ServiceStartupEntry> services = new ArrayList<ServiceStartupEntry>(addedServices);
+
+		List<ServiceStartupEntry> allRequired = new ArrayList<ServiceStartupEntry>();
+
+		// The roots are services that are not required by any service.
+		// Build a list of the services required by all other services.
+		for(ServiceStartupEntry service : services) {
+			// Add each child to the list of required
+			for(String serviceKey : service.getDescriptor().getRequiredServiceKeys()) {
+				try {
+
+					ServiceStartupEntry child = keyServiceMap.getChecked(serviceKey);
+					allRequired.add(child);
+				} catch (ServiceNotFoundException e) {
+					// Do nothing, we have already reported the problems with
+					// checkServices;
+				}
+			}
+
+		}
+
+		// Roots are those that are not required.
+		// So it is the original list minus the required.
+		services.removeAll(allRequired);
+
+		return services;
+	}
+
+	/**
+	 * Dispose all services for this registry and its parents.
+	 * 
+	 * @throws ServiceMultiException
+	 */
+	public void disposeRegistry() throws ServiceMultiException {
+
+		disposeRegistry(true);
+	}
+
+	/**
+	 * Dispose all services, and parent registries if any.
+	 * 
+	 * @throws ServiceMultiException
+	 */
+	public void disposeRegistry(boolean isRecursive) throws ServiceMultiException {
+
+		// List of keys of service in error.
+		ServiceMultiException errors = new ServiceMultiException();
+		disposeRegistry(errors, isRecursive);
+		// Report errors if any
+		if(errors.getExceptions().size() > 0)
+			throw errors;
+	}
+
+	/**
+	 * Dispose all services, and parent registries if any.
+	 * 
+	 * @throws ServiceMultiException
+	 */
+	protected void disposeRegistry(ServiceMultiException errors, boolean isRecursive) throws ServiceMultiException {
+
+		// List of keys of service in error.
+		disposeServices(namedServices.values(), errors);
+		disposeServices(anonymousServices, errors);
+
+		// Clean up properties to help GC
+		addedServices.clear();
+		addedServices = null;
+		anonymousServices.clear();
+		anonymousServices = null;
+		namedServices.clear();
+		namedServices = null;
+		
+		// Do parents
+		if( isRecursive ) {
+			for( ServicesRegistry parent : parents) {
+				parent.disposeRegistry( errors, true);
+			}
+		}
+	}
+
+	/**
+	 * Create all services provided in the list
+	 * 
+	 * @param toStart
+	 *        List of services to create.
+	 * @param errors
+	 *        Exception to collect errors.
+	 * 
+	 * @throws ServiceMultiException
+	 *         If an error occure during the creation
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	private void createServices(List<ServiceStartupEntry> toStart, ServiceMultiException errors) throws ServiceMultiException {
+
+		// Loop on all services
+		for(ServiceStartupEntry serviceEntry : toStart) {
+			try {
+
+				serviceEntry.createService();
+			} catch (ServiceException e) {
+				log.log(Level.SEVERE, "Can't create service '" + serviceEntry + "'", e); //$NON-NLS-1$ //$NON-NLS-2$
+
+				errors.addException(serviceEntry.getDescriptor().getKey(), e);
+			}
+		}
+
+	}
+
+	/**
+	 * Register all services provided in the list. After this operation,
+	 * services are available thru {@link #getService(Class)}.
+	 * 
+	 * @param toStart
+	 *        List of services to register.
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	private void registerServices(Collection<ServiceStartupEntry> toStart) {
+
+		// Loop on all services
+		for(ServiceStartupEntry serviceEntry : toStart) {
+			ServiceDescriptor desc = serviceEntry.getDescriptor();
+			if(desc.isAnonymous()) {
+				anonymousServices.add(serviceEntry);
+			} else {
+				namedServices.put(desc.getKey(), serviceEntry);
+			}
+		}
+	}
+
+	/**
+	 * Init all services provided in the list
+	 * 
+	 * @param toStart
+	 *        List of services to init.
+	 * @param errors
+	 * 
+	 * @throws ServiceMultiException
+	 *         If an error occure during the process
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	private void initServices(List<ServiceStartupEntry> toStart, ServiceMultiException errors) throws ServiceMultiException {
+
+		// Loop on all services
+		for(ServiceStartupEntry serviceEntry : toStart) {
+			try {
+
+				serviceEntry.initService(this);
+			} catch (ServiceException e) {
+				log.log(Level.SEVERE, "Can't initialize service '" + serviceEntry + "'", e); //$NON-NLS-1$ //$NON-NLS-2$
+				errors.addException(serviceEntry.getDescriptor().getKey(), e);
+			}
+		}
+
+	}
+
+	/**
+	 * Init all services provided in the list
+	 * 
+	 * @param toStart
+	 *        List of services to init.
