content: /*
   * 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
   *
   *     https://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.avro.mapred;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  
  import org.apache.avro.Schema;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.mapred.FileInputFormat;
  import org.apache.hadoop.mapred.InputFormat;
  import org.apache.hadoop.mapred.InputSplit;
  import org.apache.hadoop.mapred.JobConf;
  import org.apache.hadoop.mapred.RecordReader;
  import org.apache.hadoop.mapred.Reporter;
  import org.apache.hadoop.mapred.lib.MultipleInputs;
  import org.apache.hadoop.util.ReflectionUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * An {@link InputFormat} that delegates read behavior of paths based on their
   * associated avro schema.
   *
   * @see MultipleInputs#addInputPath(JobConf, Path, Class, Class)
   */
  class DelegatingInputFormat<K, V> implements InputFormat<K, V> {
    private static final Logger LOG = LoggerFactory.getLogger(DelegatingInputFormat.class);
  
    @Override
    public InputSplit[] getSplits(JobConf conf, int numSplits) throws IOException {
  
      JobConf confCopy = new JobConf(conf);
      List<InputSplit> splits = new ArrayList<>();
  
      Map<Path, Class<? extends AvroMapper>> mapperMap = AvroMultipleInputs.getMapperTypeMap(conf);
      Map<Path, Schema> schemaMap = AvroMultipleInputs.getInputSchemaMap(conf);
      Map<Schema, List<Path>> schemaPaths = new HashMap<>();
  
      // First, build a map of Schemas to Paths
      for (Entry<Path, Schema> entry : schemaMap.entrySet()) {
        if (!schemaPaths.containsKey(entry.getValue())) {
          schemaPaths.put(entry.getValue(), new ArrayList<>());
          LOG.info(entry.getValue().toString());
          LOG.info(String.valueOf(entry.getKey()));
        }
  
        schemaPaths.get(entry.getValue()).add(entry.getKey());
      }
  
      for (Entry<Schema, List<Path>> schemaEntry : schemaPaths.entrySet()) {
        Schema schema = schemaEntry.getKey();
        LOG.info(schema.toString());
        InputFormat format = ReflectionUtils.newInstance(AvroInputFormat.class, conf);
        List<Path> paths = schemaEntry.getValue();
  
        Map<Class<? extends AvroMapper>, List<Path>> mapperPaths = new HashMap<>();
  
        // Now, for each set of paths that have a common Schema, build
        // a map of Mappers to the paths they're used for
        for (Path path : paths) {
          Class<? extends AvroMapper> mapperClass = mapperMap.get(path);
          if (!mapperPaths.containsKey(mapperClass)) {
            mapperPaths.put(mapperClass, new ArrayList<>());
          }
  
          mapperPaths.get(mapperClass).add(path);
        }
  
        // Now each set of paths that has a common InputFormat and Mapper can
        // be added to the same job, and split together.
        for (Entry<Class<? extends AvroMapper>, List<Path>> mapEntry : mapperPaths.entrySet()) {
          paths = mapEntry.getValue();
          Class<? extends AvroMapper> mapperClass = mapEntry.getKey();
  
          if (mapperClass == null) {
            mapperClass = (Class<? extends AvroMapper>) conf.getMapperClass();
          }
  
          FileInputFormat.setInputPaths(confCopy, paths.toArray(new Path[0]));
  
          // Get splits for each input path and tag with InputFormat
          // and Mapper types by wrapping in a TaggedInputSplit.
          InputSplit[] pathSplits = format.getSplits(confCopy, numSplits);
          for (InputSplit pathSplit : pathSplits) {
            splits.add(new TaggedInputSplit(pathSplit, conf, format.getClass(), mapperClass, schema));
          }
        }
      }
  
      return splits.toArray(new InputSplit[0]);
    }
  
    @SuppressWarnings("unchecked")
    @Override
    public RecordReader<K, V> getRecordReader(InputSplit split, JobConf conf, Reporter reporter) throws IOException {
  
      // Find the Schema and then build the RecordReader from the
      // TaggedInputSplit.
  
      TaggedInputSplit taggedInputSplit = (TaggedInputSplit) split;
      Schema schema = taggedInputSplit.getSchema();
      AvroJob.setInputSchema(conf, schema);
      InputFormat<K, V> inputFormat = (InputFormat<K, V>) ReflectionUtils
          .newInstance(taggedInputSplit.getInputFormatClass(), conf);
      return inputFormat.getRecordReader(taggedInputSplit.getInputSplit(), conf, reporter);
    }
  }
  