hadoop DirectoryListing 源码

  • 2022-10-20
  • 浏览 (21)

haddop DirectoryListing 代码

文件路径:/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/DirectoryListing.java

/**
 * 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.hadoop.hdfs.protocol;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

/**
 * This class defines a partial listing of a directory to support
 * iterative directory listing.
 */
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class DirectoryListing {
  private HdfsFileStatus[] partialListing;
  private int remainingEntries;

  /**
   * constructor
   * @param partialListing a partial listing of a directory
   * @param remainingEntries number of entries that are left to be listed
   */
  public DirectoryListing(HdfsFileStatus[] partialListing,
      int remainingEntries) {
    if (partialListing == null) {
      throw new IllegalArgumentException("partial listing should not be null");
    }
    if (partialListing.length == 0 && remainingEntries != 0) {
      throw new IllegalArgumentException("Partial listing is empty but " +
          "the number of remaining entries is not zero");
    }
    this.partialListing = partialListing;
    this.remainingEntries = remainingEntries;
  }

  /**
   * Get the partial listing of file status
   * @return the partial listing of file status
   */
  public HdfsFileStatus[] getPartialListing() {
    return partialListing;
  }

  /**
   * Get the number of remaining entries that are left to be listed
   * @return the number of remaining entries that are left to be listed
   */
  public int getRemainingEntries() {
    return remainingEntries;
  }

  /**
   * Check if there are more entries that are left to be listed
   * @return true if there are more entries that are left to be listed;
   *         return false otherwise.
   */
  public boolean hasMore() {
    return remainingEntries != 0;
  }

  /**
   * Get the last name in this list
   * @return the last name in the list if it is not empty; otherwise return null
   */
  public byte[] getLastName() {
    if (partialListing.length == 0) {
      return null;
    }
    return partialListing[partialListing.length-1].getLocalNameInBytes();
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop AclException 源码

hadoop AddErasureCodingPolicyResponse 源码

hadoop AlreadyBeingCreatedException 源码

hadoop BatchedDirectoryListing 源码

hadoop Block 源码

hadoop BlockChecksumOptions 源码

hadoop BlockChecksumType 源码

hadoop BlockLocalPathInfo 源码

hadoop BlockStoragePolicy 源码

hadoop BlockType 源码

0  赞