de.rwth.i2.attestor.graph.morphism.feasibility

Class TwoStepLookahead

java.lang.Object

de.rwth.i2.attestor.graph.morphism.feasibility.TwoStepLookahead

All Implemented Interfaces:

FeasibilityFunction

public class TwoStepLookahead
extends Object
implements FeasibilityFunction

Determines the whether the current candidate pair cannot belong to a graph morphism due to a mismatch in the lookahead sets in the successors or predecessors of one of the candidate nodes. This set corresponds to the number of nodes in the predecessors or successors of a candidate node that have not been matched yet. A mismatch may either consist of less ingoing edges in the target than in the pattern (checkEqualityOnExternal=false) or an unequal number (checkEqualityOnExternal=true).

Author:

Christoph

Constructor Summary

Constructors

Constructor and Description
TwoStepLookahead(boolean checkEqualityOnExternal)

Method Summary

Modifier and Type	Method and Description
boolean	eval(VF2State state, int p, int t) Evaluates whether extending the given state by a candidate pair results in a partial mapping between pattern and target Graph might still lead to a valid Morphism.

Methods inherited from class java.lang.Object

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

Constructor Detail

TwoStepLookahead

public TwoStepLookahead(boolean checkEqualityOnExternal)

Parameters:

checkEqualityOnExternal - Determines whether equal lookahead sets are required.

Method Detail

eval

public boolean eval(VF2State state,
                    int p,
                    int t)

Description copied from interface: FeasibilityFunction

Evaluates whether extending the given state by a candidate pair results in a partial mapping between pattern and target Graph might still lead to a valid Morphism.

Specified by:

eval in interface FeasibilityFunction

Parameters:

state - The current VF2State determining the partial Morphism computed so far.

p - The new pattern candidate node that should be added to the morphism.

t - The new target candidate node that should be added to the morphism.

Returns:

True if and only if adding the candidate pair to the current state of the morphism might still lead to a valid Morphism.