org.springframework/spring-context/5.1.5.RELEASE : org/springframework/remoting/rmi/RmiRegistryFactoryBean.java

RmiRegistryFactoryBean
https://github.com/spring-projects/spring-framework: Spring Context (Spring IO)
Apache License, Version 2.0
Juergen Hoeller
/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.remoting.rmi;

import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.RMIClientSocketFactory;
import java.rmi.server.RMIServerSocketFactory;
import java.rmi.server.UnicastRemoteObject;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.lang.Nullable;

FactoryBean that locates a Registry and exposes it for bean references. Can also create a local RMI registry on the fly if none exists already. Can be used to set up and pass around the actual Registry object to applications objects that need to work with RMI. One example for such an object that needs to work with RMI is Spring's RmiServiceExporter, which either works with a passed-in Registry reference or falls back to the registry as specified by its local properties and defaults. 
Also useful to enforce creation of a local RMI registry at a given port, for example for a JMX connector. If used in conjunction with ConnectorServerFactoryBean, it is recommended to mark the connector definition (ConnectorServerFactoryBean) as "depends-on" the registry definition (RmiRegistryFactoryBean), to guarantee starting up the registry first. 
Note: The implementation of this class mirrors the corresponding logic in RmiServiceExporter, and also offers the same customization hooks. RmiServiceExporter implements its own registry lookup as a convenience: It is very common to simply rely on the registry defaults. 
Author: Juergen Hoeller
See Also: RmiServiceExporter.setRegistry
ConnectorServerFactoryBean
Registry
LocateRegistry
Since: 1.2.3/**
 * {@link FactoryBean} that locates a {@link java.rmi.registry.Registry} and
 * exposes it for bean references. Can also create a local RMI registry
 * on the fly if none exists already.
 *
 * <p>Can be used to set up and pass around the actual Registry object to
 * applications objects that need to work with RMI. One example for such an
 * object that needs to work with RMI is Spring's {@link RmiServiceExporter},
 * which either works with a passed-in Registry reference or falls back to
 * the registry as specified by its local properties and defaults.
 *
 * <p>Also useful to enforce creation of a local RMI registry at a given port,
 * for example for a JMX connector. If used in conjunction with
 * {@link org.springframework.jmx.support.ConnectorServerFactoryBean},
 * it is recommended to mark the connector definition (ConnectorServerFactoryBean)
 * as "depends-on" the registry definition (RmiRegistryFactoryBean),
 * to guarantee starting up the registry first.
 *
 * <p>Note: The implementation of this class mirrors the corresponding logic
 * in {@link RmiServiceExporter}, and also offers the same customization hooks.
 * RmiServiceExporter implements its own registry lookup as a convenience:
 * It is very common to simply rely on the registry defaults.
 *
 * @author Juergen Hoeller
 * @since 1.2.3
 * @see RmiServiceExporter#setRegistry
 * @see org.springframework.jmx.support.ConnectorServerFactoryBean
 * @see java.rmi.registry.Registry
 * @see java.rmi.registry.LocateRegistry
 */
public class RmiRegistryFactoryBean implements FactoryBean<Registry>, InitializingBean, DisposableBean {

	protected final Log logger = LogFactory.getLog(getClass());

	private String host;

	private int port = Registry.REGISTRY_PORT;

	private RMIClientSocketFactory clientSocketFactory;

	private RMIServerSocketFactory serverSocketFactory;

	private Registry registry;

	private boolean alwaysCreate = false;

	private boolean created = false;


	Set the host of the registry for the exported RMI service, i.e. rmi://HOST:port/name Default is localhost.
/**
	 * Set the host of the registry for the exported RMI service,
	 * i.e. {@code rmi://HOST:port/name}
	 * <p>Default is localhost.
	 */
	public void setHost(String host) {
		this.host = host;
	}

	Return the host of the registry for the exported RMI service.
/**
	 * Return the host of the registry for the exported RMI service.
	 */
	public String getHost() {
		return this.host;
	}

	Set the port of the registry for the exported RMI service, i.e. rmi://host:PORT/name Default is Registry.REGISTRY_PORT (1099). /**
	 * Set the port of the registry for the exported RMI service,
	 * i.e. {@code rmi://host:PORT/name}
	 * <p>Default is {@code Registry.REGISTRY_PORT} (1099).
	 */
	public void setPort(int port) {
		this.port = port;
	}

	Return the port of the registry for the exported RMI service.
/**
	 * Return the port of the registry for the exported RMI service.
	 */
	public int getPort() {
		return this.port;
	}

	Set a custom RMI client socket factory to use for the RMI registry.
If the given object also implements java.rmi.server.RMIServerSocketFactory, it will automatically be registered as server socket factory too. 
See Also: setServerSocketFactory
RMIClientSocketFactory
RMIServerSocketFactory
LocateRegistry.getRegistry(String, int, RMIClientSocketFactory)/**
	 * Set a custom RMI client socket factory to use for the RMI registry.
	 * <p>If the given object also implements {@code java.rmi.server.RMIServerSocketFactory},
	 * it will automatically be registered as server socket factory too.
	 * @see #setServerSocketFactory
	 * @see java.rmi.server.RMIClientSocketFactory
	 * @see java.rmi.server.RMIServerSocketFactory
	 * @see java.rmi.registry.LocateRegistry#getRegistry(String, int, java.rmi.server.RMIClientSocketFactory)
	 */
	public void setClientSocketFactory(RMIClientSocketFactory clientSocketFactory) {
		this.clientSocketFactory = clientSocketFactory;
	}

