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Cleaned up PathEvaluator and InitialBranchState
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@tinwelint
tinwelint committed Sep 27, 2012
1 parent 64085e1 commit fb70f96
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Showing 23 changed files with 222 additions and 255 deletions.
14 changes: 5 additions & 9 deletions graph-algo/src/main/java/org/neo4j/graphalgo/GraphAlgoFactory.java
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Expand Up @@ -19,8 +19,6 @@
*/
package org.neo4j.graphalgo;

import static org.neo4j.kernel.Traversal.wrapInitialStateFactory;

import org.neo4j.graphalgo.impl.path.AStar;
import org.neo4j.graphalgo.impl.path.AllPaths;
import org.neo4j.graphalgo.impl.path.AllSimplePaths;
Expand Down Expand Up @@ -157,7 +155,7 @@ public static PathFinder<Path> shortestPath( PathExpander expander, int maxDepth
* {@link Relationship}s for each {@link Node}.
* @param maxDepth the max {@link Path#length()} returned paths are allowed
* to have.
* @param maxResultCount the maximum number of {@link Path}s to return.
* @param maxHitCount the maximum number of {@link Path}s to return.
* If this number of found paths are encountered the traversal will stop.
* @return an algorithm which finds shortest paths between two nodes.
*/
Expand All @@ -177,7 +175,7 @@ public static PathFinder<Path> shortestPath( RelationshipExpander expander, int
* {@link Relationship}s for each {@link Path}.
* @param maxDepth the max {@link Path#length()} returned paths are allowed
* to have.
* @param maxResultCount the maximum number of {@link Path}s to return.
* @param maxHitCount the maximum number of {@link Path}s to return.
* If this number of found paths are encountered the traversal will stop.
* @return an algorithm which finds shortest paths between two nodes.
*/
Expand Down Expand Up @@ -373,15 +371,14 @@ public static PathFinder<WeightedPath> dijkstra( PathExpander expander,
* @param expander the {@link PathExpander} to use for expanding
* {@link Relationship}s for each {@link Path}.
* @param stateFactory initial state for the traversal branches.
* @param relationshipPropertyRepresentingCost the property to represent cost
* on each relationship the algorithm traverses.
* @param costEvaluator the cost evaluator for each relationship the algorithm traverses.
* @return an algorithm which finds the cheapest path between two nodes
* using the Dijkstra algorithm.
*/
public static PathFinder<WeightedPath> dijkstra( PathExpander expander,
InitialStateFactory stateFactory, CostEvaluator<Double> costEvaluator )
{
return new Dijkstra( expander, wrapInitialStateFactory( stateFactory ), costEvaluator );
return new Dijkstra( expander, new InitialStateFactory.AsInitialBranchState( stateFactory ), costEvaluator );
}

/**
Expand All @@ -393,8 +390,7 @@ public static PathFinder<WeightedPath> dijkstra( PathExpander expander,
* @param expander the {@link PathExpander} to use for expanding
* {@link Relationship}s for each {@link Path}.
* @param stateFactory initial state for the traversal branches.
* @param relationshipPropertyRepresentingCost the property to represent cost
* on each relationship the algorithm traverses.
* @param costEvaluator the cost evaluator for each relationship the algorithm traverses.
* @return an algorithm which finds the cheapest path between two nodes
* using the Dijkstra algorithm.
*/
Expand Down
8 changes: 4 additions & 4 deletions graph-algo/src/main/java/org/neo4j/graphalgo/impl/path/AStar.java
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Expand Up @@ -19,8 +19,6 @@
*/
package org.neo4j.graphalgo.impl.path;

import static org.neo4j.kernel.StandardExpander.toPathExpander;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
Expand All @@ -46,9 +44,11 @@
import org.neo4j.graphdb.PropertyContainer;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipExpander;
import org.neo4j.graphdb.traversal.BranchState;
import org.neo4j.graphdb.traversal.TraversalMetadata;
import org.neo4j.helpers.collection.PrefetchingIterator;
import org.neo4j.kernel.Traversal;

import static org.neo4j.kernel.StandardExpander.toPathExpander;

