com.facebook.hiveio.common.FileSystems.java Source code

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Here is the source code for com.facebook.hiveio.common.FileSystems.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 com.facebook.hiveio.common;

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;

import java.io.IOException;
import java.net.URI;

/**
 * Helpers for Hadopo FileSystems
 */
public class FileSystems {
    /** Filter for hidden files starting with '_' or '.' */
    public static final PathFilter HIDDEN_FILTER = new PathFilter() {
        @Override
        public boolean accept(Path path) {
            String name = path.getName();
            return !name.startsWith("_") && !name.startsWith(".");
        }
    };

    /** Don't construct, allow inheritance */
    protected FileSystems() {
    }

    /**
     * List files in directory that are not hidden.
     *
     * @param fs FileSystem
     * @param dir directory to list
     * @return FileStatus[] of non-hidden entries
     * @throws IOException I/O problems
     */
    public static FileStatus[] listNonHidden(FileSystem fs, Path dir) throws IOException {
        return fs.globStatus(new Path(dir, "*"), HIDDEN_FILTER);
    }

    /**
     * Check if directory has any non-hidden files.
     *
     * @param fs FileSystem
     * @param dir directory to check
     * @return true if directory has no non-hidden files
     * @throws IOException I/O problems
     */
    public static boolean dirHasNonHiddenFiles(FileSystem fs, Path dir) throws IOException {
        return listNonHidden(fs, dir).length != 0;
    }

    /**
     * Get path to file from source directory in a target directory.
     * Computes relative path of file in source and adds that to destination.
     *
     * @param file path to file
     * @param srcDir path to source directory
     * @param destDir path to target directory
     * @return path of file in destination
     */
    public static Path pathInDestination(Path file, Path srcDir, Path destDir) {
        URI fileUri = file.toUri();
        URI relativeUri = srcDir.toUri().relativize(fileUri);
        if (relativeUri == fileUri) {
            throw new IllegalArgumentException("Could not get file " + file + " relative path in " + srcDir);
        }
        String relativePath = relativeUri.getPath();
        if (relativePath.isEmpty()) {
            return destDir;
        } else {
            return new Path(destDir, relativePath);
        }
    }

    /**
     * Move a file or directory from source to destination, recursively copying
     * subdirectories.
     *
     * @param fs FileSystem
     * @param file path to copy (file or directory)
     * @param src path to source directory
     * @param dest path to destination directory
     * @throws IOException I/O problems
     */
    public static void move(FileSystem fs, Path file, Path src, Path dest) throws IOException {
        Path destFilePath = pathInDestination(file, src, dest);
        if (fs.isFile(file)) {
            if (fs.exists(destFilePath)) {
                if (!fs.delete(destFilePath, true)) {
                    throw new IllegalArgumentException("Could not remove existing file " + destFilePath);
                }
            }
            if (!fs.rename(file, destFilePath)) {
                throw new IllegalArgumentException("Could not move " + file + " to " + destFilePath);
            }
        } else if (fs.getFileStatus(file).isDir()) {
            FileStatus[] statuses = fs.listStatus(file);
            fs.mkdirs(destFilePath);
            if (statuses != null) {
                for (FileStatus status : statuses) {
                    move(fs, status.getPath(), src, dest);
                }
            }
        }
    }
}