src/java/org/apache/nutch/indexer/IndexerOutputFormat.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.nutch.indexer;

import java.io.IOException;
import java.lang.invoke.MethodHandles;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class IndexerOutputFormat
    extends FileOutputFormat<Text, NutchIndexAction> {

  private static final Logger LOG = LoggerFactory
      .getLogger(MethodHandles.lookup().lookupClass());

  @Override
  public RecordWriter<Text, NutchIndexAction> getRecordWriter(
      TaskAttemptContext context) throws IOException {

    Configuration conf = context.getConfiguration();
    final IndexWriters writers = IndexWriters.get(conf);

    String name = getUniqueFile(context, "part", "");
    writers.open(conf, name);
    LOG.info(writers.describe());

    return new RecordWriter<Text, NutchIndexAction>() {

      public void close(TaskAttemptContext context) throws IOException {
        // do the commits once and for all the reducers in one go
        boolean noCommit = conf
            .getBoolean(IndexerMapReduce.INDEXER_NO_COMMIT, false);
        if (!noCommit) {
          writers.commit();
        }
        writers.close();
      }

      public void write(Text key, NutchIndexAction indexAction)
          throws IOException {
        if (indexAction.action == NutchIndexAction.ADD) {
          writers.write(indexAction.doc);
        } else if (indexAction.action == NutchIndexAction.DELETE) {
          writers.delete(key.toString());
        }
      }
    };
  }
}