Class ReturnExpression


public class ReturnExpression extends Expression
A return expression which is used in a rule action to cause a return from the rule trigger method, supplying a return value where appropriate.
  • Field Details

  • Constructor Details

  • Method Details

    • 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
    • typeCheck

      public Type typeCheck(Type expected) throws TypeException
      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 contxt in which it occurs. this may be void but should not be undefined at the point where type checking is performed.
      Returns:
      the expression type
      Throws:
      TypeException - if type checking fails
    • interpret

      public Object interpret(HelperAdapter helper) throws ExecuteException
      evaluate the expression by interpreting the expression tree
      Specified by:
      interpret in class Expression
      Parameters:
      helper - an execution context associated with the rule whcih contains a map of current bindings for rule variables and another map of their declared types both of which are indexed by varoable 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
    • compile

      public void compile(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext) throws CompileException
      Specified by:
      compile in class RuleElement
      Throws:
      CompileException
    • writeTo

      public void writeTo(StringWriter stringWriter)
      Specified by:
      writeTo in class Expression