/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 package org.apache.giraph.graph;

 import org.apache.giraph.edge.Edge;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import java.util.List;

 /**

  * Structure to hold all the possible graph mutations that can occur during a

  * superstep.

  *

  * @param <I> Vertex index value

  * @param <V> Vertex value

  * @param <E> Edge value

  */

 @SuppressWarnings("rawtypes")

 public interface VertexChanges<I extends WritableComparable,

     V extends Writable, E extends Writable> {

   /**

    * Get the added vertices for this particular vertex index from the previous

    * superstep.

    *

    * @return List of vertices for this vertex index.

    */

   List<Vertex<I, V, E>> getAddedVertexList();

   /**

    * Get the number of times this vertex was removed in the previous

    * superstep.

    *

    * @return Count of time this vertex was removed in the previous superstep

    */

   int getRemovedVertexCount();

   /**

    * Get the added edges for this particular vertex index from the previous

    * superstep

    *

    * @return List of added edges for this vertex index

    */

   List<Edge<I, E>> getAddedEdgeList();

   /**

    * Get the removed edges by their destination vertex index.

    *

    * @return List of destination edges for removal from this vertex index

    */

   List<I> getRemovedEdgeList();

 }