| /* |
| * Copyright 2009-2010 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.InputSplit; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| |
| import edu.uci.ics.pregelix.api.graph.Vertex; |
| |
| /** |
| * Analogous to {@link RecordReader} for vertices. Will read the vertices from |
| * an input split. |
| * |
| * @param <I> |
| * Vertex id |
| * @param <V> |
| * Vertex data |
| * @param <E> |
| * Edge data |
| * @param <M> |
| * Message data |
| */ |
| @SuppressWarnings("rawtypes") |
| public interface VertexReader<I extends WritableComparable, V extends Writable, E extends Writable, M extends Writable> { |
| /** |
| * Use the input split and context t o setup reading the vertices. |
| * Guaranteed to be called prior to any other function. |
| * |
| * @param inputSplit |
| * Input split to be used for reading vertices. |
| * @param context |
| * Context from the task. |
| * @throws IOException |
| * @throws InterruptedException |
| */ |
| void initialize(InputSplit inputSplit, TaskAttemptContext context) throws IOException, InterruptedException; |
| |
| /** |
| * @return false iff there are no more vertices |
| * @throws IOException |
| * @throws InterruptedException |
| */ |
| boolean nextVertex() throws IOException, InterruptedException; |
| |
| /** |
| * Get the current vertex. |
| * |
| * @return the current vertex which has been read. nextVertex() should be |
| * called first. |
| * @throws IOException |
| * @throws InterruptedException |
| */ |
| Vertex<I, V, E, M> getCurrentVertex() throws IOException, InterruptedException; |
| |
| /** |
| * Close this {@link VertexReader} to future operations. |
| * |
| * @throws IOException |
| */ |
| void close() throws IOException; |
| |
| /** |
| * How much of the input has the {@link VertexReader} consumed i.e. has been |
| * processed by? |
| * |
| * @return Progress from <code>0.0</code> to <code>1.0</code>. |
| * @throws IOException |
| * @throws InterruptedException |
| */ |
| float getProgress() throws IOException, InterruptedException; |
| } |