Thanks Peter. Really appreciate your help.
Yes, in somecases the path is exactly 4.
But in others, it may not be. I am wondering what would be the prune
criterion if the path is not exactly 4.
Say,
REL1 REL2 REL3
A ---------> P ---------> Q -----------> T
And I would like to get A->P->Q->T returned as a path along the with
previous 2 paths.
On Mon, Feb 14, 2011 at 6:17 PM, Peter Neubauer <
peter.neuba...@neotechnology.com> wrote:
> Hi John,
> see the following example on something that should roughly work as you
> want. Notice that I only check for the existence of "relProp" on REL3,
> you can of course check for a value, but I didn't have a good example.
>
> This gives you the paths:
>
> (1)--[REL1,3]-->(2)--[REL2,4]-->(3)--[REL3,5]-->(4)--[REL4,6]-->(5)
> (1)--[REL1,7]-->(6)--[REL3,8]-->(7)--[REL4,10]-->(8)--[REL2,12]-->(9)
>
> Which is what you want - paths of length exactly 4, with unordered
> REL1, REL2, REL3, REL4 and a constraint on REL3?
>
> /peter
>
>
> package org.neo4j.examples.orderedpath;
>
> import static org.neo4j.graphdb.DynamicRelationshipType.withName;
>
> import java.util.ArrayList;
>
> import org.junit.BeforeClass;
> import org.junit.Test;
> import org.neo4j.graphdb.Direction;
> import org.neo4j.graphdb.Node;
> import org.neo4j.graphdb.Path;
> import org.neo4j.graphdb.Relationship;
> import org.neo4j.graphdb.RelationshipType;
> import org.neo4j.graphdb.Transaction;
> import org.neo4j.graphdb.traversal.Evaluation;
> import org.neo4j.graphdb.traversal.Evaluator;
> import org.neo4j.graphdb.traversal.TraversalDescription;
> import org.neo4j.graphdb.traversal.Traverser;
> import org.neo4j.kernel.EmbeddedGraphDatabase;
> import org.neo4j.kernel.Traversal;
>
> public class NonOrderedPathTest
> {
> private static EmbeddedGraphDatabase db;
> private static RelationshipType REL1 = withName( "REL1" ),
> REL2 = withName( "REL2" ), REL3 = withName( "REL3" ),
> REL4 = withName( "REL4" ), REL8 = withName( "REL8" ),
> REL9 = withName( "REL9" ), REL10 = withName( "REL10" );
>
> @BeforeClass
> public static void createTheGraph()
> {
> db = new EmbeddedGraphDatabase( "target/db" );
> Transaction tx = db.beginTx();
> // START SNIPPET: createGraph
> Node A = db.createNode();
> Node B = db.createNode();
> Node C = db.createNode();
> Node D = db.createNode();
> Node E = db.createNode();
> Node P = db.createNode();
> Node Q = db.createNode();
> Node R = db.createNode();
> Node S = db.createNode();
> Node T = db.createNode();
> Node U = db.createNode();
> Node X = db.createNode();
> Node Y = db.createNode();
> Node Z = db.createNode();
> A.createRelationshipTo( X, REL1 );
> X.createRelationshipTo( Y, REL2 );
> Y.createRelationshipTo( Z, REL8 );
> A.createRelationshipTo( B, REL1 );
> B.createRelationshipTo( C, REL2 );
> Relationship rel3 = C.createRelationshipTo( D, REL3 );
> rel3.setProperty( "relProp", 123 );
> D.createRelationshipTo( E, REL4 );
> A.createRelationshipTo( P, REL1 );
> Relationship rel33 = P.createRelationshipTo( Q, REL3 );
> rel33.setProperty( "relProp", 123 );
> Q.createRelationshipTo( R, REL9 );
> Q.createRelationshipTo( R, REL4 );
> R.createRelationshipTo( E, REL10 );
> R.createRelationshipTo( S, REL2 );
> S.createRelationshipTo( T, REL9 );
> T.createRelationshipTo( U, REL8 );
>
> tx.success();
> tx.finish();
> }
>
> @Test
> public void testPath()
> {
> TraversalDescription td = Traversal.description().expand(
> Traversal.expanderForTypes( REL1, Direction.OUTGOING, REL2,
> Direction.OUTGOING, REL3, Direction.OUTGOING, REL4,
> Direction.OUTGOING ) ).evaluator( new Evaluator()
> {
>
> public Evaluation evaluate( Path path )
> {
> if ( path.length() == 0 )
> {
> return Evaluation.EXCLUDE_AND_CONTINUE;
> }
> ArrayList<String> relTypes = new ArrayList<String>();
> for(Relationship rel : path.relationships()) {
> String relname = rel.getType().name();
> if(relname.equals( REL3.name() )) {
> if(rel.hasProperty( "relProp" )) {
> } else {
> return Evaluation.EXCLUDE_AND_PRUNE;
> }
> }
> if(!relTypes.contains( relname )) {
> relTypes.add( relname );
> } else {
> return Evaluation.EXCLUDE_AND_PRUNE;
> }
> }
> return
>
> path.length()==4?Evaluation.INCLUDE_AND_CONTINUE:Evaluation.EXCLUDE_AND_CONTINUE;
> }
> } );
> Traverser t = td.traverse( db.getNodeById( 1 ) );
> for ( Path path : t )
> {
> System.out.println( path );
> }
>
> }
> }
>
>
> Cheers,
>
> /peter neubauer
>
> GTalk: neubauer.peter
> Skype peter.neubauer
> Phone +46 704 106975
> LinkedIn http://www.linkedin.com/in/neubauer
> Twitter http://twitter.com/peterneubauer
>
> http://www.neo4j.org - Your high performance graph database.
