Package org.jboss.byteman.rule.expression

Class ReturnExpression

java.lang.Object

org.jboss.byteman.rule.RuleElement

org.jboss.byteman.rule.expression.Expression

org.jboss.byteman.rule.expression.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 Summary

Fields

Modifier and Type	Field	Description
private Expression	returnValue

Fields inherited from class org.jboss.byteman.rule.expression.Expression

charPos, line, rule, token, type

Constructor Summary

Constructors

Constructor	Description
ReturnExpression(Rule rule, ParseNode token, Expression returnValue)

Method Summary

Modifier and Type	Method	Description
void	bind()	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
void	compile(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext)
java.lang.Object	interpret(HelperAdapter helper)	evaluate the expression by interpreting the expression tree
Type	typeCheck(Type expected)	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.
void	writeTo(java.io.StringWriter stringWriter)

Methods inherited from class org.jboss.byteman.rule.expression.Expression

getPos, getType

Methods inherited from class org.jboss.byteman.rule.RuleElement

getBindings, getTypeGroup, rebox, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

returnValue

private Expression returnValue

Constructor Detail

ReturnExpression

public ReturnExpression(Rule rule,
                        ParseNode token,
                        Expression returnValue)

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

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 java.lang.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(java.io.StringWriter stringWriter)

Specified by:

writeTo in class Expression