| /* |
| * 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.service.paxos; |
| |
| import java.security.SecureRandom; |
| import java.util.concurrent.ThreadLocalRandom; |
| |
| import org.apache.cassandra.service.ClientState; |
| import org.apache.cassandra.service.paxos.Ballot.Flag; |
| import org.apache.cassandra.utils.Shared; |
| |
| import static org.apache.cassandra.service.paxos.Ballot.atUnixMicrosWithLsb; |
| import static org.apache.cassandra.utils.Shared.Scope.SIMULATION; |
| |
| @Shared(scope = SIMULATION) |
| public interface BallotGenerator |
| { |
| static class Default implements BallotGenerator |
| { |
| private static final SecureRandom secureRandom = new SecureRandom(); |
| |
| public Ballot atUnixMicros(long unixMicros, Flag flag) |
| { |
| return atUnixMicrosWithLsb(unixMicros, secureRandom.nextLong(), flag); |
| } |
| |
| public Ballot next(long minUnixMicros, Flag flag) |
| { |
| long unixMicros = ClientState.getTimestampForPaxos(minUnixMicros); |
| return atUnixMicros(unixMicros, flag); |
| } |
| |
| public Ballot stale(long fromInMicros, long toInMicros, Flag flag) |
| { |
| long unixMicros = ThreadLocalRandom.current().nextLong(fromInMicros, toInMicros); |
| return atUnixMicros(unixMicros, flag); |
| } |
| |
| public long next(long minTimestamp) |
| { |
| return ClientState.getTimestampForPaxos(minTimestamp); |
| } |
| |
| public long prevUnixMicros() |
| { |
| return ClientState.getLastTimestampMicros(); |
| } |
| } |
| |
| static class Global |
| { |
| private static BallotGenerator instance = new Default(); |
| public static Ballot atUnixMicros(long unixMicros, Flag flag) { return instance.atUnixMicros(unixMicros, flag); } |
| public static Ballot nextBallot(Flag flag) { return instance.next(Long.MIN_VALUE, flag); } |
| public static Ballot nextBallot(long minUnixMicros, Flag flag) { return instance.next(minUnixMicros, flag); } |
| public static Ballot staleBallot(long fromUnixMicros, long toUnixMicros, Flag flag) { return instance.stale(fromUnixMicros, toUnixMicros, flag); } |
| public static long prevUnixMicros() { return instance.prevUnixMicros(); } |
| |
| public static void unsafeSet(BallotGenerator newInstance) |
| { |
| instance = newInstance; |
| } |
| } |
| |
| Ballot atUnixMicros(long unixMicros, Flag flag); |
| Ballot next(long minUnixMicros, Flag flag); |
| Ballot stale(long fromUnixMicros, long toUnixMicros, Flag flag); |
| long prevUnixMicros(); |
| } |