content: /*
   * 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.asterix.replication.logging;
  
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.asterix.common.replication.IReplicationDestination;
  import org.apache.asterix.common.transactions.ILogRecord;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  public class TxnAckTracker {
  
      private static final Logger LOGGER = LogManager.getLogger();
      private final Map<Long, TxnAck> txnsAcks = new HashMap<>();
  
      public synchronized void track(ILogRecord logRecord, Set<IReplicationDestination> replicas) {
          if (replicas.isEmpty()) {
              logRecord.setReplicated(true);
              return;
          }
          final long txnId = logRecord.getTxnId();
          //TODO use LSN instead of txnId when all logs have LSN
          txnsAcks.put(txnId, new TxnAck(logRecord, replicas));
      }
  
      public synchronized void ack(long txnId, IReplicationDestination replica) {
          if (!txnsAcks.containsKey(txnId)) {
              LOGGER.warn("Received ack for unknown txn {}", txnId);
              return;
          }
          TxnAck txnAcks = txnsAcks.get(txnId);
          txnAcks.ack(replica);
          if (txnAcks.allAcked()) {
              txnsAcks.remove(txnId);
          }
      }
  
      public synchronized void unregister(IReplicationDestination replica) {
          // assume the ack was received from leaving replicas
          final HashSet<Long> pendingTxn = new HashSet<>(txnsAcks.keySet());
          pendingTxn.forEach(txnId -> ack(txnId, replica));
      }
  }
  