org.jboss.remoting
Class ClientInvoker

java.lang.Object
  org.jboss.remoting.AbstractInvoker
      org.jboss.remoting.ClientInvoker

All Implemented Interfaces:

Invoker

public abstract class ClientInvoker

extends AbstractInvoker

ClientInvoker is an abstract client part handler that implements the bulk of the heavy lefting to process a remote method and dispatch it to a remote ServerInvoker and handle the result.

The ClientInvoker in particular handles the loading of remote classes necessary for execution of invocations, as well as the remote loading of remote classes necessary to unmarshal the results or parameters of a result returned from a ServerInvoker.

Specialized Client/Server Invokers might add additional functionality as part of the invocation - such as delivering queued notifcations from a remote server by adding the notification objects during each invocation to the invocation result payload and then having the client re-dispatch the notifications locally upon receiving the return invocation result.

Version:

$Revision: 1.10 $

Author:

Jeff Haynie

Field Summary

protected boolean	connected
protected InvokerLocator	localServerLocator

Fields inherited from class org.jboss.remoting.AbstractInvoker

classbyteloader, locator, log, logExtra

Constructor Summary

ClientInvoker(ClassLoader cl, InvokerLocator locator)

Method Summary

void	connect() connect to the remote invoker
void	disconnect() disconnect from the remote invokere
protected void	finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
InvokerLocator	getClientLocator() Gets the client locator.
protected abstract void	handleConnect() subclasses must implement this method to provide a hook to connect to the remote server, if this applies to the specific transport.
protected abstract void	handleDisconnect() subclasses must implement this method to provide a hook to disconnect from the remote server, if this applies to the specific transport.
Object	invoke(InvocationRequest in) transport a request against a remote ServerInvoker
boolean	isConnected() subclasses must provide this method to return true if their remote connection is connected and false if disconnected.
protected void	postProcess(String sessionId, Object param, Map sendPayload, Map receivedPayload) this method is called prior to returning the result for the invocation to allow the subclass the ability to modify the result result
protected void	preProcess(String sessionId, Object param, Map sendPayload, Map receivedPayload) this method is called prior to making the remote invocation to allow the subclass the ability to provide additional data or modify the invocation
void	setClientLocator(InvokerLocator locator) This should be set when want to override the default behavior of automatically getting s suitable locator.
protected abstract byte[]	transport(String sessionId, byte[] buffer) called to transport the marshalled invocation to the remote destination, and receive back the marshalled invocation bytes back.

Methods inherited from class org.jboss.remoting.AbstractInvoker

addClass, getClassBytes, getLocator, loadClass, read, setClassLoader, unmarshal

Methods inherited from class java.lang.Object

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

Field Detail

connected

protected boolean connected

localServerLocator

protected InvokerLocator localServerLocator

Constructor Detail

ClientInvoker

public ClientInvoker(ClassLoader cl,
                     InvokerLocator locator)

Method Detail

setClientLocator

public void setClientLocator(InvokerLocator locator)

This should be set when want to override the default behavior of automatically getting s suitable locator. This should be used want want to control what type of callbacks to receive (pull or push). Set to null to poll for callback messages. This can also be used to receive callbacks using another transport and subsystem, if desired.

Overrides:

setClientLocator in class AbstractInvoker

Parameters:

locator -

getClientLocator

public InvokerLocator getClientLocator()

Gets the client locator. This locator will be used by the server side to make callbacks to the handler for this locator.

Overrides:

getClientLocator in class AbstractInvoker

Returns:

invoke

public Object invoke(InvocationRequest in)
              throws Throwable

transport a request against a remote ServerInvoker

Parameters:

in -

Returns:

Throws:

Throwable

preProcess

protected void preProcess(String sessionId,
                          Object param,
                          Map sendPayload,
                          Map receivedPayload)

this method is called prior to making the remote invocation to allow the subclass the ability to provide additional data or modify the invocation

Parameters:

sessionId -

param -

sendPayload -

receivedPayload -

postProcess

protected void postProcess(String sessionId,
                           Object param,
                           Map sendPayload,
                           Map receivedPayload)

this method is called prior to returning the result for the invocation to allow the subclass the ability to modify the result result

Parameters:

sessionId -

param -

sendPayload -

receivedPayload -

transport

protected abstract byte[] transport(String sessionId,
                                    byte[] buffer)
                             throws IOException,
                                    ConnectionFailedException

called to transport the marshalled invocation to the remote destination, and receive back the marshalled invocation bytes back. this method allows the subclass to provide the specific mechanism, protocol, etc. for delivering and returning remote invocations in a transport-specific way.

Parameters:

sessionId - session id to pass along

buffer - buffer of the serialized method invocation to send to the server

Returns:

result of the method invocation as serialized bytes

Throws:

IOException - fatal exception should only be raised in the case the transport write fails (but is still a valid connection)

ConnectionFailedException - this exception is raised in the case the remote side is no longer available

isConnected

public boolean isConnected()

subclasses must provide this method to return true if their remote connection is connected and false if disconnected. in some transports, such as SOAP, this method may always return true, since the remote connectivity is done on demand and not kept persistent like other transports (such as socket-based transport).

Returns:

boolean true if connected, false if not

connect

public void connect()
             throws ConnectionFailedException

connect to the remote invoker

Throws:

ConnectionFailedException

handleConnect

protected abstract void handleConnect()
                               throws ConnectionFailedException

subclasses must implement this method to provide a hook to connect to the remote server, if this applies to the specific transport. However, in some transport implementations, this may not make must difference since the connection is not persistent among invocations, such as SOAP. In these cases, the method should silently return without any processing.

Throws:

ConnectionFailedException

handleDisconnect

protected abstract void handleDisconnect()

subclasses must implement this method to provide a hook to disconnect from the remote server, if this applies to the specific transport. However, in some transport implementations, this may not make must difference since the connection is not persistent among invocations, such as SOAP. In these cases, the method should silently return without any processing.

disconnect

public void disconnect()

disconnect from the remote invokere

finalize

protected void finalize()
                 throws Throwable

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java^TM virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will transport the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

Throws:

Throwable - the Exception raised by this method