Normalizer

Short Description

Normalizer creates one or more output records from each single input record. Input records do not have to be sorted.

COMPONENT	SAME INPUT METADATA	SORTED INPUTS	INPUTS	OUTPUTS	JAVA	CTL	AUTO-PROPAGATED METADATA
Normalizer	-	x	1	1	✓	✓	x

Ports

PORT TYPE	NUMBER	REQUIRED	DESCRIPTION	METADATA
Input	0	✓	For input data records	Any1
Output	0	✓	For normalized data records	Any2

Metadata

Normalizer does not propagate metadata. Normalizer does not have metadata templates. Normalizer does not require any specific metadata fields.

Normalizer Attributes

ATTRIBUTE	REQ	DESCRIPTION	POSSIBLE VALUES
BASIC
Normalize	[1]	The definition of the way how records should be normalized, written in the graph in CTL or Java.
Normalize URL	[1]	The name of an external file, including the path, containing the definition of the way how records should be normalized written in CTL or Java.
Normalize class	[1]	The name of an external class defining the way how records should be normalized.
Normalize source charset		Encoding of an external file defining the transformation. The default encoding depends on DEFAULT_SOURCE_CODE_CHARSET in defaultProperties.	E.g. UTF-8
DEPRECATED
Error actions		Definition of the action that should be performed when the specified transformation returns some Error code. See Return Values of Transformations.
Error log		The URL of the file to which error messages for specified Error actions should be written. If not set, they are written to Console.

[1] One of these must specified.

Details

Normalizer requires transformation. The transformation can be defined in CTL (see CTL Interface below) or in Java (see Java Interface below). The transformation is defined using several functions. Each of them has its own purpose. The order of function calls is depicted in diagram below.

The number of calls of transform() function depends on the result of the count() (or countOnError()) function.

CTL Interface

The transformation written in CTL uses a CTL template for Normalizer. Only the functions count() and transform() are mandatory. Other functions are optional.

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

CTL Templates for Normalizer

CTL TEMPLATE FUNCTIONS	boolean init()
Required	No
Description	Initializes the component, sets up the environment and global variables
Invocation	Called before processing the first record
Returns	true | false (in case of false graph fails)

CTL TEMPLATE FUNCTIONS	integer count()
Required	Yes
Input Parameters	None
Returns	The returned number defines the number of new output records that will be created by the transform() function. If the count() function returns 0, the subsequent call of transform() is skipped (transform() is called zero times).
Invocation	Called repeatedly, once for each input record
Description	For each input record it generates the number of output records that will be created from this input. If count() fails and user has not defined any countOnError(), the whole graph will fail. If any of the input records causes the count() function to fail, and if user has defined another function (countOnError()), processing continues in this countOnError() at the place where count() failed. The countOnError() function gets the information gathered by count() that was received from previously successfully processed input records. Also the error message and stack trace are passed to countOnError().
Example	See here below

function integer count() {
   customers = split($in.0.customers,"-");
   return length(customers);
}

CTL TEMPLATE FUNCTIONS	integer transform()
Required	Yes
Input Parameters	integer idx integer numbers from 0 to count-1 (Here count is the number returned by the count() function.)
Returns	Integer numbers. The number corresponds to the return value of transformation. For detailed information, see Return Values of Transformations.
Invocation	Called repeatedly, once for each output record. The number of calls is defined by return value of function count().
Description	Creates output records. If transform() fails and the user has not defined any transformOnError(), the whole graph will fail. 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. The transformOnError() function gets the information gathered by transform() that was received from previously successfully processed code. Also the error message and stack trace are passed to transformOnError().
Example	See here below

function integer transform(integer idx) {
   myString = customers[idx];
   $out.0.OneCustomer = str2integer(myString);
   $out.0.RecordNo = $in.0.recordNo;
   $out.0.OrderWithinRecord = idx;
   return OK;
}

