Defining Local Data Interface Modules

To create a Local Data Interface Module (DIM), you must define a class that implements jas.jds.module.LocalDIM interface.  To implement that interface,

• Give a definition for the following method:
  public JASWizardPage getSetupPage()
This method should return a wizard page that will appear on the 'New Job Wizard' if the user selects this DIM.  Use it to prompt the user for whatever setup parameters are relevant to your DIM.  See the documentation on defining wizard pages.
• Give a definition for the following method:
  public void setLocalJobBuilder(LocalJobBuilder ljb)
  LocalJobBuilder is an interface that allows you to interact with the application to create a job.  The definition of this method need do nothing more than copy the argument to a member variable, i.e.:
  this.ljb = ljb;
  Some notes about the LocalJobBuilder interface:
  • The interface has a method setProgressModel() which you can use to set the progress model for the application window.  You do not need to do this, but you may wish to if you want to have the progress displayed as the data source is opened.  Pass as an argument an instance of BoundedRangeModel.   Normally you would use DefaultBoundedRangeModel.
  • The interface has a method setMessage(String) which you can use to show messages on the application window.
  • The interface has a method createJob(String) where you will actually open the job.   The string argument can be anything you define it to be.  It will be the file name if you are reading a file, or an SQL command if reading from a data base, etc.   This string will simply be passed to the method openDataSet() in the LocalDIM, which is described in detail below.
  • You may wish to remember the user's last settings and restore the wizard to those settings the next time it is open.  Use a UserProperties object which you can get as follows:
    UserProperties prop = Application.getApplication().getUserProperties();
• Give a definition for the following method:
  public EventSource openDataSet(String name) throws ModuleException
This method will be called after createJob() is called in the LocalJobBuilder.   It must return an EventSource, which the application will use to access the events in your data set.  See the documentation on defining an EventSource.
• Override the method toString() that your class inherits from java.lang.Object and have it return a suitable description of your DIM.  The Flat File DIM simply has:
  public String toString()
{
    return "Flat file";
}
Whatever this method returns will be displayed as a choice in the local DIM registry.
• The LocalDIM interface implements java.io.Serializable, so you must define a serializable class.  This means that all objects refered to by member variables of your class will be serialized unless marked transient.  Be aware that traisient variables are null when the object is read from disk, so be sure to initialize them in a readObject() method.

To use a local DIM, you must add your class to the Local DIM registry.

Page maintained by Jonas Gifford.   Last updated 01/14/04.