codelipenghui commented on a change in pull request #8256:
URL: https://github.com/apache/pulsar/pull/8256#discussion_r513366936



##########
File path: 
pulsar-broker/src/main/java/org/apache/pulsar/broker/transaction/pendingack/impl/PendingAckHandleImpl.java
##########
@@ -0,0 +1,414 @@
+/**
+ * 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.pulsar.broker.transaction.pendingack.impl;
+
+import com.google.common.collect.ComparisonChain;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.bookkeeper.mledger.Position;
+import org.apache.bookkeeper.mledger.impl.ManagedCursorImpl;
+import org.apache.bookkeeper.mledger.impl.PositionImpl;
+import org.apache.bookkeeper.util.collections.ConcurrentLongLongPairHashMap;
+import org.apache.commons.lang3.tuple.MutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import 
org.apache.pulsar.broker.service.BrokerServiceException.NotAllowedException;
+import org.apache.pulsar.broker.service.Consumer;
+import org.apache.pulsar.broker.service.persistent.PersistentSubscription;
+import org.apache.pulsar.broker.transaction.pendingack.PendingAckHandle;
+import org.apache.pulsar.client.api.transaction.TxnID;
+import org.apache.pulsar.common.api.proto.PulsarApi.CommandAck.AckType;
+import org.apache.pulsar.common.util.FutureUtil;
+import org.apache.pulsar.common.util.collections.BitSetRecyclable;
+import 
org.apache.pulsar.transaction.common.exception.TransactionConflictException;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.CompletableFuture;
+
+@Slf4j
+public class PendingAckHandleImpl implements PendingAckHandle {
+
+    private Map<TxnID, HashMap<PositionImpl, PositionImpl>> 
pendingIndividualAckMessagesMap;
+
+    private Map<PositionImpl, PositionImpl> pendingAckMessages;
+
+    private Map<PositionImpl, HashSet<TxnID>> pendingAckBatchMessageMap;
+
+    private Pair<TxnID, PositionImpl> cumulativeAckPair;
+
+    private final String topicName;
+
+    private final String subName;
+
+    private final PersistentSubscription persistentSubscription;
+
+    public PendingAckHandleImpl(PersistentSubscription persistentSubscription) 
{
+        this.topicName = persistentSubscription.getTopicName();
+        this.subName = persistentSubscription.getName();
+        this.persistentSubscription = persistentSubscription;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> acknowledgeMessage(TxnID txnId,
+                                                                   
List<Position> positions, AckType ackType) {
+        if (txnId == null) {
+            return FutureUtil.failedFuture(new 
NotAllowedException("TransactionID can not be null."));
+        }
+        if (positions == null) {
+            return FutureUtil.failedFuture(new NotAllowedException("Positions 
can not be null."));
+        }
+        if (AckType.Cumulative == ackType) {
+            return acknowledgeMessageCumulative(positions, txnId);
+        } else {
+            return acknowledgeMessageIndividual(positions, txnId);
+        }
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageCumulative(List<Position> positions, TxnID txnID) {
+
+        if (positions.size() != 1) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with multiple message 
ids.";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        if (!(positions.get(0) instanceof PositionImpl)) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with position is not 
PositionImpl";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        PositionImpl position = (PositionImpl) positions.get(0);
+
+        if (position.compareTo((PositionImpl) 
persistentSubscription.getCursor().getMarkDeletedPosition()) <= 0) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative ack position: " + position + " within 
range of cursor's " +
+                    "markDeletePosition: " + 
persistentSubscription.getCursor().getMarkDeletedPosition();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+
+        if (log.isDebugEnabled()) {
+            log.debug("[{}][{}] TxnID:[{}] Cumulative ack on {}.", topicName, 
subName, txnID.toString(), position);
+        }
+
+        if (this.cumulativeAckPair == null) {
+            this.cumulativeAckPair = MutablePair.of(txnID, position);
+        } else if (this.cumulativeAckPair.getKey().equals(txnID)
+                && compareToWithAckSetForCumulativeAck(position, 
this.cumulativeAckPair.getValue()) > 0) {
+            this.cumulativeAckPair.setValue(position);
+
+        } else {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative batch ack position: " + position + " 
within range of current " +
+                    "currentPosition: " + this.cumulativeAckPair.getValue();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+        return CompletableFuture.completedFuture(null);
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageIndividual(List<Position> positions, TxnID txnID) {
+        CompletableFuture<Void> completableFuture = new CompletableFuture<>();
+        List<CompletableFuture<Void>> positionsFuture = new 
ArrayList<>(positions.size());
+        for (int i = 0; i < positions.size(); i++) {
+            if (!(positions.get(i) instanceof PositionImpl)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " invalid individual ack received with position is not 
PositionImpl";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
NotAllowedException(errorMsg)));
+                continue;
+            }
+            if (log.isDebugEnabled()) {
+                log.debug("[{}][{}] TxnID:[{}] Individual acks on {}", 
topicName, subName, txnID.toString(), positions);
+            }
+            if (pendingIndividualAckMessagesMap == null) {
+                pendingIndividualAckMessagesMap = new HashMap<>();
+            }
+
+            if (pendingAckMessages == null) {
+                pendingAckMessages = new HashMap<>();
+            }
+            PositionImpl position = (PositionImpl) positions.get(i);
+            // If try to ack message already acked by committed transaction or 
normal acknowledge, throw exception.
+            if (((ManagedCursorImpl) 
persistentSubscription.getCursor()).isMessageDeleted(position)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " try to ack message:" + position + " already acked 
before.";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                continue;
+            }
+
+            if (position.hasAckSet()) {
+
+                if (pendingAckMessages.containsKey(position)
+                        && isAckSetRepeated(pendingAckMessages.get(position), 
position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack batch message:" + position + " in 
pending ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+
+                if (pendingAckBatchMessageMap == null) {
+                    this.pendingAckBatchMessageMap = new HashMap<>();
+                }
+
+                HashSet<TxnID> txnSet = this.pendingAckBatchMessageMap
+                        .computeIfAbsent(position, txn -> new HashSet<>());
+
+                if (pendingAckMessageForCurrentTxn.containsKey(position)) {
+                    andAckSet(pendingAckMessageForCurrentTxn.get(position), 
position);
+                } else {
+                    pendingAckMessageForCurrentTxn.put(position, position);
+                }
+
+                if (!pendingAckMessages.containsKey(position)) {
+                    this.pendingAckMessages.put(position, position);
+                } else {
+                    andAckSet(this.pendingAckMessages.get(position), position);
+                }
+                txnSet.add(txnID);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            } else {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack message:" + position + " in pending 
ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+                pendingAckMessageForCurrentTxn.put(position, position);
+                this.pendingAckMessages.put(position, position);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            }
+        }
+        FutureUtil.waitForAll(positionsFuture).whenComplete((v, e) -> {
+            if (e != null) {
+                completableFuture.completeExceptionally(e);
+            } else {
+                completableFuture.complete(null);
+            }
+        });
+        return completableFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> commitTxn(TxnID txnId, 
Map<String, Long> properties) {
+
+        CompletableFuture<Void> commitFuture = new CompletableFuture<>();
+        // It's valid to create transaction then commit without doing any 
operation, which will cause
+        // pendingAckMessagesMap to be null.
