hadoop ImageVisitor 源码

haddop ImageVisitor 代码

文件路径：/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/ImageVisitor.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.tools.offlineImageViewer;

import java.io.IOException;

/**
 * An implementation of ImageVisitor can traverse the structure of an
 * Hadoop fsimage and respond to each of the structures within the file.
 */
abstract class ImageVisitor {

  /**
   * Structural elements of an FSImage that may be encountered within the
   * file. ImageVisitors are able to handle processing any of these elements.
   */
  public enum ImageElement {
    FS_IMAGE,
    IMAGE_VERSION,
    NAMESPACE_ID,
    IS_COMPRESSED,
    COMPRESS_CODEC,
    LAYOUT_VERSION,
    NUM_INODES,
    GENERATION_STAMP,
    GENERATION_STAMP_V2,
    GENERATION_STAMP_V1_LIMIT,
    LAST_ALLOCATED_BLOCK_ID,
    INODES,
    INODE,
    INODE_PATH,
    REPLICATION,
    MODIFICATION_TIME,
    ACCESS_TIME,
    BLOCK_SIZE,
    NUM_BLOCKS,
    BLOCKS,
    BLOCK,
    BLOCK_ID,
    NUM_BYTES,
    NS_QUOTA,
    DS_QUOTA,
    PERMISSIONS,
    SYMLINK,
    NUM_INODES_UNDER_CONSTRUCTION,
    INODES_UNDER_CONSTRUCTION,
    INODE_UNDER_CONSTRUCTION,
    PREFERRED_BLOCK_SIZE,
    CLIENT_NAME,
    CLIENT_MACHINE,
    USER_NAME,
    GROUP_NAME,
    PERMISSION_STRING,
    CURRENT_DELEGATION_KEY_ID,
    NUM_DELEGATION_KEYS,
    DELEGATION_KEYS,
    DELEGATION_KEY,
    DELEGATION_TOKEN_SEQUENCE_NUMBER,
    NUM_DELEGATION_TOKENS,
    DELEGATION_TOKENS,
    DELEGATION_TOKEN_IDENTIFIER,
    DELEGATION_TOKEN_IDENTIFIER_KIND,
    DELEGATION_TOKEN_IDENTIFIER_SEQNO,
    DELEGATION_TOKEN_IDENTIFIER_OWNER,
    DELEGATION_TOKEN_IDENTIFIER_RENEWER,
    DELEGATION_TOKEN_IDENTIFIER_REALUSER,
    DELEGATION_TOKEN_IDENTIFIER_ISSUE_DATE,
    DELEGATION_TOKEN_IDENTIFIER_MAX_DATE,
    DELEGATION_TOKEN_IDENTIFIER_EXPIRY_TIME,
    DELEGATION_TOKEN_IDENTIFIER_MASTER_KEY_ID,
    TRANSACTION_ID,
    LAST_INODE_ID,
    INODE_ID,

    SNAPSHOT_COUNTER,
    NUM_SNAPSHOTS_TOTAL,
    NUM_SNAPSHOTS,
    SNAPSHOTS,
    SNAPSHOT,
    SNAPSHOT_ID,
    SNAPSHOT_ROOT,
    SNAPSHOT_QUOTA,
    NUM_SNAPSHOT_DIR_DIFF,
    SNAPSHOT_DIR_DIFFS,
    SNAPSHOT_DIR_DIFF,
    SNAPSHOT_DIFF_SNAPSHOTID,
    SNAPSHOT_DIR_DIFF_CHILDREN_SIZE,
    SNAPSHOT_INODE_FILE_ATTRIBUTES,
    SNAPSHOT_INODE_DIRECTORY_ATTRIBUTES,
    SNAPSHOT_DIR_DIFF_CREATEDLIST,
    SNAPSHOT_DIR_DIFF_CREATEDLIST_SIZE,
    SNAPSHOT_DIR_DIFF_CREATED_INODE,
    SNAPSHOT_DIR_DIFF_DELETEDLIST,
    SNAPSHOT_DIR_DIFF_DELETEDLIST_SIZE,
    SNAPSHOT_DIR_DIFF_DELETED_INODE,
    IS_SNAPSHOTTABLE_DIR,
    IS_WITHSNAPSHOT_DIR,
    SNAPSHOT_FILE_DIFFS,
    SNAPSHOT_FILE_DIFF,
    NUM_SNAPSHOT_FILE_DIFF,
    SNAPSHOT_FILE_SIZE,
    SNAPSHOT_DST_SNAPSHOT_ID,
    SNAPSHOT_LAST_SNAPSHOT_ID,
    SNAPSHOT_REF_INODE_ID,
    SNAPSHOT_REF_INODE,

