edu.mssm.crover.domain2d
Class RExpression

java.lang.Object
  |
  +--edu.mssm.crover.domain2d.RExpression

Direct Known Subclasses:

RAdd, RConstAdaptor, RConstant, REqual, RGE, RSub, RVariable

public abstract class RExpression

extends java.lang.Object

Reflex expression. This abstract class represents simple arithmetic expressions required to constrain the layout of the SSE. An expression can be observed by other RExpressions. The observers are asked to accept or reject any change that the RExpression can go through its life, via calls to setValue(). The exception RInvalidChange is thrown whenever a single of the observer declares the change cannot be done (this can happen when an inequality constraint has been built out of RGE, a constant and a RExpression). If no RInvalidChange is thrown, the call to setValue() succeeds and the value is accepted. The method check() is the mechanism by which changes to an RExpression are repercuted among the constrain relationship. This Constraining scheme is really simple and is not recommended for complex projects. It has the advantages of being fast and sufficient for the needs of the domain2d package.

Field Summary

protected double	epsilon Precision of the equality comparison between doubles.
RExpression	main

Constructor Summary

RExpression()

RExpression(RExpression e)

Method Summary

void	add(RExpression increment)
void	check()
void	dispose() Dispose of this RExpression.
java.util.Set	getObservers()
abstract double	getValue()
void	register(RExpression observer)
void	register(java.util.Set observers)
abstract void	setValue(double v)

Methods inherited from class java.lang.Object

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

Field Detail

main

public RExpression main

epsilon

protected final double epsilon

Precision of the equality comparison between doubles.

See Also:

Constant Field Values

Constructor Detail

RExpression

public RExpression(RExpression e)

RExpression

public RExpression()

Method Detail

getValue

public abstract double getValue()

setValue

public abstract void setValue(double v)
                       throws RInvalidChange

RInvalidChange

add

public void add(RExpression increment)

register

public void register(RExpression observer)

dispose

public void dispose()

Dispose of this RExpression. Release the references on the observers so that they can be garbage collected.

register

public void register(java.util.Set observers)

getObservers

public java.util.Set getObservers()

check

public void check()
           throws RInvalidChange

RInvalidChange