org.springframework.remoting.rmi
Class RmiClientInterceptor

java.lang.Object
  org.springframework.remoting.support.RemoteAccessor
      org.springframework.remoting.support.UrlBasedRemoteAccessor
          org.springframework.remoting.support.RemoteInvocationBasedAccessor
              org.springframework.remoting.rmi.RmiClientInterceptor

All Implemented Interfaces:

Advice, Interceptor, MethodInterceptor, InitializingBean

Direct Known Subclasses:

RmiProxyFactoryBean

public class RmiClientInterceptor
extends RemoteInvocationBasedAccessor
implements MethodInterceptor, InitializingBean

Interceptor for accessing conventional RMI services or RMI invokers. The service URL must be a valid RMI URL like "rmi://localhost:1099/myservice".

RMI invokers work at the RmiInvocationHandler level, needing only one stub for any service. Service interfaces do not have to extend java.rmi.Remote or throw java.rmi.RemoteException. Spring's unchecked RemoteAccessException will be thrown on remote invocation failure. Of course, in and out parameters have to be serializable.

With conventional RMI services, this invoker is typically used with the RMI service interface. Alternatively, this invoker can also proxy a remote RMI service with a matching non-RMI business interface, i.e. an interface that mirrors the RMI service methods but does not declare RemoteExceptions. In the latter case, RemoteExceptions thrown by the RMI stub will automatically get converted to Spring's unchecked RemoteAccessException.

Since:

29.09.2003

Author:

Juergen Hoeller

See Also:

RmiServiceExporter, RmiProxyFactoryBean, RmiInvocationHandler, RemoteAccessException, RemoteException, Remote

Field Summary

Fields inherited from class org.springframework.remoting.support.RemoteAccessor

logger

Constructor Summary

RmiClientInterceptor()

Method Summary

void	afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
protected Object	doInvoke(MethodInvocation invocation, Remote stub) Perform the given invocation on the given RMI stub.
protected Object	doInvoke(MethodInvocation methodInvocation, RmiInvocationHandler invocationHandler) Apply the given AOP method invocation to the given RmiInvocationHandler.
protected Remote	getStub() Return the RMI stub to use.
Object	invoke(MethodInvocation invocation) Fetches an RMI stub and delegates to doInvoke.
protected boolean	isConnectFailure(RemoteException ex) Determine whether the given RMI exception indicates a connect failure.
protected Remote	lookupStub() Create the RMI stub, typically by looking it up.
void	prepare() Fetches RMI stub on startup, if necessary.
protected Object	refreshAndRetry(MethodInvocation invocation) Refresh the RMI stub and retry the given invocation.
void	setCacheStub(boolean cacheStub) Set whether to cache the RMI stub once it has been located.
void	setLookupStubOnStartup(boolean lookupStubOnStartup) Set whether to look up the RMI stub on startup.
void	setRefreshStubOnConnectFailure(boolean refreshStubOnConnectFailure) Set whether to refresh the RMI stub on connect failure.

Methods inherited from class org.springframework.remoting.support.RemoteInvocationBasedAccessor

createRemoteInvocation, getRemoteInvocationFactory, recreateRemoteInvocationResult, setRemoteInvocationFactory

Methods inherited from class org.springframework.remoting.support.UrlBasedRemoteAccessor

getServiceUrl, setServiceUrl

Methods inherited from class org.springframework.remoting.support.RemoteAccessor

getServiceInterface, setServiceInterface

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RmiClientInterceptor

public RmiClientInterceptor()

Method Detail

setLookupStubOnStartup

public void setLookupStubOnStartup(boolean lookupStubOnStartup)

Set whether to look up the RMI stub on startup. Default is "true".

Can be turned off to allow for late start of the RMI server. In this case, the RMI stub will be fetched on first access.

See Also:

setCacheStub(boolean)

setCacheStub

public void setCacheStub(boolean cacheStub)

Set whether to cache the RMI stub once it has been located. Default is "true".

Can be turned off to allow for hot restart of the RMI server. In this case, the RMI stub will be fetched for each invocation.

See Also:

setLookupStubOnStartup(boolean)

setRefreshStubOnConnectFailure

public void setRefreshStubOnConnectFailure(boolean refreshStubOnConnectFailure)

Set whether to refresh the RMI stub on connect failure. Default is "false".

