CustomJavaTransformer

By default, CustomJavaTransformer does not propagate metadata. Metadata propagation can be configured using the Metadata propagation algorithm and Metadata propagation algorithm class attributes.

CustomJavaTransformer has no metadata templates.

Requirements on metadata depend on a user-defined transformation.

CustomJavaTransformer attributes

Attribute	Req	Description	Possible values
Basic
Algorithm	^[1]	A runnable transformation in Java defined in the graph.
Algorithm URL	^[1]	A URL to an external file defining a runnable transformation in Java.
Algorithm class	^[1]	An external runnable transformation class.
Advanced
Metadata propagation algorithm		An algorithm for metadata propagation written in Java.
Metadata propagation algorithm class		An external metadata propagation class.
Algorithm source charset		The encoding of the external file defining the transformation. The default encoding depends on DEFAULT_SOURCE_CODE_CHARSET in defaultProperties.	UTF-8

Attribute

Req

Description

Possible values

Basic

Algorithm

^[1]

A runnable transformation in Java defined in the graph.

Algorithm URL

^[1]

A URL to an external file defining a runnable transformation in Java.

Algorithm class

^[1]

An external runnable transformation class.

Advanced

Metadata propagation algorithm

An algorithm for metadata propagation written in Java.

Metadata propagation algorithm class

An external metadata propagation class.

Algorithm source charset

The encoding of the external file defining the transformation.

The default encoding depends on DEFAULT_SOURCE_CODE_CHARSET in defaultProperties.

UTF-8

¹	One of these must be set. These transformation attributes must be specified.

Details

CustomJavaTransformer executes the Java transformation. CustomJavaTransformer is a more specific CustomJavaComponent focused on transforming data.

There are other similar Java components: CustomJavaReader, CustomJavaWriter and CustomJavaComponent. All these components use a transformation defined in Java, they differ in templates being used.

You can use Public CloverDX API in this component. General parts of custom Java components and Public CloverDX API are described in CustomJavaComponent.

Java interfaces for CustomJavaTransformer

A transformation required by the component must extend the org.jetel.component.AbstractGenericTransform class.

The component has the same Java interface as CustomJavaComponent, but it provides a different Java template. See Java interfaces for CustomJavaComponent.

Custom metadata propagation for CustomJavaTransformer

CustomJavaTransformer can propagate metadata using a custom algorithm. Metadata propagation algorithm must extend the org.jetel.component.GenericMetadataProvider class.

The component has the same Java interface as CustomJavaComponent, see Custom metadata propagation for CustomJavaComponent.

Examples

Record Duplicator

Create a component duplicating input records.

Solution

package jk;

import org.jetel.component.AbstractGenericTransform;
import org.jetel.data.DataRecord;
import org.jetel.exception.JetelRuntimeException;

/**
 * This is an example custom transformer. It shows how you can
 * duplicate all incoming records.
 */
public class CustomJavaTransformerExample01 extends AbstractGenericTransform {

    @Override
    public void execute() {
        try {
            DataRecord inRecord = inRecords[0];

            while ((inRecord = readRecordFromPort(0)) != null) {
                writeRecordToPort(0, inRecord);
                writeRecordToPort(0, inRecord);
            }
        } catch (Exception e) {
            throw new JetelRuntimeException(e);
        }
    }
}

Metadata on the input and output port must be the same for this example.

Best practices

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

Compatibility

Version	Compatibility Notice
4.1.0-M1	CustomJavaTransformer is available since 4.1.0-M1. It replaced JavaExecute.
5.3.0	CustomJavaTransformer can now propagate metadata - added new attributes Metadata propagation algorithm and Metadata propagation algorithm class.

Version

Compatibility Notice

4.1.0-M1

CustomJavaTransformer is available since 4.1.0-M1. It replaced JavaExecute.

5.3.0

CustomJavaTransformer can now propagate metadata - added new attributes Metadata propagation algorithm and Metadata propagation algorithm class.

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