HadoopBasicFileAttributeView.java

/*
 * Copyright 2016 Damien Carol <damien.carol@gmail.com>
 *
 * 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 hdfs.jsr203;

import java.io.IOException;
import java.nio.file.LinkOption;
import java.nio.file.attribute.BasicFileAttributeView;
import java.nio.file.attribute.FileTime;
import java.util.LinkedHashMap;
import java.util.Map;

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

/**
 * Implement {@link BasicFileAttributeView}.
 */
public class HadoopBasicFileAttributeView
    implements BasicFileAttributeView, IAttributeReader, IAttributeWriter {

  private enum AttrID {
    size,

    creationTime,

    lastAccessTime,

    lastModifiedTime,

    isDirectory,

    isRegularFile,

    isSymbolicLink,

    isOther,

    fileKey,

    accessTime,

    blockSize,

    group,

    len,

    modificationTime,

    owner,

    replication,

    isFile,

    isSymLink
  };

  private final HadoopPath path;
  private final boolean isHadoopView;

  public HadoopBasicFileAttributeView(HadoopPath path, boolean isHadoopView) {
    this.path = path;
    this.isHadoopView = isHadoopView;
  }

  @Override
  public String name() {
    return isHadoopView ? "hadoop" : "basic";
  }

  public HadoopBasicFileAttributes readAttributes() throws IOException {
    Path resolvedPath = path.getRawResolvedPath();
    FileStatus fileStatus = path.getFileSystem().getHDFS()
        .getFileStatus(resolvedPath);
    String fileKey = resolvedPath.toString();
    return new HadoopBasicFileAttributes(fileKey, fileStatus);
  }

  @Override
  public void setTimes(FileTime lastModifiedTime, FileTime lastAccessTime,
      FileTime createTime) throws IOException {
    path.setTimes(lastModifiedTime, lastAccessTime, createTime);
  }

  @Override
  public void setAttribute(String attribute, Object value, LinkOption[] options)
      throws IOException {
    if (AttrID.valueOf(attribute) == AttrID.lastModifiedTime) {
      setTimes((FileTime) value, null, null);
    }
    if (AttrID.valueOf(attribute) == AttrID.lastAccessTime) {
      setTimes(null, (FileTime) value, null);
    }
    if (AttrID.valueOf(attribute) == AttrID.creationTime) {
      setTimes(null, null, (FileTime) value);
    }
  }

  @Override
  public Map<String, Object> readAttributes(String attributes,
      LinkOption[] options) throws IOException {
    HadoopBasicFileAttributes zfas = readAttributes();
    LinkedHashMap<String, Object> map = new LinkedHashMap<>();
    if ("*".equals(attributes)) {
      for (AttrID id : AttrID.values()) {
        map.put(id.name(), attribute(id, zfas));
      }
    } else {
      String[] as = attributes.split(",");
      for (String a : as) {
        map.put(a, attribute(AttrID.valueOf(a), zfas));
      }
    }
    return map;
  }

  private Object attribute(AttrID id, HadoopBasicFileAttributes hfas) {
    if (isHadoopView) {
      switch (id) {
      case accessTime:
        return hfas.getFileStatus().getAccessTime();
      case blockSize:
        return hfas.getFileStatus().getBlockSize();
      case group:
        return hfas.getFileStatus().getGroup();
      case len:
        return hfas.getFileStatus().getLen();
      case modificationTime:
        return hfas.getFileStatus().getModificationTime();
      case owner:
        return hfas.getFileStatus().getOwner();
      case replication:
        return hfas.getFileStatus().getReplication();
      case isDirectory:
        return hfas.getFileStatus().isDirectory();
      case isFile:
        return hfas.getFileStatus().isFile();
      case isSymLink:
        return hfas.getFileStatus().isSymlink();
      default:
        return null;
      }
    } else {
      switch (id) {
      case size:
        return hfas.size();
      case creationTime:
        return hfas.creationTime();
      case lastAccessTime:
        return hfas.lastAccessTime();
      case lastModifiedTime:
        return hfas.lastModifiedTime();
      case isDirectory:
        return hfas.isDirectory();
      case isRegularFile:
        return hfas.isRegularFile();
      case isSymbolicLink:
        return hfas.isSymbolicLink();
      case isOther:
        return hfas.isOther();
      case fileKey:
        return hfas.fileKey();
      default:
        return null;
      }
    }
  }
}