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

import io.netty.buffer.ByteBuf;

import java.io.Closeable;
import java.nio.ByteBuffer;
import java.util.Iterator;
import java.util.Map;
import java.util.NavigableMap;

import static org.apache.hadoop.hdfs.server.namenode.INodeId.INVALID_INODE_ID;

abstract class Transaction implements Closeable {
  protected final FSDirectory fsd;
  protected Transaction(FSDirectory fsd) {
    this.fsd = fsd;
  }

  abstract FlatINode getINode(long id);
  abstract long getChild(long parentId, ByteBuffer localName);

  abstract DBChildrenView childrenView(long parent);

  protected FlatINode getINodeFromDB(long id) {
    DB.INodeContainer c = fsd.db().getINode(id);
    return c == null ? null : FlatINode.wrap(c.inode());
  }

  protected long getChildFromDB(long parentId, ByteBuffer localName) {
    DB.INodeContainer c = fsd.db().getINode(parentId);
    return c == null ? INVALID_INODE_ID : c.getChild(localName);
  }


}