IBM Integration Bus - Filter Node

Filter Node
The “Filter” node is the simplest of the routing nodes and provides a simple “If-Then-Else” routing mechanism within a Message Flow. The “Filter” node is an ESQL node. The ESQL executed in this node must terminate with an ESQL RETURN statement. This statement must return a Boolean value. The route taken from this node depends upon the value of the RETURN statement.
This node has four output terminals. These terminals are:

•  Failure (A failure in the ESQL code)
• True (ESQL code returns a “True” value)
• False (ESQL code returns a “False” value)
• Unknown (ESQL code returns a “NULL” value or does not “RETURN” a boolean)

Note: The “Filter” node propagates an unchanged input message to an output terminal. If you are referring to the input message to interrogate its contents in a Database or Filter node, use correlation name Body to refer to the start of the message. Body is equivalent to Root followed by the parser name (for example, Root.XMLNS), which you can use if you prefer. You cannot use the Body correlation name in a DatabaseInput node.

You must use these different correlation names because there is only one message to which to refer in a Database or Filter node; you cannot create an output message in these nodes. Use a Compute node to create an output message.

Example:

CREATE FILTER MODULE HTTPInputMessageFlow_Filter

    CREATE FUNCTION Main() RETURNS BOOLEAN

    BEGIN

        

        DECLARE space1 NAMESPACE 'namespace1';

        IF Body.space1:root.space1:example = 'ABCDE' THEN

            RETURN TRUE;

        ELSE

            RETURN FALSE;

        END IF;

    END;

END MODULE;