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Person.java
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Person.java
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/**
* Licensed to Neo Technology under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Neo Technology licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.neo4j.examples.socnet;
import static org.neo4j.examples.socnet.RelTypes.FRIEND;
import static org.neo4j.examples.socnet.RelTypes.NEXT;
import static org.neo4j.examples.socnet.RelTypes.STATUS;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import org.neo4j.graphalgo.GraphAlgoFactory;
import org.neo4j.graphalgo.PathFinder;
import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Path;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.traversal.Evaluators;
import org.neo4j.graphdb.traversal.TraversalDescription;
import org.neo4j.graphdb.traversal.Traverser;
import org.neo4j.helpers.collection.IterableWrapper;
import org.neo4j.helpers.collection.IteratorUtil;
import org.neo4j.kernel.Traversal;
import org.neo4j.kernel.Uniqueness;
public class Person
{
static final String NAME = "name";
// START SNIPPET: the-node
private final Node underlyingNode;
Person( Node personNode )
{
this.underlyingNode = personNode;
}
protected Node getUnderlyingNode()
{
return underlyingNode;
}
// END SNIPPET: the-node
// START SNIPPET: delegate-to-the-node
public String getName()
{
return (String)underlyingNode.getProperty( NAME );
}
// END SNIPPET: delegate-to-the-node
// START SNIPPET: override
@Override
public int hashCode()
{
return underlyingNode.hashCode();
}
@Override
public boolean equals( Object o )
{
return o instanceof Person &&
underlyingNode.equals( ( (Person)o ).getUnderlyingNode() );
}
@Override
public String toString()
{
return "Person[" + getName() + "]";
}
// END SNIPPET: override
public void addFriend( Person otherPerson )
{
Transaction tx = underlyingNode.getGraphDatabase().beginTx();
try
{
if ( !this.equals( otherPerson ) )
{
Relationship friendRel = getFriendRelationshipTo( otherPerson );
if ( friendRel == null )
{
underlyingNode.createRelationshipTo( otherPerson.getUnderlyingNode(), FRIEND );
}
tx.success();
}
}
finally
{
tx.finish();
}
}
public int getNrOfFriends()
{
return IteratorUtil.count( getFriends() );
}
public Iterable<Person> getFriends()
{
return getFriendsByDepth( 1 );
}
public void removeFriend( Person otherPerson )
{
Transaction tx = underlyingNode.getGraphDatabase().beginTx();
try
{
if ( !this.equals( otherPerson ) )
{
Relationship friendRel = getFriendRelationshipTo( otherPerson );
if ( friendRel != null )
{
friendRel.delete();
}
tx.success();
}
}
finally
{
tx.finish();
}
}
public Iterable<Person> getFriendsOfFriends()
{
return getFriendsByDepth( 2 );
}
public Iterable<Person> getShortestPathTo( Person otherPerson,
int maxDepth )
{
// use graph algo to calculate a shortest path
PathFinder<Path> finder = GraphAlgoFactory.shortestPath(
Traversal.expanderForTypes( FRIEND, Direction.BOTH ), maxDepth );
Path path = finder.findSinglePath( underlyingNode,
otherPerson.getUnderlyingNode() );
return createPersonsFromNodes( path );
}
public Iterable<Person> getFriendRecommendation(
int numberOfFriendsToReturn )
{
HashSet<Person> friends = new HashSet<Person>();
IteratorUtil.addToCollection( getFriends(), friends );
HashSet<Person> friendsOfFriends = new HashSet<Person>();
IteratorUtil.addToCollection( getFriendsOfFriends(), friendsOfFriends );
friendsOfFriends.removeAll( friends );
ArrayList<RankedPerson> rankedFriends = new ArrayList<RankedPerson>();
for ( Person friend : friendsOfFriends )
{
int rank = getNumberOfPathsToPerson( friend );
rankedFriends.add( new RankedPerson( friend, rank ) );
}
Collections.sort( rankedFriends, new RankedComparer() );
trimTo( rankedFriends, numberOfFriendsToReturn );
return onlyFriend( rankedFriends );
}
public Iterable<StatusUpdate> getStatus()
{
Relationship firstStatus = underlyingNode.getSingleRelationship(
STATUS, Direction.OUTGOING );
if ( firstStatus == null )
{
return Collections.emptyList();
}
// START SNIPPET: getStatusTraversal
TraversalDescription traversal = Traversal.description().
