MongoInputFormat.java

/*
 * Copyright 2010-2013 10gen Inc.
 *
 * 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.mongodb.hadoop.mapred;

import com.mongodb.hadoop.input.MongoInputSplit;
import com.mongodb.hadoop.io.BSONWritable;
import com.mongodb.hadoop.mapred.input.MongoRecordReader;
import com.mongodb.hadoop.splitter.MongoSplitter;
import com.mongodb.hadoop.splitter.MongoSplitterFactory;
import com.mongodb.hadoop.splitter.SplitFailedException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
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 java.io.IOException;
import java.util.List;

public class MongoInputFormat implements InputFormat<BSONWritable, BSONWritable> {

    private static final Log LOG = LogFactory.getLog(MongoInputFormat.class);

    @SuppressWarnings("deprecation")
    public RecordReader<BSONWritable, BSONWritable> getRecordReader(final InputSplit split, final JobConf job,
                                                                                             final Reporter reporter) {
        if (!(split instanceof MongoInputSplit)) {
            throw new IllegalStateException("Creation of a new RecordReader requires a MongoInputSplit instance.");
        }

        final MongoInputSplit mis = (MongoInputSplit) split;

        return new MongoRecordReader(mis);
    }

    public InputSplit[] getSplits(final JobConf job, final int numSplits) throws IOException {
        try {
            MongoSplitter splitterImpl = MongoSplitterFactory.getSplitter(job);
            LOG.info("Using " + splitterImpl + " to calculate splits. (old mapreduce API)");
            final List<org.apache.hadoop.mapreduce.InputSplit> splits = splitterImpl.calculateSplits();
            return splits.toArray(new InputSplit[splits.size()]);
        } catch (SplitFailedException spfe) {
            throw new IOException(spfe);
        }
    }

    public boolean verifyConfiguration(final Configuration conf) {
        return true;
    }

}