+        if (this.cumulativeAckPair != null) {
+            if (cumulativeAckPair.getKey().equals(txnId)) {
+                persistentSubscription.acknowledgeMessage(Collections
+                        .singletonList(this.cumulativeAckPair.getValue()), 
AckType.Cumulative, properties);
+                this.cumulativeAckPair = null;
+            }
+        } else {
+            if (pendingIndividualAckMessagesMap != null && 
pendingIndividualAckMessagesMap.containsKey(txnId)) {
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.remove(txnId);
+                if (pendingAckMessageForCurrentTxn != null) {
+                    for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                        if (pendingAckBatchMessageMap != null
+                                && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                            HashSet<TxnID> txnIDConcurrentOpenHashSet = 
pendingAckBatchMessageMap.get(entry.getValue());
+                            txnIDConcurrentOpenHashSet.remove(txnId);
+                            if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                                
pendingAckBatchMessageMap.remove(entry.getValue());
+                                pendingAckMessages.remove(entry.getValue());
+                            }
+                        } else {
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    }
+                    persistentSubscription.acknowledgeMessage(new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()),
+                            AckType.Individual, properties);
+                }
+            }
+        }
+        commitFuture.complete(null);
+        return commitFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> abortTxn(TxnID txnId, Consumer 
consumer) {
+        CompletableFuture<Void> abortFuture = new CompletableFuture<>();
+        if (this.cumulativeAckPair != null) {
+            if (this.cumulativeAckPair.getKey().equals(txnId)) {
+                this.cumulativeAckPair = null;
+                redeliverUnacknowledgedMessages(consumer);
+            }
+        } else if (this.pendingIndividualAckMessagesMap != null){
+            HashMap<PositionImpl, PositionImpl> pendingAckMessageForCurrentTxn 
=
+                    pendingIndividualAckMessagesMap.remove(txnId);
+            if (pendingAckMessageForCurrentTxn != null) {
+                for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                    if (pendingAckBatchMessageMap != null && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                        HashSet<TxnID> txnIDConcurrentOpenHashSet =
+                                
pendingAckBatchMessageMap.get(entry.getValue());
+                        txnIDConcurrentOpenHashSet.remove(txnId);
+                        if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                            pendingAckBatchMessageMap.remove(entry.getValue());
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    } else {
+                        this.pendingAckMessages.remove(entry.getValue());
+                    }
+                }
+                redeliverUnacknowledgedMessages(consumer, new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()));
+            }
+        }
+        abortFuture.complete(null);
+        return abortFuture;
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer) {
+        ConcurrentLongLongPairHashMap positionMap = consumer.getPendingAcks();
+        // Only check if message is in pending_ack status when there's ongoing 
transaction.
+        if (null != positionMap && ((pendingAckMessages != null && 
pendingAckMessages.size() != 0)
+                || this.cumulativeAckPair != null)) {
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positionMap.asMap().forEach((key, value) -> {
+                PositionImpl position = new PositionImpl(key.first, 
key.second);
+                redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition);
+            });
+
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer);
+        }
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer, 
List<PositionImpl> positions) {
+        // If there's ongoing transaction.
+        if ((pendingAckMessages != null && pendingAckMessages.size() != 0) || 
this.cumulativeAckPair != null) {
+            // Check if message is in pending_ack status.
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positions.forEach(position ->
+                    redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition));
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 positions);
+        }
+    }
+
+    private void redeliverUnacknowledgedMessagesCommon(PositionImpl position, 
List<PositionImpl> pendingPositions,
+                                                       PositionImpl 
cumulativeAckPosition) {
+        if (position.hasAckSet()) {
+            if (this.pendingAckMessages != null) {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    if 
(!isAckSetRepeated(this.pendingAckMessages.get(position), position)) {
+                        pendingPositions.add(position);
+                    }
+                } else {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null) {
+                int compareNumber = 
position.compareTo((cumulativeAckPosition));
+                if (compareNumber > 0 || (compareNumber == 0 && 
!isAckSetRepeated(position, cumulativeAckPosition))) {
+                    pendingPositions.add(position);
+                }
+            }
+        } else {
+            if (this.pendingAckMessages != null) {
+                if (!this.pendingAckMessages.containsKey(position)) {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null ) {
+                if (position.compareTo(cumulativeAckPosition) > 0) {
+                    pendingPositions.add(position);
+                }
+            }
+        }
+    }
+
+    public int compareToWithAckSetForCumulativeAck(PositionImpl 
currentPosition,PositionImpl otherPosition) {
+        int result = 
ComparisonChain.start().compare(currentPosition.getLedgerId(),
+                
otherPosition.getLedgerId()).compare(currentPosition.getEntryId(), 
otherPosition.getEntryId())
+                .result();
+        if (result == 0) {
+            if (otherPosition.getAckSet() == null && 
currentPosition.getAckSet() == null) {
+                return result;
+            }
+            BitSetRecyclable otherAckSet = 
BitSetRecyclable.valueOf(otherPosition.getAckSet());
+            BitSetRecyclable thisAckSet = 
BitSetRecyclable.valueOf(currentPosition.getAckSet());
+            if (otherAckSet.equals(thisAckSet)) {
+                return result;
+            }
+            otherAckSet.and(thisAckSet);
+            boolean flag = otherAckSet.equals(thisAckSet);
+            thisAckSet.recycle();
+            otherAckSet.recycle();
+            return flag ? 1 : 0;
+        }
+        return result;
+    }
+
+    public boolean isAckSetRepeated(PositionImpl currentPosition, PositionImpl 
otherPosition) {

Review comment:
       ```suggestion
       public boolean isAckSetOverlap(PositionImpl currentPosition, 
PositionImpl otherPosition) {
   ```

##########
File path: 
pulsar-broker/src/main/java/org/apache/pulsar/broker/transaction/pendingack/impl/PendingAckHandleImpl.java
##########
@@ -0,0 +1,414 @@
+/**
+ * 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.pulsar.broker.transaction.pendingack.impl;
+
+import com.google.common.collect.ComparisonChain;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.bookkeeper.mledger.Position;
+import org.apache.bookkeeper.mledger.impl.ManagedCursorImpl;
+import org.apache.bookkeeper.mledger.impl.PositionImpl;
+import org.apache.bookkeeper.util.collections.ConcurrentLongLongPairHashMap;
+import org.apache.commons.lang3.tuple.MutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import 
