| /** |
| * 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.protocol; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableFactories; |
| import org.apache.hadoop.io.WritableFactory; |
| import org.apache.hadoop.hdfs.server.namenode.CheckpointSignature; |
| |
| /** |
| * Checkpoint command. |
| * <p> |
| * Returned to the backup node by the name-node as a reply to the |
| * {@link NamenodeProtocol#startCheckpoint(NamenodeRegistration)} |
| * request.<br> |
| * Contains: |
| * <ul> |
| * <li>{@link CheckpointSignature} identifying the particular checkpoint</li> |
| * <li>indicator whether the backup image should be discarded before starting |
| * the checkpoint</li> |
| * <li>indicator whether the image should be transfered back to the name-node |
| * upon completion of the checkpoint.</li> |
| * </ul> |
| */ |
| public class CheckpointCommand extends NamenodeCommand { |
| private CheckpointSignature cSig; |
| private boolean isImageObsolete; |
| private boolean needToReturnImage; |
| |
| public CheckpointCommand() { |
| this(null, false, false); |
| } |
| |
| public CheckpointCommand(CheckpointSignature sig, |
| boolean isImgObsolete, |
| boolean needToReturnImg) { |
| super(NamenodeProtocol.ACT_CHECKPOINT); |
| this.cSig = sig; |
| this.isImageObsolete = isImgObsolete; |
| this.needToReturnImage = needToReturnImg; |
| } |
| |
| /** |
| * Checkpoint signature is used to ensure |
| * that nodes are talking about the same checkpoint. |
| */ |
| public CheckpointSignature getSignature() { |
| return cSig; |
| } |
| |
| /** |
| * Indicates whether current backup image is obsolete, and therefore |
| * need to be discarded? |
| * |
| * @return true if current image should be discarded. |
| */ |
| public boolean isImageObsolete() { |
| return isImageObsolete; |
| } |
| |
| /** |
| * Indicates whether the new checkpoint image needs to be transfered |
| * back to the name-node after the checkpoint is done. |
| * |
| * @return true if the checkpoint should be returned back. |
| */ |
| public boolean needToReturnImage() { |
| return needToReturnImage; |
| } |
| |
| /////////////////////////////////////////// |
| // Writable |
| /////////////////////////////////////////// |
| static { |
| WritableFactories.setFactory(CheckpointCommand.class, |
| new WritableFactory() { |
| public Writable newInstance() {return new CheckpointCommand();} |
| }); |
| } |
| |
| public void write(DataOutput out) throws IOException { |
| super.write(out); |
| cSig.write(out); |
| out.writeBoolean(isImageObsolete); |
| out.writeBoolean(needToReturnImage); |
| } |
| |
| public void readFields(DataInput in) throws IOException { |
| super.readFields(in); |
| cSig = new CheckpointSignature(); |
| cSig.readFields(in); |
| isImageObsolete = in.readBoolean(); |
| needToReturnImage = in.readBoolean(); |
| } |
| } |