content: /*
   * Copyright 2022 Alibaba Group Holding Limited.
   *
   * 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.
   */
  
  package com.alibaba.graphscope.example.giraph.format;
  
  import com.google.common.collect.Lists;
  
  import org.apache.giraph.edge.Edge;
  import org.apache.giraph.io.formats.TextVertexInputFormat;
  import org.apache.hadoop.io.DoubleWritable;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapreduce.InputSplit;
  import org.apache.hadoop.mapreduce.TaskAttemptContext;
  
  import java.io.IOException;
  import java.util.List;
  
  public class DatagenVertexInputFormat
          extends TextVertexInputFormat<LongWritable, DoubleWritable, DoubleWritable> {
  
      /**
       * The factory method which produces the {@link org.apache.giraph.io.formats.TextVertexInputFormat.TextVertexReader}
       * used by this input format.
       *
       * @param split   the split to be read
       * @param context the information about the task
       * @return the text vertex reader to be used
       */
      @Override
      public TextVertexInputFormat<LongWritable, DoubleWritable, DoubleWritable>.TextVertexReader
              createVertexReader(InputSplit split, TaskAttemptContext context) throws IOException {
          return new P2PVertexReader();
      }
  
      public class P2PVertexReader extends TextVertexReaderFromEachLineProcessed<String[]> {
  
          String SEPARATOR = " ";
  
          /**
           * Cached vertex id for the current line
           */
          private LongWritable id;
  
          private DoubleWritable value;
  
          @Override
          protected String[] preprocessLine(Text line) throws IOException {
              String[] tokens = line.toString().split(SEPARATOR);
              id = new LongWritable(Long.parseLong(tokens[0]));
              value = new DoubleWritable(0.0d);
              return tokens;
          }
  
          @Override
          protected LongWritable getId(String[] tokens) throws IOException {
              return id;
          }
  
          @Override
          protected DoubleWritable getValue(String[] tokens) throws IOException {
              return value;
          }
  
          @Override
          protected Iterable<Edge<LongWritable, DoubleWritable>> getEdges(String[] tokens)
                  throws IOException {
              List<Edge<LongWritable, DoubleWritable>> edges = Lists.newArrayListWithCapacity(0);
              return edges;
          }
      }
  }
  