/*-
 * ============LICENSE_START=======================================================
 * org.openecomp.aai
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.aai.serialization.tinkerpop;

import java.util.Iterator;

import org.apache.tinkerpop.gremlin.structure.Direction;
import org.apache.tinkerpop.gremlin.structure.Edge;
import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedEdge;
import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils;


/**
 * Represents a {@link Edge} that is disconnected from a {@link Graph} however, 
 * traversals are supported as they are backed by a Tree with saturated {@link Vertex} and {@link Edge} objects.
 * These objects are not mutable and can only be used to read information out.
 *
 */
public class TreeBackedEdge extends DetachedEdge implements Edge {

	private static final long serialVersionUID = 5419650145562077538L;
	private TreeBackedVertex inVertex;
	private TreeBackedVertex outVertex;
	public TreeBackedEdge(Edge edge, TreeBackedVertex inVertex, TreeBackedVertex outVertex) {
		super(edge, true);
		this.inVertex = inVertex;
		this.outVertex = outVertex;
	}
	
	@Override
	public Vertex inVertex() {
		return this.inVertex;
	}
	
	@Override
	public Vertex outVertex() {
		return this.outVertex;
	}
	
	@Override
	public Iterator<Vertex> bothVertices() {
		return this.vertices(Direction.BOTH);
	}
	
	@Override
	public Iterator<Vertex> vertices(Direction direction) {
		 switch (direction) {
         case OUT:
             return IteratorUtils.of(this.outVertex);
         case IN:
             return IteratorUtils.of(this.inVertex);
         default:
             return IteratorUtils.of(this.outVertex, this.inVertex);
     }
	}


	

}