Package org.tweetyproject.logics.cl.semantics

Class ConditionalStructure

java.lang.Object

org.tweetyproject.logics.cl.semantics.ConditionalStructure

All Implemented Interfaces:

Comparator<NicePossibleWorld>

public class ConditionalStructure
extends Object
implements Comparator<NicePossibleWorld>

Represents a conditional structure as introduced in Section 3.5 "Conditionals in Nonmonotonic Reasoning and Belief Revision" of Gabrielle Kern-Isberner Internally it saves the data to two nested Maps. The first map maps to each PossibleWorld a map of Conditionals to Generators and the second map maps to each Conditional a map of PossibleWorlds to Generators. Those two maps allow fast access to the data of the ConditionalStructure. The first map can be used to support a nice representation of the ConditionalStructure and the second map can be used for further processing depending on the Conditionals (for Kappa values in C-Representation for example). To change the representation of the ConditionalStructure the user can provide a Comparator<NicePossibleWorld> implementation that changes the sort behavior of the world data map or he/she can provide a Comparator<Pair<Proposition, Boolean>> to change the ordering of the literals in the NicePossibleWorld representation. The later approach will fit for most situations. The default sorting behavior depends on the representation behavior of NicePossibleWorld that can also be adapt because it uses the toString method() and sorts this string alphabetically so that all possible worlds for a,b,c are represented in the following order: a b c a b-c a-b c a-b-c -a b c -a b-c -a-b c -a-b-c The default Sorting provides a clean binary switching of true/false like counting a bit string. If the user wants another ordering like c a b the Sorting behavior of the NicePossibleWorld shall be adapted by providing a Comparator<Pair<Proposition, Boolean>> implementation that implements the relation "c < a < b" by using the setWorldRepresentation() method. If the user wants to use a sorting depending on the Generator count for the worlds the setWorldSorting() method can be used to provide the correct sorting method.

Author:

Tim Janus

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	ConditionalStructure.Generator	The possible values of a conditional for a possible world

Constructor Summary

Constructors

Constructor	Description
ConditionalStructure()	Default-Ctor generates empty Conditional structure
ConditionalStructure(Collection<Conditional> conditionals)	Ctor: generates a conditional structure containing the given conditionals
ConditionalStructure(Collection<Conditional> conditionals, Comparator<NicePossibleWorld> comparator)	Ctor: Generates a ConditionalStructure containing the given conditionals and using the given comparator to sort the worldData map.
ConditionalStructure(Comparator<NicePossibleWorld> comparator)	Ctor: Generates an empty ConditionalStructure that uses the given Comparator to sort its worldData map.

Method Summary

Modifier and Type	Method	Description
boolean	addConditional(Conditional cond)	Adds the given Conditional to the ConditionalStructure and updates the structure.
void	clear()	Clears the ConditionalStructure, after calling this method the Structure is empty.
int	compare(NicePossibleWorld o1, NicePossibleWorld o2)
Map<NicePossibleWorld,ConditionalStructure.Generator>	getConditionalGenerators(Conditional conditional)	Processes the Map form PossibleWorlds to the Generators of the given Conditional
Set<Conditional>	getConditionals()	Return An unmodifiable set of all conditionals in this ConditionalStructure
List<NicePossibleWorld>	getFalsifiyingWorlds(Conditional cond)	Retrieves an unmodifiable list of possible worlds that falsify the given conditional.
Set<NicePossibleWorld>	getPossibleWorlds()	Return An unmodifiable set of all possible worlds in this ConditionalStructure
Collection<Proposition>	getSignature()	Return An unmodifiable Collection containing all propositions that altogether form the signature of the ConditionalStructure
List<NicePossibleWorld>	getVerifyingWorlds(Conditional cond)	Retrieves an unmodifiable list of possible worlds that verify the given conditional.
Map<Conditional,ConditionalStructure.Generator>	getWorldGenerators(NicePossibleWorld world)	Processes the map from Conditionals to Generators for a given PossibleWorld
boolean	removeConditional(Conditional cond)	Removes the given Conditional from the ConditionalStructure and updates the structure.
void	setWorldRepresentation(Comparator<Pair<Proposition,Boolean>> comparator)	Changes the internal representations of the worlds, normally the propositions of a world are ordered alphabetically but this behavior can be changed using this method.
void	setWorldSorting(Comparator<NicePossibleWorld> comparator)	Changes the ordering of the PossibleWorlds for representation purposes, before using this method proof if the goal can be easier achieved using the setWorldRepresentation() method that allows changing the ordering of the literals in the world representation.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

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

Constructor Details

ConditionalStructure

public ConditionalStructure()

Default-Ctor generates empty Conditional structure

ConditionalStructure

public ConditionalStructure(Comparator<NicePossibleWorld> comparator)

Ctor: Generates an empty ConditionalStructure that uses the given Comparator to sort its worldData map.

