de.tu_berlin.dima.aim3.naivebayes.io.BinaryInputFormat.java Source code

Introduction

Here is the source code for de.tu_berlin.dima.aim3.naivebayes.io.BinaryInputFormat.java

Source

/**
 * Copyright (C) 2011 AIM III course DIMA TU Berlin
 *
 * This programm is free software; you can redistribute it and/or modify
 * it under the terms of 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 de.tu_berlin.dima.aim3.naivebayes.io;

import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.LinkedList;
import java.util.Queue;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import eu.stratosphere.nephele.fs.FSDataInputStream;
import eu.stratosphere.nephele.fs.FileStatus;
import eu.stratosphere.nephele.fs.FileSystem;
import eu.stratosphere.nephele.fs.Path;
import eu.stratosphere.pact.common.type.Key;
import eu.stratosphere.pact.common.type.Value;

public abstract class BinaryInputFormat<K extends Key, V extends Value> {

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

    protected DataInputStream dataInputStream;

    private Queue<FileStatus> files = new LinkedList<FileStatus>();
    private FileSystem fs;

    public BinaryInputFormat(String pathString) throws IOException, URISyntaxException {

        fs = FileSystem.get(new URI(pathString));
        Path path = new Path(pathString);
        final FileStatus pathFile = fs.getFileStatus(path);

        if (pathFile.isDir()) {
            // input is directory. list all contained files
            final FileStatus[] dir = fs.listStatus(path);
            for (int i = 0; i < dir.length; i++) {
                if (!dir[i].isDir()) {
                    String fileName = dir[i].getPath().getName();
                    if (fileName.startsWith(".") == false) {
                        files.add(dir[i]);
                    }
                }
            }

        } else {
            files.add(pathFile);
        }
        getNextReader();
    }

    private boolean getNextReader() {
        if (files.isEmpty() == false) {
            FileStatus fileStatus = files.poll();
            FSDataInputStream fsDataInputStream;
            try {
                LOG.info("Opening reader :" + fileStatus.getPath());
                fsDataInputStream = fs.open(fileStatus.getPath());
                dataInputStream = new DataInputStream(fsDataInputStream);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                return false;
            }
            return true;
        } else {
            return false;
        }
    }

    public boolean readPair(K keyHolder, V valueHolder) throws IOException {
        try {
            keyHolder.read(dataInputStream);
            valueHolder.read(dataInputStream);
            return true;
        } catch (EOFException e) {
            dataInputStream.close();
            LOG.info("Data input stream closed");
            if (getNextReader() == true) {
                return readPair(keyHolder, valueHolder);
            }
            return false;
        }
    }

}