Hi,
Personally I'd prefer and/not.
It's intuitive to any programmer and has the bonus of being much shorter, so
long complex expansions will appear less messy in practice.
On Wed, Jun 23, 2010 at 5:45 PM, Tobias Ivarsson <
tobias.ivars...@neotechnology.com> wrote:
> Did anyone have an opinion on what to call the methods on the Expansion
> interface that specify which types to expand.
>
> Alternative 1)
> Expansion<T> and( RelationshipType type );
> Expansion<T> and( RelationshipType type, Direction direction );
> Expansion<T> not( RelationshipType type );
>
> Examples:
> for (Node node : startNode.expand( KNOWS )
> .and( LIKES )
> .and( LOVES ) ) {
> doSomethingWith(node);
> }
>
> Expansion<Relationship> expansion = startNode.expand( KNOWS );
> expansion = expansion.and( LIKES );
> expansion = expansion.and( LOVES );
>
>
> Alternative 2)
> Expansion<T> including( RelationshipType type );
> Expansion<T> including( RelationshipType type, Direction direction );
> Expansion<T> excluding( RelationshipType type );
>
> Examples:
> for (Node node : startNode.expand( KNOWS )
> .including( LIKES )
> .including( LOVES ) ) {
> doSomethingWith(node);
> }
>
> Expansion<Relationship> expansion = startNode.expand( KNOWS );
> expansion = expansion.including( LIKES );
> expansion = expansion.including( LOVES );
>
>
> Cheers,
> Tobias
>
> On Wed, Jun 23, 2010 at 11:14 AM, Tobias Ivarsson <
> tobias.ivars...@neotechnology.com> wrote:
>
> > Hi Neo4j enthusiasts!
> >
> > Yesterday I committed an API that Mattias and I have been working on for
> a
> > few days. It comes in the form of two new interfaces Expander and
> Expansion
> > (in the org.neo4j.graphdb package), and four new methods in the Node
> > interface (method names starting with "expand").
> >
> > The two main problems this API solves are:
> > 1. Adds a clean way for getting related nodes from a source node.
> > 2. Adds a type safe way for declaratively specifying any combination of
> > RelationshipTypes and Directions to expand.
> >
> > This replaces what was actually an anti-pattern, but something we saw
> > people doing a lot: using a depth-one traversal to get the nodes related
> to
> > a node, without needing to bother with the Relationship interface.
> Example:
> >
> > // The most convenient way to write it in the past:
> > Node source = ...
> > Traverser traverser = source.traverse(
> > Traverser.Order.DEPTH_FIRST,
> > new StopAtDepth( 1 ),
> > ReturnableEvaluator.ALL_BUT_START_NODE,
> > TYPE_ONE, Direction.INCOMING,
> > TYPE_TWO, Direction.OUTGOING);
> > for (Node related : traverser) {
> > doSomethingWith( related );
> > }
> >
> > // The previously recommended (and bloated) way of doing it:
> > Node source = ...
> > for (Relationship rel : source.getRelationships( TYPE_ONE, TYPE_TWO )) {
> > Node related;
> > if (rel.isType(TYPE_ONE)) {
> > related = rel.getStartNode();
> > if (related.equals(source)) continue; // we only want INCOMING
> > TYPE_ONE
> > } else if (rel.isType(TYPE_TWO)) {
> > related = rel.getEndNode();
> > if (related.equals(source)) continue; // we only want OUTGOING
> > TYPE_TWO
> > } else {
> > continue; // should never happen, but makes javac know that
> related
> > is != null
> > }
> > doSomethingWith( related );
> > }
> >
> > // With the new API:
> > Node source = ...
> > for (Node related : source.expand( TYPE_ONE, Direction.INCOMING )
> > .add( TYPE_TWO, Direction.OUTGOING ).nodes()) {
> > doSomethingWith( related );
> > }
> >
> > The return type of the Node.expand(...)-methods are the new Expansion
> type,
> > it defaults to expanding to Relationship, but the
> Expansion.nodes()-method
> > makes it expand to Node. It also contains the add()-methods seen above
> for
> > specifying RelationshipTypes to include in the expansion. The spelling of
> > this method isn't perfectly decided yet, we are choosing between "add",
> > "and" and "include", we want something that reads nicely in the code, but
> > doesn't conflict with keywords in other JVM-languages ("and" is a keyword
> in
> > Python, and I think "include" means something special in Ruby). There is
> > also an Expansion.exlude(RelationshipType)-method for use together with
> the
> > Node.expandAll().
> >
> > The Expansion is backed by the newly added companion interface Expander.
> > This is an extension of RelationshipExpander that adds builder
> capabilities.
> > It turns the functionality of the DefultExpander implementation class
> (now
> > removed) into an interface in the API. RelationshipExpander is still
> around
> > as a single method interface, which is useful for when you want to
> implement
> > your own expansion logic.
> >
> > This API is added to trunk so that we can get feedback from everyone who
> > use the snapshot builds of Neo4j, if the response to this API
> > isn't positive, it will probably be removed before the release of 1.1, so
> > please submit comments in this thread on what you think about this API.
> >
> > Happy Hacking,
> > --
> > Tobias Ivarsson <tobias.ivars...@neotechnology.com>
> > Hacker, Neo Technology
> > www.neotechnology.com
> > Cellphone: +46 706 534857
> >
>
>
>
> --
> Tobias Ivarsson <tobias.ivars...@neotechnology.com>
> Hacker, Neo Technology
> www.neotechnology.com
> Cellphone: +46 706 534857
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