CTL TEMPLATE FUNCTIONS	void clean()
Required	No
Input Parameters	None
Returns	void
Invocation	Called repeatedly, once for each input record. The function is called after the corresponding call(s) of transform() function.
Description	Returns the component to the initial settings.
Example	See here below

function void clean() {
   clear(customers);
}

CTL TEMPLATE FUNCTIONS	integer countOnError(string errorMessage, string stackTrace)
Required	No
Input Parameters	string errorMessage string stackTrace
Returns	The returned number defines the number of new output records that will be created by the transform() function. If the count() function returns 0, the subsequent call of transform() is skipped.
Invocation	Called if count() throws an exception.
Description	For each input record it generates the number of output records that will be created from this input. If any of the input records causes fail of the count() function, and if user has defined another function (countOnError()), processing continues in this countOnError() at the place where count() failed.
Example	See here below

function integer countOnError(
                  string errorMessage,
                  string stackTrace) {
   printErr(errorMessage);
   return 1;
}

CTL TEMPLATE FUNCTIONS	integer transformOnError(string errorMessage, string stackTrace, integer idx)
Required	No
Input Parameters	string errorMessage string stackTrace integer idx
Returns	Integer numbers. For more information, see Return Values of Transformations.
Invocation	Called if transform() throws an exception.
Description	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. The transformOnError() function gets the information gathered by transform() that was received from previously successfully processed code. Also the error message and stack trace are passed to transformOnError().
Example	See here below

function integer transformOnError(
                  string errorMessage,
                  string stackTrace,
                  integer idx) {
   printErr(errorMessage);
   printErr(stackTrace);
   $out.0.OneCustomerOnError = customers[idx];
   $out.0.RecordNo = $recordNo;
   $out.0.OrderWithinRecord = idx;
   return OK;
}

CTL TEMPLATE FUNCTIONS	string getMessage()
Required	No
Description	Prints the error message specified and invoked by the user.
Invocation	Called in any time specified by the user (called only when either count(), transform(), countOnError(), or transformOnError() returns value less than or equal to -2).
Returns	string

CTL TEMPLATE FUNCTIONS	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.

CTL TEMPLATE FUNCTIONS	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.

Access to input and output fields

Input records or fields Input records or fields are accessible within the count(), countOnError(),transform() and transformOnError() functions only.

Output records or fields Output records or fields are accessible within the transform() and transformOnError() functions only.

Warning: All of the other CTL template functions allow to access neither inputs nor outputs. Remember that if you do not hold these rules, NPE will be thrown!

Java Interface

The transformation implements methods of the RecordNormalize interface and inherits other common methods from the Transform interface. See Common Java Interfaces. Following are the methods of the RecordNormalize interface:

• boolean init(Properties parameters, DataRecordMetadata sourceMetadata, DataRecordMetadata targetMetadata) Initializes normalize class/function. This method is called only once at the beginning of normalization process. Any object allocation/initialization should happen here.

• int count(DataRecord source) Returns the number of output records which will be created from specified input record.

• int countOnError(Exception exception, DataRecord source) Called only if count(DataRecord) throws an exception.

• int transform(DataRecord source, DataRecord target, int idx) idx is a sequential number of output record (starting from 0). For detailed information about return values and their meaning, see Return Values of Transformations. In Normalizer, only ALL, 0, SKIP, and Error codes have some meaning.

• int transformOnError(Exception exception, DataRecord source, DataRecord target, int idx) Called only if transform(DataRecord, DataRecord, int) throws an exception.

• void clean() Finalizes current round/clean after current round - called after the transform method was called for the input record.

Examples

Converting multivalue fields to multiple records

Input records contain group name and list of users of the group. Convert records into tuples having group name and one username.

accounting  | [johnsmith, elisabethtaylor]
development | [georgegreen, janegreen, peterbrown]

Solution Define the transformation using **Normalize **attribute.

//#CTL2

function integer count() {
    return length($in.0.users);
}

function integer transform(integer idx) {
    $out.0.group = $in.0.group;
    $out.0.user = $in.0.users[idx];
    return OK;
}

Normalizer returns following records:

accounting |johnsmith
accounting |elisabethtaylor
development|georgegreen
development|janegreen
development|peterbrown

Best Practices

If the transformation is specified in an external file (with Normalize URL), we recommend users to explicitly specify Normalize source charset.

See also

Denormalizer Rollup Common Properties of Components Specific attribute types Common Properties of Transformers Defining Transformations