When we defined the BLDRAPPL application in AppMaster Buider, we created a global user rule object named CALCINV. Because CALCINV is global, all programs generated from our application automatically include the CALCINV rule. In this tutorial, we populate the user rule object with code. In a later tutorial, we call the rule from Online Express.
We use the following code to populate the CALCINV user rule. We have added line numbers so that each line is easily identified for the purpose of discussing what this user rule does:
0001 % DEFINE $CALC-INV-VALUE( &PRE, 0002 % ... &PRICE-FLD, &UNITS-FLD ) 0003 % IF NOT &DEFINED( &PART-INVENTORY-SEEN ) 0004 % &PART-INVENTORY-SEEN = 1 0005 % SET WORKING-STORAGE 0006 &08+01 WS-INVENTORY-VALUE PIC S9(08)V99. 0007 % SET PROCEDURE 0008 % END 0009 IF &PRE+-&PRICE-FLD = ZERO 0010 ... OR &PRE+-&UNITS-FLD = ZERO 0011 MOVE ZERO TO WS-INVENTORY-VALUE 0012 ELSE 0013 COMPUTE WS-INVENTORY-VALUE = 0014 ... &PRE+-&PRICE-FLD 0015 ... * &PRE+-&UNITS-FLD 0016 % END
% DEFINE $CALC-INV-VALUE( &PRE, % ... &PRICE-FLD, &UNITS-FLD )
These lines identify the name of the rule, $CALC-INV-VALUE, and three parameters, &PRE, &PRICE-FLD, and &UNITS-FLD. All user rule names begin with a dollar sign ($). Values for the three parameters must be supplied when the rule is called. In this case, the user rule is looking for a prefix, which in this case represents a prefix for the Working-Storage field names, the remainder of the name of a Working-Storage field that contains the price of an item (&PRICE-FIELD), and remainder of the name of the Working-Storage field that contains the number of units being ordered (&UNITS-FLD).
The two lines here comprise one logical line of code, continued on a second line using the % sign to identify the line as Customizer code, and ellipses (...) to indicate the continuation.
0003 % IF NOT &DEFINED( &PART-INVENTORY-SEEN ) 0004 % &PART-INVENTORY-SEEN = 1 0005 % SET WORKING-STORAGE 0006 &08+01 WS-INVENTORY-VALUE PIC S9(08)V99. 0007 % SET PROCEDURE 0008 % END
Here we have an IF structure comprised of MFG structures. MFG structures are identified by the percent (%) sign in column 8 of each line. This % IF structure does the following:
0003 % IF NOT &DEFINED( &PART-INVENTORY-SEEN ) 0004 % &PART-INVENTORY-SEEN = 1
If the parameter &PART-INVENTORY-SEEN is not defined, &PART-INVENTORY-SEEN is defined and its value set to 1. If this Customizer rule is encountered again in the generation process, the MFG will not execute the remainder of the % IF structure, preventing the code it generates from being generated twice.
0005 % SET WORKING-STORAGE
The MFG is set to create a Working-Storage structure. Because this code appears in our program in the Procedure Division, it is necessary to temporarily assign the code generator back to Working Storage so that the structure created appears in the proper section of the generated code.
0006 &08+01 WS-INVENTORY-VALUE PIC S9(08)V99.
In the Working-Storage section, on a new line beginning in column 8, the MFG writes an 01-level data structure for WS-INVENTORY-VALUE. This data structure holds the value that is eventually sent to the INV-VALUE screen field.
0007 % SET PROCEDURE
0008 % END
0009 IF &PRE+-&PRICE-FLD = ZERO 0010 ... OR &PRE+-&UNITS-FLD = ZERO 0011 MOVE ZERO TO WS-INVENTORY-VALUE 0012 ELSE 0013 COMPUTE WS-INVENTORY-VALUE = 0014 ... &PRE+-&PRICE-FLD 0015 ... * &PRE+-&UNITS-FLD
This IF/ELSE structure is comprised of COBOL syntax, using the variables defined in lines 0001 and 0002 of this user rule. This IF component of the structure checks to see if the value in the Working-Storage fields that store the price of an item or the number of units is zero (0). If so, zero is moved to the WS-INVENTORY-VALUE field. If the value in either field is not zero, the ELSE component of the structure calculates the value of the inventory and puts that value into the WS-INVENTORY-VALUE field.
The MFG writes this IF/ELSE structure to the generated program, substituting the parameter values you provide when you call the user rule.
0016 % END
Indicates the end of the user rule.
Before attempting this tutorial, you must complete:
If you have closed Enterprise Developer, start it; then open the AppMaster Builder perspective.
% DEFINE $CALC-INV-VALUE( &PRE, % ... &PRICE-FLD, &UNITS-FLD ) % IF NOT &DEFINED( &PART-INVENTORY-SEEN ) % &PART-INVENTORY-SEEN = 1 % SET WORKING-STORAGE &08+01 WS-INVENTORY-VALUE PIC S9(08)V99. % SET PROCEDURE % END IF &PRE+-&PRICE-FLD = ZERO ... OR &PRE+-&UNITS-FLD = ZERO MOVE ZERO TO WS-INVENTORY-VALUE ELSE COMPUTE WS-INVENTORY-VALUE = ... &PRE+-&PRICE-FLD ... * &PRE+-&UNITS-FLD % END
This completes the tutorial. Next, please complete Tutorial: Map Screen Fields.