> http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party.
>
>
>
> On Mon, Feb 14, 2011 at 6:34 PM, John Howard <johnyho...@gmail.com>
> wrote:
> > Thanks Peter & Craig.
> >
> > There are no such constraints, that is, relationship types can reoccur if
> a
> > path satisfies the input criteria.
> > For ex: If there was another path in our graph example, say,
> > REL1 REL3 REL4 REL2 REL9 REL8
> > A ---------> P ---------> Q -----------> R ---------> S
> > ---------->T----------->U
> >
> > we would like to see 2 paths, viz, A ->B->C->D-> E and A ->P->Q->R-> S
> >
> > I tried with the map suggestion, the prune logic doesn't seem to fit with
> > the existing evaluators.
> > Again, my understanding of the prune evaluators may be wrong.
> > Appreciate your help.
> >
> > Thank you.
> >
> >
> > On Mon, Feb 14, 2011 at 5:22 AM, Peter Neubauer <
> > peter.neuba...@neotechnology.com> wrote:
> >
> >> John,
> >> In your example, are there any constraints on that of the four
> >> relationship types, every one need to be exactly one time in the path,
> >> or is it just any of these?
> >>
> >> Instead of using a List like in the previous example, you can the use
> >> a Map to tick the visited relationship types and check the property
> >> when you get to REL3? I can do it for you in neo4j-examples again if
> >> you give me some more details :)
> >>
> >> Cheers,
> >>
> >> /peter neubauer
> >>
> >> GTalk: neubauer.peter
> >> Skype peter.neubauer
> >> Phone +46 704 106975 <+46704106975>
> >> LinkedIn http://www.linkedin.com/in/neubauer
> >> Twitter http://twitter.com/peterneubauer
> >>
> >> http://www.neo4j.org - Your high performance graph
> database.
> >> http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party.
> >>
> >>
> >>
> >> On Sun, Feb 13, 2011 at 10:16 AM, John Howard <johnyho...@gmail.com>
> >> wrote:
> >> > Thanks Peter. That was very useful.
> >> >
> >> > I am trying to get the path A ->B->C->D-> E in the below graph, with
> the
> >> > following inputs
> >> > Start Node: A,
> >> > Relationships: REL1, REL4, REL2 (that is, order is not known)
> >> > Relationship Property: relProp= "abc" in REL3
> >> >
> >> > I was not able to define an evaluator which takes the combination of
> >> > relationship types(without regard to order) and relationship
> properties
> >> to
> >> > return the desired path.
> >> > Can it be achievable in the current traversal framework?
> >> >
> >> > REL1 REL2 REL8
> >> > A ---------> X ---------> Y -----------> Z
> >> >
> >> > REL1 REL2 REL3 REL4
> >> > A ---------> B ---------> C -----------> D ---------> E
> >> >
> >> > REL1 REL3 REL9 REL10
> >> > A ---------> P ---------> Q -----------> R ---------> E
> >> >
> >> >
> >> > As always, appreciate your guidance.
