org.apache.solr.util.FileUtils.java Source code

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Here is the source code for org.apache.solr.util.FileUtils.java

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/*
 * 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.solr.util;

import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.file.Files;
import java.nio.file.Path;

import org.apache.commons.io.FileExistsException;

/**
 *
 */
public class FileUtils {

    /**
     * Resolves a path relative a base directory.
     *
     * <p>
     * This method does what "new File(base,path)" <b>Should</b> do, if it wasn't
     * completely lame: If path is absolute, then a File for that path is returned;
     * if it's not absolute, then a File is returned using "path" as a child
     * of "base")
     * </p>
     */
    public static File resolvePath(File base, String path) {
        File r = new File(path);
        return r.isAbsolute() ? r : new File(base, path);
    }

    public static void copyFile(File src, File destination) throws IOException {
        FileChannel in = null;
        FileChannel out = null;
        try {
            in = new FileInputStream(src).getChannel();
            out = new FileOutputStream(destination).getChannel();
            in.transferTo(0, in.size(), out);
        } finally {
            try {
                if (in != null)
                    in.close();
            } catch (IOException e) {
            }
            try {
                if (out != null)
                    out.close();
            } catch (IOException e) {
            }
        }
    }

    /**
     * Copied from Lucene's FSDirectory.fsync(String)
     *
     * @param fullFile the File to be synced to disk
     * @throws IOException if the file could not be synced
     */
    public static void sync(File fullFile) throws IOException {
        if (fullFile == null || !fullFile.exists())
            throw new FileNotFoundException("File does not exist " + fullFile);

        boolean success = false;
        int retryCount = 0;
        IOException exc = null;
        while (!success && retryCount < 5) {
            retryCount++;
            RandomAccessFile file = null;
            try {
                try {
                    file = new RandomAccessFile(fullFile, "rw");
                    file.getFD().sync();
                    success = true;
                } finally {
                    if (file != null)
                        file.close();
                }
            } catch (IOException ioe) {
                if (exc == null)
                    exc = ioe;
                try {
                    // Pause 5 msec
                    Thread.sleep(5);
                } catch (InterruptedException ie) {
                    Thread.currentThread().interrupt();
                }
            }
        }
        if (!success)
            // Throw original exception
            throw exc;
    }

    public static boolean fileExists(String filePathString) {
        return new File(filePathString).exists();
    }

    // Files.createDirectories has odd behavior if the path is a symlink and it already exists
    // _even if it's a symlink to a directory_. 
    // 
    // oddly, if the path to be created just contains a symlink in intermediate levels, Files.createDirectories
    // works just fine.
    //
    // This works around that issue
    public static Path createDirectories(Path path) throws IOException {
        if (Files.exists(path) && Files.isSymbolicLink(path)) {
            Path real = path.toRealPath();
            if (Files.isDirectory(real))
                return real;
            throw new FileExistsException(
                    "Tried to create a directory at to an existing non-directory symlink: " + path.toString());
        }
        return Files.createDirectories(path);
    }
}