hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/FileDiffList.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.server.namenode.snapshot;


import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hdfs.server.namenode.INodeFile;
import org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction;
import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiff;

/**
 * A list of FileDiffs for storing snapshot data.
 */
@InterfaceAudience.Private
public class FileDiffList
    extends AbstractINodeDiffList<INodeFile, FileDiff> {

  
  @Override
  FileDiff createDiff(Snapshot snapshot, INodeFile file) {
    return new FileDiff(snapshot, file);
  }

  @Override
  INodeFile createSnapshotCopy(INodeFile currentINode) {
    if (currentINode instanceof INodeFileUnderConstructionWithSnapshot) {
      final INodeFileUnderConstruction uc = 
          (INodeFileUnderConstruction) currentINode;
      
      final INodeFileUnderConstruction copy = new INodeFileUnderConstruction(
          uc, uc.getClientName(), uc.getClientMachine(), uc.getClientNode());
      
      copy.setBlocks(null);
      return copy;
    } else {
      final INodeFile copy = new INodeFile(currentINode);
      copy.setBlocks(null);
      return copy;
    }
  }
}