/**
* Copyright (c) 2002-2010 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.kernel.impl.traversal;
import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.Expander;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Path;
import org.neo4j.graphdb.RelationshipExpander;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.traversal.BranchOrderingPolicy;
import org.neo4j.graphdb.traversal.PruneEvaluator;
import org.neo4j.graphdb.traversal.TraversalDescription;
import org.neo4j.graphdb.traversal.Traverser;
import org.neo4j.graphdb.traversal.UniquenessFactory;
import org.neo4j.helpers.Predicate;
import org.neo4j.kernel.StandardExpander;
import org.neo4j.kernel.Traversal;
import org.neo4j.kernel.Uniqueness;
public final class TraversalDescriptionImpl implements TraversalDescription
{
public TraversalDescriptionImpl()
{
this( StandardExpander.DEFAULT, Uniqueness.NODE_GLOBAL, null,
PruneEvaluator.NONE, Traversal.returnAll(),
Traversal.preorderDepthFirst() );
}
final Expander expander;
final UniquenessFactory uniqueness;
final Object uniquenessParameter;
final PruneEvaluator pruning;
final Predicate<Path> filter;
final BranchOrderingPolicy branchSelector;
private TraversalDescriptionImpl( Expander expander,
UniquenessFactory uniqueness, Object uniquenessParameter,
PruneEvaluator pruning, Predicate<Path> filter,
BranchOrderingPolicy branchSelector )
{
this.expander = expander;
this.uniqueness = uniqueness;
this.uniquenessParameter = uniquenessParameter;
this.pruning = pruning;
this.filter = filter;
this.branchSelector = branchSelector;
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#traverse(org.neo4j.graphdb.Node)
*/
public Traverser traverse( Node startNode )
{
return new TraverserImpl( this, startNode );
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#uniqueness(org.neo4j.graphdb.traversal.Uniqueness)
*/
public TraversalDescription uniqueness( UniquenessFactory uniqueness )
{
return new TraversalDescriptionImpl( expander, uniqueness, null, pruning,
filter, branchSelector );
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#uniqueness(org.neo4j.graphdb.traversal.Uniqueness, java.lang.Object)
*/
public TraversalDescription uniqueness( UniquenessFactory uniqueness,
Object parameter )
{
if ( this.uniqueness == uniqueness )
{
if ( uniquenessParameter == null ? parameter == null
: uniquenessParameter.equals( parameter ) )
{
return this;
}
}
return new TraversalDescriptionImpl( expander, uniqueness, parameter,
pruning, filter, branchSelector );
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#prune(org.neo4j.graphdb.traversal.PruneEvaluator)
*/
public TraversalDescription prune( PruneEvaluator pruning )
{
if ( this.pruning == pruning )
{
return this;
}
nullCheck( pruning, PruneEvaluator.class, "NO_PRUNING" );
return new TraversalDescriptionImpl( expander, uniqueness,
uniquenessParameter, addPruneEvaluator( pruning ),
filter, branchSelector );
}
private PruneEvaluator addPruneEvaluator( PruneEvaluator pruning )
{
if ( this.pruning instanceof MultiPruneEvaluator )
{
return ((MultiPruneEvaluator) this.pruning).add( pruning );
}
else
{
if ( this.pruning == PruneEvaluator.NONE )
{
return pruning;
}
else
{
return new MultiPruneEvaluator( new PruneEvaluator[] {
this.pruning, pruning } );
}
}
}
public TraversalDescription filter( Predicate<Path> filter )
{
if ( this.filter == filter )
{
return this;
}
if ( filter == null )
{
throw new IllegalArgumentException( "Return filter may not be null, " +
"use " + Traversal.class.getSimpleName() + ".returnAll() instead." );
}
return new TraversalDescriptionImpl( expander, uniqueness,
uniquenessParameter, pruning, addFilter( filter ), branchSelector );
}
private Predicate<Path> addFilter( Predicate<Path> filter )
{
if ( this.filter instanceof MultiFilter )
{
return ((MultiFilter) this.pruning).add( filter );
}
else
{
if ( this.filter == Traversal.returnAll() )
{
return filter;
}
else
{
return new MultiFilter( new Predicate[] {
this.filter, filter } );
}
}
}
private static <T> void nullCheck( T parameter, Class<T> parameterType,
String defaultName )
{
if ( parameter == null )
{
String typeName = parameterType.getSimpleName();
throw new IllegalArgumentException( typeName
+ " may not be null, use "
+ typeName + "." + defaultName
+ " instead." );
}
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#order(org.neo4j.graphdb.traversal.Order)
*/
public TraversalDescription order( BranchOrderingPolicy selector )
{
if ( this.branchSelector == selector )
{
return this;
}
return new TraversalDescriptionImpl( expander, uniqueness,
uniquenessParameter, pruning, filter, selector );
}
public TraversalDescription depthFirst()
{
return order( Traversal.preorderDepthFirst() );
}
public TraversalDescription breadthFirst()
{
return order( Traversal.preorderBreadthFirst() );
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#relationships(org.neo4j.graphdb.RelationshipType)
*/
public TraversalDescription relationships( RelationshipType type )
{
return relationships( type, Direction.BOTH );
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#relationships(org.neo4j.graphdb.RelationshipType, org.neo4j.graphdb.Direction)
*/
public TraversalDescription relationships( RelationshipType type,
Direction direction )
{
return expand( expander.add( type, direction ) );
}
/* (non-Javadoc)
* @see org.neo4j.graphdb.traversal.TraversalDescription#expand(org.neo4j.graphdb.RelationshipExpander)
*/
public TraversalDescription expand(RelationshipExpander expander)
{
if ( expander.equals( this.expander ) )
{
return this;
}
return new TraversalDescriptionImpl(
Traversal.expander( expander ), uniqueness,
uniquenessParameter, pruning, filter, branchSelector );
}
}