Eelco,
there is at least one issue that I can see -> different type + dir might have
the same hashcode overriding each other.
I would use "Rel" as a real class.
- so implement hashcode and equals in it correctly
- remove the getters from Rel, add a toJson() method
- don't use String name in the Rel class
- then you can use a Set<Rel> instead of the map and check for
rels.contains(new Rel(type,dir)
Alternative for the return serialization
for the serialization you could probably return a ListRepresentation from your
method, subclasses of Representation are also allowed.
this list representation would contain a list of ObjectRepresentations for Rel,
you can look at an example at NameDescriptionValueRepresentation.
Probably you can also have Rel extend from ObjectRepresentation, then you have
to keep the getters :( but if you annotate them with @Mapping("key-name") you
get your
representation generated.
Cheers
Michael
Am 13.07.2011 um 21:06 schrieb Eelco Hillenius:
> Hi,
>
>> The unmanaged extensions simply give you access to the underlying Graph
>> Database instance (through the annotations).
>>
>> The managed plugins do far more than this - they also provide a way of
>> generating JSON/HTML responses automatically (using HTTP content
>> negotiation).
>>
>> In either case you can host arbitrary code.
>>
>> From your mail, it seems that JSON/HTML would be fine for you, e.g.:
>>
>> [
>> {
>> "node_id" : 28,
>> "Incoming_friend_rels" : 156
>> },
>> "node_id" : 29,
>> "Incoming_friend_rels" : 32
>> }
>> ]
>
> Right. I implemented this as an unmanaged extension. Now what I'm
> wondering is if I can implement the same as a server plugin.
>
> Also, somewhat related, what would be the best way to develop a server
> plugin that is a daemon? I need to write some database synchronization
> code that would run in the background, and for the sake of efficiency,
> that would best run directly in the server.
>
> FWIW, here's my code as it is now (and if anything doesn't make sense
> in that code, please share :-) )
>
> @Path("/rels")
> public class RelationshipsExtApi {
>
> static class Rel {
> String name; // name of the relationship
> int count; // number of nodes the relationship is connected to
> Direction direction; // direction of the relationship (as seen
> from the originating node)
>
> public Rel(String name, Direction direction) {
> this.name = name;
> this.direction = direction;
> }
>
> public String getName() {
> return name;
> }
>
> public void setName(String name) {
> this.name = name;
> }
>
> public int getCount() {
> return count;
> }
>
> public void setCount(int count) {
> this.count = count;
> }
>
> public Direction getDirection() {
> return direction;
> }
>
> public void setDirection(Direction direction) {
> this.direction = direction;
> }
> }
>
> private final GraphDatabaseService graphDb;
>
> public RelationshipsExtApi(@Context GraphDatabaseService graphDb) {
> this.graphDb = graphDb;
> }
>
> @GET
> @Consumes(MediaType.TEXT_PLAIN)
> @Produces(MediaType.APPLICATION_JSON)
> @Path("{id}")
> public String getRelationships(@PathParam("id") long id) {
> Node node = graphDb.getNodeById(id);
> Map<Integer, Rel> rels = new HashMap<Integer, Rel>();
> for (Relationship r : node.getRelationships()) {
> Direction direction = node.equals(r.getStartNode()) ?
> Direction.OUTGOING : Direction.INCOMING;
> int hash = hash(r.getType(), direction);
> Rel rel = rels.get(hash);
> if (rel == null) {
> rel = new Rel(r.getType().name(), direction);
> rels.put(hash, rel);
> }
> rel.count++;
> }
>
> StringBuilder b = new StringBuilder("[");
> for (Iterator<Rel> i = rels.values().iterator(); i.hasNext(); ) {
> Rel rel = i.next();
> b.append("{")
> .append("\"name\": \"").append(rel.getName()).append("\",
> ")
> .append("\"direction\":
> \"").append(rel.getDirection().name()).append("\", ")
> .append("\"count\": ").append(rel.getCount()).append(" }");
> if (i.hasNext()) {
> b.append(", ");
> }
> }
> b.append("]");
> return b.toString();
> }
>
> int hash(RelationshipType type, Direction direction) {
> return 31 * type.hashCode() + direction.hashCode();
> }
> }
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