    CACHE_NEXT_ENTRY_ID,
    CACHE_NUM_POOLS,
    CACHE_POOL_NAME,
    CACHE_POOL_OWNER_NAME,
    CACHE_POOL_GROUP_NAME,
    CACHE_POOL_PERMISSION_STRING,
    CACHE_POOL_WEIGHT,
    CACHE_NUM_ENTRIES,
    CACHE_ENTRY_PATH,
    CACHE_ENTRY_REPLICATION,
    CACHE_ENTRY_POOL_NAME
  }
  
  /**
   * Begin visiting the fsimage structure.  Opportunity to perform
   * any initialization necessary for the implementing visitor.
   */
  abstract void start() throws IOException;

  /**
   * Finish visiting the fsimage structure.  Opportunity to perform any
   * clean up necessary for the implementing visitor.
   */
  abstract void finish() throws IOException;

  /**
   * Finish visiting the fsimage structure after an error has occurred
   * during the processing.  Opportunity to perform any clean up necessary
   * for the implementing visitor.
   */
  abstract void finishAbnormally() throws IOException;

  /**
   * Visit non enclosing element of fsimage with specified value.
   *
   * @param element FSImage element
   * @param value Element's value
   */
  abstract void visit(ImageElement element, String value) throws IOException;

  // Convenience methods to automatically convert numeric value types to strings
  void visit(ImageElement element, int value) throws IOException {
    visit(element, Integer.toString(value));
  }

  void visit(ImageElement element, long value) throws IOException {
    visit(element, Long.toString(value));
  }

  /**
   * Begin visiting an element that encloses another element, such as
   * the beginning of the list of blocks that comprise a file.
   *
   * @param element Element being visited
   */
  abstract void visitEnclosingElement(ImageElement element)
     throws IOException;

  /**
   * Begin visiting an element that encloses another element, such as
   * the beginning of the list of blocks that comprise a file.
   *
   * Also provide an additional key and value for the element, such as the
   * number items within the element.
   *
   * @param element Element being visited
   * @param key Key describing the element being visited
   * @param value Value associated with element being visited
   */
  abstract void visitEnclosingElement(ImageElement element,
      ImageElement key, String value) throws IOException;

  // Convenience methods to automatically convert value types to strings
  void visitEnclosingElement(ImageElement element,
      ImageElement key, int value)
     throws IOException {
    visitEnclosingElement(element, key, Integer.toString(value));
  }

  void visitEnclosingElement(ImageElement element,
      ImageElement key, long value)
     throws IOException {
    visitEnclosingElement(element, key, Long.toString(value));
  }

  /**
   * Leave current enclosing element.  Called, for instance, at the end of
   * processing the blocks that compromise a file.
   */
  abstract void leaveEnclosingElement() throws IOException;
}

相关信息

hadoop 源码目录

相关文章

hadoop DelimitedImageVisitor 源码

hadoop DepthCounter 源码

hadoop FSImageHandler 源码

hadoop FSImageLoader 源码

hadoop FileDistributionCalculator 源码

hadoop FileDistributionVisitor 源码

hadoop IgnoreSnapshotException 源码

hadoop ImageLoader 源码

hadoop ImageLoaderCurrent 源码

hadoop IndentedImageVisitor 源码