public class AStar implements PathFinder<WeightedPath>
{
Expand Down Expand Up @@ -220,7 +220,7 @@ protected Node fetchNextOrNull()
@SuppressWarnings( "unchecked" )
private void expand()
{
for ( Relationship rel : expander.expand( this, Traversal.NO_BRANCH_STATE ) )
for ( Relationship rel : expander.expand( this, BranchState.NO_STATE ) )
{
lastMetadata.rels++;
Node node = rel.getOtherNode( this.lastNode );
Expand Down
8 changes: 4 additions & 4 deletions graph-algo/src/main/java/org/neo4j/graphalgo/impl/path/ShortestPath.java
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Expand Up @@ -19,8 +19,6 @@
*/
package org.neo4j.graphalgo.impl.path;

import static org.neo4j.kernel.StandardExpander.toPathExpander;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
Expand All @@ -42,11 +40,13 @@
import org.neo4j.graphdb.PropertyContainer;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipExpander;
import org.neo4j.graphdb.traversal.BranchState;
import org.neo4j.graphdb.traversal.TraversalMetadata;
import org.neo4j.helpers.collection.IterableWrapper;
import org.neo4j.helpers.collection.NestingIterator;
import org.neo4j.helpers.collection.PrefetchingIterator;
import org.neo4j.kernel.Traversal;

import static org.neo4j.kernel.StandardExpander.toPathExpander;

/**
* Find (all or one) simple shortest path(s) between two nodes. It starts
Expand Down Expand Up @@ -311,7 +311,7 @@ private void prepareNextLevel()
protected Iterator<Relationship> createNestedIterator( Node node )
{
lastParentTraverserNode = node;
return expander.expand( DirectionData.this, Traversal.NO_BRANCH_STATE ).iterator();
return expander.expand( DirectionData.this, BranchState.NO_STATE ).iterator();
}
};
this.currentDepth++;
Expand Down
2 changes: 1 addition & 1 deletion ...algo/src/main/java/org/neo4j/graphalgo/impl/shortestpath/SingleSourceShortestPathBFS.java
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Expand Up @@ -211,7 +211,7 @@ public List<List<Relationship>> getPathsAsRelationships( Node targetNode )

/**
* Iterator-style "next" method.
* @return True if advance was made. False if no more computation could be
* @return True if evaluate was made. False if no more computation could be
* done.
*/
public boolean processNextNode()
Expand Down
15 changes: 1 addition & 14 deletions graph-algo/src/test/java/org/neo4j/graphalgo/path/TestDijkstra.java
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Expand Up @@ -210,20 +210,7 @@ public void withState() throws Exception
setWeight( "b", "c", 2 );
setWeight( "c", "d", 5 );

InitialBranchState<Integer> state = new InitialBranchState<Integer>()
{
@Override
public Integer initialState( Path path )
{
return 0;
}

@Override
public InitialBranchState<Integer> reverse()
{
return this;
}
};
InitialBranchState<Integer> state = new InitialBranchState.State<Integer>( 0, 0 );
final Map<Node, Integer> encounteredState = new HashMap<Node, Integer>();
PathExpander<Integer> expander = new PathExpander<Integer>()
{
Expand Down
33 changes: 0 additions & 33 deletions kernel/src/main/java/org/neo4j/graphdb/traversal/AbstractPathEvaluator.java
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This file was deleted.

19 changes: 19 additions & 0 deletions kernel/src/main/java/org/neo4j/graphdb/traversal/BranchState.java
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Expand Up @@ -47,4 +47,23 @@ public interface BranchState<STATE>
* children.
*/
void setState( STATE state );

/**
* Instance representing no state, usage resulting in
* {@link IllegalStateException} being thrown.
*/
public static final BranchState NO_STATE = new BranchState()
{
@Override
public Object getState()
{
throw new IllegalStateException( "Branch state disabled, pass in an initial state to enable it" );
}

@Override
public void setState( Object state )
{
throw new IllegalStateException( "Branch state disabled, pass in an initial state to enable it" );
}
};
}
27 changes: 26 additions & 1 deletion kernel/src/main/java/org/neo4j/graphdb/traversal/Evaluator.java
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Expand Up @@ -32,7 +32,6 @@
* @see Evaluation
* @see Evaluators
* @see TraversalDescription#evaluator(Evaluator)
* @deprecated replaced by {@link PathEvaluator}
*/
public interface Evaluator
{
Expand All @@ -50,4 +49,30 @@ public interface Evaluator
* down that path.
*/
Evaluation evaluate( Path path );