Can be turned on to allow for hot restart of the RMI server. If a cached RMI stub throws an RMI exception that indicates a remote connect failure, a fresh proxy will be fetched and the invocation will be retried.

See Also:

ConnectException, ConnectIOException, NoSuchObjectException

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Description copied from interface: InitializingBean

Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

Specified by:

afterPropertiesSet in interface InitializingBean

Throws:

Exception - in the event of misconfiguration (such as failure to set an essential property) or if initialization fails.

prepare

public void prepare()
             throws Exception

Fetches RMI stub on startup, if necessary.

Throws:

Exception - if thrown by RMI API

See Also:

setLookupStubOnStartup(boolean), lookupStub()

lookupStub

protected Remote lookupStub()
                     throws Exception

Create the RMI stub, typically by looking it up. Called on interceptor initialization if cacheStub is true; else called for each invocation by getStub().

Default implementation looks up the service URL via java.rmi.Naming. Can be overridden in subclasses.

Returns:

the RMI stub to store in this interceptor

Throws:

Exception - if proxy creation failed

See Also:

setCacheStub(boolean), getStub(), Naming.lookup(java.lang.String)

getStub

protected Remote getStub()
                  throws Exception

Return the RMI stub to use. Called for each invocation.

Default implementation returns the proxy created on initialization, if any; else, it invokes lookupStub to get a new proxy for each invocation.

Can be overridden in subclasses, for example to cache a proxy for a given amount of time before recreating it, or to test the proxy whether it is still alive.

Returns:

the RMI stub to use for an invocation

Throws:

Exception - if proxy creation failed

See Also:

lookupStub()

invoke

public Object invoke(MethodInvocation invocation)
              throws Throwable

Fetches an RMI stub and delegates to doInvoke. If configured to refresh on connect failure, it will call refreshAndRetry on corresponding RMI exceptions.

Specified by:

invoke in interface MethodInterceptor

Throws:

Throwable

See Also:

getStub(), doInvoke(MethodInvocation, Remote), refreshAndRetry(org.aopalliance.intercept.MethodInvocation), ConnectException, ConnectIOException, NoSuchObjectException

isConnectFailure

protected boolean isConnectFailure(RemoteException ex)

Determine whether the given RMI exception indicates a connect failure. Default implementation delegates to RmiClientInterceptorUtils.

Parameters:

ex - the RMI exception to check

Returns:

whether the exception should be treated as connect failure

See Also:

RmiClientInterceptorUtils.isConnectFailure(java.rmi.RemoteException)

refreshAndRetry

protected Object refreshAndRetry(MethodInvocation invocation)
                          throws Throwable

Refresh the RMI stub and retry the given invocation. Called by invoke on connect failure.

Parameters:

invocation - the AOP method invocation

Returns:

the invocation result, if any

Throws:

Throwable - in case of invocation failure

See Also:

invoke(org.aopalliance.intercept.MethodInvocation)

doInvoke

protected Object doInvoke(MethodInvocation invocation,
                          Remote stub)
                   throws Throwable

Perform the given invocation on the given RMI stub.

Parameters:

invocation - the AOP method invocation

stub - the RMI stub to invoke

Returns:

the invocation result, if any

Throws:

Throwable - in case of invocation failure

doInvoke

protected Object doInvoke(MethodInvocation methodInvocation,
                          RmiInvocationHandler invocationHandler)
                   throws RemoteException,
                          NoSuchMethodException,
                          IllegalAccessException,
                          InvocationTargetException

Apply the given AOP method invocation to the given RmiInvocationHandler. The default implementation calls invoke with a plain RemoteInvocation.

Can be overridden in subclasses to provide custom RemoteInvocation subclasses, containing additional invocation parameters like user credentials. Can also process the returned result object.

Parameters:

methodInvocation - the current AOP method invocation

invocationHandler - the RmiInvocationHandler to apply the invocation to

Returns:

the invocation result

Throws:

NoSuchMethodException - if the method name could not be resolved

IllegalAccessException - if the method could not be accessed

InvocationTargetException - if the method invocation resulted in an exception

RemoteException

See Also:

RemoteInvocation