src/main/java/org/apache/giraph/graph/VertexChanges.java

/*
 * 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 java.util.List;

import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;

/**
 * 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
 * @param <M> Message value
 */
@SuppressWarnings("rawtypes")
public interface VertexChanges<
        I extends WritableComparable,
        V extends Writable,
        E extends Writable,
        M extends Writable> {

    /**
     * Get the added vertices for this particular vertex index from the previous
     * superstep.
     *
     * @return List of vertices for this vertex index.
     */
    List<BasicVertex<I, V, E, M>> 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();
}