net.sf.tweety.logics.pl.semantics

Class NicePossibleWorld

java.lang.Object

net.sf.tweety.commons.AbstractInterpretation

net.sf.tweety.commons.InterpretationSet<Proposition>

net.sf.tweety.logics.pl.semantics.NicePossibleWorld

All Implemented Interfaces:

java.lang.Iterable<Proposition>, java.util.Collection<Proposition>, java.util.Comparator<Pair<Proposition,java.lang.Boolean>>, Interpretation

public class NicePossibleWorld
extends InterpretationSet<Proposition>
implements java.util.Comparator<Pair<Proposition,java.lang.Boolean>>

Wrapper for the PossibleWorld providing better representation mechanisms, it knows all the possible propositions (the signature) and therefore provides a complete representation that maps a boolean to the Proposition. It also provides ordering of the (proposition, boolean) pairs in the enhanced representation. The default behavior is an alphabetically ordering of the Propositions but it can be changed by the user. Internally it uses the smaller and therefore faster implementation of PossibleWorld for satisfication test

Author:

Tim Janus

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.SortedSet<Pair<Proposition,java.lang.Boolean>>	representation The set saving all the proposition boolean pairs that represent this world assuming the current signature.
private PossibleWorld	world Implementation of possible world with a small memory print and fast satisfication tests.

Constructor Summary

Constructors

Constructor and Description
NicePossibleWorld(java.util.Collection<Proposition> trueInWorld, java.util.Collection<Proposition> signature) Ctor: Generates the possible world using the given set of true propositions and generated a representation of the possible world using the given signature.
NicePossibleWorld(java.util.Collection<Proposition> trueInWorld, java.util.Collection<Proposition> signature, java.util.Comparator<Pair<Proposition,java.lang.Boolean>> comparator) Ctor: Generates the possible world using the given set of true propositions and generated a representation of the possible world using the given signature.

Method Summary

Modifier and Type	Method and Description
int	compare(Pair<Proposition,java.lang.Boolean> o1, Pair<Proposition,java.lang.Boolean> o2)
boolean	equals(java.lang.Object other)
static java.util.Set<NicePossibleWorld>	getAllPossibleWorlds(java.util.Collection<Proposition> signature)
PossibleWorld	getOptimizedWorld()
java.util.Set<Pair<Proposition,java.lang.Boolean>>	getRepresentationStructure()
int	hashCode()
boolean	satisfies(BeliefBase beliefBase) Checks whether this interpretation satisfies the given knowledge base.
boolean	satisfies(Formula formula) Checks whether this interpretation satisfies the given formula.
void	setComparator(java.util.Comparator<Pair<Proposition,java.lang.Boolean>> comparator) Changes the used comparator to sort the representation structure and resorts the representation.
boolean	setSignature(java.util.Collection<Proposition> signature) Changes the signature of the world.
java.lang.String	toString()

Methods inherited from class net.sf.tweety.commons.InterpretationSet

add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray

Methods inherited from class net.sf.tweety.commons.AbstractInterpretation

satisfies

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Methods inherited from interface java.util.Collection

parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

world

private PossibleWorld world

Implementation of possible world with a small memory print and fast satisfication tests.

representation

private java.util.SortedSet<Pair<Proposition,java.lang.Boolean>> representation

The set saving all the proposition boolean pairs that represent this world assuming the current signature.

Constructor Detail

NicePossibleWorld

public NicePossibleWorld(java.util.Collection<Proposition> trueInWorld,
                         java.util.Collection<Proposition> signature)

Ctor: Generates the possible world using the given set of true propositions and generated a representation of the possible world using the given signature. The default alphabetically sort behavior is used to order the representation.

Parameters:

trueInWorld - A set of propositions describing those propositions that are true in this possible world. It has to be a subset of signature.

signature - A set of propositions describing all know propositions by the the problem, the signature. It has to be a super set of trueInWorld

NicePossibleWorld

public NicePossibleWorld(java.util.Collection<Proposition> trueInWorld,
                         java.util.Collection<Proposition> signature,
                         java.util.Comparator<Pair<Proposition,java.lang.Boolean>> comparator)

Ctor: Generates the possible world using the given set of true propositions and generated a representation of the possible world using the given signature. The sort behavior given in comparator is used to order the representation.

Parameters:

trueInWorld - A set of propositions describing those propositions that are true in this possible world. It has to be a subset of signature.

signature - A set of propositions describing all know propositions by the the problem, the signature. It has to be a super set of trueInWorld

Method Detail

setSignature

public boolean setSignature(java.util.Collection<Proposition> signature)

Changes the signature of the world. That means the set of propositions has changed. The new set might contain new propositions and delete old propositions. The representation data structure is updated to reflect the new signature. There is a border case if a Proposition is deleted that is true in this world. Then the world is not representable with the given signature anymore, if this is the case then the representation data structure is cleared.

Parameters:

signature - A collection of propositions defining the new signature.

Returns:

true if representation is successfully updated and false if the world is not representable by the given signature anymore.

setComparator

public void setComparator(java.util.Comparator<Pair<Proposition,java.lang.Boolean>> comparator)

Changes the used comparator to sort the representation structure and resorts the representation. The default behavior is an alphabetically ordering. The default behavior is selected if null is given as argument or if an instance of the NicePossibleWorld is given as argument.

Parameters:

comparator - The new comparator used to sort the representation. If a null is given the default alphabetically ordering is used.

getOptimizedWorld

public PossibleWorld getOptimizedWorld()

Returns:

The PossibleWorld instance that is used for satification tests etc.

getRepresentationStructure

public java.util.Set<Pair<Proposition,java.lang.Boolean>> getRepresentationStructure()

Returns:

The representation structure as a set of (proposition, boolean) pairs.

satisfies

public boolean satisfies(Formula formula)
                  throws java.lang.IllegalArgumentException

Description copied from interface: Interpretation

Checks whether this interpretation satisfies the given formula.

Specified by:

satisfies in interface Interpretation

Parameters:

formula - a formula .

Returns:

"true" if this interpretation satisfies the given formula.

Throws:

java.lang.IllegalArgumentException - if the formula does not correspond to the expected language.

satisfies

public boolean satisfies(BeliefBase beliefBase)
                  throws java.lang.IllegalArgumentException

Description copied from interface: Interpretation

Checks whether this interpretation satisfies the given knowledge base.

Specified by:

satisfies in interface Interpretation

Parameters:

beliefBase - a knowledge base.

Returns:

"true" if this interpretation satisfies the given knowledge base.

Throws:

java.lang.IllegalArgumentException - IllegalArgumentException if the knowledgebase does not correspond to the expected language.

equals

public boolean equals(java.lang.Object other)

Specified by:

equals in interface java.util.Collection<Proposition>

Specified by:

equals in interface java.util.Comparator<Pair<Proposition,java.lang.Boolean>>

Overrides:

equals in class InterpretationSet<Proposition>

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<Proposition>

Overrides:

hashCode in class InterpretationSet<Proposition>

toString

public java.lang.String toString()

Overrides:

toString in class InterpretationSet<Proposition>

compare

public int compare(Pair<Proposition,java.lang.Boolean> o1,
                   Pair<Proposition,java.lang.Boolean> o2)

Specified by:

compare in interface java.util.Comparator<Pair<Proposition,java.lang.Boolean>>

getAllPossibleWorlds

public static java.util.Set<NicePossibleWorld> getAllPossibleWorlds(java.util.Collection<Proposition> signature)