rmiserviceexporter.java

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		prepare();
	}

	/**
	 * Initialize this service exporter, registering the service as RMI object.
	 * <p>Creates an RMI registry on the specified port if none exists.
	 * @throws RemoteException if service registration failed
	 */
	public void prepare() throws RemoteException {
		checkService();

		if (this.serviceName == null) {
			throw new IllegalArgumentException("Property 'serviceName' is required");
		}

		// Check socket factories for exported object.
		if (this.clientSocketFactory instanceof RMIServerSocketFactory) {
			this.serverSocketFactory = (RMIServerSocketFactory) this.clientSocketFactory;
		}
		if ((this.clientSocketFactory != null && this.serverSocketFactory == null) ||
				(this.clientSocketFactory == null && this.serverSocketFactory != null)) {
			throw new IllegalArgumentException(
					"Both RMIClientSocketFactory and RMIServerSocketFactory or none required");
		}

		// Check socket factories for RMI registry.
		if (this.registryClientSocketFactory instanceof RMIServerSocketFactory) {
			this.registryServerSocketFactory = (RMIServerSocketFactory) this.registryClientSocketFactory;
		}
		if (this.registryClientSocketFactory == null && this.registryServerSocketFactory != null) {
			throw new IllegalArgumentException(
					"RMIServerSocketFactory without RMIClientSocketFactory for registry not supported");
		}

		// Determine RMI registry to use.
		if (this.registry == null) {
			this.registry = getRegistry(this.registryHost, this.registryPort,
				this.registryClientSocketFactory, this.registryServerSocketFactory);
		}

		// Initialize and cache exported object.
		this.exportedObject = getObjectToExport();

		if (logger.isInfoEnabled()) {
			logger.info("Binding service '" + this.serviceName + "' to RMI registry: " + this.registry);
		}

		// Export RMI object.
		if (this.clientSocketFactory != null) {
			UnicastRemoteObject.exportObject(
					this.exportedObject, this.servicePort, this.clientSocketFactory, this.serverSocketFactory);
		}
		else {
			UnicastRemoteObject.exportObject(this.exportedObject, this.servicePort);
		}

		// Bind RMI object to registry.
		try {
			if (this.replaceExistingBinding) {
				this.registry.rebind(this.serviceName, this.exportedObject);
			}
			else {
				this.registry.bind(this.serviceName, this.exportedObject);
			}
		}
		catch (AlreadyBoundException ex) {
			// Already an RMI object bound for the specified service name...
			unexportObjectSilently();
			throw new IllegalStateException(
					"Already an RMI object bound for name '"  + this.serviceName + "': " + ex.toString());
		}
		catch (RemoteException ex) {
			// Registry binding failed: let's unexport the RMI object as well.
			unexportObjectSilently();
			throw ex;
		}
	}


	/**
	 * Locate or create the RMI registry for this exporter.
	 * @param registryHost the registry host to use (if this is specified,
	 * no implicit creation of a RMI registry will happen)
	 * @param registryPort the registry port to use
	 * @param clientSocketFactory the RMI client socket factory for the registry (if any)
	 * @param serverSocketFactory the RMI server socket factory for the registry (if any)
	 * @return the RMI registry
	 * @throws RemoteException if the registry couldn't be located or created
	 */
	protected Registry getRegistry(String registryHost, int registryPort,
			RMIClientSocketFactory clientSocketFactory, RMIServerSocketFactory serverSocketFactory)
			throws RemoteException {

		if (registryHost != null) {
			// Host explictly specified: only lookup possible.
			if (logger.isInfoEnabled()) {
				logger.info("Looking for RMI registry at port '" + registryPort + "' of host [" + registryHost + "]");
			}
			Registry reg = LocateRegistry.getRegistry(registryHost, registryPort, clientSocketFactory);
			testRegistry(reg);
			return reg;
		}

		else {
			return getRegistry(registryPort, clientSocketFactory, serverSocketFactory);
		}
	}