org.apache.pulsar.broker.service.BrokerServiceException.NotAllowedException;
+import org.apache.pulsar.broker.service.Consumer;
+import org.apache.pulsar.broker.service.persistent.PersistentSubscription;
+import org.apache.pulsar.broker.transaction.pendingack.PendingAckHandle;
+import org.apache.pulsar.client.api.transaction.TxnID;
+import org.apache.pulsar.common.api.proto.PulsarApi.CommandAck.AckType;
+import org.apache.pulsar.common.util.FutureUtil;
+import org.apache.pulsar.common.util.collections.BitSetRecyclable;
+import 
org.apache.pulsar.transaction.common.exception.TransactionConflictException;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.CompletableFuture;
+
+@Slf4j
+public class PendingAckHandleImpl implements PendingAckHandle {
+
+    private Map<TxnID, HashMap<PositionImpl, PositionImpl>> 
pendingIndividualAckMessagesMap;
+
+    private Map<PositionImpl, PositionImpl> pendingAckMessages;
+
+    private Map<PositionImpl, HashSet<TxnID>> pendingAckBatchMessageMap;
+
+    private Pair<TxnID, PositionImpl> cumulativeAckPair;
+
+    private final String topicName;
+
+    private final String subName;
+
+    private final PersistentSubscription persistentSubscription;
+
+    public PendingAckHandleImpl(PersistentSubscription persistentSubscription) 
{
+        this.topicName = persistentSubscription.getTopicName();
+        this.subName = persistentSubscription.getName();
+        this.persistentSubscription = persistentSubscription;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> acknowledgeMessage(TxnID txnId,
+                                                                   
List<Position> positions, AckType ackType) {
+        if (txnId == null) {
+            return FutureUtil.failedFuture(new 
NotAllowedException("TransactionID can not be null."));
+        }
+        if (positions == null) {
+            return FutureUtil.failedFuture(new NotAllowedException("Positions 
can not be null."));
+        }
+        if (AckType.Cumulative == ackType) {
+            return acknowledgeMessageCumulative(positions, txnId);
+        } else {
+            return acknowledgeMessageIndividual(positions, txnId);
+        }
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageCumulative(List<Position> positions, TxnID txnID) {
+
+        if (positions.size() != 1) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with multiple message 
ids.";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        if (!(positions.get(0) instanceof PositionImpl)) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with position is not 
PositionImpl";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        PositionImpl position = (PositionImpl) positions.get(0);
+
+        if (position.compareTo((PositionImpl) 
persistentSubscription.getCursor().getMarkDeletedPosition()) <= 0) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative ack position: " + position + " within 
range of cursor's " +
+                    "markDeletePosition: " + 
persistentSubscription.getCursor().getMarkDeletedPosition();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+
+        if (log.isDebugEnabled()) {
+            log.debug("[{}][{}] TxnID:[{}] Cumulative ack on {}.", topicName, 
subName, txnID.toString(), position);
+        }
+
+        if (this.cumulativeAckPair == null) {
+            this.cumulativeAckPair = MutablePair.of(txnID, position);
+        } else if (this.cumulativeAckPair.getKey().equals(txnID)
+                && compareToWithAckSetForCumulativeAck(position, 
this.cumulativeAckPair.getValue()) > 0) {
+            this.cumulativeAckPair.setValue(position);
+
+        } else {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative batch ack position: " + position + " 
within range of current " +
+                    "currentPosition: " + this.cumulativeAckPair.getValue();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+        return CompletableFuture.completedFuture(null);
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageIndividual(List<Position> positions, TxnID txnID) {
+        CompletableFuture<Void> completableFuture = new CompletableFuture<>();
+        List<CompletableFuture<Void>> positionsFuture = new 
ArrayList<>(positions.size());
+        for (int i = 0; i < positions.size(); i++) {
+            if (!(positions.get(i) instanceof PositionImpl)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " invalid individual ack received with position is not 
PositionImpl";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
NotAllowedException(errorMsg)));
+                continue;
+            }
+            if (log.isDebugEnabled()) {
+                log.debug("[{}][{}] TxnID:[{}] Individual acks on {}", 
topicName, subName, txnID.toString(), positions);
+            }
+            if (pendingIndividualAckMessagesMap == null) {
+                pendingIndividualAckMessagesMap = new HashMap<>();
+            }
+
+            if (pendingAckMessages == null) {
+                pendingAckMessages = new HashMap<>();
+            }
+            PositionImpl position = (PositionImpl) positions.get(i);
+            // If try to ack message already acked by committed transaction or 
normal acknowledge, throw exception.
+            if (((ManagedCursorImpl) 
persistentSubscription.getCursor()).isMessageDeleted(position)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " try to ack message:" + position + " already acked 
before.";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                continue;
+            }
+
+            if (position.hasAckSet()) {
+
+                if (pendingAckMessages.containsKey(position)
+                        && isAckSetRepeated(pendingAckMessages.get(position), 
position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack batch message:" + position + " in 
pending ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+
+                if (pendingAckBatchMessageMap == null) {
+                    this.pendingAckBatchMessageMap = new HashMap<>();
+                }
+
+                HashSet<TxnID> txnSet = this.pendingAckBatchMessageMap
+                        .computeIfAbsent(position, txn -> new HashSet<>());
+
+                if (pendingAckMessageForCurrentTxn.containsKey(position)) {
+                    andAckSet(pendingAckMessageForCurrentTxn.get(position), 
position);
+                } else {
+                    pendingAckMessageForCurrentTxn.put(position, position);
+                }
+
+                if (!pendingAckMessages.containsKey(position)) {
+                    this.pendingAckMessages.put(position, position);
+                } else {
+                    andAckSet(this.pendingAckMessages.get(position), position);
+                }
+                txnSet.add(txnID);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            } else {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack message:" + position + " in pending 
ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+                pendingAckMessageForCurrentTxn.put(position, position);
+                this.pendingAckMessages.put(position, position);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            }
+        }
+        FutureUtil.waitForAll(positionsFuture).whenComplete((v, e) -> {
+            if (e != null) {
+                completableFuture.completeExceptionally(e);
+            } else {
+                completableFuture.complete(null);
+            }
+        });
+        return completableFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> commitTxn(TxnID txnId, 
Map<String, Long> properties) {
+
+        CompletableFuture<Void> commitFuture = new CompletableFuture<>();
+        // It's valid to create transaction then commit without doing any 
operation, which will cause
+        // pendingAckMessagesMap to be null.
