de.danet.an.workflow.api
Interface Channel

All Superinterfaces:

WfObject

public interface Channel

extends WfObject

This interface defines a named connection with a process that can be used to receive messages from activities and send messages to activities.

Note that messages sent from the workflow engine to clients on a channel may be lost when no client has opened the channel.

Version:

$Revision: 1.3 $

Author:

Michael Lipp

Method Summary

java.lang.String	name() Return the channel name.
Process	process() Return the process this channel belongs to.
java.util.Map	receiveMessage() Wait for the next message from the process on this channel.
java.util.Map	receiveMessage(long timeout) Wait for the next message from the process on this channel within the specified timeout interval.
void	sendMessage(java.util.Map msg) Send a message on this channel to the process.

Method Detail

process

public Process process()
                throws InvalidKeyException,
                       java.rmi.RemoteException

Return the process this channel belongs to.

Returns:

the process

Throws:

InvalidKeyException - if the process no longer exists

java.rmi.RemoteException - if a system-level error occurs

name

public java.lang.String name()
                      throws java.rmi.RemoteException

Return the channel name.

Returns:

the name

Throws:

java.rmi.RemoteException - if a system-level error occurs

receiveMessage

public java.util.Map receiveMessage()
                             throws java.rmi.RemoteException

Wait for the next message from the process on this channel. The message consists of all IN or INOUT parameters of the sender tool, stored in the Map object by formal parameter name.

Returns:

the message or null if the process has been closed or removed

Throws:

java.rmi.RemoteException - if a system-level error occurs

receiveMessage

public java.util.Map receiveMessage(long timeout)
                             throws java.rmi.RemoteException

Wait for the next message from the process on this channel within the specified timeout interval. The message consists of all IN or INOUT parameters of the sender tool, stored in the Map object by formal parameter name.

Parameters:

timeout - the timeout value in milliseconds. A timeout of zero never expires.

Returns:

the message or null if the process has been closed or removed or the timeout expires

Throws:

java.rmi.RemoteException - if a system-level error occurs

sendMessage

public void sendMessage(java.util.Map msg)
                 throws InvalidKeyException,
                        InvalidDataException,
                        java.rmi.RemoteException

Send a message on this channel to the process. The message will be received by an active or subsequently activated receiver tool listening on this channel. If two or more receiver tools listen on the same channel concurrently, the message delivery (only to one or to every receiver) is undefined.

The message sent is mapped to the formal OUT parameters of the receiver tool by matching the parameter names with the data entry names in the message.

Parameters:

msg - the message

Throws:

InvalidKeyException - if the process no longer exists

InvalidDataException - if the message contains invalid data, i.e. entries that do not match the name of a formal parameter

java.rmi.RemoteException - if a system-level error occurs