org.kitesdk.data.spi.filesystem.FileSystemUtil.java Source code

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Here is the source code for org.kitesdk.data.spi.filesystem.FileSystemUtil.java

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/*
 * Copyright 2013 Cloudera Inc.
 *
 * 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 org.kitesdk.data.spi.filesystem;

import com.google.common.base.Preconditions;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.kitesdk.data.DatasetDescriptor;
import org.kitesdk.data.DatasetIOException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class FileSystemUtil {

    private static final Logger LOG = LoggerFactory.getLogger(FileSystemUtil.class);

    /**
     * Creates, if necessary, the given the location for {@code descriptor}.
     *
     * @param conf A Configuration
     * @param descriptor A DatasetDescriptor
     * @throws DatasetIOException
     * @since 0.13.0
     */
    public static void ensureLocationExists(DatasetDescriptor descriptor, Configuration conf) {
        Preconditions.checkNotNull(descriptor.getLocation(),
                "Cannot get FileSystem for a descriptor with no location");

        Path dataPath = new Path(descriptor.getLocation());
        FileSystem fs = null;

        try {
            fs = dataPath.getFileSystem(conf);
        } catch (IOException e) {
            throw new DatasetIOException("Cannot get FileSystem for descriptor: " + descriptor, e);
        }

        try {
            if (!fs.exists(dataPath)) {
                fs.mkdirs(dataPath);
            }
        } catch (IOException e) {
            throw new DatasetIOException("Cannot access data location", e);
        }
    }

    static boolean cleanlyDelete(FileSystem fs, Path root, Path path) {
        try {
            boolean deleted;
            if (path.isAbsolute()) {
                LOG.debug("Deleting path {}", path);
                deleted = fs.delete(path, true /* include any files */ );
            } else {
                // the path should be treated as relative to the root path
                Path absolute = new Path(root, path);
                LOG.debug("Deleting path {}", absolute);
                deleted = fs.delete(absolute, true /* include any files */ );
                // iterate up to the root, removing empty directories
                for (Path current = absolute.getParent(); !current.equals(root)
                        && !(current.getParent() == null); current = current.getParent()) {
                    final FileStatus[] stats = fs.listStatus(current);
                    if (stats == null || stats.length == 0) {
                        // dir is empty and should be removed
                        LOG.debug("Deleting empty path {}", current);
                        deleted = fs.delete(current, true) || deleted;
                    } else {
                        // all parent directories will be non-empty
                        break;
                    }
                }
            }
            return deleted;
        } catch (IOException ex) {
            throw new DatasetIOException("Could not cleanly delete path:" + path, ex);
        }
    }
}