depthFirst().
relationships( NEXT );
// END SNIPPET: getStatusTraversal
return new IterableWrapper<StatusUpdate, Path>(
traversal.traverse( firstStatus.getEndNode() ) )
{
@Override
protected StatusUpdate underlyingObjectToObject( Path path )
{
return new StatusUpdate( path.endNode() );
}
};
}
public Iterator<StatusUpdate> friendStatuses()
{
return new FriendsStatusUpdateIterator( this );
}
public void addStatus( String text )
{
Transaction tx = graphDb().beginTx();
try
{
StatusUpdate oldStatus;
if ( getStatus().iterator().hasNext() )
{
oldStatus = getStatus().iterator().next();
} else
{
oldStatus = null;
}
Node newStatus = createNewStatusNode( text );
if ( oldStatus != null )
{
underlyingNode.getSingleRelationship( RelTypes.STATUS, Direction.OUTGOING ).delete();
newStatus.createRelationshipTo( oldStatus.getUnderlyingNode(), RelTypes.NEXT );
}
underlyingNode.createRelationshipTo( newStatus, RelTypes.STATUS );
tx.success();
}
finally
{
tx.finish();
}
}
private GraphDatabaseService graphDb()
{
return underlyingNode.getGraphDatabase();
}
private Node createNewStatusNode( String text )
{
Node newStatus = graphDb().createNode();
newStatus.setProperty( StatusUpdate.TEXT, text );
newStatus.setProperty( StatusUpdate.DATE, new Date().getTime() );
return newStatus;
}
private final class RankedPerson
{
final Person person;
final int rank;
private RankedPerson( Person person, int rank )
{
this.person = person;
this.rank = rank;
}
public Person getPerson()
{
return person;
}
public int getRank()
{
return rank;
}
}
private class RankedComparer implements Comparator<RankedPerson>
{
public int compare( RankedPerson a, RankedPerson b )
{
return b.getRank() - a.getRank();
}
}
private void trimTo( ArrayList<RankedPerson> rankedFriends,
int numberOfFriendsToReturn )
{
while ( rankedFriends.size() > numberOfFriendsToReturn )
{
rankedFriends.remove( rankedFriends.size() - 1 );
}
}
private Iterable<Person> onlyFriend( Iterable<RankedPerson> rankedFriends )
{
ArrayList<Person> retVal = new ArrayList<Person>();
for ( RankedPerson person : rankedFriends )
{
retVal.add( person.getPerson() );
}
return retVal;
}
private Relationship getFriendRelationshipTo( Person otherPerson )
{
Node otherNode = otherPerson.getUnderlyingNode();
for ( Relationship rel : underlyingNode.getRelationships( FRIEND ) )
{
if ( rel.getOtherNode( underlyingNode ).equals( otherNode ) )
{
return rel;
}
}
return null;
}
private Iterable<Person> getFriendsByDepth( int depth )
{
// return all my friends and their friends using new traversal API
TraversalDescription travDesc = Traversal.description()
.breadthFirst()
.relationships( FRIEND )
.uniqueness( Uniqueness.NODE_GLOBAL )
.evaluator( Evaluators.toDepth( depth ) )
.evaluator( Evaluators.excludeStartPosition() );
return createPersonsFromPath( travDesc.traverse( underlyingNode ) );
}
private IterableWrapper<Person, Path> createPersonsFromPath(
Traverser iterableToWrap )
{
return new IterableWrapper<Person, Path>( iterableToWrap )
{
@Override
protected Person underlyingObjectToObject( Path path )
{
return new Person( path.endNode() );
}
};
}
private int getNumberOfPathsToPerson( Person otherPerson )
{
PathFinder<Path> finder = GraphAlgoFactory.allPaths( Traversal.expanderForTypes( FRIEND, Direction.BOTH ), 2 );
Iterable<Path> paths = finder.findAllPaths( getUnderlyingNode(), otherPerson.getUnderlyingNode() );
return IteratorUtil.count( paths );
}
private Iterable<Person> createPersonsFromNodes( final Path path )
{
return new IterableWrapper<Person, Node>( path.nodes() )
{
@Override
protected Person underlyingObjectToObject( Node node )
{
return new Person( node );
}
};
}
}