Parameters:

comparator - An implementation for sorting the world data if null is given the default sorting behavior is used.

ConditionalStructure

public ConditionalStructure(Collection<Conditional> conditionals)

Ctor: generates a conditional structure containing the given conditionals

Parameters:

conditionals - A collection of conditionals that shall form the ConditionalStructure

ConditionalStructure

public ConditionalStructure(Collection<Conditional> conditionals,
 Comparator<NicePossibleWorld> comparator)

Ctor: Generates a ConditionalStructure containing the given conditionals and using the given comparator to sort the worldData map.

Parameters:

conditionals - A collection of conditionals that shall form the ConditionalStructure

comparator - An implementation for sorting the world data

Method Details

getConditionals

public Set<Conditional> getConditionals()

Return An unmodifiable set of all conditionals in this ConditionalStructure

Returns:

An unmodifiable set of all conditionals in this ConditionalStructure

getPossibleWorlds

public Set<NicePossibleWorld> getPossibleWorlds()

Return An unmodifiable set of all possible worlds in this ConditionalStructure

Returns:

An unmodifiable set of all possible worlds in this ConditionalStructure

getFalsifiyingWorlds

public List<NicePossibleWorld> getFalsifiyingWorlds(Conditional cond)

Retrieves an unmodifiable list of possible worlds that falsify the given conditional.

This method fetches the worlds from the internal cache (`falsifyingWorlds`) and returns them as an unmodifiable list. If no worlds are available for the given conditional, it returns null.

Parameters:

cond - the conditional for which the falsifying worlds are to be retrieved.

Returns:

an unmodifiable list of falsifying worlds for the given conditional, or null if no such worlds exist.

getVerifyingWorlds

public List<NicePossibleWorld> getVerifyingWorlds(Conditional cond)

Retrieves an unmodifiable list of possible worlds that verify the given conditional.

This method fetches the worlds from the internal cache (`verifyingWorlds`) and returns them as an unmodifiable list. If no worlds are available for the given conditional, it returns null.

Parameters:

cond - the conditional for which the verifying worlds are to be retrieved.

Returns:

an unmodifiable list of verifying worlds for the given conditional, or null if no such worlds exist.

getWorldGenerators

public Map<Conditional,ConditionalStructure.Generator> getWorldGenerators(NicePossibleWorld world)

Processes the map from Conditionals to Generators for a given PossibleWorld

Parameters:

world - The PossibleWorld thats Generators shall be returned

Returns:

A map containing all Generators for the world as values and the associated conditionals as key.

getConditionalGenerators

public Map<NicePossibleWorld,ConditionalStructure.Generator> getConditionalGenerators(Conditional conditional)

Processes the Map form PossibleWorlds to the Generators of the given Conditional

Parameters:

conditional - The Conditional

Returns:

null if no such map exists or the map mapping the PossibleWorlds to Generators for the given Conditional

getSignature

public Collection<Proposition> getSignature()

Return An unmodifiable Collection containing all propositions that altogether form the signature of the ConditionalStructure

Returns:

An unmodifiable Collection containing all propositions that altogether form the signature of the ConditionalStructure

setWorldSorting

public void setWorldSorting(Comparator<NicePossibleWorld> comparator)

Changes the ordering of the PossibleWorlds for representation purposes, before using this method proof if the goal can be easier achieved using the setWorldRepresentation() method that allows changing the ordering of the literals in the world representation.

Parameters:

comparator - The implementation sorting the possible worlds

setWorldRepresentation

public void setWorldRepresentation(Comparator<Pair<Proposition,Boolean>> comparator)

Changes the internal representations of the worlds, normally the propositions of a world are ordered alphabetically but this behavior can be changed using this method.

Parameters:

comparator - The new implementation of a Comparator that provides the new sorting behavior for the Propositions in a PossibleWorld.

addConditional

public boolean addConditional(Conditional cond)

Adds the given Conditional to the ConditionalStructure and updates the structure.

Parameters:

cond - The new Conditional

Returns:

True if the conditional is added and ConditionalStructure is updated, false if the Conditional is already part of the ConditionalStructure

removeConditional

public boolean removeConditional(Conditional cond)

Removes the given Conditional from the ConditionalStructure and updates the structure.

Parameters:

cond - The Conditional that shall be removed

Returns:

True if the Conditional is part of the ConditionalStructure and was removed, false if the Conditional is not part of the ConditionalStructure and nothing happened.

clear

public void clear()

Clears the ConditionalStructure, after calling this method the Structure is empty.

toString

public String toString()

Overrides:

toString in class Object

compare

public int compare(NicePossibleWorld o1,
 NicePossibleWorld o2)

Specified by:

compare in interface Comparator<NicePossibleWorld>