Querying a Web service to access content

You can query a Web service using standard Java™ methods.

About this task

By developing a user exit, you can call a web service with the CDC Replication Engine for Event Server. For example, you may be using a web service application to keep track of new customers that have just registered online. You can access content from the Web service application to include it in an XML message you configured with the CDC Replication Engine for Event Server.

For an example of a user exit that queries a Web service, see SampleUserExit3.java located in the samples folder or directory of your installation of the CDC Replication Engine for Event Server.

Procedure

  1. Click Configuration > Datastores.

    Ensure that you are connected to a CDC Replication Engine for Event Server datastore.

  2. Click Configuration > Subscriptions.

    Ensure that you have created a subscription that uses the CDC Replication Engine for Event Server datastore as the target.

  3. Ensure that you have created at least one source table to XML message destination mapping within this subscription.
  4. Select the table mapping and right-click Open Details....
  5. Click the User Exits tab.
  6. Choose Java Class from the User Exit Type box.
  7. In the Class Name box, enter the Java class name of the user exit that implements the UserExitIF interface if you have developed the user exit in Java.
  8. In the Class Name box, type:
    Option Description
    UE1 If it is a stand-alone class
    <Java package>.UE1 If the class is included in a Java package (for example, com.datamirror.interface.UE1). The files you generate from compiling the user exit program must be located in a library or folder that is referenced by the CLASSPATH environment variable.
  9. Enter the parameters that you want to make available to the user exit program in the Parameter box.

    You can access the parameters in the Java class by invoking the getParameter() method during the initialization process. There are no conventions for specifying the parameters. The values you type in this box are free-form. The string of parameter values cannot exceed 255 characters in length.

  10. Enable the Before or After check box for one or more of the following operations:
    Insert
    The CDC Replication Engine for Event Server runs the user exit before or after applying an insert operation to a table you have staged, before or after applying an insert operation to a JMS message destination, or both.
    Update
    The CDC Replication Engine for Event Server runs the user exit before or after applying an update operation to a table you have staged, before or after applying an update operation to a JMS message destination, or both.
    Delete
    The CDC Replication Engine for Event Server runs the user exit before or after applying a delete operation to a table you have staged, before or after applying a delete operation to a JMS message destination, or both.
    Refresh
    The CDC Replication Engine for Event Server runs the user exit before or after applying a refresh operation to a table you have staged, before or after applying a refresh operation to a JMS message destination, or both.
    Truncate
    The CDC Replication Engine for Event Server runs the user exit before or after applying a truncate operation to a table you have staged, before or after applying a truncate operation to a JMS message destination, or both.
  11. Click Save.

    You can start mirroring on the subscription that contains the source table assigned to a JMS message destination. The user exit program will set the new destination before the CDC Replication Engine for Event Server applies the operation to a JMS message destination.