Rollup

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Commercial Component

We suppose that you have already learned what is described in:

If you want to find the right Transformer for your purposes, see Transformers Comparison.

Short Summary

Rollup creates one or more output records from one or more input records.

Component	Same input metadata	Sorted inputs	Inputs	Outputs	Java	CTL
Rollup	-	no	1	1-N	yes	yes

Abstract

Rollup receives potentially unsorted data through single input port, transforms them and creates one or more output records from one or more input records.

Component can sent different records to different output ports as specified by user.

A transformation must be defined. The transformation uses a CTL template for Rollup, implements a RecordRollup interface or inherits from a DataRecordRollup superclass. The interface methods are listed below.

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Ports

Port type	Number	Required	Description	Metadata
Input	0	yes	For input data records	Any(In0)
Output	0	yes	For output data records	Any(Out0)
Output	1-N	no	For output data records	Any(Out1-N)

Rollup Attributes

Attribute	Req	Description	Possible values
Basic
Group key		Key according to which the records are considered to be included into one group. Expressed as the sequence of individual input field names separated from each other by semicolon. See Group Key for more information. If not specified, all records are considered to be members of a single group.
Group accumulator		ID of metadata that serve to create group accumulators. Metadata serve to store values used for transformation of individual groups of data records.	no metadata (default) \| any metadata
Transform	1)	Definition of the transformation written in the graph in CTL or Java.
Transform URL	1)	Name of external file, including path, containing the definition of the transformation written in CTL or Java.
Transform class	1)	Name of external class defining the transformation.
Transform source charset		Encoding of external file defining the transformation.	ISO-8859-1 (default)
Sorted input		By default, records are considered to be sorted. Either in ascending or descending order. Different fields may even have different sort order. If your records are not sorted, switch this attribute to `false`.	true (default) \| false
Equal NULL		By default, records with null values of key fields are considered to be equal. If set to `false`, they are considered to be different from each other.	true (default) \| false

Legend:

1): One of these must specified. Any of these transformation attributes uses a CTL template for Rollup or implements a RecordRollup interface.

See CTL Scripting Specifics or Java Interfaces for Rollup for more information.

See also Defining Transformations for detailed information about transformations.

CTL Scripting Specifics

When you define any of the three transformation attributes, you must specify the way how input should be transformed into output.

Transformations implement a RecordRollup interface or inherit from a DataRecordRollup superclass. Below is the list of RecordRollup interface methods. See Java Interfaces for Rollup for detailed information this interface.

For detailed information about CloudConnect Transformation Language see Part XI, CTL - CloudConnect Transformation Language. (CTL is a full-fledged, yet simple language that allows you to perform almost any imaginable transformation.)

CTL scripting allows you to specify custom transformation using the simple CTL scripting language.

Once you have written your transformation, you can also convert it to Java language code by clicking corresponding button at the upper right corner of the tab.

You can open the transformation definition as another tab of the graph (in addition to the Graph and Source tabs of Graph Editor) by clicking corresponding button at the upper right corner of the tab.

CTL Templates for Rollup

Here is an example of how the Source tab for defining the transformation looks like:

Figure 55.6. Source Tab of the Transform Editor in the Rollup Component (I)

Figure 55.7. Source Tab of the Transform Editor in the Rollup Component (II)

Figure 55.8. Source Tab of the Transform Editor in the Rollup Component (III)