/**
* Exposes an {@link Evaluator} as a {@link PathEvaluator}.
* @param <STATE> the type of state passed into the evaluator.
*/
public static class AsPathEvaluator<STATE> implements PathEvaluator<STATE>
{
private final Evaluator evaluator;

public AsPathEvaluator( Evaluator evaluator )
{
this.evaluator = evaluator;
}

@Override
public Evaluation evaluate( Path path, BranchState<STATE> state )
{
return evaluator.evaluate( path );
}

@Override
public Evaluation evaluate( Path path )
{
return evaluator.evaluate( path );
}
}
}
26 changes: 13 additions & 13 deletions kernel/src/main/java/org/neo4j/graphdb/traversal/Evaluators.java
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Expand Up @@ -41,7 +41,7 @@
public abstract class Evaluators
{
@SuppressWarnings( "rawtypes" )
private static final PathEvaluator ALL = new AbstractPathEvaluator()
private static final PathEvaluator ALL = new PathEvaluator.Adapter()
{
public Evaluation evaluate( Path path, BranchState state )
{
Expand Down Expand Up @@ -83,7 +83,7 @@ public static PathEvaluator excludeStartPosition()
@SuppressWarnings( "rawtypes" )
public static PathEvaluator toDepth( final int depth )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
public Evaluation evaluate( Path path, BranchState state )
{
Expand All @@ -104,7 +104,7 @@ public Evaluation evaluate( Path path, BranchState state )
@SuppressWarnings( "rawtypes" )
public static PathEvaluator fromDepth( final int depth )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
public Evaluation evaluate( Path path, BranchState state )
{
Expand All @@ -124,7 +124,7 @@ public Evaluation evaluate( Path path, BranchState state )
@SuppressWarnings( "rawtypes" )
public static PathEvaluator atDepth( final int depth )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
public Evaluation evaluate( Path path, BranchState state )
{
Expand All @@ -147,7 +147,7 @@ public Evaluation evaluate( Path path, BranchState state )
@SuppressWarnings( "rawtypes" )
public static PathEvaluator includingDepths( final int minDepth, final int maxDepth )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
public Evaluation evaluate( Path path, BranchState state )
{
Expand Down Expand Up @@ -181,7 +181,7 @@ public static PathEvaluator lastRelationshipTypeIs( final Evaluation evaluationI
{
if ( orAnyOfTheseTypes.length == 0 )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand All @@ -199,7 +199,7 @@ public Evaluation evaluate( Path path, BranchState state )
expectedTypes.add( otherType.name() );
}

return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand Down Expand Up @@ -283,7 +283,7 @@ public static PathEvaluator endNodeIs( final Evaluation evaluationIfMatch, final
if ( possibleEndNodes.length == 1 )
{
final Node target = possibleEndNodes[0];
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand All @@ -294,7 +294,7 @@ public Evaluation evaluate( Path path, BranchState state )
}

final Set<Node> endNodes = new HashSet<Node>( asList( possibleEndNodes ) );
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand Down Expand Up @@ -345,7 +345,7 @@ public static PathEvaluator includeIfContainsAll( final Node... nodes )
{
if ( nodes.length == 1 )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand All @@ -364,7 +364,7 @@ public Evaluation evaluate( Path path, BranchState state )
else
{
final Set<Node> fullSet = new HashSet<Node>( Arrays.asList( nodes ) );
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand Down Expand Up @@ -395,7 +395,7 @@ public Evaluation evaluate( Path path, BranchState state )
@SuppressWarnings( "rawtypes" )
public static PathEvaluator includeIfAcceptedByAny( final PathEvaluator... evaluators )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@SuppressWarnings( "unchecked" )
@Override
Expand Down Expand Up @@ -425,7 +425,7 @@ public Evaluation evaluate( Path path, BranchState state )
@SuppressWarnings( "rawtypes" )
public static PathEvaluator includeIfAcceptedByAny( final Evaluator... evaluators )
{
return new AbstractPathEvaluator()
return new PathEvaluator.Adapter()
{
@Override
public Evaluation evaluate( Path path, BranchState state )
Expand Down
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