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Version: 7.0

CHANGECLASS operator

The CHANGECLASS operator creates an action that changes objects classes.

Syntax​

CHANGECLASS expr TO className [WHERE whereExpr]

Description​

The CHANGECLASS operator creates an action that assigns the class className to the object given by expr for every set of arguments where whereExpr is not NULL.

The operator may introduce a local parameter in expr; in that case the WHERE block is required. Such a parameter corresponds to objects being iterated and is not a parameter of the created action.

Parameters​

  • expr

    Expression or typed parameter for the object whose class is changed. As a typed parameter, you can both reference an already declared parameter and declare a new local parameter; as an expression, new local parameters cannot be added.

  • className

    Name of the custom class to which the object's class is changed. Composite ID. The class must be concrete.

  • whereExpr

    Expression whose value is the condition under which the class is changed. If not specified, it is considered equal to TRUE.

Examples​

CLASS Document;
date = DATA DATE (Document);

CLASS ClosedDocument : Document;
// sets status to closed for all documents with a date older than 2 weeks
changeStatus()  {
    CHANGECLASS Document d TO ClosedDocument WHERE sum(date(d), 14) <= currentDate();
}