CTL Templates for Joiners

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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.

Figure 56.1. Source Tab of the Transform Editor in Joiners

Table 56.2. Functions in Joiners, DataIntersection and Reformat

CTL Template Functions
boolean init()
Required	No
Description	Initialize the component, setup the environment, global variables
Invocation	Called before processing the first record
Returns	`true` \| `false` (in case of `false`, the graph fails)
integer transform()
Required	yes
Input Parameters	none
Returns	Integer numbers. See Return Values of Transformations for detailed information.
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 user has defined another function (`transformOnError()`), processing continues in this `transformOnError()` at the place where `transform()` failed. If `transform()` fails and 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 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)
Required	no
Input Parameters	`string errorMessage`
Input Parameters	`string stackTrace`
Returns	Integer numbers. See Return Values of Transformations for detailed information.
Invocation	Called 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 user has defined another function (`transformOnError()`), processing continues in this `transformOnError()` at the place where `transform()` failed. If `transform()` fails and 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 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()
Required	No
Description	Prints error message specified and invoked by user
Invocation	Called in any time specified by user (called only when `transform()` returns value less than or equal to -2).
Returns	`string`
void preExecute()
Required	No
Input parameters	None
Returns	`void`
Description	May be used to allocate and initialize resources required by the transform. All resources allocated within this function should be released by the `postExecute()` function.
Invocation	Called during each graph run before the transform is executed.
void postExecute()
Required	No
Input parameters	None
Returns	`void`
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
	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
	Remember that if you do not hold these rules, NPE will be thrown!

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