com.screenslicer.common.CommonFile.java Source code

Introduction

Here is the source code for com.screenslicer.common.CommonFile.java

Source

/* 
 * ScreenSlicer (TM) -- automatic, zero-config web scraping (TM)
 * Copyright (C) 2013-2014 Machine Publishers, LLC
 * ops@machinepublishers.com | screenslicer.com | machinepublishers.com
 * 717 Martin Luther King Dr W Ste I, Cincinnati, Ohio 45220
 *
 * You can redistribute this program and/or modify it under the terms of the
 * GNU Affero General Public License version 3 as published by the Free
 * Software Foundation. Additional permissions or commercial licensing may be
 * available--see LICENSE file or contact Machine Publishers, LLC for details.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License version 3
 * for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * version 3 along with this program. If not, see <http://www.gnu.org/licenses/>.
 * 
 * For general details about how to investigate and report license violations,
 * please see: https://www.gnu.org/licenses/gpl-violation.html
 * and email the author: ops@machinepublishers.com
 * Keep in mind that paying customers have more rights than the AGPL alone offers.
 */
package com.screenslicer.common;

import java.io.File;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.FileUtils;

public class CommonFile {
    private static final Map<String, Object> fileLocks = new HashMap<String, Object>();
    private static final Map<String, Integer> fileLocksCount = new HashMap<String, Integer>();
    private static final Object fileLocksMutex = new Object();

    private static Object lock(String filepath) {
        synchronized (fileLocksMutex) {
            Object fileLock;
            if (fileLocks.containsKey(filepath)) {
                fileLock = fileLocks.get(filepath);
                fileLocksCount.put(filepath, fileLocksCount.get(filepath).intValue() + 1);
            } else {
                final Object newFileLock = new Object();
                fileLocks.put(filepath, newFileLock);
                fileLocksCount.put(filepath, 1);
                fileLock = newFileLock;
            }
            return fileLock;
        }
    }

    private static void unlock(String filepath) {
        synchronized (fileLocksMutex) {
            fileLocksCount.put(filepath, fileLocksCount.get(filepath).intValue() - 1);
            if (fileLocksCount.get(filepath).intValue() == 0) {
                fileLocks.remove(filepath);
                fileLocksCount.remove(filepath);
            }
        }
    }

    public static void writeStringToFile(File file, String data, boolean append) {
        synchronized (lock(file.getAbsolutePath())) {
            try {
                FileUtils.writeStringToFile(file, data, "utf-8", append);
            } catch (Throwable t) {
                Log.exception(t);
            }
        }
        unlock(file.getAbsolutePath());
    }

    public static void writeByteArrayToFile(File file, byte[] data, boolean append) {
        synchronized (lock(file.getAbsolutePath())) {
            try {
                FileUtils.writeByteArrayToFile(file, data, append);
            } catch (Throwable t) {
                Log.exception(t);
            }
        }
        unlock(file.getAbsolutePath());
    }

    public static byte[] readFileToByteArray(File file) {
        byte[] content = null;
        synchronized (lock(file.getAbsolutePath())) {
            try {
                content = FileUtils.readFileToByteArray(file);
            } catch (Throwable t) {
                Log.exception(t);
            }
        }
        unlock(file.getAbsolutePath());
        return content;
    }

    public static String readFileToString(File file) {
        String content = null;
        synchronized (lock(file.getAbsolutePath())) {
            try {
                content = FileUtils.readFileToString(file, "utf-8");
            } catch (Throwable t) {
                Log.exception(t);
            }
        }
        unlock(file.getAbsolutePath());
        return content;
    }

    public static List<String> readLines(File file) {
        List<String> content = null;
        synchronized (lock(file.getAbsolutePath())) {
            try {
                content = FileUtils.readLines(file, "utf-8");
            } catch (Throwable t) {
                Log.exception(t);
            }
        }
        unlock(file.getAbsolutePath());
        return content;
    }

    public static void writeLines(File file, Collection<String> lines, boolean append) {
        synchronized (lock(file.getAbsolutePath())) {
            try {
                FileUtils.writeLines(file, "utf-8", lines, append);
            } catch (Throwable t) {
                Log.exception(t);
            }
        }
        unlock(file.getAbsolutePath());
    }
}