Package org.tweetyproject.logics.pl.semantics

Class NicePossibleWorld

java.lang.Object

org.tweetyproject.commons.AbstractInterpretation<B,S>

org.tweetyproject.commons.InterpretationSet<Proposition,PlBeliefSet,PlFormula>

org.tweetyproject.logics.pl.semantics.NicePossibleWorld

All Implemented Interfaces:

Iterable<Proposition>, Collection<Proposition>, Comparator<Pair<Proposition,Boolean>>, Interpretation<PlBeliefSet,PlFormula>

public class NicePossibleWorld
extends InterpretationSet<Proposition,PlBeliefSet,PlFormula>
implements Comparator<Pair<Proposition,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

Constructor Summary

Constructors

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

Methods inherited from class org.tweetyproject.commons.InterpretationSet

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

Methods inherited from class org.tweetyproject.commons.AbstractInterpretation

satisfies

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, spliterator, stream, toArray

Methods inherited from interface java.util.Comparator

reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Methods inherited from interface java.lang.Iterable

forEach

Constructor Details

NicePossibleWorld

public NicePossibleWorld(Collection<Proposition> trueInWorld,
 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(Collection<Proposition> trueInWorld,
 Collection<Proposition> signature,
 Comparator<Pair<Proposition,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

comparator - The comparator

Method Details

setSignature

public boolean setSignature(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(Comparator<Pair<Proposition,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 Set<Pair<Proposition,Boolean>> getRepresentationStructure()

Returns:

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

satisfies

public boolean satisfies(PlFormula formula)
                  throws IllegalArgumentException

Description copied from interface: Interpretation

Checks whether this interpretation satisfies the given formula.

Specified by:

satisfies in interface Interpretation<PlBeliefSet,PlFormula>

Parameters:

formula - a formula .

Returns:

"true" if this interpretation satisfies the given formula.

Throws:

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

satisfies

public boolean satisfies(PlBeliefSet beliefBase)
                  throws IllegalArgumentException

Description copied from interface: Interpretation

Checks whether this interpretation satisfies the given knowledge base.

Specified by:

satisfies in interface Interpretation<PlBeliefSet,PlFormula>

Parameters:

beliefBase - a knowledge base.

Returns:

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

Throws:

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

equals

public boolean equals(Object other)

Specified by:

equals in interface Collection<Proposition>

Specified by:

equals in interface Comparator<Pair<Proposition,Boolean>>

Overrides:

equals in class InterpretationSet<Proposition,PlBeliefSet,PlFormula>

hashCode

public int hashCode()

Specified by:

hashCode in interface Collection<Proposition>

Overrides:

hashCode in class InterpretationSet<Proposition,PlBeliefSet,PlFormula>

toString

public String toString()

Overrides:

toString in class InterpretationSet<Proposition,PlBeliefSet,PlFormula>

compare

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

Specified by:

compare in interface Comparator<Pair<Proposition,Boolean>>

getAllPossibleWorlds

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

Parameters:

signature - collection of propositions

Returns:

all possible nice worlds