	Set a custom RMI server socket factory to use for the RMI registry.
Only needs to be specified when the client socket factory does not implement java.rmi.server.RMIServerSocketFactory already. 
See Also: setClientSocketFactory
RMIClientSocketFactory
RMIServerSocketFactory
LocateRegistry.createRegistry(int, RMIClientSocketFactory, RMIServerSocketFactory)/**
	 * Set a custom RMI server socket factory to use for the RMI registry.
	 * <p>Only needs to be specified when the client socket factory does not
	 * implement {@code java.rmi.server.RMIServerSocketFactory} already.
	 * @see #setClientSocketFactory
	 * @see java.rmi.server.RMIClientSocketFactory
	 * @see java.rmi.server.RMIServerSocketFactory
	 * @see java.rmi.registry.LocateRegistry#createRegistry(int, RMIClientSocketFactory, java.rmi.server.RMIServerSocketFactory)
	 */
	public void setServerSocketFactory(RMIServerSocketFactory serverSocketFactory) {
		this.serverSocketFactory = serverSocketFactory;
	}

	Set whether to always create the registry in-process,
not attempting to locate an existing registry at the specified port.
Default is "false". Switch this flag to "true" in order to avoid
the overhead of locating an existing registry when you always
intend to create a new registry in any case.
/**
	 * Set whether to always create the registry in-process,
	 * not attempting to locate an existing registry at the specified port.
	 * <p>Default is "false". Switch this flag to "true" in order to avoid
	 * the overhead of locating an existing registry when you always
	 * intend to create a new registry in any case.
	 */
	public void setAlwaysCreate(boolean alwaysCreate) {
		this.alwaysCreate = alwaysCreate;
	}


	@Override
	public void afterPropertiesSet() throws Exception {
		// Check socket factories for registry.
		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");
		}

		// Fetch RMI registry to expose.
		this.registry = getRegistry(this.host, this.port, this.clientSocketFactory, this.serverSocketFactory);
	}


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

		if (registryHost != null) {
			// Host explicitly specified: only lookup possible.
			if (logger.isDebugEnabled()) {
				logger.debug("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.
Params: registryPort – the registry port to use
clientSocketFactory – the RMI client socket factory for the registry (if any)
serverSocketFactory – the RMI server socket factory for the registry (if any)
Throws: RemoteException – if the registry couldn't be located or created
Returns: the RMI registry/**
	 * Locate or create the RMI registry.
	 * @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,
			@Nullable RMIClientSocketFactory clientSocketFactory, @Nullable RMIServerSocketFactory serverSocketFactory)
			throws RemoteException {

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

		else {
			return getRegistry(registryPort);
		}
	}

	Locate or create the RMI registry.
Params: registryPort – the registry port to use
Throws: RemoteException – if the registry couldn't be located or created
Returns: the RMI registry/**
	 * Locate or create the RMI registry.
	 * @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.alwaysCreate) {
			logger.debug("Creating new RMI registry");
			this.created = true;
			return LocateRegistry.createRegistry(registryPort);
		}
		if (logger.isDebugEnabled()) {
			logger.debug("Looking for RMI registry at port '" + registryPort + "'");
		}
		synchronized (LocateRegistry.class) {
			try {
				// Retrieve existing registry.
				Registry reg = LocateRegistry.getRegistry(registryPort);
				testRegistry(reg);
				return reg;
			}
			catch (RemoteException ex) {
				logger.trace("RMI registry access threw exception", ex);
				logger.debug("Could not detect RMI registry - creating new one");
				// Assume no registry found -> create new one.
				this.created = true;
				return LocateRegistry.createRegistry(registryPort);
			}
		}
	}

	Test the given RMI registry, calling some operation on it to
check whether it is still active.
Default implementation calls Registry.list(). 
Params: registry – the RMI registry to test
Throws: RemoteException – if thrown by registry methods
See Also: Registry.list()/**
	 * Test the given RMI registry, calling some operation on it to
	 * check whether it is still active.
	 * <p>Default implementation calls {@code Registry.list()}.
	 * @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();
	}


	@Override
	public Registry getObject() throws Exception {
		return this.registry;
	}

	@Override
	public Class<? extends Registry> getObjectType() {
		return (this.registry != null ? this.registry.getClass() : Registry.class);
	}

	@Override
	public boolean isSingleton() {
		return true;
	}


	Unexport the RMI registry on bean factory shutdown,
provided that this bean actually created a registry.
/**
	 * Unexport the RMI registry on bean factory shutdown,
	 * provided that this bean actually created a registry.
	 */
	@Override
	public void destroy() throws RemoteException {
		if (this.created) {
			logger.debug("Unexporting RMI registry");
			UnicastRemoteObject.unexportObject(this.registry, true);
		}
	}

}
Author:	Juergen Hoeller
See Also:	RmiServiceExporter.setRegistry ConnectorServerFactoryBean Registry LocateRegistry
Since:	1.2.3
Params:	registryHost – the registry host to use (if this is specified, no implicit creation of a RMI registry will happen) registryPort – the registry port to use clientSocketFactory – the RMI client socket factory for the registry (if any) serverSocketFactory – the RMI server socket factory for the registry (if any)
Throws:	RemoteException – if the registry couldn't be located or created
Returns:	the RMI registry
Params:	registryPort – the registry port to use clientSocketFactory – the RMI client socket factory for the registry (if any) serverSocketFactory – the RMI server socket factory for the registry (if any)
Throws:	RemoteException – if the registry couldn't be located or created
Returns:	the RMI registry
Params:	registryPort – the registry port to use
Throws:	RemoteException – if the registry couldn't be located or created
Returns:	the RMI registry
Params:	registry – the RMI registry to test
Throws:	RemoteException – if thrown by registry methods
See Also:	Registry.list()
/

org.springframework/ spring-context/ 5.1.5.RELEASE/ org/springframework/remoting/rmi/RmiRegistryFactoryBean.java
