Normalizer
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| Short Description |
| Ports |
| Metadata |
| Normalizer Attributes |
| Details |
| CTL Interface |
| Java Interface |
| Examples |
| Best Practices |
| See also |
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 | - |  | 1 | 1 |  | | |
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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 any metadata template.
Normalizer does not require any specific metadata fields.
Normalizer Attributes
| Attribute | Req | Description | Possible values |
|---|---|---|---|
| Basic | |||
| Normalize | [1] | Definition of the way how records should be normalized written in the graph in CTL or Java. | |
| Normalize URL | [1] | Name of external file, including path, containing the definition of the way how records should be normalized written in CTL or Java. | |
| Normalize class | [1] | Name of external class defining the way how records should be normalized. | |
| Normalize source charset |
Encoding of 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 | 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 it's own purpose. The order of function calls is depicted in diagram below.
Figure 55.3. Normalizer code workflow
Number of calls of transform() function depends on
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 optionals.
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 55.4. Functions in Normalizer
| 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 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
If the |
| 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 If any of the input records causes fail of the |
| 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 |
It creates output records. If If any part of the |
| 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 |
| 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 |
string stackTrace | |
| Returns |
The returned number defines the number of new output records that will be created by the
If the |
| 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 |
| 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. 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
The |
| 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 error message specified and invoked by user |
| Invocation | Called in any time specified by 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 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]](figures/warning.png) | 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.
See Public Clover 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)idxis a sequential number of output record (starting from 0). See Return Values of Transformations for detailed information about return values and their meaning. In Normalizer, onlyALL,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.