+        if (this.cumulativeAckPair != null) {
+            if (cumulativeAckPair.getKey().equals(txnId)) {
+                persistentSubscription.acknowledgeMessage(Collections
+                        .singletonList(this.cumulativeAckPair.getValue()), 
AckType.Cumulative, properties);
+                this.cumulativeAckPair = null;
+            }
+        } else {
+            if (pendingIndividualAckMessagesMap != null && 
pendingIndividualAckMessagesMap.containsKey(txnId)) {
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.remove(txnId);
+                if (pendingAckMessageForCurrentTxn != null) {
+                    for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                        if (pendingAckBatchMessageMap != null
+                                && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                            HashSet<TxnID> txnIDConcurrentOpenHashSet = 
pendingAckBatchMessageMap.get(entry.getValue());
+                            txnIDConcurrentOpenHashSet.remove(txnId);
+                            if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                                
pendingAckBatchMessageMap.remove(entry.getValue());
+                                pendingAckMessages.remove(entry.getValue());
+                            }
+                        } else {
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    }
+                    persistentSubscription.acknowledgeMessage(new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()),
+                            AckType.Individual, properties);
+                }
+            }
+        }
+        commitFuture.complete(null);
+        return commitFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> abortTxn(TxnID txnId, Consumer 
consumer) {
+        CompletableFuture<Void> abortFuture = new CompletableFuture<>();
+        if (this.cumulativeAckPair != null) {
+            if (this.cumulativeAckPair.getKey().equals(txnId)) {
+                this.cumulativeAckPair = null;
+                redeliverUnacknowledgedMessages(consumer);
+            }
+        } else if (this.pendingIndividualAckMessagesMap != null){
+            HashMap<PositionImpl, PositionImpl> pendingAckMessageForCurrentTxn 
=
+                    pendingIndividualAckMessagesMap.remove(txnId);
+            if (pendingAckMessageForCurrentTxn != null) {
+                for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                    if (pendingAckBatchMessageMap != null && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                        HashSet<TxnID> txnIDConcurrentOpenHashSet =
+                                
pendingAckBatchMessageMap.get(entry.getValue());
+                        txnIDConcurrentOpenHashSet.remove(txnId);
+                        if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                            pendingAckBatchMessageMap.remove(entry.getValue());
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    } else {
+                        this.pendingAckMessages.remove(entry.getValue());
+                    }
+                }
+                redeliverUnacknowledgedMessages(consumer, new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()));
+            }
+        }
+        abortFuture.complete(null);
+        return abortFuture;
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer) {
+        ConcurrentLongLongPairHashMap positionMap = consumer.getPendingAcks();
+        // Only check if message is in pending_ack status when there's ongoing 
transaction.
+        if (null != positionMap && ((pendingAckMessages != null && 
pendingAckMessages.size() != 0)
+                || this.cumulativeAckPair != null)) {
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positionMap.asMap().forEach((key, value) -> {
+                PositionImpl position = new PositionImpl(key.first, 
key.second);
+                redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition);
+            });
+
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer);
+        }
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer, 
List<PositionImpl> positions) {
+        // If there's ongoing transaction.
+        if ((pendingAckMessages != null && pendingAckMessages.size() != 0) || 
this.cumulativeAckPair != null) {
+            // Check if message is in pending_ack status.
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positions.forEach(position ->
+                    redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition));
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 positions);
+        }
+    }
+
+    private void redeliverUnacknowledgedMessagesCommon(PositionImpl position, 
List<PositionImpl> pendingPositions,
+                                                       PositionImpl 
cumulativeAckPosition) {
+        if (position.hasAckSet()) {
+            if (this.pendingAckMessages != null) {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    if 
(!isAckSetRepeated(this.pendingAckMessages.get(position), position)) {
+                        pendingPositions.add(position);
+                    }
+                } else {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null) {
+                int compareNumber = 
position.compareTo((cumulativeAckPosition));
+                if (compareNumber > 0 || (compareNumber == 0 && 
!isAckSetRepeated(position, cumulativeAckPosition))) {
+                    pendingPositions.add(position);
+                }
+            }
+        } else {
+            if (this.pendingAckMessages != null) {
+                if (!this.pendingAckMessages.containsKey(position)) {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null ) {
+                if (position.compareTo(cumulativeAckPosition) > 0) {
+                    pendingPositions.add(position);
+                }
+            }
+        }
+    }
+
+    public int compareToWithAckSetForCumulativeAck(PositionImpl 
currentPosition,PositionImpl otherPosition) {
+        int result = 
ComparisonChain.start().compare(currentPosition.getLedgerId(),
+                
otherPosition.getLedgerId()).compare(currentPosition.getEntryId(), 
otherPosition.getEntryId())
+                .result();
+        if (result == 0) {
+            if (otherPosition.getAckSet() == null && 
currentPosition.getAckSet() == null) {
+                return result;
+            }
+            BitSetRecyclable otherAckSet = 
BitSetRecyclable.valueOf(otherPosition.getAckSet());
+            BitSetRecyclable thisAckSet = 
BitSetRecyclable.valueOf(currentPosition.getAckSet());
+            if (otherAckSet.equals(thisAckSet)) {
+                return result;
+            }
+            otherAckSet.and(thisAckSet);
+            boolean flag = otherAckSet.equals(thisAckSet);
+            thisAckSet.recycle();
+            otherAckSet.recycle();
+            return flag ? 1 : 0;
+        }
+        return result;
+    }
+
+    public boolean isAckSetRepeated(PositionImpl currentPosition, PositionImpl 
otherPosition) {
+        if (currentPosition.getAckSet() == null || otherPosition.getAckSet() 
== null) {

Review comment:
       Add check to ensure the ledger Id and the entry Id of the current 
position equals to the other position

##########
File path: 
pulsar-broker/src/main/java/org/apache/pulsar/broker/transaction/pendingack/impl/PendingAckHandleImpl.java
##########
@@ -0,0 +1,414 @@
+/**
+ * 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.pulsar.broker.transaction.pendingack.impl;
+
+import com.google.common.collect.ComparisonChain;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.bookkeeper.mledger.Position;
+import org.apache.bookkeeper.mledger.impl.ManagedCursorImpl;
+import org.apache.bookkeeper.mledger.impl.PositionImpl;
+import org.apache.bookkeeper.util.collections.ConcurrentLongLongPairHashMap;
