com.ibm.bi.dml.runtime.matrix.mapred.MMCJMRCache.java Source code

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Here is the source code for com.ibm.bi.dml.runtime.matrix.mapred.MMCJMRCache.java

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/**
 * (C) Copyright IBM Corp. 2010, 2015
 *
 * 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.ibm.bi.dml.runtime.matrix.mapred;

import java.io.IOException;
import java.util.HashMap;
import java.util.Random;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.JobConf;

import com.ibm.bi.dml.runtime.matrix.data.MatrixIndexes;
import com.ibm.bi.dml.runtime.matrix.data.MatrixValue;
import com.ibm.bi.dml.runtime.matrix.data.Pair;
import com.ibm.bi.dml.runtime.util.LocalFileUtils;
import com.ibm.bi.dml.runtime.util.MapReduceTool;

/**
 * Base class for MMCJ partial aggregator and MMCJ input cache to factor out
 * common file management.
 * 
 */
public abstract class MMCJMRCache {

    protected Pair<MatrixIndexes, MatrixValue>[] _buffer = null;
    protected int _bufferCapacity = 0;
    protected int _bufferSize = 0;
    protected HashMap<MatrixIndexes, Integer> _bufferMap = null; //optional

    protected JobConf _job = null;
    protected FileSystem _fs = null;
    protected int _fileCursor = -1;
    protected String _filePrefix = null;
    protected int _fileN = -1;

    /**
     * 
     * @return
     */
    public HashMap<MatrixIndexes, Integer> getBufferMap() {
        return _bufferMap;
    }

    /**
     * 
     * @param buffCapacity
     * @param valueClass
     * @param buffMap
     * @throws IllegalAccessException
     * @throws InstantiationException
     */
    @SuppressWarnings("unchecked")
    protected void allocateBuffer(int buffCapacity, Class<? extends MatrixValue> valueClass, boolean buffMap)
            throws IllegalAccessException, InstantiationException {
        _bufferCapacity = buffCapacity;
        _buffer = new Pair[_bufferCapacity];
        for (int i = 0; i < _bufferCapacity; i++)
            _buffer[i] = new Pair<MatrixIndexes, MatrixValue>(new MatrixIndexes(), valueClass.newInstance());
        if (buffMap)
            _bufferMap = new HashMap<MatrixIndexes, Integer>();

        //System.out.println("allocated buffer: "+_bufferCapacity);
    }

    /**
     * 
     * @param fname
     */
    protected void constructLocalFilePrefix(String fname) {
        //get random localdir (to spread load across available disks)
        String[] localDirs = _job.get("mapred.local.dir").split(",");
        Random rand = new Random();
        int randPos = rand.nextInt(localDirs.length);

        //construct file prefix
        String hadoopLocalDir = localDirs[randPos];
        String uniqueSubDir = MapReduceTool.getGloballyUniqueName(_job);
        _filePrefix = new Path(hadoopLocalDir, uniqueSubDir + fname).toString();
    }

    /**
     * 
     * @param fileCursor
     * @return
     */
    protected Path getFilePath(int fileCursor) {
        Path path = new Path(_filePrefix + fileCursor);
        return path;
    }

    /**
     * 
     * @throws IOException
     */
    protected void loadBuffer() throws IOException {
        _bufferSize = 0;
        if (_bufferMap != null)
            _bufferMap.clear();

        Path path = getFilePath(_fileCursor);

        if (_fs.exists(path)) {
            //System.out.println( "load buffer: "+path.toString() );
            _bufferSize = LocalFileUtils.readBlockSequenceFromLocal(path.toString(), _buffer, _bufferMap);
        }
    }

    /**
     * 
     * @throws IOException
     */
    protected void writeBuffer() throws IOException {
        if (_fileCursor < 0 || _bufferSize <= 0)
            return;

        //the old file will be overwritten
        Path path = getFilePath(_fileCursor);
        //System.out.println( "write buffer: "+path.toString() );
        LocalFileUtils.writeBlockSequenceToLocal(path.toString(), _buffer, _bufferSize);
    }

    /**
     * 
     * @throws IOException
     */
    protected void deleteAllWorkingFiles() throws IOException {
        //delete existing files
        for (int i = 0; i < _fileN; i++) {
            Path ifile = new Path(_filePrefix + i);
            MapReduceTool.deleteFileIfExistOnLFS(ifile, _job);
        }
    }
}