
org.neo4j.kernel.impl.traversal.AbstractTraverser Maven / Gradle / Ivy
/**
* Copyright (c) 2002-2013 "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 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
package org.neo4j.kernel.impl.traversal;
import java.util.Iterator;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Path;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.traversal.TraversalMetadata;
import org.neo4j.graphdb.traversal.Traverser;
import org.neo4j.helpers.collection.CombiningIterator;
import org.neo4j.helpers.collection.IterableWrapper;
public abstract class AbstractTraverser implements Traverser
{
TraversalMetadata lastIterator;
@Override
public Iterable nodes()
{
return new IterableWrapper( this )
{
@Override
protected Node underlyingObjectToObject( Path position )
{
return position.endNode();
}
};
}
@Override
public Iterable relationships()
{
return new IterableWrapper( this )
{
@Override
public Iterator iterator()
{
Iterator iter = super.iterator();
if ( iter.hasNext() )
{
Relationship first = iter.next();
// If the first position represents the start node, the
// first relationship will be null, in that case skip it.
if ( first == null ) return iter;
// Otherwise re-include it.
return new CombiningIterator( first, iter );
}
else
{
return iter;
}
}
@Override
protected Relationship underlyingObjectToObject( Path position )
{
return position.lastRelationship();
}
};
}
public Iterator iterator()
{
Iterator iterator = instantiateIterator();
lastIterator = (TraversalMetadata) iterator;
return iterator;
}
protected abstract Iterator instantiateIterator();
@Override
public TraversalMetadata metadata()
{
return lastIterator;
}
}
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