code: public final <A extends NodeInterface, B extends NodeInterface, S extends Source, T extends Target> boolean hasRelationship(final Class<? extends Relation<A, B, S, T>> type) {
  		return this.getRelationships(type).iterator().hasNext();
  	}
docs: Return true if this node has a relationship of given type and
  direction.
  
  @param <A>
  @param <B>
  @param <S>
  @param <T>
  @param type
  @return relationships