com.tinkerpop.gremlin.tinkergraph.process.computer.TinkerMessenger Maven / Gradle / Ivy
package com.tinkerpop.gremlin.tinkergraph.process.computer;
import com.tinkerpop.gremlin.process.computer.MessageCombiner;
import com.tinkerpop.gremlin.process.computer.MessageType;
import com.tinkerpop.gremlin.process.computer.Messenger;
import com.tinkerpop.gremlin.structure.Edge;
import com.tinkerpop.gremlin.structure.Vertex;
import com.tinkerpop.gremlin.util.StreamFactory;
import java.util.Arrays;
import java.util.Optional;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public class TinkerMessenger implements Messenger {
private final Vertex vertex;
private final TinkerMessageBoard messageBoard;
private final Optional> combiner;
public TinkerMessenger(final Vertex vertex, final TinkerMessageBoard messageBoard, final Optional> combiner) {
this.vertex = vertex;
this.messageBoard = messageBoard;
this.combiner = combiner;
}
@Override
public Iterable receiveMessages(final MessageType messageType) {
if (messageType instanceof MessageType.Local) {
final MessageType.Local localMessageType = (MessageType.Local) messageType;
final Edge[] edge = new Edge[1]; // simulates storage side-effects available in Gremlin, but not Java8 streams
return StreamFactory.iterable(StreamFactory.stream(localMessageType.edges(this.vertex).reverse())
.map(e -> {
edge[0] = e;
return this.messageBoard.receiveMessages.get(e.toV(localMessageType.getDirection()).next());
})
.filter(q -> null != q)
.flatMap(q -> q.stream())
.map(message -> localMessageType.getEdgeFunction().apply(message, edge[0])));
} else {
return StreamFactory.iterable(Arrays.asList(this.vertex).stream()
.map(this.messageBoard.receiveMessages::get)
.filter(q -> null != q)
.flatMap(q -> q.stream()));
}
}
@Override
public void sendMessage(final MessageType messageType, final M message) {
if (messageType instanceof MessageType.Local) {
getMessageList(this.vertex).add(message);
} else {
((MessageType.Global) messageType).vertices().forEach(v -> {
final Queue queue = getMessageList(v);
if (this.combiner.isPresent() && !queue.isEmpty()) {
this.combiner.get().combine(queue.remove(), message).forEachRemaining(queue::add);
} else
queue.add(message);
});
}
}
private Queue getMessageList(final Vertex vertex) {
Queue messages = this.messageBoard.sendMessages.get(vertex);
if (null == messages) {
messages = new ConcurrentLinkedQueue<>();
this.messageBoard.sendMessages.put(vertex, messages);
}
return messages;
}
}