	/**
	 * Locate or create the RMI registry for this exporter.
	 * @param registryPort the registry port to use
	 * @param clientSocketFactory the RMI client socket factory for the registry (if any)
	 * @param serverSocketFactory the RMI server socket factory for the registry (if any)
	 * @return the RMI registry
	 * @throws RemoteException if the registry couldn't be located or created
	 */
	protected Registry getRegistry(
			int registryPort, RMIClientSocketFactory clientSocketFactory, RMIServerSocketFactory serverSocketFactory)
			throws RemoteException {

		if (clientSocketFactory != null) {
			if (this.alwaysCreateRegistry) {
				logger.info("Creating new RMI registry");
				return LocateRegistry.createRegistry(registryPort, clientSocketFactory, serverSocketFactory);
			}
			if (logger.isInfoEnabled()) {
				logger.info("Looking for RMI registry at port '" + registryPort + "', using custom socket factory");
			}
			try {
				// Retrieve existing registry.
				Registry reg = LocateRegistry.getRegistry(null, registryPort, clientSocketFactory);
				testRegistry(reg);
				return reg;
			}
			catch (RemoteException ex) {
				logger.debug("RMI registry access threw exception", ex);
				logger.info("Could not detect RMI registry - creating new one");
				// Assume no registry found -> create new one.
				return LocateRegistry.createRegistry(registryPort, clientSocketFactory, serverSocketFactory);
			}
		}

		else {
			return getRegistry(registryPort);
		}
	}

	/**
	 * Locate or create the RMI registry for this exporter.
	 * @param registryPort the registry port to use
	 * @return the RMI registry
	 * @throws RemoteException if the registry couldn't be located or created
	 */
	protected Registry getRegistry(int registryPort) throws RemoteException {
		if (this.alwaysCreateRegistry) {
			logger.info("Creating new RMI registry");
			return LocateRegistry.createRegistry(registryPort);
		}
		if (logger.isInfoEnabled()) {
			logger.info("Looking for RMI registry at port '" + registryPort + "'");
		}
		try {
			// Retrieve existing registry.
			Registry reg = LocateRegistry.getRegistry(registryPort);
			testRegistry(reg);
			return reg;
		}
		catch (RemoteException ex) {
			logger.debug("RMI registry access threw exception", ex);
			logger.info("Could not detect RMI registry - creating new one");
			// Assume no registry found -> create new one.
			return LocateRegistry.createRegistry(registryPort);
		}
	}

	/**
	 * Test the given RMI registry, calling some operation on it to
	 * check whether it is still active.
	 * <p>Default implementation calls <code>Registry.list()</code>.
	 * @param registry the RMI registry to test
	 * @throws RemoteException if thrown by registry methods
	 * @see java.rmi.registry.Registry#list()
	 */
	protected void testRegistry(Registry registry) throws RemoteException {
		registry.list();
	}


	/**
	 * Unbind the RMI service from the registry on bean factory shutdown.
	 */
	public void destroy() throws RemoteException {
		if (logger.isInfoEnabled()) {
			logger.info("Unbinding RMI service '" + this.serviceName +
					"' from registry at port '" + this.registryPort + "'");
		}
		try {
			this.registry.unbind(this.serviceName);
		}
		catch (NotBoundException ex) {
			if (logger.isWarnEnabled()) {
				logger.warn("RMI service '" + this.serviceName + "' is not bound to registry at port '" +
						this.registryPort + "' anymore", ex);
			}
		}
		finally {
			unexportObjectSilently();
		}
	}

	/**
	 * Unexport the registered RMI object, logging any exception that arises.
	 */
	private void unexportObjectSilently() {
		try {
			UnicastRemoteObject.unexportObject(this.exportedObject, true);
		}
		catch (NoSuchObjectException ex) {
			if (logger.isWarnEnabled()) {
				logger.warn("RMI object for service '" + this.serviceName + "' isn't exported anymore", ex);
			}
		}
	}

}