/*-
 * ============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 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;

import java.util.Iterator;


/**
 * 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);
     }
	}


	

}