ark.util.FileUtil.java Source code

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Here is the source code for ark.util.FileUtil.java

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/**
 * Copyright 2014 Bill McDowell 
 *
 * This file is part of ARKWater (https://github.com/forkunited/ARKWater)
 *
 * 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 ark.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.json.JSONException;
import org.json.JSONObject;

/**
 * 
 * FileUtil helps deal with files on a typical file system or 
 * HDFS (in Hadoop).  Given a path for which to read/write, it
 * determines whether the path points to an HDFS or local
 * file system, and then performs operations accordingly.
 * 
 * @author Bill McDowell
 *
 */
public class FileUtil {
    public static String readFile(File file) {
        return readFile(file.getAbsolutePath());
    }

    public static String readFile(String path) {
        BufferedReader reader = FileUtil.getFileReader(path);
        StringBuilder str = new StringBuilder();
        try {
            String line = null;
            while ((line = reader.readLine()) != null) {
                str = str.append(line).append("\n");
            }
        } catch (IOException e) {
            return null;
        }

        return str.toString();
    }

    public static JSONObject readJSONFile(String path) {
        String str = readFile(path);
        try {
            return new JSONObject(str);
        } catch (JSONException e) {
            return null;
        }
    }

    public static JSONObject readJSONFile(File file) {
        return readJSONFile(file.getAbsolutePath());
    }

    public static BufferedReader getFileReader(String path) {
        InputStream resource = FileUtil.class.getClassLoader().getResourceAsStream(path);
        try {
            if (resource != null)
                return new BufferedReader(new InputStreamReader(resource));
            File file = new File(path);
            if (file.exists())
                return new BufferedReader(new FileReader(file));

            System.err.println("WARNING: FileUtil failed to read file at " + path); // Do something better later
        } catch (Exception e) {
            System.err.println("WARNING: FileUtil failed to read file at " + path);
            e.printStackTrace();
        }
        return HadoopUtil.getFileReader(path);
    }

    public static boolean fileExists(String path) {
        return FileUtil.class.getClassLoader().getResource(path) != null || (new File(path)).exists();
    }

    public static BufferedReader getFileReader(String path, String encoding) {
        File localFile = new File(path);
        try {
            if (localFile.exists())
                return new BufferedReader(new InputStreamReader(new FileInputStream(path), encoding));
            else
                System.err.println("WARNING: FileUtil failed to read file at " + path); // Do something better later
        } catch (Exception e) {
        }

        return null;
    }

    public static BufferedReader getPropertiesReader(String[] possiblePaths) {
        for (int i = 0; i < possiblePaths.length; i++) {
            BufferedReader r = getFileReader(possiblePaths[i]);
            if (r != null)
                return r;
        }
        return null;
    }
}