USER DEFINED PROPERTIES(VARIABLES)

          User Defined Property(UDP)  is a property that is defined when you construct a message flow by using the message flow editor.

          This property is used by the ESQL or JAVA program inside the message flow nodes, such as compute node.
 
          UDP is a configurable property defined on the message flow itself. UDP helps us to creating custom variables of which the values can be changed with out re-touching the code.

Note:- set at run time to dynamically change the behavior of the message flow.

         The advantage of UDP is that their values can be changed by operational staff(production) at deployment in run-time.  you do not need to change your application programs or with out having to change the code at the message flow node level.

UDP defined at 3 levels:-

1. In ESQL/JAVA code :-   Define User Defined Properties  in ESQL by using a DECLARE statement                                                   with the EXTERNAL keyword.
                   
syntax:-       DECLARE  broker  EXTERNAL  CHARACTER;

2.Message flow editor's TAB:- You also have the option of defining & giving initial values to same user defined properties. use the User Defined Properties tab at the bottom of the Edit window.