Hi, I had mentioned in a previous thread that I was working on introducing a NodeCollection interface to remove the dependency from IndexedRelationship to SortedTree. I have an initial cut of this up now in my github repo: https://github.com/brycenz/graph-collections
It would be great to get community feedback on this as I think that having a well designed and common NodeCollection interface would help for multiple use cases, e.g. sortedTreeNodeCollection.addAll(linkedListNodeCollection) doing exactly what you think it would. IndexedRelationship now takes a node to index relationships from, a relationship type, and a direction, as well as a NodeCollection at creation time. As in the unit tests this then leads to: Node indexedNode = graphDb().createNode(); SortedTree st = new SortedTree( graphDb(), graphDb().createNode(), new IdComparator(), true, RelTypes.INDEXED_RELATIONSHIP.name() ); IndexedRelationship ir = new IndexedRelationship( indexedNode, RelTypes.INDEXED_RELATIONSHIP, Direction.OUTGOING, st ); To create the IndexedRelationship. To later add nodes to the relationship you need to create an instance of IndexedRelationship without the NodeCollection: IndexedRelationship ir = new IndexedRelationship( indexedNode, RelTypes.INDEXED_RELATIONSHIP, Direction.OUTGOING ); What this means from a NodeCollection implementation point of view is that firstly it needs to use the NodeCollection.RelationshipType.VALUE relationship to connect from its internal data structure to the nodes being added to the collection, and it needs to be able to recreate itself from a base node that is passed into a constructor (that only takes the base node). A node collection also needs to store its class name on the base node for later construction purposes, as well as any other data required to recreate the NodeCollection instance (in the case of SortedTree this is the comparator class, the tree name, and whether it is a unique index. Niels, you may want to have a good look over SortedTree, I have made a few changes to it, mainly around introduction of a base node, and changing of the end value relationships. This could be cleaned up better, but I wanted to start with minimal changes. Both IndexedRelationship and IndexedRelationshipExpander have no dependencies on SortedTree now, and should work with any properly implemented NodeCollection. I will be putting together a paged linked list NodeCollection next to try this. Some future thoughts for NodeCollection, addition of as many of the java.util.Collection methods (e.g. addAll, removeAll, retainAll, contains, containsAll) as well as an abstract base NodeCollection to help provide non-optimised support for these methods. Cheers Bryce _______________________________________________ Neo4j mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