> >> >
> >> >
> >> >
> >> > =======================================================
> >> > John,
> >> > if the order of the relationships doesn't matter, you could do
> >> > something like this with the Traversal API (holding an ordered Path to
> >> > test against in your Evaluator):
> >> >
> >> > public void testPath()
> >> > {
> >> > final ArrayList<RelationshipType> orderedPath = new
> >> > ArrayList<RelationshipType>();
> >> > orderedPath.add( withName( "REL1" ) );
> >> > orderedPath.add( withName( "REL2" ) );
> >> > orderedPath.add( withName( "REL3" ) );
> >> > orderedPath.add( withName( "REL4" ) );
> >> >
> >> > TraversalDescription td = Traversal.description().evaluator(
> >> > new Evaluator()
> >> > {
> >> >
> >> > public Evaluation evaluate( Path path )
> >> > {
> >> > if ( path.length() == 0 )
> >> > {
> >> > return Evaluation.EXCLUDE_AND_CONTINUE;
> >> > }
> >> > String currentName=
> >> > path.lastRelationship().getType().name();
> >> > String relationshipType = orderedPath.get(
> >> > path.length() - 1 ).name();
> >> > if ( path.length() == orderedPath.size() )
> >> > {
> >> > if ( currentName.equals(
> >> > relationshipType ) )
> >> > {
> >> > return Evaluation.INCLUDE_AND_PRUNE;
> >> > }
> >> > else
> >> > {
> >> > return Evaluation.EXCLUDE_AND_PRUNE;
> >> > }
> >> > }
> >> > else
> >> > {
> >> > if ( currentName.equals(
> >> > relationshipType ) )
> >> > {
> >> > return Evaluation.EXCLUDE_AND_CONTINUE;
> >> > }
> >> > else
> >> > {
> >> > return Evaluation.EXCLUDE_AND_PRUNE;
> >> > }
> >> > }
> >> > }
> >> > } );
> >> > Traverser t = td.traverse( getNodeWithName( "A" ) );
> >> > for ( Path path : t )
> >> > {
> >> > System.out.println(path);
> >> > }
> >> >
> >> > }
> >> >
> >> > I am attaching the classes for your reference, so you have full code.
> >> >
> >> > Also, you could try JRuby, Gremlin or other along the same lines. But
> >> > this is a basic Java example in creating an ordered Path information
> >> > and checking against it during the traversal. You can add in more
> >> > stuff of course ...
> >> >
> >> > Cheers,
> >> >
> >> > /peter neubauer
> >> >
> >> > GTalk: neubauer.peter
> >> > Skype peter.neubauer
> >> > Phone +46 704 106975 <+46704106975>
> >> > LinkedIn http://www.linkedin.com/in/neubauer
> >> > Twitter http://twitter.com/peterneubauer
> >> >
> >> > http://www.neo4j.org - Your high performance graph
> >> database.
> >> > http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing
> party.
> >> >
> >> >
> >> >
> >> > On Tue, Jan 25, 2011 at 10:59 PM, John Howard <johnyhowdy at
> gmail.com>
> >> > wrote:
> >> >> Hello,
> >> >>
> >> >> We are trying to use neo4j graph database in one of our applications.
> >> >> I think we hit a roadblock with traversal framework. It could be due
> to
> >> > our
> >> >> limited knowledge of neo4j framework.
> >> >>
> >> >> Here is what we are trying to accomplish:
> >> >> We need to get a path(from the graph below) from the nodes A to E
> >> through
> >> >> relations REL1, REL2, REL3 & REL4.
> >> >> All we know before the traversal is: Node A, REL1, REL2, REL3,
> >> >> REL4..(sometime we even know the end node E)
> >> >> So how can we get the path A to E? I can't seem to achieve it using
> >> >> evaluator and/or relationships in TraversalDescription. It always
> >> returns
> >> > me
> >> >> nodes X, P,Q since they have one my relationships(REL1, REL3).
> >> >>
> >> >>
> >> >> REL1 REL2 REL8
> >> >> A ---------> X ---------> Y -----------> Z
> >> >>
> >> >> REL1 REL2 REL3 REL4
> >> >> A ---------> B ---------> C -----------> D ---------> E
> >> >>
> >> >> REL1 REL3 REL9 REL10
> >> >> A ---------> P ---------> Q -----------> R ---------> E
> >> >>
> >> >>
> >> >> Nodes: A, B, C, D,E,X,Y,Z,P,Q,R,
> >> >> Relations: REL1....REL10
> >> >>
> >> >>
> >> >> Thank you for your help.
> >> >>
> >> >> John
> >> >> _______________________________________________
> >> >> Neo4j mailing list
> >> >> User at lists.neo4j.org
> >> >> https://lists.neo4j.org/mailman/listinfo/user
> >> >>
> >> > -------------- next part --------------
> >> > A non-text attachment was scrubbed...
> >> > Name: gist.zip
> >> > Type: application/zip
> >> > Size: 5718 bytes
> >> > Desc: not available
> >> > Url :
> >> >
> >>
> http://lists.neo4j.org/pipermail/user/attachments/20110126/f2e3cac5/attachment-0001.zip
> >> > _______________________________________________
> >> > Neo4j mailing list
> >> > User@lists.neo4j.org
> >> > https://lists.neo4j.org/mailman/listinfo/user
> >> >
> >> _______________________________________________
> >> Neo4j mailing list
> >> User@lists.neo4j.org
> >> https://lists.neo4j.org/mailman/listinfo/user
> >>
> > _______________________________________________
> > Neo4j mailing list
> > User@lists.neo4j.org
> > https://lists.neo4j.org/mailman/listinfo/user
> >
> _______________________________________________
> Neo4j mailing list
> User@lists.neo4j.org
> https://lists.neo4j.org/mailman/listinfo/user
>
_______________________________________________
Neo4j mailing list
User@lists.neo4j.org
https://lists.neo4j.org/mailman/listinfo/user
