Class Variable


  • public class Variable
    extends AssignableExpression
    an expression which identifies a variable occurring either as an LVALUE on the LHS of an event binding in the rule's event or as an RVALUE mentioned in the RHS of an event binding or in thre rule's conditon or action.
    • Method Detail

      • bind

        public void bind()
                  throws TypeException
        verify that variables mentioned in this expression are actually available in the supplied bindings list and infer/validate the type of this expression or its subexpressions where possible
        Specified by:
        bind in class Expression
        Throws:
        TypeException - if any variable is missing or has the wrong type
      • bindAssign

        public void bindAssign()
                        throws TypeException
        verify that variables mentioned in this expression are actually available in the supplied bindings list. infer/validate the type of this expression or its subexpressions where possible
        Specified by:
        bindAssign in class AssignableExpression
        Throws:
        TypeException - if any variable is missing or has the wrong type
      • typeCheck

        public Type typeCheck​(Type expected)
                       throws TypeException
        Description copied from class: Expression
        ensure that all type references in the expression and its component expressions can be resolved, that the type of the expression is well-defined and that it is compatible with the type expected in the context in which it occurs.
        Specified by:
        typeCheck in class Expression
        Parameters:
        expected - the type expected for the expression in the contxet in which it occurs. this may be void but should not be undefined at the point where type checking is performed.
        Returns:
        the type of the expression
        Throws:
        TypeException - if a type check failure occurs
      • interpret

        public Object interpret​(HelperAdapter helper)
                         throws ExecuteException
        Description copied from class: Expression
        evaluate the expression by interpreting the expression tree
        Specified by:
        interpret in class Expression
        Parameters:
        helper - an execution context associated with the rule which contains a map of current bindings for rule variables and another map of their declared types both of which are indexed by variable name. This includes entries for the helper (name "-1"), the recipient if the trigger method is not static (name "0") and the trigger method arguments (names "1", ...)
        Returns:
        the result of evaluation as an Object
        Throws:
        ExecuteException - if an error occurs during execution
      • interpretAssign

        public Object interpretAssign​(HelperAdapter helperAdapter,
                                      Object value)
                               throws ExecuteException
        Description copied from class: AssignableExpression
        execute an assignment to the referenced location by interpretation of the expression, using the object passed in this call
        Specified by:
        interpretAssign in class AssignableExpression
        Parameters:
        helperAdapter - an execution context associated with the rule which contains a map of current bindings for rule variables and another map of their declared types both of which are indexed by variable name. This includes entries for the helper (name "-1"), the recipient if the trigger method is not static (name "0") and the trigger method arguments (names "1", ...)
        value - the value to be assigned to this object
        Returns:
        the result of evaluation as an Object
        Throws:
        ExecuteException - if an error occurs during execution