DATA DIVISION for defining a client
You can use any of the sections of the DATA
DIVISION
to
describe the data that the client needs.
Data Division.
Local-storage section.
01 anAccount usage object reference Account.
01 aCheckingAccount usage object reference CheckingAccount.
01 aCheck usage object reference Check.
01 payee usage object reference Account.
. . .
Because
a client references classes, it needs one or more special data items
called object references, that is, references to instances
of those classes. All requests to instance methods require an object
reference to an instance of a class in which the method is supported
(that is, either defined or available by inheritance). You code object
references to refer to instances of Java™ classes
using the same syntax as you use to refer to instances of COBOL classes.
In the example above, the phrase usage object reference
indicates
an object reference data item.
All four object references in the code
above are called typed object references because a class-name
appears after the OBJECT REFERENCE
phrase. A typed
object reference can refer only to an instance of the class named
in the OBJECT REFERENCE
phrase or to one of its subclasses.
Thus anAccount can refer to instances of the Account class or one
of its subclasses, but cannot refer to instances of any other class.
Similarly, aCheck can refer only to instances of the Check class or
any subclasses that it might have.
Another type of object reference, not
shown above, does not have a class-name after the OBJECT REFERENCE
phrase.
Such a reference is called a universal object reference,
which means that it can refer to instances of any class. Avoid coding
universal object references, because they are interoperable with Java in only very limited circumstances
(when used in the RETURNING
phrase of the INVOKE class-name NEW
. . .
statement).
You must define, in the REPOSITORY
paragraph
of the CONFIGURATION SECTION
, class-names that you
use in the OBJECT REFERENCE
phrase.
Choosing LOCAL-STORAGE or WORKING-STORAGE
Coding interoperable data types in COBOL and Java
Invoking methods (INVOKE)
REPOSITORY paragraph for defining a client