pregelix/pregelix-api/src/main/java/edu/uci/ics/pregelix/api/io/VertexWriter.java

/*
 * Copyright 2009-2013 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.pregelix.api.io;

import java.io.IOException;

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

import edu.uci.ics.pregelix.api.graph.Vertex;

/**
 * Implement to output a vertex range of the graph after the computation
 * 
 * @param <I>
 *            Vertex id
 * @param <V>
 *            Vertex value
 * @param <E>
 *            Edge value
 */
@SuppressWarnings("rawtypes")
public interface VertexWriter<I extends WritableComparable, V extends Writable, E extends Writable> {
    /**
     * Use the context to setup writing the vertices. Guaranteed to be called
     * prior to any other function.
     * 
     * @param context
     *            Context used to write the vertices.
     * @throws IOException
     * @throws InterruptedException
     */
    void initialize(TaskAttemptContext context) throws IOException, InterruptedException;

    /**
     * Writes the next vertex and associated data
     * 
     * @param vertex
     *            set the properties of this vertex
     * @throws IOException
     * @throws InterruptedException
     */
    void writeVertex(Vertex<I, V, E, ?> vertex) throws IOException, InterruptedException;

    /**
     * Close this {@link VertexWriter} to future operations.
     * 
     * @param context
     *            the context of the task
     * @throws IOException
     * @throws InterruptedException
     */
    void close(TaskAttemptContext context) throws IOException, InterruptedException;
}