cetus.analysis

Class NullDomain

java.lang.Object

cetus.analysis.NullDomain

All Implemented Interfaces:

Domain

public class NullDomain
extends java.lang.Object
implements Domain

Class NullDomain represents a Domain that contains no data. The meaning of a null domain depends on the type of the domain that are used for a specific data flow problem. For example, a null domain means an empty set for a domain with a "set" type whereas it represents the least upper bound (TOP) for a lattice-based problem.

Constructor Summary

Constructors

Constructor and Description
NullDomain()

Method Summary

Methods

Modifier and Type	Method and Description
NullDomain	clone() Clones the domain.
Domain	diffStrong(Domain other) Returns the result of strong difference.
Domain	diffWeak(Domain other) Returns the result of weak difference.
boolean	equals(Domain other) Checks if the other domain is equal to the current domain.
static Domain	getNull()
Domain	intersect(Domain other) Returns intersection of the two domains.
void	kill(java.util.Set<Symbol> vars) Kills the data containing the specified set of symbols.
Domain	merge(Domain other) Returns merge of the two domains (join operation).
java.lang.String	toString()
Domain	union(Domain other) Returns union of the two domains if applicable.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

NullDomain

public NullDomain()

Method Detail

union

public Domain union(Domain other)

Description copied from interface: Domain

Returns union of the two domains if applicable.

Specified by:

union in interface Domain

Parameters:

other - the domain to be unioned.

Returns:

the resulting Domain.

merge

public Domain merge(Domain other)

Description copied from interface: Domain

Returns merge of the two domains (join operation).

Specified by:

merge in interface Domain

Parameters:

other - the domain to be merged.

Returns:

the resulting Domain.

intersect

public Domain intersect(Domain other)

Description copied from interface: Domain

Returns intersection of the two domains.

Specified by:

intersect in interface Domain

Parameters:

other - the domain to be intersected.

Returns:

the resulting Domain.

diffStrong

public Domain diffStrong(Domain other)

Description copied from interface: Domain

Returns the result of strong difference. Strong difference means d1-d2 = {} if the difference is not computatble.

Specified by:

diffStrong in interface Domain

Parameters:

other - the domain to be subtracted.

Returns:

the resulting Domain.

diffWeak

public Domain diffWeak(Domain other)

Description copied from interface: Domain

Returns the result of weak difference. Weak difference means d1-d2 = d1 if the difference is not computable.

Specified by:

diffWeak in interface Domain

Parameters:

other - the domain to be subtracted.

Returns:

the resulting Domain.

kill

public void kill(java.util.Set<Symbol> vars)

Description copied from interface: Domain

Kills the data containing the specified set of symbols.

Specified by:

kill in interface Domain

Parameters:

vars - the input set of symbols.

equals

public boolean equals(Domain other)

Description copied from interface: Domain

Checks if the other domain is equal to the current domain.

Specified by:

equals in interface Domain

Parameters:

other - the domain to be compared.

Returns:

true if they are equal, false otherwise.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getNull

public static Domain getNull()

clone

public NullDomain clone()

Description copied from interface: Domain

Clones the domain.

Specified by:

clone in interface Domain

Overrides:

clone in class java.lang.Object

Returns:

the cloned domain.