| /** |
| * 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.datanode; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.ReplicaState; |
| import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi; |
| |
| /** |
| * This represents block replicas which are stored in DataNode. |
| */ |
| @InterfaceAudience.Private |
| public interface Replica { |
| /** Get the block ID */ |
| public long getBlockId(); |
| |
| /** Get the generation stamp */ |
| public long getGenerationStamp(); |
| |
| /** |
| * Get the replica state |
| * @return the replica state |
| */ |
| public ReplicaState getState(); |
| |
| /** |
| * Get the number of bytes received |
| * @return the number of bytes that have been received |
| */ |
| public long getNumBytes(); |
| |
| /** |
| * Get the number of bytes that have written to disk |
| * @return the number of bytes that have written to disk |
| */ |
| public long getBytesOnDisk(); |
| |
| /** |
| * Get the number of bytes that are visible to readers |
| * @return the number of bytes that are visible to readers |
| */ |
| public long getVisibleLength(); |
| |
| /** |
| * Return the storageUuid of the volume that stores this replica. |
| */ |
| public String getStorageUuid(); |
| |
| /** |
| * Return true if the target volume is backed by RAM. |
| */ |
| public boolean isOnTransientStorage(); |
| |
| /** |
| * Get the volume of replica. |
| * @return the volume of replica |
| */ |
| public FsVolumeSpi getVolume(); |
| } |