The Handlers are integrations with target applications which plug into the Oracle GoldenGate Java Delivery module. It is the Java Handlers which provide the functionality to push data to integration targets such as JMS or Big Data applications. The Java Adapter properties file is used to configure Java Delivery and Java handlers. To test the configuration, users may use the built-in file handler. Here are some example properties, followed by explanations of the properties (comment lines start with #):

# the list of active handlers
gg.handlerlist=myhandler
# set properties on 'myhandler'
gg.handler.myhandler.type=file
gg.handler.myhandler.format=tx2xml.vm
gg.handler.myhandler.file=output.xml

This property file declares the following:

• Active event handlers. In the example a single event handler is active, called myhandler. Multiple handlers may be specified, separated by commas. For example: gg.handlerlist=myhandler, yourhandler

  Note:

  Starting Oracle GoldenGate for Big Data 23c release, you will be able to specify only a single handler.

• Configuration of the handlers. In the example myhandler is declared to be a file type of handler: gg.handler.myhandler.type=file

  Note:

  See the documentation for each type of handler (for example, the JMS handler or the file writer handler) for the list of valid properties that can be set.

• The format of the output is defined by the Velocity template tx2xml.vm. You may specify your own custom template to define the message format; just specify the path to your template relative to the Java classpath.

This property file is actually a complete example that will write captured transactions to the output file output.xml. Other handler types can be specified using the keywords: jms_text (or jms), jms_map, singlefile (a file that does not roll), and others. Custom handlers can be implemented, in which case the type would be the fully qualified name of the Java class for the handler. Oracle GoldenGate Big Data package also contains built in Big Data target types.