| /* |
| * 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.cassandra.gms; |
| |
| import java.io.*; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| |
| import org.apache.cassandra.db.TypeSizes; |
| import org.apache.cassandra.io.IVersionedSerializer; |
| import org.apache.cassandra.io.util.DataInputPlus; |
| import org.apache.cassandra.io.util.DataOutputPlus; |
| |
| /** |
| * HeartBeat State associated with any given endpoint. |
| */ |
| |
| public class HeartBeatState |
| { |
| public static final int EMPTY_VERSION = -1; |
| |
| public static final IVersionedSerializer<HeartBeatState> serializer = new HeartBeatStateSerializer(); |
| |
| private volatile int generation; |
| private volatile int version; |
| |
| HeartBeatState(int gen) |
| { |
| this(gen, 0); |
| } |
| |
| public HeartBeatState(HeartBeatState other) |
| { |
| generation = other.generation; |
| version = other.version; |
| } |
| |
| public HeartBeatState(int gen, int ver) |
| { |
| generation = gen; |
| version = ver; |
| } |
| |
| public static HeartBeatState empty() |
| { |
| return new HeartBeatState(0, EMPTY_VERSION); |
| } |
| |
| public boolean isEmpty() |
| { |
| // Instance I1 will update this value for I1's state, no other instance should. |
| // It is also known that negative version isn't allowed, so can leverage this to |
| // know that the state was not generated by I1 but rather than instance (normally |
| // happens on startup, the peers are added to gossip with the empty state). |
| return version == EMPTY_VERSION; |
| } |
| |
| public int getGeneration() |
| { |
| return generation; |
| } |
| |
| void updateHeartBeat() |
| { |
| version = VersionGenerator.getNextVersion(); |
| } |
| |
| public int getHeartBeatVersion() |
| { |
| return version; |
| } |
| |
| void forceNewerGenerationUnsafe() |
| { |
| generation += 1; |
| } |
| |
| @VisibleForTesting |
| public void forceHighestPossibleVersionUnsafe() |
| { |
| version = Integer.MAX_VALUE; |
| } |
| |
| public String toString() |
| { |
| return String.format("HeartBeat: generation = %d, version = %d", generation, version); |
| } |
| } |
| |
| class HeartBeatStateSerializer implements IVersionedSerializer<HeartBeatState> |
| { |
| public void serialize(HeartBeatState hbState, DataOutputPlus out, int version) throws IOException |
| { |
| out.writeInt(hbState.getGeneration()); |
| out.writeInt(hbState.getHeartBeatVersion()); |
| } |
| |
| public HeartBeatState deserialize(DataInputPlus in, int version) throws IOException |
| { |
| return new HeartBeatState(in.readInt(), in.readInt()); |
| } |
| |
| public long serializedSize(HeartBeatState state, int version) |
| { |
| return TypeSizes.sizeof(state.getGeneration()) + TypeSizes.sizeof(state.getHeartBeatVersion()); |
| } |
| } |