org.apache.mahout.text.WholeFileRecordReader.java Source code

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Here is the source code for org.apache.mahout.text.WholeFileRecordReader.java

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/**
 * 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.mahout.text;

import java.io.IOException;

import com.google.common.io.Closeables;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.CombineFileSplit;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;

import static org.apache.mahout.text.SequenceFilesFromDirectory.FILE_FILTER_CLASS_OPTION;

/**
 * RecordReader used with the MultipleTextFileInputFormat class to read full files as
 * k/v pairs and groups of files as single input splits.
 */
public class WholeFileRecordReader extends RecordReader<IntWritable, BytesWritable> {

    private FileSplit fileSplit;
    private boolean processed = false;
    private Configuration configuration;
    private BytesWritable value = new BytesWritable();
    private IntWritable index;
    private String fileFilterClassName = null;
    private PathFilter pathFilter = null;

    public WholeFileRecordReader(CombineFileSplit fileSplit, TaskAttemptContext taskAttemptContext, Integer idx)
            throws IOException {
        this.fileSplit = new FileSplit(fileSplit.getPath(idx), fileSplit.getOffset(idx), fileSplit.getLength(idx),
                fileSplit.getLocations());
        this.configuration = taskAttemptContext.getConfiguration();
        this.index = new IntWritable(idx);
        this.fileFilterClassName = this.configuration.get(FILE_FILTER_CLASS_OPTION[0]);
    }

    @Override
    public IntWritable getCurrentKey() {
        return index;
    }

    @Override
    public BytesWritable getCurrentValue() {
        return value;
    }

    @Override
    public float getProgress() throws IOException {
        return processed ? 1.0f : 0.0f;
    }

    @Override
    public void initialize(InputSplit inputSplit, TaskAttemptContext taskAttemptContext)
            throws IOException, InterruptedException {
        if (!StringUtils.isBlank(fileFilterClassName)
                && !PrefixAdditionFilter.class.getName().equals(fileFilterClassName)) {
            try {
                pathFilter = (PathFilter) Class.forName(fileFilterClassName).newInstance();
            } catch (ClassNotFoundException e) {
                throw new IllegalStateException(e);
            } catch (InstantiationException e) {
                throw new IllegalStateException(e);
            } catch (IllegalAccessException e) {
                throw new IllegalStateException(e);
            }
        }
    }

    @Override
    public boolean nextKeyValue() throws IOException {
        if (!processed) {
            byte[] contents = new byte[(int) fileSplit.getLength()];
            Path file = fileSplit.getPath();
            FileSystem fs = file.getFileSystem(this.configuration);

            if (!fs.isFile(file)) {
                return false;
            }

            FileStatus[] fileStatuses;
            if (pathFilter != null) {
                fileStatuses = fs.listStatus(file, pathFilter);
            } else {
                fileStatuses = fs.listStatus(file);
            }

            FSDataInputStream in = null;
            if (fileStatuses.length == 1) {
                try {
                    in = fs.open(fileStatuses[0].getPath());
                    IOUtils.readFully(in, contents, 0, contents.length);
                    value.setCapacity(contents.length);
                    value.set(contents, 0, contents.length);
                } finally {
                    Closeables.close(in, false);
                }
                processed = true;
                return true;
            }
        }
        return false;
    }

    @Override
    public void close() throws IOException {
    }
}