| /* |
| * 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.uncommitted; |
| |
| import java.util.Comparator; |
| import java.util.Iterator; |
| import java.util.Objects; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Iterators; |
| import com.google.common.collect.Lists; |
| import com.google.common.primitives.Longs; |
| |
| import org.apache.cassandra.db.ConsistencyLevel; |
| import org.apache.cassandra.db.DecoratedKey; |
| import org.apache.cassandra.schema.TableId; |
| import org.apache.cassandra.service.paxos.Ballot; |
| import org.apache.cassandra.utils.CloseableIterator; |
| import org.apache.cassandra.utils.MergeIterator; |
| |
| public class PaxosKeyState implements UncommittedPaxosKey |
| { |
| static final Comparator<PaxosKeyState> KEY_COMPARATOR = Comparator.comparing(o -> o.key); |
| static final Comparator<PaxosKeyState> BALLOT_COMPARATOR = (o1, o2) -> Longs.compare(o1.ballot.uuidTimestamp(), o2.ballot.uuidTimestamp()); |
| |
| final TableId tableId; |
| final DecoratedKey key; |
| final Ballot ballot; |
| final boolean committed; |
| |
| public PaxosKeyState(TableId tableId, DecoratedKey key, Ballot ballot, boolean committed) |
| { |
| Preconditions.checkNotNull(tableId); |
| Preconditions.checkNotNull(ballot); |
| this.tableId = tableId; |
| this.key = key; |
| this.ballot = ballot; |
| this.committed = committed; |
| } |
| |
| public DecoratedKey getKey() |
| { |
| return key; |
| } |
| |
| public ConsistencyLevel getConsistencyLevel() |
| { |
| switch (ballot.flag()) |
| { |
| default: throw new IllegalStateException(); |
| case GLOBAL: return ConsistencyLevel.SERIAL; |
| case LOCAL: return ConsistencyLevel.LOCAL_SERIAL; |
| case NONE: return null; |
| } |
| } |
| |
| @Override |
| public Ballot ballot() |
| { |
| return ballot; |
| } |
| |
| public boolean equals(Object o) |
| { |
| if (this == o) return true; |
| if (o == null || getClass() != o.getClass()) return false; |
| PaxosKeyState that = (PaxosKeyState) o; |
| return committed == that.committed && |
| Objects.equals(key, that.key) && |
| Objects.equals(ballot, that.ballot); |
| } |
| |
| public int hashCode() |
| { |
| return Objects.hash(key, ballot, committed); |
| } |
| |
| public String toString() |
| { |
| return "BallotState{" + |
| "tableId=" + tableId + |
| ", key=" + key + |
| ", ballot=" + ballot + |
| ", committed=" + committed + |
| '}'; |
| } |
| |
| static PaxosKeyState merge(PaxosKeyState left, PaxosKeyState right) |
| { |
| if (left == null) |
| return right; |
| |
| if (right == null) |
| return left; |
| |
| int cmp = BALLOT_COMPARATOR.compare(left, right); |
| |
| // prefer committed operations if the ballots are the same so they can be filtered out later |
| if (cmp == 0) |
| return left.committed ? left : right; |
| else |
| return cmp > 0 ? left : right; |
| } |
| |
| static class Reducer extends MergeIterator.Reducer<PaxosKeyState, PaxosKeyState> |
| { |
| private PaxosKeyState mostRecent = null; |
| |
| public void reduce(int idx, PaxosKeyState current) |
| { |
| mostRecent = merge(mostRecent, current); |
| } |
| |
| protected PaxosKeyState getReduced() |
| { |
| return mostRecent; |
| } |
| |
| protected void onKeyChange() |
| { |
| super.onKeyChange(); |
| mostRecent = null; |
| } |
| } |
| |
| public static CloseableIterator<PaxosKeyState> mergeUncommitted(CloseableIterator<PaxosKeyState>... iterators) |
| { |
| return MergeIterator.get(Lists.newArrayList(iterators), PaxosKeyState.KEY_COMPARATOR, new Reducer()); |
| } |
| |
| public static CloseableIterator<UncommittedPaxosKey> toUncommittedInfo(CloseableIterator<PaxosKeyState> iter) |
| { |
| Iterator<PaxosKeyState> filtered = Iterators.filter(iter, k -> !k.committed); |
| return new CloseableIterator<UncommittedPaxosKey>() |
| { |
| public void close() |
| { |
| iter.close(); |
| } |
| |
| public boolean hasNext() |
| { |
| return filtered.hasNext(); |
| } |
| |
| public UncommittedPaxosKey next() |
| { |
| return filtered.next(); |
| } |
| }; |
| } |
| } |