+import org.apache.commons.lang3.tuple.MutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import 
org.apache.pulsar.broker.service.BrokerServiceException.NotAllowedException;
+import org.apache.pulsar.broker.service.Consumer;
+import org.apache.pulsar.broker.service.persistent.PersistentSubscription;
+import org.apache.pulsar.broker.transaction.pendingack.PendingAckHandle;
+import org.apache.pulsar.client.api.transaction.TxnID;
+import org.apache.pulsar.common.api.proto.PulsarApi.CommandAck.AckType;
+import org.apache.pulsar.common.util.FutureUtil;
+import org.apache.pulsar.common.util.collections.BitSetRecyclable;
+import 
org.apache.pulsar.transaction.common.exception.TransactionConflictException;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.CompletableFuture;
+
+@Slf4j
+public class PendingAckHandleImpl implements PendingAckHandle {
+
+    private Map<TxnID, HashMap<PositionImpl, PositionImpl>> 
pendingIndividualAckMessagesMap;
+
+    private Map<PositionImpl, PositionImpl> pendingAckMessages;
+
+    private Map<PositionImpl, HashSet<TxnID>> pendingAckBatchMessageMap;
+
+    private Pair<TxnID, PositionImpl> cumulativeAckPair;
+
+    private final String topicName;
+
+    private final String subName;
+
+    private final PersistentSubscription persistentSubscription;
+
+    public PendingAckHandleImpl(PersistentSubscription persistentSubscription) 
{
+        this.topicName = persistentSubscription.getTopicName();
+        this.subName = persistentSubscription.getName();
+        this.persistentSubscription = persistentSubscription;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> acknowledgeMessage(TxnID txnId,
+                                                                   
List<Position> positions, AckType ackType) {
+        if (txnId == null) {
+            return FutureUtil.failedFuture(new 
NotAllowedException("TransactionID can not be null."));
+        }
+        if (positions == null) {
+            return FutureUtil.failedFuture(new NotAllowedException("Positions 
can not be null."));
+        }
+        if (AckType.Cumulative == ackType) {
+            return acknowledgeMessageCumulative(positions, txnId);
+        } else {
+            return acknowledgeMessageIndividual(positions, txnId);
+        }
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageCumulative(List<Position> positions, TxnID txnID) {
+
+        if (positions.size() != 1) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with multiple message 
ids.";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        if (!(positions.get(0) instanceof PositionImpl)) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with position is not 
PositionImpl";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        PositionImpl position = (PositionImpl) positions.get(0);
+
+        if (position.compareTo((PositionImpl) 
persistentSubscription.getCursor().getMarkDeletedPosition()) <= 0) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative ack position: " + position + " within 
range of cursor's " +
+                    "markDeletePosition: " + 
persistentSubscription.getCursor().getMarkDeletedPosition();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+
+        if (log.isDebugEnabled()) {
+            log.debug("[{}][{}] TxnID:[{}] Cumulative ack on {}.", topicName, 
subName, txnID.toString(), position);
+        }
+
+        if (this.cumulativeAckPair == null) {
+            this.cumulativeAckPair = MutablePair.of(txnID, position);
+        } else if (this.cumulativeAckPair.getKey().equals(txnID)
+                && compareToWithAckSetForCumulativeAck(position, 
this.cumulativeAckPair.getValue()) > 0) {
+            this.cumulativeAckPair.setValue(position);
+
+        } else {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative batch ack position: " + position + " 
within range of current " +
+                    "currentPosition: " + this.cumulativeAckPair.getValue();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+        return CompletableFuture.completedFuture(null);
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageIndividual(List<Position> positions, TxnID txnID) {
+        CompletableFuture<Void> completableFuture = new CompletableFuture<>();
+        List<CompletableFuture<Void>> positionsFuture = new 
ArrayList<>(positions.size());
+        for (int i = 0; i < positions.size(); i++) {
+            if (!(positions.get(i) instanceof PositionImpl)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " invalid individual ack received with position is not 
PositionImpl";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
NotAllowedException(errorMsg)));
+                continue;
+            }
+            if (log.isDebugEnabled()) {
+                log.debug("[{}][{}] TxnID:[{}] Individual acks on {}", 
topicName, subName, txnID.toString(), positions);
+            }
+            if (pendingIndividualAckMessagesMap == null) {
+                pendingIndividualAckMessagesMap = new HashMap<>();
+            }
+
+            if (pendingAckMessages == null) {
+                pendingAckMessages = new HashMap<>();
+            }
+            PositionImpl position = (PositionImpl) positions.get(i);
+            // If try to ack message already acked by committed transaction or 
normal acknowledge, throw exception.
+            if (((ManagedCursorImpl) 
persistentSubscription.getCursor()).isMessageDeleted(position)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " try to ack message:" + position + " already acked 
before.";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                continue;
+            }
+
+            if (position.hasAckSet()) {
+
+                if (pendingAckMessages.containsKey(position)
+                        && isAckSetRepeated(pendingAckMessages.get(position), 
position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack batch message:" + position + " in 
pending ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+
+                if (pendingAckBatchMessageMap == null) {
+                    this.pendingAckBatchMessageMap = new HashMap<>();
+                }
+
+                HashSet<TxnID> txnSet = this.pendingAckBatchMessageMap
+                        .computeIfAbsent(position, txn -> new HashSet<>());
+
+                if (pendingAckMessageForCurrentTxn.containsKey(position)) {
+                    andAckSet(pendingAckMessageForCurrentTxn.get(position), 
position);
+                } else {
+                    pendingAckMessageForCurrentTxn.put(position, position);
+                }
+
+                if (!pendingAckMessages.containsKey(position)) {
+                    this.pendingAckMessages.put(position, position);
+                } else {
+                    andAckSet(this.pendingAckMessages.get(position), position);
+                }
+                txnSet.add(txnID);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            } else {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack message:" + position + " in pending 
ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+                pendingAckMessageForCurrentTxn.put(position, position);
+                this.pendingAckMessages.put(position, position);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            }
+        }
+        FutureUtil.waitForAll(positionsFuture).whenComplete((v, e) -> {
+            if (e != null) {
+                completableFuture.completeExceptionally(e);
+            } else {
+                completableFuture.complete(null);
+            }
+        });
+        return completableFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> commitTxn(TxnID txnId, 
Map<String, Long> properties) {
+
+        CompletableFuture<Void> commitFuture = new CompletableFuture<>();
+        // It's valid to create transaction then commit without doing any 
operation, which will cause
+        // pendingAckMessagesMap to be null.
