JCX Files: Extending Controls

Files with the extension JCX are WebLogic Workshop Java control extensions. They typically include a collection of method definitions that allow you to easily access a resource such as a database or another enterprise resource.

Note: In previous releases, JCX files were known as CTRL files. CTRL files are still supported.

Types of JCX Files

The contents of a JCX file depend on the type of control the file extends. JCX files can represent the following types of controls:

Database control: used to access a database from your web service. To learn more about Database Controls, see Database Control.
EJB control: used to access an existing Enterprise JavaBean (EJB) from your web service. To learn more about EJB Controls, see EJB Control.
JMS control: used to access an existing Java Message Service (JMS) queue or topic from your web service. To learn more about JMS Controls, see JMS Control.
Web Service control: used to communicate with another web service from your service. Web Service Control.
Extensible custom control: Advanced users of WebLogic Workshop can create custom controls that are extensible in the same way built-in controls are extensible. To learn more, consult the documentation for the Control Developer's Kit.

For more information on WebLogic Workshop's built-in controls, see Using WebLogic Built-In Controls.

Using Existing JCX Files

In some cases, you may use an existing JCX file that was produced by another member of your team or another organization. For example, if many web services will use the same database, a single author might create a Database control extension (JCX file) that describes the interface to the database. Then multiple web service authors might use that JCX file to create a Database Control in their service and use it to access the common database. The same situation can occur for all of the control types.

Generating a JCX File

Whenever you create a control while editing a web service or other container, WebLogic Workshop generates a JCX file to contain a local representation of the control. The following are examples of situations in which a JCX file will be generated:

When you create a new Database control: WebLogic Workshop generates a new JCX file to hold the Database control extensions definition. When you add methods to the Database control via the IDE, you are adding methods to the JCX file.
When you add a Web Service control to access a web service based on the service's WSDL file: you can generate a Web Service control JCX file from the WSDL file, then use the new Web Service control from any control container.

For more information on WSDL files, see WSDL Files.

For more information on Web Service controls, see Web Service Control.

Note: You should not use a Web Service control to invoke a web service that resides in the same application. Invoking a web service via a Web Service control means marshalling the method parameters into a SOAP message on the calling end and unmarshalling the SOAP message on the receiving end, then again for the method return value. This is very inefficient when the invocation is local. You would usually be tempted to invoke one web service from another if the called web service included business logic you want to access from the calling web service.

In general, you should place business logic in custom Java controls instead of in web services. This allows you to access the business logic from various contexts in the application (web services, other controls, page flows) without incurring the cost of data marshalling and unmarshalling. Web Service controls should only be used to invoke web services that are truly external to your application.