org.jboss.byteman.rule.expression

Class AssignableExpression

java.lang.Object

org.jboss.byteman.rule.RuleElement

org.jboss.byteman.rule.expression.Expression

org.jboss.byteman.rule.expression.AssignableExpression

Direct Known Subclasses:

ArrayExpression, DollarExpression, FieldExpression, StaticExpression, Variable

public abstract class AssignableExpression
extends Expression

an expression which can appear on the left hand side of an assignment expression as well as in any other expression context. assignable expressions provide extra methods which support assignment, either interpreted or compiled, on top of the usual evaluation methods.

Field Summary

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

charPos, line, rule, token, type

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AssignableExpression(Rule rule, Type type, ParseNode token) Create a new expression.

Method Summary

Modifier and Type	Method and Description
abstract void	bindAssign() bind as an assignable expression.
abstract void	compileAssign(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext) compile an assignment to the referenced location using the value on the top of the Java stack.
abstract Object	interpretAssign(HelperAdapter helperAdapter, Object value) execute an assignment to the referenced location by interpretation of the expression, using the object passed in this call
abstract Type	typeCheckAssign(Type expected) typecheck the expression as an lvalue of an assignment operation

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

bind, getPos, getType, interpret, typeCheck, writeTo

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

compile, compileBooleanConversion, compileBox, compileNumericConversion, compileObjectConversion, compilePrimitiveConversion, compileStringConversion, compileTypeConversion, compileUnbox, getBindings, getTypeGroup, rebox, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

AssignableExpression

protected AssignableExpression(Rule rule,
                               Type type,
                               ParseNode token)

Create a new expression.

Parameters:

rule - the rule this expression belongs to

type - the current type for this expression.

token - the token for this expression.

Method Detail

typeCheckAssign

public abstract Type typeCheckAssign(Type expected)
                              throws TypeException

typecheck the expression as an lvalue of an assignment operation

Parameters:

expected - the expected type for the expression

Returns:

the expression type

Throws:

TypeException - if a type check error occurs

interpretAssign

public abstract Object interpretAssign(HelperAdapter helperAdapter,
                                       Object value)
                                throws ExecuteException

execute an assignment to the referenced location by interpretation of the expression, using the object passed in this call

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

compileAssign

public abstract void compileAssign(org.objectweb.asm.MethodVisitor mv,
                                   CompileContext compileContext)
                            throws CompileException

compile an assignment to the referenced location using the value on the top of the Java stack.

Parameters:

mv - the current method visitor

compileContext - the current compile context

Throws:

CompileException - if a compile error occurs

bindAssign

public abstract void bindAssign()
                         throws TypeException

bind as an assignable expression. for variables and dollar expressions this will ensure that a binding exists and that it is marked as potentially updateable.

Throws:

TypeException - if the expression contains an invalid or unassignable reference