com.tibco.as.space.remote

Interface Invocable

public interface Invocable

The Invocable interface allows applications to define custom code to be executed on the members of a space. Determination of the member who should execute the Invocable interface is dependent upon where data resides in the space as opposed to the MemberInvocable interface where the application specifies which members should execute the interface.

Execution of the Invocable interface is triggered by an application which can be running on the same member or a different member of the space. In ActiveSpaces, this is referred to as remote invocation. The remote invocation code is colocated with the data which increases performance.

With the Invocable interface, the application indicates the key of an entry stored in the space. ActiveSpaces determines which space member stores the element associated with the key or which space member would be used to store the element, if the element does not exist in the space. Execution of the Invocable interface will then occur on that space member.

The code implementing the Invocable interface needs to be included in the CLASSPATH for each member of the space.

Method Summary

Methods

Modifier and Type	Method and Description
Tuple	invoke(Space space, Tuple tuple, Tuple context) The invoke method is executed on the space member where the entry associated with the key specified in the tuple parameter is stored.

Method Detail

invoke

Tuple invoke(Space space,
           Tuple tuple,
           Tuple context)

The invoke method is executed on the space member where the entry associated with the key specified in the tuple parameter is stored. Execution of the invoke method is initiated by the client application calling the following method:

     Space.invoke(com.tibco.as.space.Tuple, java.lang.String, com.tibco.as.space.InvokeOptions)
 

The invoke method is executed regardless of whether or not an entry exists for the specified key.

The invoke method is guaranteed to be called at least once, but may be called multiple times. Therefore, the invoke method should be idempotent.

Parameters:

space - Space object that the invocation request is coming from

tuple - Contains a field named "key" whose integer value is used to direct invocation to a specific space member

context - Tuple used to pass in user defined context information

Returns:

Tuple Contains the result of the invocation