+        if (this.cumulativeAckPair != null) {
+            if (cumulativeAckPair.getKey().equals(txnId)) {
+                persistentSubscription.acknowledgeMessage(Collections
+                        .singletonList(this.cumulativeAckPair.getValue()), 
AckType.Cumulative, properties);
+                this.cumulativeAckPair = null;
+            }
+        } else {
+            if (pendingIndividualAckMessagesMap != null && 
pendingIndividualAckMessagesMap.containsKey(txnId)) {
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.remove(txnId);
+                if (pendingAckMessageForCurrentTxn != null) {
+                    for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                        if (pendingAckBatchMessageMap != null
+                                && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                            HashSet<TxnID> txnIDConcurrentOpenHashSet = 
pendingAckBatchMessageMap.get(entry.getValue());
+                            txnIDConcurrentOpenHashSet.remove(txnId);
+                            if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                                
pendingAckBatchMessageMap.remove(entry.getValue());
+                                pendingAckMessages.remove(entry.getValue());
+                            }
+                        } else {
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    }
+                    persistentSubscription.acknowledgeMessage(new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()),
+                            AckType.Individual, properties);
+                }
+            }
+        }
+        commitFuture.complete(null);
+        return commitFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> abortTxn(TxnID txnId, Consumer 
consumer) {
+        CompletableFuture<Void> abortFuture = new CompletableFuture<>();
+        if (this.cumulativeAckPair != null) {
+            if (this.cumulativeAckPair.getKey().equals(txnId)) {
+                this.cumulativeAckPair = null;
+                redeliverUnacknowledgedMessages(consumer);
+            }
+        } else if (this.pendingIndividualAckMessagesMap != null){
+            HashMap<PositionImpl, PositionImpl> pendingAckMessageForCurrentTxn 
=
+                    pendingIndividualAckMessagesMap.remove(txnId);
+            if (pendingAckMessageForCurrentTxn != null) {
+                for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                    if (pendingAckBatchMessageMap != null && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                        HashSet<TxnID> txnIDConcurrentOpenHashSet =
+                                
pendingAckBatchMessageMap.get(entry.getValue());
+                        txnIDConcurrentOpenHashSet.remove(txnId);
+                        if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                            pendingAckBatchMessageMap.remove(entry.getValue());
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    } else {
+                        this.pendingAckMessages.remove(entry.getValue());
+                    }
+                }
+                redeliverUnacknowledgedMessages(consumer, new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()));
+            }
+        }
+        abortFuture.complete(null);
+        return abortFuture;
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer) {
+        ConcurrentLongLongPairHashMap positionMap = consumer.getPendingAcks();
+        // Only check if message is in pending_ack status when there's ongoing 
transaction.
+        if (null != positionMap && ((pendingAckMessages != null && 
pendingAckMessages.size() != 0)
+                || this.cumulativeAckPair != null)) {
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positionMap.asMap().forEach((key, value) -> {
+                PositionImpl position = new PositionImpl(key.first, 
key.second);
+                redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition);
+            });
+
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer);
+        }
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer, 
List<PositionImpl> positions) {
+        // If there's ongoing transaction.
+        if ((pendingAckMessages != null && pendingAckMessages.size() != 0) || 
this.cumulativeAckPair != null) {
+            // Check if message is in pending_ack status.
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positions.forEach(position ->
+                    redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition));
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 positions);
+        }
+    }
+
+    private void redeliverUnacknowledgedMessagesCommon(PositionImpl position, 
List<PositionImpl> pendingPositions,
+                                                       PositionImpl 
cumulativeAckPosition) {
+        if (position.hasAckSet()) {
+            if (this.pendingAckMessages != null) {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    if 
(!isAckSetRepeated(this.pendingAckMessages.get(position), position)) {
+                        pendingPositions.add(position);
+                    }
+                } else {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null) {
+                int compareNumber = 
position.compareTo((cumulativeAckPosition));
+                if (compareNumber > 0 || (compareNumber == 0 && 
!isAckSetRepeated(position, cumulativeAckPosition))) {
+                    pendingPositions.add(position);
+                }
+            }
+        } else {
+            if (this.pendingAckMessages != null) {
+                if (!this.pendingAckMessages.containsKey(position)) {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null ) {
+                if (position.compareTo(cumulativeAckPosition) > 0) {
+                    pendingPositions.add(position);
+                }
+            }
+        }
+    }
+
+    public int compareToWithAckSetForCumulativeAck(PositionImpl 
currentPosition,PositionImpl otherPosition) {
+        int result = 
ComparisonChain.start().compare(currentPosition.getLedgerId(),

Review comment:
       Check currentPosition and otherPosition not null.

