org.apache.pirk.utils.HDFS.java Source code

Introduction

Here is the source code for org.apache.pirk.utils.HDFS.java

Source

/*
 * 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.pirk.utils;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.json.simple.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Class for basic HDFS fileIO utils
 */
public class HDFS {
    private static final Logger logger = LoggerFactory.getLogger(HDFS.class);

    public static void writeFile(Collection<String> elements, FileSystem fs, String path, boolean deleteOnExit) {
        Path filePath = new Path(path);

        try {
            // create writer
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fs.create(filePath, true)));

            // write each element on a new line
            for (String element : elements) {
                bw.write(element);
                bw.newLine();
            }

            bw.close();

            // delete file once the filesystem is closed
            if (deleteOnExit) {
                fs.deleteOnExit(filePath);
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void writeFile(List<JSONObject> elements, FileSystem fs, String path, boolean deleteOnExit) {
        Path filePath = new Path(path);

        try {
            // create writer
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fs.create(filePath, true)));

            // write each element on a new line
            for (JSONObject element : elements) {
                bw.write(element.toString());
                bw.newLine();
            }
            bw.close();

            // delete file once the filesystem is closed
            if (deleteOnExit) {
                fs.deleteOnExit(filePath);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void writeFile(List<BigInteger> elements, FileSystem fs, Path path, boolean deleteOnExit) {
        try {
            // create writer
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fs.create(path, true)));

            // write each element on a new line
            for (BigInteger element : elements) {
                bw.write(element.toString());
                bw.newLine();
            }
            bw.close();

            // delete file once the filesystem is closed
            if (deleteOnExit) {
                fs.deleteOnExit(path);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void writeFile(Map<String, Integer> sortedMap, FileSystem fs, String path, boolean deleteOnExit) {
        Path filePath = new Path(path);

        try {
            // create writer
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fs.create(filePath, true)));

            // write each element on a new line
            for (Entry<String, Integer> entry : sortedMap.entrySet()) {
                bw.write(entry.getKey() + "," + entry.getValue());
                bw.newLine();
            }
            bw.close();

            // delete file once the filesystem is closed
            if (deleteOnExit) {
                fs.deleteOnExit(filePath);
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static ArrayList<String> readFile(FileSystem fs, String filepath) {
        Path path = new Path(filepath);
        return readFile(fs, path);
    }

    public static ArrayList<String> readFile(FileSystem fs, Path path) {
        ArrayList<String> rv = new ArrayList<>();
        try (BufferedReader br = new BufferedReader(new InputStreamReader(fs.open(path)))) {
            String line;
            while ((line = br.readLine()) != null) {
                rv.add(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        return rv;
    }

    public static HashSet<String> readFileHashSet(FileSystem fs, Path path) {
        HashSet<String> rv = new HashSet<>();
        try (BufferedReader br = new BufferedReader(new InputStreamReader(fs.open(path)))) {
            String line;
            while ((line = br.readLine()) != null) {
                rv.add(line);
            }

        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }

        return rv;
    }

    public static ArrayList<Path> getFilesInDirectory(FileSystem fs, String directory) {

        ArrayList<Path> files = new ArrayList<>();

        try {

            Path path = new Path(directory);
            FileStatus[] statuses = fs.listStatus(path);

            if (statuses != null) {
                for (FileStatus status : statuses) {
                    files.add(status.getPath());
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }

        return files;

    }

    public static Path findFileInDirectory(FileSystem fs, String directory, String startsWith) {

        ArrayList<Path> files = getFilesInDirectory(fs, directory);

        if (files == null) {
            return null;
        }

        for (Path file : files) {
            if (file.getName().startsWith(startsWith)) {
                return file;
            }
        }

        return null;
    }

    public static void deletePath(FileSystem fs, String filepath) {
        Path path = new Path(filepath);

        try {
            fs.delete(path, true);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void writeFileIntegers(List<Integer> elements, FileSystem fs, Path path, boolean deleteOnExit) {
        try {
            // create writer
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fs.create(path, true)));

            // write each element on a new line
            for (Integer element : elements) {
                bw.write(element.toString());
                bw.newLine();
            }
            bw.close();

            // delete file once the filesystem is closed
            if (deleteOnExit) {
                fs.deleteOnExit(path);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

}