+	 * @param errors
+	 * 
+	 * @throws ServiceMultiException
+	 *         If an error occure during the process
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	private void startServices(List<ServiceStartupEntry> toStart, ServiceMultiException errors) throws ServiceMultiException {
+
+		// Loop on all services
+		for(ServiceStartupEntry serviceEntry : toStart) {
+			try {
+
+				serviceEntry.startService();
+			} catch (ServiceException e) {
+				log.log(Level.SEVERE, "Can't start service '" + serviceEntry + "'", e); //$NON-NLS-1$ //$NON-NLS-2$
+
+				errors.addException(serviceEntry.getDescriptor().getKey(), e);
+			}
+		}
+
+	}
+
+	/**
+	 * Dispose all started services.
+	 * Services are disposed in creation reverse order
+	 * 
+	 * @throws ServiceMultiException
+	 * 
+	 * @throws ServiceException
+	 *         If a service can't be started.
+	 */
+	private void disposeServices(Collection<ServiceStartupEntry> services, ServiceMultiException errors) {
+
+		// Dispose services
+		for(ServiceStartupEntry serviceEntry : services) {
+			try {
+				serviceEntry.disposeService();
+			} catch (ServiceException e) {
+				log.log(Level.SEVERE, "Can't dispose service '" + serviceEntry.getDescriptor().getKey() + "'", e); //$NON-NLS-1$ //$NON-NLS-2$
+				errors.addException(serviceEntry.getDescriptor(), e);
+			}
+		}
+	}
+
+	/**
+	 * This class represents a union of two maps of <String,
+	 * ServiceStartupEntry>. It provide specific methods to retrieve a {@link ServiceStartupEntry} by its key.
+	 * <br>
+	 * This class is used to lookup {@link ServiceStartupEntry} in multiple namespaces (2 maps, and then registries).
+	 * 
+	 * 
+	 * @author cedric dumoulin
+	 * 
+	 */
+	private class LookupMap {
+
+		Map<String, ServiceStartupEntry> map1;
+
+		Map<String, ServiceStartupEntry> map2;
+		
+		// additional service registries into which we should search
+		List<ServicesRegistry> registries;
+
+		/**
+		 * 
+		 * Constructor. Build a union of two maps.
+		 * 
+		 * @param map1
+		 * @param map2
+		 */
+		public LookupMap(Map<String, ServiceStartupEntry> map1, Map<String, ServiceStartupEntry> map2) {
+			this.map1 = map1;
+			this.map2 = map2;
+		}
+
+		public LookupMap(Map<String, ServiceStartupEntry> space1, Map<String, ServiceStartupEntry> space2, List<ServicesRegistry> registries) {
+			this( space1, space2);
+			this.registries = registries;
+		}
+
+		/**
+		 * 
+		 * Constructor. Build a union of one map (sic).
+		 * 
+		 * @param map
+		 */
+		@SuppressWarnings("unused")
+		public LookupMap(Map<String, ServiceStartupEntry> map) {
+			this(map, null);
+		}
+
+		/**
+		 * Get a service by its key.
+		 * 
+		 * @param key
+		 * @return the service or null if not found.
+		 */
+		@SuppressWarnings("unused")
+		public ServiceStartupEntry get(String key) {
+
+			ServiceStartupEntry res = map1.get(key);
+			if(res != null)
+				return res;
+			if(map2 != null) {
+				res = map2.get(key);
+			}
+			if( res == null && registries != null) {
+				// lookup in registries
+				res = getFromRegistries(key);
+			}
+
+			return res;
+		}
+
+		/**
+		 * Get a service by its key.
+		 * 
+		 * @param key
+		 * @return The requested service.
+		 * @throws ServiceNotFoundException
+		 *         if the service can't be found.
+		 */
+		public ServiceStartupEntry getChecked(String key) throws ServiceNotFoundException {
+
+			ServiceStartupEntry res = map1.get(key);
+			if(res != null)
+				return res;
+			if(map2 != null)
+				res = map2.get(key);
+			if( res == null && registries != null) {
+				// lookup in registries
+				res = getFromRegistries(key);
+			}
+			if(res != null)
+				return res;
+
+			throw new ServiceNotFoundException("No service found under key '" + key.toString() + "'"); //$NON-NLS-1$ //$NON-NLS-2$
+		}
+		
+		/**
+		 * Try to get the entry from the registries.
+		 * @param key
+		 * @return
+		 */
+		private ServiceStartupEntry getFromRegistries(String key) {
+			
+			ServiceStartupEntry service;
+			// Lookup in parents
+			for(ServicesRegistry registry : registries) {
+				service = registry.getServiceStartupEntry(key);
+				if( service != null) {
+					return service;
+				}	
+			}
+
+			return null;
+		}
+	}
+
+}