Appendix G: Menu System Operation

When running the menu system has the following structure:-

A session starts by activating MNU_0001, the logon screen, which asks the user to enter a user ID and a password. These are validated by service component MNH_H001 which performs the following steps:-

Retrieve all control options set by screen MNU_0070U.
If session logging is turned ON then create a new SESSION record by using the next available session id as the primary key.
Validate the User ID and password, returning to the logon screen if there are any errors.
Check that the user has not been disabled.
If the password needs to be changed then inform the logon screen so that it can activate screen MNU_0021U automatically.
Read the contents of MNU_TRAN_ACCESS into memory so that a user's access to any transaction can be validated without going to the database again. Note that if any changes are subsequently made to the user's access profile they will not be effective until the user next logs on.
The MNU_USER record is updated as follows:-
- LOGON_DATE and LOGON_TIME are set.
- PASSWORD_COUNT is incremented.
- IN_USE is set ON.

If this validation is successful MNU_0001 will call MNU_0090L2 in case there are other active sessions for the same user ID. Unless the ALLOW MULTIPLE LOGONS switch in MNU_0070U is set ON the only way for other sessions to be shown here is if they did not terminate normally. Screen MNU_0090L2 gives the user the ability to set any such sessions as 'inactive'.

After MNU_0090L2 is closed the application start-up shell passes control to MNU_0002, the menu screen, so that the starting transaction as identified on the user's Security Class can be activated. This is usually a menu screen, but it may be any transaction within the system. MNU_0002 validates the user's selection by calling MNU_H001 which performs the following steps:-

Check that the transaction actually exists on the menu database.
Check that the transaction has not been disabled.
Check that the user is allowed to access the transaction.
Pass back the details of the selected transaction to the menu screen.

If the transaction is of type 'Online' then MNU_0002 will activate the component using details obtained from the menu database:-

VERT_POS and HORIZ_POS are used to position the screen.
EXTRA_PARAMS is added to the parameter string that is passed to the component.
CHILD_PROPERTIES is used when a child screen is activated from that component.
INSTANCE_NAME is used to construct the name for the component instance. This allows multiple instances of the same component to be active at any one time.
INITIAL_VALUES, if defined using screen MNU_0080M, will be added to the parameter string which is passed to the component under the ID of ' $init_values$ '.

If the transaction is of type 'menu' then MNU_0002 will display the list of options that were defined using screen MNU_0050M. Note that any options which are not on the user's access profile will not be shown. Although the user may select a series of menus one after the other only one instance of the menu screen will be used. The screen's contents are cleared and rebuilt for each menu, with a history of menu ID's being maintained so that it is possible to reverse through all the previous selections. If there are no previous menu screens then the standard message '1909 - Do you really want to leave this application? (Y?N)' will be displayed.

When a session ends, either by returning to the logon screen or leaving the application completely, the following will be performed:-

The IN_USE flag on the MNU_USER record will be set OFF.
If session logging is turned ON the SESSION record will either be marked as inactive or deleted depending on the DELETE_AT_LOGOFF switch in MNU_0070U.
The session closedown routine will call the CLOSE form for each application subsystem that was activated during the session.

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