Table 55.5. Functions in Rollup

CTL Template Functions
void init()
Required	No
Description	Initialize the component, setup the environment, global variables
Invocation	Called before processing the first record
Returns	`void`
void initGroup(<metadata name> groupAccumulator)
Required	yes
Input Parameters	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	void
Invocation	Called repeatedly, once for the first input record of each group. Called before updateGroup(groupAccumulator).
Description	Initializes information for specific group.
Example	function void initGroup( companyCustomers groupAccumulator) { groupAccumulator.count = 0; groupAccumulator.totalFreight = 0; }
boolean updateGroup(<metadata name> groupAccumulator)
Required	yes
Input Parameters	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	false (updateTransform(counter,groupAccumulator) is not called) \| true (updateTransform(counter,groupAccumulator) is called)
Invocation	Called repeatedly (once for each input record of the group, including the first and the last record) after the initGroup(groupAccumulator) function has already been called for the whole group.
Description	Updates information for specific group. If any of the input records causes fail of the `updateGroup()` function, and if user has defined another function (`updateGroupOnError()`), processing continues in this `updateGroupOnError()` at the place where `updateGroup()` failed. If `updateGroup()` fails and user has not defined any `updateGroupOnError()`, the whole graph will fail. The `updateGroup()` passes to `updateGroupOnError()` error message and stack trace as arguments.
Example	function boolean updateGroup(companyCustomers groupAccumulator) { groupAccumulator.count++; groupAccumulator.totalFreight = groupAccumulator.totalFreight + $0.Freight; return true; }
boolean finishGroup(<metadata name> groupAccumulator)
Required	yes
Input Parameters	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	true (transform(counter,groupAccumulator) is called) \| false (transform(counter,groupAccumulator) is not called)
Invocation	Called repeatedly, once for the last input record of each group. Called after updateGroup(groupAccumulator) has already been called for all input records of the group.
Description	Finalizes the group information. If any of the input records causes fail of the `finishGroup()` function, and if user has defined another function (`finishGroupOnError()`), processing continues in this `finishGroupOnError()` at the place where `finishGroup()` failed. If `finishGroup()` fails and user has not defined any `finishGroupOnError()`, the whole graph will fail. The `finishGroup()` passes to `finishGroupOnError()` error message and stack trace as arguments.
Example	function boolean finishGroup(companyCustomers groupAccumulator) { groupAccumulator.avgFreight = groupAccumulator.totalFreight / groupAccumulator.count; return true; }
integer updateTransform(integer counter, <metadata name> groupAccumulator)
Required	yes
Input Parameters	`integer counter` (starts from 0, specifies the number of created records. should be terminated as shown in example below. Function calls end when `SKIP` is returned.)
Input Parameters	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	Integer numbers. See Return Values of Transformations for detailed information.
Invocation	Called repeatedly as specified by user. Called after updateGroup(groupAccumulator) returns `true`. The function is called until `SKIP` is returned.
Description	It creates output records based on individual record information. If any part of the `transform()` function for some output record causes fail of the `updateTransform()` function, and if user has defined another function (`updateTransformOnError()`), processing continues in this `updateTransformOnError()` at the place where `updateTransform()` failed. If `updateTransform()` fails and user has not defined any `updateTransformOnError()`, the whole graph will fail. The `updateTransformOnError()` function gets the information gathered by `updateTransform()` that was get from previously successfully processed code. Also error message and stack trace are passed to `updateTransformOnError()`.
Example	function integer updateTransform(integer counter, companyCustomers groupAccumulator) { if (counter >= Length) { clear(customers); return SKIP; } $0.customers = customers[counter]; $0.EmployeeID = $0.EmployeeID; return ALL; }
integer transform(integer counter, <metadata name> groupAccumulator)
Required	yes
Input Parameters	`integer counter` (starts from 0, specifies the number of created records. should be terminated as shown in example below. Function calls end when `SKIP` is returned.)
