Normalizer

Development > Component reference > Transformers > Normalizer

Short description

Ports

Metadata

Normalizer attributes

Short description

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

Same input metadata	Sorted inputs	Inputs	Outputs	Java	CTL	Auto-propagated metadata
-	⨯	1	1	✓	✓	⨯

Same input metadata

Sorted inputs

Inputs

Outputs

Java

CTL

Auto-propagated metadata

⨯

✓

⨯

Ports

Port type	Number	Required	Description	Metadata
Input	0	✓	For input data records	Any1
Output	0	✓	For normalized data records	Any2

Port type

Number

Required

Description

Metadata

Input

✓

For input data records

Any1

Output

✓

For normalized data records

Any2

Metadata

Normalizer does not propagate metadata.

Normalizer does not have any metadata template.

Normalizer does not require any specific metadata fields.

Normalizer attributes

Attribute Req Description Possible values

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.

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) or in Java (see Java interface).

The transformation is defined using several functions. Each of them has its own purpose. The order of function calls is depicted in diagram below.

Figure 406. Normalizer code workflow

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

CTL interface

CTL Templates for Normalizer

Access to input and output fields

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

Table 72. Functions in Normalizer
CTL Template Functions
boolean init()
Required	No
Description	Initializes the component, sets up the environment, global variables.
Invocation	Called before processing the first record.
Returns	`true` \| `false` (in case of `false` graph fails)
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	`function integer count() { customers = split($in.0.customers,"-"); return length(customers); }`
integer transform(integer idx)
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 number. The number corresponds to the return value of transformation. 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	`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; }`
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	`function void clean() { clear(customers); }`
integer countOnError(string errorMessage, string stackTrace)
Required	no
Input Parameters	`string errorMessage`
Input Parameters	`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	`function integer countOnError( string errorMessage, string stackTrace) { printErr(errorMessage); return 1; }`
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	`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; }`
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`
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 up 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.

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 and Public CloverDX API.

Following are the methods of 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 will return 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.

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Normalizer

Short description

Ports

Metadata

Normalizer attributes

Details

CTL interface

CTL Templates for Normalizer

Access to input and output fields

Input records or fields

Output records or fields

Java interface

Examples

Converting multivalue fields to multiple records

Solution

Best practices

See also