org.semanticweb.HermiT.tableau

Class ExtensionTable

java.lang.Object

org.semanticweb.HermiT.tableau.ExtensionTable

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

ExtensionTableWithFullIndex, ExtensionTableWithTupleIndexes

public abstract class ExtensionTable
extends Object
implements Serializable

An extension table keeps track of the assertions in the ABox during a run of the tableau. For this purpose, it holds a binary (concept, node) and a ternary (role, node, node) tuple table, which represent concept and role assertions respectively. Since this is one of the most crucial parts regarding memory usage, reusing already allocated space is the main design goal. In case of backtracking during the expansion, we just set the pointer to a previous entry in the table that then becomes the current one. When merging or pruning, we leave the entries for the merged/pruned nodes in the table so that we do not have holes in there. The tuple tables are indexed (tries/prefix trees) to speed-up the search for matching atoms during rule applications.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ExtensionTable.Retrieval Retrieval.
static class	ExtensionTable.View View.

Constructor Summary

Constructors

Constructor and Description
ExtensionTable(Tableau tableau, int tupleArity, boolean needsDependencySets)

Method Summary

Modifier and Type	Method and Description
abstract boolean	addTuple(Object[] tuple, DependencySet dependencySet, boolean isCore)
void	backtrack() Backtrack.
void	branchingPointPushed() Branching point pushed.
void	clear() Clear.
abstract boolean	containsTuple(Object[] tuple)
ExtensionTable.Retrieval	createRetrieval(boolean[] bindingPattern, ExtensionTable.View extensionView)
abstract ExtensionTable.Retrieval	createRetrieval(int[] bindingPositions, Object[] bindingsBuffer, Object[] tupleBuffer, boolean ownsBuffers, ExtensionTable.View extensionView)
int	getArity()
DependencySet	getDependencySet(int tupleIndex)
abstract DependencySet	getDependencySet(Object[] tuple)
Object	getTupleObject(int tupleIndex, int objectIndex)
boolean	isCore(int tupleIndex)
abstract boolean	isCore(Object[] tuple)
boolean	isTupleActive(int tupleIndex)
boolean	isTupleActive(Object[] tuple)
boolean	propagateDeltaNew()
void	retrieveTuple(Object[] tupleBuffer, int tupleIndex)
abstract int	sizeInMemory()

Methods inherited from class java.lang.Object

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

Constructor Detail

ExtensionTable

public ExtensionTable(Tableau tableau,
                      int tupleArity,
                      boolean needsDependencySets)

Parameters:

tableau - tableau

tupleArity - tupleArity

needsDependencySets - needsDependencySets

Method Detail

sizeInMemory

public abstract int sizeInMemory()

Returns:

size in memory

getArity

public int getArity()

Returns:

arity

retrieveTuple

public void retrieveTuple(Object[] tupleBuffer,
                          int tupleIndex)

Parameters:

tupleBuffer - tupleBuffer

tupleIndex - tupleIndex

getTupleObject

public Object getTupleObject(int tupleIndex,
                             int objectIndex)

Parameters:

tupleIndex - tupleIndex

objectIndex - objectIndex

Returns:

tuple

getDependencySet

public DependencySet getDependencySet(int tupleIndex)

Parameters:

tupleIndex - tupleIndex

Returns:

dependency set

isCore

public boolean isCore(int tupleIndex)

Parameters:

tupleIndex - tupleIndex

Returns:

true if core

addTuple

public abstract boolean addTuple(Object[] tuple,
                                 DependencySet dependencySet,
                                 boolean isCore)

Parameters:

tuple - tuple

dependencySet - dependencySet

isCore - isCore

Returns:

true if tuple added

containsTuple

public abstract boolean containsTuple(Object[] tuple)

Parameters:

tuple - tuple

Returns:

true if contained

createRetrieval

public ExtensionTable.Retrieval createRetrieval(boolean[] bindingPattern,
                                                ExtensionTable.View extensionView)

Parameters:

bindingPattern - bindingPattern

extensionView - extensionView

Returns:

retrieval

createRetrieval

public abstract ExtensionTable.Retrieval createRetrieval(int[] bindingPositions,
                                                         Object[] bindingsBuffer,
                                                         Object[] tupleBuffer,
                                                         boolean ownsBuffers,
                                                         ExtensionTable.View extensionView)

Parameters:

bindingPositions - bindingPositions

bindingsBuffer - bindingsBuffer

tupleBuffer - tupleBuffer

ownsBuffers - ownsBuffers

extensionView - extensionView

Returns:

retrieval

getDependencySet

public abstract DependencySet getDependencySet(Object[] tuple)

Parameters:

tuple - tuple

Returns:

dependency set

isCore

public abstract boolean isCore(Object[] tuple)

Parameters:

tuple - tuple

Returns:

true if core

propagateDeltaNew

public boolean propagateDeltaNew()

Returns:

true if delta was present

branchingPointPushed

public void branchingPointPushed()

Branching point pushed.

backtrack

public void backtrack()

Backtrack.

clear

public void clear()

Clear.

isTupleActive

public boolean isTupleActive(Object[] tuple)

Parameters:

tuple - tuple

Returns:

true if tuple active

isTupleActive

public boolean isTupleActive(int tupleIndex)

Parameters:

tupleIndex - tupleIndex

Returns:

true if tuple active