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FOCUS provides you with several ways to develop a Maintain procedure:

• Event-driven development. Most data source procedures are event-driven: a user performs an event—such as entering data, clicking a button, or selecting a list item—and this event triggers some logic. You can develop such procedures most effectively if you follow the same model: first identify an action that the user needs to perform, then develop the user interface to enable it, and finally code the logic that performs the action.

  For example, consider a data entry procedure in which the user needs to enter data and write it to the data source. You can create a Winform with entry fields and a command button, then assign a trigger with a function to the button, and finally code the function to update the data source. You perform all of these steps seamlessly within the Winform Painter. The Painter even generates some of the code for you.

• Process-driven development. You can develop the procedure's data source logic separately from its user interface logic: code the Maintain procedure using an editor such as TED, and develop the Winforms using the Winform Painter.

Because each Maintain procedure must reside in its own FOCEXEC, you cannot create ad hoc procedures at the FOCUS command prompt. For more information about using the Winform Painter to develop procedures, see Tutorial: Painting a Procedure, and Using the Winform Painter. For more information about using TED, see the Overview and Operating Environments manual.

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Each Maintain procedure is stored in two files:

• FOCEXEC. The procedure's business logic is stored in a FOCEXEC file. The file should contain a single Maintain request: it should not contain multiple requests, and should not contain other elements such as Dialogue Manager commands or SET commands. For more information about FOCEXECs, see the Developing Applications manual.
• WINFORMS. Most of the procedure's presentation logic is stored as Winforms in a WINFORMS file. You create and edit Winforms using the Winform Painter. You should make changes to WINFORMS files using the Painter only, and not attempt to edit them directly: all changes made outside the Painter are lost the next time the file is edited in the Painter. The file is stored in a PDS allocated to ddname WINFORMS; if you wish you can concatenate several data sets together. If you neglect to allocate the WINFORMS PDS, FOCUS will dynamically allocate it for you. The following lines show sample commands for allocating WINFORMS under TSO:

  • In z/OS

    ALLOC F(WIcoNFORMS) DA(WINFORMS.DATA) SHR

    and under MSO or z/OS FOCUS:

    DYNAM ALLOC FILE WINFORMS DATASET user.WINFORMS.DATA

    The PDS's DCB attributes are RECFM=FB, LRECL=80, and BLKSIZE, a multiple of LRECL. When FOCUS searches for a WINFORMS file, it first looks for ddname WINFORMS. If ddname WINFORMS is not allocated, FOCUS attempts to allocate the data set prefix.WINFORMS.data to ddname WINFORMS. If the specified member is not there, FOCUS displays an error message.

Each procedure has one FOCEXEC file and—if it has a user interface—one WINFORMS file. The two files share the same member name. For example, the Payroll procedure is stored in the member PAYROLL of the FOCEXEC PDS and member PAYROLL in the WINFORMSPDS.

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FOCUS provides you with the flexibility of executing a Maintain procedure from different kinds of environments, and employing different control techniques.

In addition, you can accelerate execution by compiling a procedure using the COMPILE command. You may wish to work with the procedure in its regular form while you are developing it, and then—once it is finished—compile it to make it faster.

You can run a procedure from the following environments:

• The FOCUS command prompt. You can run a Maintain procedure at the FOCUS command prompt by issuing the EXEC command (for uncompiled procedures) or the RUN command (for compiled procedures).
• Maintain procedures. You can run one Maintain procedure from another by issuing the CALL command in the parent procedure. If the child procedure exists in both compiled and uncompiled form, Maintain executes the compiled version. You can pass data between the two procedures.
• Other types of procedures. You can run a Maintain procedure from a non-Maintain procedure by issuing the EXEC command (for uncompiled procedures) or the RUN command (for compiled procedures) in the calling procedure. You can issue the command in the calling procedure's FOCEXEC file, or in an Execution window in the calling procedure's FMU or TRF file. When using EXEC you can pass data to the Maintain procedure.

  Alternatively, you can run an uncompiled Maintain procedure by naming it in a Menu window (using the Window Painter's FOCEXEC Name option) in the calling procedure's FMU or TRF file.

The EXEC command, Execution and Menu windows, and the Window Painter are all described in the Developing Applications manual. The CALL, COMPILE, and RUN commands are described in Command Reference.