Input Parameters	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	Integer numbers. See Return Values of Transformations for detailed information.
Invocation	Called repeatedly as specified by user. Called after finishGroup(groupAccumulator) returns `true`. The function is called until `SKIP` is returned.
Description	It creates output records based on all of the records of the whole group. 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 get from previously successfully processed code. Also error message and stack trace are passed to `transformOnError()`.
Example	function integer transform(integer counter, companyCustomers groupAccumulator) { if (counter > 0) return SKIP; $0.ShipCountry = $0.ShipCountry; $0.Count = groupAccumulator.count; $0.AvgFreight = groupAccumulator.avgFreight; return ALL; }
void initGroupOnError(string errorMessage, string stackTrace, <metadata name> groupAccumulator)
Required	no
Input Parameters	`string errorMessage`
	`string stackTrace`
	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	void
Invocation	Called if `initGroup()` throws an exception.
Description	Initializes information for specific group.
Example	function void initGroupOnError( string errorMessage, string stackTrace, companyCustomers groupAccumulator) printErr(errorMessage); }
boolean updateGroupOnError(string errorMessage, string stackTrace, <metadata name> groupAccumulator)
Required	no
Input Parameters	`string errorMessage`
	`string stackTrace`
	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	false (updateTransform(counter,groupAccumulator) is not called) \| true (updateTransform(counter,groupAccumulator) is called)
Invocation	Called if `updateGroup()` throws an exception for a record of the group. Called repeatedly (once for each of the other input records of the group).
Description	Updates information for specific group.
Example	function boolean updateGroupOnError(string errorMessage, string stackTrace, companyCustomers groupAccumulator) { printErr(errorMessage); return true; }
boolean finishGroupOnError(string errorMessage, string stackTrace, <metadata name> groupAccumulator)
Required	no
Input Parameters	`string errorMessage`
	`string stackTrace`
	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	true (transform(counter,groupAccumulator) is called) \| false (transform(counter,groupAccumulator) is not called)
Invocation	Called if `finishGroup()` throws an exception.
Description	Finalizes the group information.
Example	function boolean finishGroupOnError(string errorMessage, string stackTrace, <metadata name> groupAccumulator) { printErr(errorMessage); return true; }
integer updateTransformOnError(string errorMessage, string stackTrace, integer counter, <metadata name> groupAccumulator)
Required	yes
Input Parameters	`string errorMessage`
	`string stackTrace`
	`integer counter` (starts from 0, specifies the number of created records. should be terminated as shown in example below. Function calls end when `SKIP` is returned.)
	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	Integer numbers. See Return Values of Transformations for detailed information.
Invocation	Called if `updateTransform()` throws an exception.
Description	It creates output records based on individual record information
Example	function integer updateTransformOnError(string errorMessage, string stackTrace, integer counter, companyCustomers groupAccumulator) { if (counter >= 0) { return SKIP; } printErr(errorMessage); return ALL; }
integer transformOnError(string errorMessage, string stackTrace, integer counter, <metadata name> groupAccumulator)
Required	no
Input Parameters	`string errorMessage`
	`string stackTrace`
	`integer counter` (starts from 0, specifies the number of created records. should be terminated as shown in example below. Function calls end when `SKIP` is returned.)
	`<metadata name> groupAccumulator` (metadata specified by user) If `groupAccumulator` is not defined, `VoidMetadata Accumulator` is used in the function signature.
Returns	Integer numbers. See Return Values of Transformations for detailed information.
Invocation	Called if `transform()` throws an exception.
Description	It creates output records based on all of the records of the whole group.
Example	function integer transformOnError(string errorMessage, string stackTrace, integer counter, companyCustomers groupAccumulator) { if (counter >= 0) { return SKIP; } printErr(errorMessage); return ALL; }
string getMessage()
Required	No
Description	Prints error message specified and invocated by user
Invocation	Called in any time specified by user (called only when either `updateTransform()`, `transform()`, `updateTransformOnError()`, or `transformOnError()` 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

