com.ibm.wala.fixedpoint.impl

Class GeneralStatement<T extends IVariable<T>>

java.lang.Object

com.ibm.wala.util.graph.impl.NodeWithNumber

com.ibm.wala.fixpoint.AbstractStatement<T,AbstractOperator<T>>

com.ibm.wala.fixedpoint.impl.GeneralStatement<T>

All Implemented Interfaces:

IFixedPointStatement<T>, INodeWithNumber

Direct Known Subclasses:

AbstractFixedPointSolver.Statement

public abstract class GeneralStatement<T extends IVariable<T>>
extends AbstractStatement<T,AbstractOperator<T>>

Represents a single step in an iterative solver

Field Summary

Fields

Modifier and Type	Field and Description
protected T	lhs
protected T[]	rhs

Constructor Summary

Constructors

Constructor and Description
GeneralStatement(T lhs, AbstractOperator<T> operator) Constructor for case of zero operands on the right-hand side.
GeneralStatement(T lhs, AbstractOperator<T> operator, T[] rhs) Constructor for case of more than three operands on the right-hand side.
GeneralStatement(T lhs, AbstractOperator<T> operator, T op1, T op2) Constructor for case of two operands on the right-hand side.
GeneralStatement(T lhs, AbstractOperator<T> operator, T op1, T op2, T op3) Constructor for case of three operands on the right-hand side.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
byte	evaluate() Evaluate this equation, setting a new value for the left-hand side.
T	getLHS() Return the left-hand side of this equation.
AbstractOperator<T>	getOperator()
T[]	getRHS() returns the list of free variables appearing in the right-hand side of the statement
int	hashCode() Subclasses must implement this, to prevent non-determinism.
boolean	hasVariable(T cell) Does this equation contain an appearance of a given cell?
protected abstract T[]	makeRHS(int size)

Methods inherited from class com.ibm.wala.fixpoint.AbstractStatement

getOrderNumber, toString

Methods inherited from class com.ibm.wala.util.graph.impl.NodeWithNumber

getGraphNodeId, setGraphNodeId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.ibm.wala.util.graph.INodeWithNumber

getGraphNodeId, setGraphNodeId

Field Detail

lhs

protected final T extends IVariable<T> lhs

rhs

protected final T extends IVariable<T>[] rhs

Constructor Detail

GeneralStatement

public GeneralStatement(T lhs,
                        AbstractOperator<T> operator)

Constructor for case of zero operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

GeneralStatement

public GeneralStatement(T lhs,
                        AbstractOperator<T> operator,
                        T op1,
                        T op2)

Constructor for case of two operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

op1 - the first operand on the rhs

op2 - the second operand on the rhs

GeneralStatement

public GeneralStatement(T lhs,
                        AbstractOperator<T> operator,
                        T op1,
                        T op2,
                        T op3)

Constructor for case of three operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

op1 - the first operand on the rhs

op2 - the second operand on the rhs

op3 - the third operand on the rhs

GeneralStatement

public GeneralStatement(T lhs,
                        AbstractOperator<T> operator,
                        T[] rhs)

Constructor for case of more than three operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

rhs - the operands of the right-hand side in order

Throws:

IllegalArgumentException - if rhs is null

Method Detail

evaluate

public byte evaluate()

Evaluate this equation, setting a new value for the left-hand side.

Returns:

true if the lhs value changed. false otherwise

getLHS

public T getLHS()

Return the left-hand side of this equation.

Returns:

the lattice cell this equation computes

hasVariable

public boolean hasVariable(T cell)

Does this equation contain an appearance of a given cell?

Note: this uses reference equality, assuming that the variables are canonical! This is fragile. TODO: Address it perhaps, but be careful not to sacrifice efficiency.

Parameters:

cell - the cell in question

Returns:

true or false

makeRHS

protected abstract T[] makeRHS(int size)

hashCode

public int hashCode()

Description copied from class: AbstractStatement

Subclasses must implement this, to prevent non-determinism.

Specified by:

hashCode in class AbstractStatement<T extends IVariable<T>,AbstractOperator<T extends IVariable<T>>>

equals

public boolean equals(Object o)

Specified by:

equals in class AbstractStatement<T extends IVariable<T>,AbstractOperator<T extends IVariable<T>>>

getOperator

public AbstractOperator<T> getOperator()

Specified by:

getOperator in class AbstractStatement<T extends IVariable<T>,AbstractOperator<T extends IVariable<T>>>

getRHS

public T[] getRHS()

Description copied from interface: IFixedPointStatement

returns the list of free variables appearing in the right-hand side of the statement