[TINKERPOP-1237] ProjectMap: For the Love of Die Faterland

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Affects Version/s: 3.1.1-incubating
• Fix Version/s: 3.2.0-incubating
• Component/s: process
• Assignee: Marko A. Rodriguez
• Reporter: Marko A. Rodriguez
• Created: 24/Mar/16 02:34
• Updated: 29/Mar/16 19:04
• Resolved: 29/Mar/16 19:04

Description

gremlin> g.V(1).out("knows").
           project("a","b").by("name").by(outE().count())
==>{a:josh, b:2}
==>{a:vadas, b:0}

Its like select() by inverted – thus, project()! Moreover, its a generalization of valueMap() and propertyMap.

public class ProjectStep<S,E> extends MapStep<S,Map<String,E>> {
  TraversalRing<S,E> ...
  String... keys;  

   public Map<String,E> map(final Traverser.Admin<S> traverser) {
      final Map<String,E> result = new HashMap<>(keys.length);
      for(final String key : keys) {
        result.put(key, TraversalUtil.apply(traverser, traversalRing.next());
      }
      traversalRing.reset();
      return result;
    }
}

cc/ Mein Obergruppenführer mbroecheler.