NOTE: You can use REDEFINES to create client operations that generate Java-based beans using the Attachmate ITask interface. REDEFINES are not supported when generating ICA task files. Information for processing REDEFINE fields at runtime is provided to the client developer through the Javadocs of the bean.
When the host program behind a client operation implements variable and type-exclusive data (both input and output), use the REDEFINES feature to properly supply data of a particular format into the REDEFINED data area of the client operation.
You can also use REDEFINES when you are processing the outputs of a host transaction to correctly process completely different sets of instance information. This provides a mechanism to reliably process the results of a transaction where the data is dynamic.
In the following example, which illustrates the typical mutually exclusive REDEFINES option, the data types are not compatible; the response bytes differ in type between text and numeric interpretations. To access this data, you need an indicator field to tell you which of these is appropriate for each particular execution of the operation.
* these statements define an area of memory that can contain any one of * three distinct sets of account data at any given point in time 15 Account-Type-Indicator PIC X(1). 88 Type-Savings VALUE 'S'. 88 Type-Checking VALUE 'C'. 88 Type-Investment VALUE 'I'. 15 Savings. 20 Current-Balance PIC 9(12)V99. 20 Minimum-Balance PIC 9(5)V99. 20 Interest-Rate PIC 9(3)V9(5). … etc … 15 Checking REDEFINES Savings. 20 Date-Established PIC 9(6) Date Format yyxxxx. 20 Available-Balance PIC 9(12)V99. … etc … 15 Investment REDEFINES Savings. 20 Fund-Name PIC X(10) . 20 Current-Value PIC 9(12)V9(4). … etc …
There are additional properties to set after you create the host transaction. In this example they are:
Type-Savingsfor the "Savings" option. This tells the client developer that
Account-Type-Indicatorwill contain the value of "C" when the instance data being exchanged is "Savings" data.
REDEFINES can also provide alternative ways to access or set the content of a data area that contains data of the same type and format. You might want to return a large portion of contiguous data, perhaps for further processing, or grab a single piece of information from the middle of the data. REDEFINES lets you parse the data, in different ways, depending on what is meaningful to the application that is processing the results from a transaction.
In this example the REDEFINES is providing a more detailed or granular view of the same data.
* * the first field provides a macro view of a 16 byte account code. * the group and fields under it show a parsed view of the encoded fields * within those same 16 bytes, 15 Account-Code PIC X(16). 15 Account-Parsed REDEFINES Account-Code. 20 Account-Branch PIC X(7). 20 Customer-Identifier PIC X(9).
Set the Exclusive OR property to "False" for this REDEFINES so the client developer can access any of the alternate formats of the REDEFINES area for a given client operation.
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|Using Elementary Item Input and Output Properties|