| /** |
| * 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 java.util.Collections; |
| import java.util.List; |
| |
| import org.apache.hadoop.io.Writable; |
| |
| import com.google.common.base.Joiner; |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Lists; |
| |
| /** |
| * An enumeration of logs available on a remote NameNode. |
| */ |
| public class RemoteEditLogManifest implements Writable { |
| |
| private List<RemoteEditLog> logs; |
| |
| public RemoteEditLogManifest() { |
| } |
| |
| public RemoteEditLogManifest(List<RemoteEditLog> logs) { |
| this.logs = logs; |
| checkState(); |
| } |
| |
| |
| /** |
| * Check that the logs are contiguous and non-overlapping |
| * sequences of transactions, in sorted order |
| * @throws IllegalStateException if incorrect |
| */ |
| private void checkState() { |
| Preconditions.checkNotNull(logs); |
| |
| RemoteEditLog prev = null; |
| for (RemoteEditLog log : logs) { |
| if (prev != null) { |
| if (log.getStartTxId() != prev.getEndTxId() + 1) { |
| throw new IllegalStateException("Invalid log manifest:" + this); |
| } |
| } |
| |
| prev = log; |
| } |
| } |
| |
| public List<RemoteEditLog> getLogs() { |
| return Collections.unmodifiableList(logs); |
| } |
| |
| |
| |
| @Override |
| public String toString() { |
| return "[" + Joiner.on(", ").join(logs) + "]"; |
| } |
| |
| |
| @Override |
| public void write(DataOutput out) throws IOException { |
| out.writeInt(logs.size()); |
| for (RemoteEditLog log : logs) { |
| log.write(out); |
| } |
| } |
| |
| @Override |
| public void readFields(DataInput in) throws IOException { |
| int numLogs = in.readInt(); |
| logs = Lists.newArrayList(); |
| for (int i = 0; i < numLogs; i++) { |
| RemoteEditLog log = new RemoteEditLog(); |
| log.readFields(in); |
| logs.add(log); |
| } |
| checkState(); |
| } |
| } |