##########
File path: 
pulsar-broker/src/main/java/org/apache/pulsar/broker/transaction/pendingack/impl/PendingAckHandleImpl.java
##########
@@ -0,0 +1,414 @@
+/**
+ * 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.pulsar.broker.transaction.pendingack.impl;
+
+import com.google.common.collect.ComparisonChain;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.bookkeeper.mledger.Position;
+import org.apache.bookkeeper.mledger.impl.ManagedCursorImpl;
+import org.apache.bookkeeper.mledger.impl.PositionImpl;
+import org.apache.bookkeeper.util.collections.ConcurrentLongLongPairHashMap;
+import org.apache.commons.lang3.tuple.MutablePair;
+import org.apache.commons.lang3.tuple.Pair;
+import 
org.apache.pulsar.broker.service.BrokerServiceException.NotAllowedException;
+import org.apache.pulsar.broker.service.Consumer;
+import org.apache.pulsar.broker.service.persistent.PersistentSubscription;
+import org.apache.pulsar.broker.transaction.pendingack.PendingAckHandle;
+import org.apache.pulsar.client.api.transaction.TxnID;
+import org.apache.pulsar.common.api.proto.PulsarApi.CommandAck.AckType;
+import org.apache.pulsar.common.util.FutureUtil;
+import org.apache.pulsar.common.util.collections.BitSetRecyclable;
+import 
org.apache.pulsar.transaction.common.exception.TransactionConflictException;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.CompletableFuture;
+
+@Slf4j
+public class PendingAckHandleImpl implements PendingAckHandle {
+
+    private Map<TxnID, HashMap<PositionImpl, PositionImpl>> 
pendingIndividualAckMessagesMap;
+
+    private Map<PositionImpl, PositionImpl> pendingAckMessages;
+
+    private Map<PositionImpl, HashSet<TxnID>> pendingAckBatchMessageMap;
+
+    private Pair<TxnID, PositionImpl> cumulativeAckPair;
+
+    private final String topicName;
+
+    private final String subName;
+
+    private final PersistentSubscription persistentSubscription;
+
+    public PendingAckHandleImpl(PersistentSubscription persistentSubscription) 
{
+        this.topicName = persistentSubscription.getTopicName();
+        this.subName = persistentSubscription.getName();
+        this.persistentSubscription = persistentSubscription;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> acknowledgeMessage(TxnID txnId,
+                                                                   
List<Position> positions, AckType ackType) {
+        if (txnId == null) {
+            return FutureUtil.failedFuture(new 
NotAllowedException("TransactionID can not be null."));
+        }
+        if (positions == null) {
+            return FutureUtil.failedFuture(new NotAllowedException("Positions 
can not be null."));
+        }
+        if (AckType.Cumulative == ackType) {
+            return acknowledgeMessageCumulative(positions, txnId);
+        } else {
+            return acknowledgeMessageIndividual(positions, txnId);
+        }
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageCumulative(List<Position> positions, TxnID txnID) {
+
+        if (positions.size() != 1) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with multiple message 
ids.";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        if (!(positions.get(0) instanceof PositionImpl)) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " invalid cumulative ack received with position is not 
PositionImpl";
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new NotAllowedException(errorMsg));
+        }
+
+        PositionImpl position = (PositionImpl) positions.get(0);
+
+        if (position.compareTo((PositionImpl) 
persistentSubscription.getCursor().getMarkDeletedPosition()) <= 0) {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative ack position: " + position + " within 
range of cursor's " +
+                    "markDeletePosition: " + 
persistentSubscription.getCursor().getMarkDeletedPosition();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+
+        if (log.isDebugEnabled()) {
+            log.debug("[{}][{}] TxnID:[{}] Cumulative ack on {}.", topicName, 
subName, txnID.toString(), position);
+        }
+
+        if (this.cumulativeAckPair == null) {
+            this.cumulativeAckPair = MutablePair.of(txnID, position);
+        } else if (this.cumulativeAckPair.getKey().equals(txnID)
+                && compareToWithAckSetForCumulativeAck(position, 
this.cumulativeAckPair.getValue()) > 0) {
+            this.cumulativeAckPair.setValue(position);
+
+        } else {
+            String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                    " try to cumulative batch ack position: " + position + " 
within range of current " +
+                    "currentPosition: " + this.cumulativeAckPair.getValue();
+            log.error(errorMsg);
+            return FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg));
+        }
+        return CompletableFuture.completedFuture(null);
+    }
+
+    private CompletableFuture<Void> 
acknowledgeMessageIndividual(List<Position> positions, TxnID txnID) {
+        CompletableFuture<Void> completableFuture = new CompletableFuture<>();
+        List<CompletableFuture<Void>> positionsFuture = new 
ArrayList<>(positions.size());
+        for (int i = 0; i < positions.size(); i++) {
+            if (!(positions.get(i) instanceof PositionImpl)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " invalid individual ack received with position is not 
PositionImpl";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
NotAllowedException(errorMsg)));
+                continue;
+            }
+            if (log.isDebugEnabled()) {
+                log.debug("[{}][{}] TxnID:[{}] Individual acks on {}", 
topicName, subName, txnID.toString(), positions);
+            }
+            if (pendingIndividualAckMessagesMap == null) {
+                pendingIndividualAckMessagesMap = new HashMap<>();
+            }
+
+            if (pendingAckMessages == null) {
+                pendingAckMessages = new HashMap<>();
+            }
+            PositionImpl position = (PositionImpl) positions.get(i);
+            // If try to ack message already acked by committed transaction or 
normal acknowledge, throw exception.
+            if (((ManagedCursorImpl) 
persistentSubscription.getCursor()).isMessageDeleted(position)) {
+                String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                        " try to ack message:" + position + " already acked 
before.";
+                log.error(errorMsg);
+                positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                continue;
+            }
+
+            if (position.hasAckSet()) {
+
+                if (pendingAckMessages.containsKey(position)
+                        && isAckSetRepeated(pendingAckMessages.get(position), 
position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack batch message:" + position + " in 
pending ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+
+                if (pendingAckBatchMessageMap == null) {
+                    this.pendingAckBatchMessageMap = new HashMap<>();
+                }
+
+                HashSet<TxnID> txnSet = this.pendingAckBatchMessageMap
+                        .computeIfAbsent(position, txn -> new HashSet<>());
+
+                if (pendingAckMessageForCurrentTxn.containsKey(position)) {
+                    andAckSet(pendingAckMessageForCurrentTxn.get(position), 
position);
+                } else {
+                    pendingAckMessageForCurrentTxn.put(position, position);
+                }
+
+                if (!pendingAckMessages.containsKey(position)) {
+                    this.pendingAckMessages.put(position, position);
+                } else {
+                    andAckSet(this.pendingAckMessages.get(position), position);
+                }
+                txnSet.add(txnID);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            } else {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    String errorMsg = "[" + topicName + "][" + subName + "] 
Transaction:" + txnID +
+                            " try to ack message:" + position + " in pending 
ack status.";
+                    log.error(errorMsg);
+                    positionsFuture.add(FutureUtil.failedFuture(new 
TransactionConflictException(errorMsg)));
+                    continue;
+                }
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.computeIfAbsent(txnID, 
txn -> new HashMap<>());
+                pendingAckMessageForCurrentTxn.put(position, position);
+                this.pendingAckMessages.put(position, position);
+                positionsFuture.add(CompletableFuture.completedFuture(null));
+            }
+        }
+        FutureUtil.waitForAll(positionsFuture).whenComplete((v, e) -> {
+            if (e != null) {
+                completableFuture.completeExceptionally(e);
+            } else {
+                completableFuture.complete(null);
+            }
+        });
+        return completableFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> commitTxn(TxnID txnId, 
Map<String, Long> properties) {
+
+        CompletableFuture<Void> commitFuture = new CompletableFuture<>();
+        // It's valid to create transaction then commit without doing any 
operation, which will cause
+        // pendingAckMessagesMap to be null.
