| /* |
| * 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.ratis.server.impl; |
| |
| import org.apache.ratis.server.RaftConfiguration; |
| import org.apache.ratis.util.JavaUtils; |
| import org.apache.ratis.util.Preconditions; |
| import org.apache.ratis.util.StringUtils; |
| |
| import java.util.*; |
| |
| /** |
| * Maintain the mappings between log index and corresponding raft configuration. |
| * Initialized when starting the raft peer. The mappings are loaded from the |
| * raft log, and updated while appending/truncating configuration related log |
| * entries. |
| */ |
| public class ConfigurationManager { |
| private final RaftConfigurationImpl initialConf; |
| private final NavigableMap<Long, RaftConfigurationImpl> configurations = new TreeMap<>(); |
| /** |
| * The current raft configuration. If configurations is not empty, should be |
| * the last entry of the map. Otherwise is initialConf. |
| */ |
| private volatile RaftConfigurationImpl currentConf; |
| |
| ConfigurationManager(RaftConfigurationImpl initialConf) { |
| this.initialConf = initialConf; |
| this.currentConf = initialConf; |
| } |
| |
| synchronized void addConfiguration(RaftConfiguration conf) { |
| final long logIndex = conf.getLogEntryIndex(); |
| final RaftConfiguration found = configurations.get(logIndex); |
| if (found != null) { |
| Preconditions.assertTrue(found.equals(conf)); |
| return; |
| } |
| addRaftConfigurationImpl(logIndex, (RaftConfigurationImpl) conf); |
| } |
| |
| private void addRaftConfigurationImpl(long logIndex, RaftConfigurationImpl conf) { |
| configurations.put(logIndex, conf); |
| if (logIndex == configurations.lastEntry().getKey()) { |
| currentConf = conf; |
| } |
| } |
| |
| RaftConfigurationImpl getCurrent() { |
| return currentConf; |
| } |
| |
| /** |
| * Remove all the configurations whose log index is >= the given index. |
| * @param index The given index. All the configurations whose log index is >= |
| * this value will be removed. |
| * @return The configuration with largest log index < the given index. |
| */ |
| synchronized RaftConfiguration removeConfigurations(long index) { |
| // remove all configurations starting at the index |
| for(final Iterator<?> iter = configurations.tailMap(index).entrySet().iterator(); iter.hasNext();) { |
| iter.next(); |
| iter.remove(); |
| } |
| currentConf = configurations.isEmpty() ? initialConf : |
| configurations.lastEntry().getValue(); |
| return currentConf; |
| } |
| |
| synchronized int numOfConf() { |
| return 1 + configurations.size(); |
| } |
| |
| @Override |
| public synchronized String toString() { |
| return JavaUtils.getClassSimpleName(getClass()) |
| + ", init=" + initialConf |
| + ", confs=" + StringUtils.map2String(configurations); |
| } |
| |
| // TODO: remove Configuration entries after they are committed |
| } |