	Important
Input records or fields Input records or fields are accessible within the `initGroup()`, `updateGroup()`, `finishGroup()`, `initGroupOnError()`, `updateGroupOnError()`, and `finishGroupOnError()` functions. They are also accessible within the `updateTransform()`, `transform()`, `updateTansformOnError()`, and `transformOnError()` functions. Output records or fields Output records or fields are accessible within the `updateTransform()`, `transform()`, `updateTansformOnError()`, and `transformOnError()` functions. Group accumulator Group accumulator is accessible within the `initGroup()`, `updateGroup()`, `finishGroup()`, `initGroupOnError()`, `updateGroupOnError()`, and `finishGroupOnError()` functions. It is also accessible within the `updateTransform()`, `transform()`, `updateTansformOnError()`, and `transformOnError()` functions. All of the other CTL template functions allow to access neither inputs nor outputs or `groupAccumulator`.

Input records or fields
Input records or fields are accessible within the initGroup(), updateGroup(), finishGroup(), initGroupOnError(), updateGroupOnError(), and finishGroupOnError() functions.
They are also accessible within the updateTransform(), transform(), updateTansformOnError(), and transformOnError() functions.
Output records or fields
Output records or fields are accessible within the updateTransform(), transform(), updateTansformOnError(), and transformOnError() functions.
Group accumulator
Group accumulator is accessible within the initGroup(), updateGroup(), finishGroup(), initGroupOnError(), updateGroupOnError(), and finishGroupOnError() functions.
It is also accessible within the updateTransform(), transform(), updateTansformOnError(), and transformOnError() functions.
All of the other CTL template functions allow to access neither inputs nor outputs or groupAccumulator.

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

Java Interfaces for Rollup

The transformation implements methods of the RecordRollup interface and inherits other common methods from the Transform interface. See Common Java Interfaces.

Following is the list of the RecordRollup interface methods:

void init(Properties parameters, DataRecordMetadata inputMetadata, DataRecordMetadata accumulatorMetadata, DataRecordMetadata[] outputMetadata)
Initializes the rollup transform. This method is called only once at the beginning of the life-cycle of the rollup transform. Any internal allocation/initialization code should be placed here.

void initGroup(DataRecord inputRecord, DataRecord groupAccumulator)
This method is called for the first data record in a group. Any initialization of the group "accumulator" should be placed here.

void initGroupOnError(Exception exception, DataRecord inputRecord, DataRecord groupAccumulator)
This method is called for the first data record in a group. Any initialization of the group "accumulator" should be placed here. Called only if initGroup(DataRecord, DataRecord) throws an exception.

boolean updateGroup(DataRecord inputRecord, DataRecord groupAccumulator)
This method is called for each data record (including the first one as well as the last one) in a group in order to update the group "accumulator".

boolean updateGroupOnError(Exception exception, DataRecord inputRecord, DataRecord groupAccumulator)
This method is called for each data record (including the first one as well as the last one) in a group in order to update the group "accumulator". Called only if updateGroup(DataRecord, DataRecord) throws an exception.

boolean finishGroup(DataRecord inputRecord, DataRecord groupAccumulator)
This method is called for the last data record in a group in order to finish the group processing.

boolean finishGroupOnError(Exception exception, DataRecord inputRecord, DataRecord groupAccumulator)
This method is called for the last data record in a group in order to finish the group processing. Called only if finishGroup(DataRecord, DataRecord) throws an exception.

int updateTransform(int counter, DataRecord inputRecord, DataRecord groupAccumulator, DataRecord[] outputRecords)
This method is used to generate output data records based on the input data record and the contents of the group "accumulator" (if it was requested). The output data record will be sent to the output when this method finishes. This method is called whenever the boolean updateGroup(DataRecord, DataRecord) method returns true. The counter argument is the number of previous calls to this method for the current group update. See Return Values of Transformations for detailed information about return values and their meaning.

int updateTransformOnError(Exception exception, int counter, DataRecord inputRecord, DataRecord groupAccumulator, DataRecord[] outputRecords)
This method is used to generate output data records based on the input data record and the contents of the group "accumulator" (if it was requested). Called only if updateTransform(int, DataRecord, DataRecord) throws an exception.

int transform(int counter, DataRecord inputRecord, DataRecord groupAccumulator, DataRecord[] outputRecords)
This method is used to generate output data records based on the input data record and the contents of the group "accumulator" (if it was requested). The output data record will be sent to the output when this method finishes. This method is called whenever the boolean finishGroup(DataRecord, DataRecord) method returns true. The counter argument is the number of previous calls to this method for the current group. See Return Values of Transformations for detailed information about return values and their meaning.

int transformOnError(Exception exception, int counter, DataRecord inputRecord, DataRecord groupAccumulator, DataRecord[] outputRecords)
This method is used to generate output data records based on the input data record and the contents of the group "accumulator" (if it was requested). Called only if transform(int, DataRecord, DataRecord) throws an exception.