CTL Templates for Joiners

This transformation template is used in every Joiner and also in Reformat and DataIntersection.

Here is an example of how the Source tab for defining the transformation in CTL looks.

Source Tab of the Transform Editor in Joiners

Figure 58.1. Source Tab of the Transform Editor in Joiners


Table 58.2. Functions in Joiners, DataIntersection and Reformat

CTL Template Functions
boolean init()
RequiredNo
DescriptionInitialize the component, setup the environment, global variables.
InvocationCalled before processing the first record
Returns

true | false (in case of false, the graph fails)

integer transform()
Requiredyes
Input Parametersnone
Returns

Integer numbers. For detailed information, see Return Values of Transformations.

Invocation

Called repeatedly for each set of joined or intersected input records (Joiners and DataIntersection) and for each input record (Reformat).

Description

Allows you to map input fields to the output fields using a script. If any part of the transform() function for some output record causes fail of the transform() function, and if the user has defined another function (transformOnError()), processing continues in this transformOnError() at the place where transform() failed. If transform() fails and the user has not defined any transformOnError(), the whole graph will fail. The transformOnError() function gets the information gathered by transform() that was gotten from previously successfully processed code. Also an error message and stack trace are passed to transformOnError().

Example
function integer transform() {
   $out.0.name = $in.0.name;
   $out.0.address = $in.0.city + $in.0.street + $in.0.zip;
   $out.0.country = toUpper($in.0.country);
   return ALL;
}
integer transformOnError(string errorMessage, string stackTrace, integer idx)
Requiredno
Input Parametersstring errorMessage
string stackTrace
Returns

Integer numbers. For detailed information, see Return Values of Transformations.

InvocationCalled if transform() throws an exception.
Description It creates output records. If any part of the transform() function for some output record causes fail of the transform() function, and if the user has defined another function (transformOnError()), processing continues in this transformOnError() at the place where transform() failed. If transform() fails and the user has not defined any transformOnError(), the whole graph will fail. The transformOnError() function gets the information gathered by transform() that was gotten from previously successfully processed code. Also an error message and stack trace are passed to transformOnError().
Example
function integer transformOnError(
                       string errorMessage, 
                       string stackTrace) {
   $in.0.name = $in.0.name;
   $in.0.address = $in.0.city + $in.0.street + $in.0.zip;
   $in.0.country = "country was empty";
   printErr(stackTrace);
   return ALL;
}
string getMessage()
RequiredNo
DescriptionPrints an error message specified and invoked by user.
Invocation

Called in any time specified by the user (called only when transform() returns value less than or equal to -2).

Returnsstring
void preExecute()
RequiredNo
Input parametersNone
Returnsvoid
Description

May be used to allocate and initialize resources required by the transformation. All resources allocated within this function should be released by the postExecute() function.

InvocationCalled during each graph run before the transform is executed.
void postExecute()
RequiredNo
Input parametersNone
Returnsvoid
Description

Should be used to free any resources allocated within the preExecute() function.

Invocation

Called during each graph run after the entire transform was executed.


[Important]Important
  • Input records or fields and output records or fields

    Both inputs and outputs are accessible within the transform() and transformOnError() functions only.

  • All of the other CTL template functions allow to access neither inputs nor outputs.

[Warning]Warning

Remember that if you do not hold these rules, NPE will be thrown.