/**
* 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.dfs;
import java.io.IOException;
import org.apache.hadoop.ipc.VersionedProtocol;
/*****************************************************************************
* Protocol that a secondary NameNode uses to communicate with the NameNode.
* It's used to get part of the name node state
*****************************************************************************/
interface NamenodeProtocol extends VersionedProtocol {
/**
* 1: changed the serialization in DatanodeInfo
*/
public static final long versionID = 1L;
/** Get a list of blocks belonged to <code>datanode</code>
* whose total size is equal to <code>size</code>
* @param datanode a data node
* @param size requested size
* @return a list of blocks & their locations
* @Exception RemoteException if size is less than or equal to 0 or
datanode does not exist
*/
public BlocksWithLocations getBlocks(DatanodeInfo datanode, long size)
throws IOException;
}