+        if (this.cumulativeAckPair != null) {
+            if (cumulativeAckPair.getKey().equals(txnId)) {
+                persistentSubscription.acknowledgeMessage(Collections
+                        .singletonList(this.cumulativeAckPair.getValue()), 
AckType.Cumulative, properties);
+                this.cumulativeAckPair = null;
+            }
+        } else {
+            if (pendingIndividualAckMessagesMap != null && 
pendingIndividualAckMessagesMap.containsKey(txnId)) {
+                HashMap<PositionImpl, PositionImpl> 
pendingAckMessageForCurrentTxn =
+                        pendingIndividualAckMessagesMap.remove(txnId);
+                if (pendingAckMessageForCurrentTxn != null) {
+                    for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                        if (pendingAckBatchMessageMap != null
+                                && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                            HashSet<TxnID> txnIDConcurrentOpenHashSet = 
pendingAckBatchMessageMap.get(entry.getValue());
+                            txnIDConcurrentOpenHashSet.remove(txnId);
+                            if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                                
pendingAckBatchMessageMap.remove(entry.getValue());
+                                pendingAckMessages.remove(entry.getValue());
+                            }
+                        } else {
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    }
+                    persistentSubscription.acknowledgeMessage(new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()),
+                            AckType.Individual, properties);
+                }
+            }
+        }
+        commitFuture.complete(null);
+        return commitFuture;
+    }
+
+    @Override
+    public synchronized CompletableFuture<Void> abortTxn(TxnID txnId, Consumer 
consumer) {
+        CompletableFuture<Void> abortFuture = new CompletableFuture<>();
+        if (this.cumulativeAckPair != null) {
+            if (this.cumulativeAckPair.getKey().equals(txnId)) {
+                this.cumulativeAckPair = null;
+                redeliverUnacknowledgedMessages(consumer);
+            }
+        } else if (this.pendingIndividualAckMessagesMap != null){
+            HashMap<PositionImpl, PositionImpl> pendingAckMessageForCurrentTxn 
=
+                    pendingIndividualAckMessagesMap.remove(txnId);
+            if (pendingAckMessageForCurrentTxn != null) {
+                for (Entry<PositionImpl, PositionImpl> entry : 
pendingAckMessageForCurrentTxn.entrySet()) {
+                    if (pendingAckBatchMessageMap != null && 
pendingAckBatchMessageMap.containsKey(entry.getValue())) {
+                        HashSet<TxnID> txnIDConcurrentOpenHashSet =
+                                
pendingAckBatchMessageMap.get(entry.getValue());
+                        txnIDConcurrentOpenHashSet.remove(txnId);
+                        if (txnIDConcurrentOpenHashSet.isEmpty()) {
+                            pendingAckBatchMessageMap.remove(entry.getValue());
+                            pendingAckMessages.remove(entry.getValue());
+                        }
+                    } else {
+                        this.pendingAckMessages.remove(entry.getValue());
+                    }
+                }
+                redeliverUnacknowledgedMessages(consumer, new 
ArrayList<>(pendingAckMessageForCurrentTxn.values()));
+            }
+        }
+        abortFuture.complete(null);
+        return abortFuture;
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer) {
+        ConcurrentLongLongPairHashMap positionMap = consumer.getPendingAcks();
+        // Only check if message is in pending_ack status when there's ongoing 
transaction.
+        if (null != positionMap && ((pendingAckMessages != null && 
pendingAckMessages.size() != 0)
+                || this.cumulativeAckPair != null)) {
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positionMap.asMap().forEach((key, value) -> {
+                PositionImpl position = new PositionImpl(key.first, 
key.second);
+                redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition);
+            });
+
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer);
+        }
+    }
+
+    @Override
+    public void redeliverUnacknowledgedMessages(Consumer consumer, 
List<PositionImpl> positions) {
+        // If there's ongoing transaction.
+        if ((pendingAckMessages != null && pendingAckMessages.size() != 0) || 
this.cumulativeAckPair != null) {
+            // Check if message is in pending_ack status.
+            List<PositionImpl> pendingPositions = new ArrayList<>();
+            PositionImpl cumulativeAckPosition =
+                    (null == this.cumulativeAckPair) ? null : 
this.cumulativeAckPair.getValue();
+
+            positions.forEach(position ->
+                    redeliverUnacknowledgedMessagesCommon(position, 
pendingPositions, cumulativeAckPosition));
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 pendingPositions);
+        } else {
+            
persistentSubscription.getDispatcher().redeliverUnacknowledgedMessages(consumer,
 positions);
+        }
+    }
+
+    private void redeliverUnacknowledgedMessagesCommon(PositionImpl position, 
List<PositionImpl> pendingPositions,
+                                                       PositionImpl 
cumulativeAckPosition) {
+        if (position.hasAckSet()) {
+            if (this.pendingAckMessages != null) {
+                if (this.pendingAckMessages.containsKey(position)) {
+                    if 
(!isAckSetRepeated(this.pendingAckMessages.get(position), position)) {
+                        pendingPositions.add(position);
+                    }
+                } else {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null) {
+                int compareNumber = 
position.compareTo((cumulativeAckPosition));
+                if (compareNumber > 0 || (compareNumber == 0 && 
!isAckSetRepeated(position, cumulativeAckPosition))) {
+                    pendingPositions.add(position);
+                }
+            }
+        } else {
+            if (this.pendingAckMessages != null) {
+                if (!this.pendingAckMessages.containsKey(position)) {
+                    pendingPositions.add(position);
+                }
+            } else if (cumulativeAckPosition != null ) {
+                if (position.compareTo(cumulativeAckPosition) > 0) {
+                    pendingPositions.add(position);
+                }
+            }
+        }
+    }
+
+    public int compareToWithAckSetForCumulativeAck(PositionImpl 
currentPosition,PositionImpl otherPosition) {
+        int result = 
ComparisonChain.start().compare(currentPosition.getLedgerId(),
+                
otherPosition.getLedgerId()).compare(currentPosition.getEntryId(), 
otherPosition.getEntryId())
+                .result();
+        if (result == 0) {
+            if (otherPosition.getAckSet() == null && 
currentPosition.getAckSet() == null) {
+                return result;
+            }
+            BitSetRecyclable otherAckSet = 
BitSetRecyclable.valueOf(otherPosition.getAckSet());
+            BitSetRecyclable thisAckSet = 
BitSetRecyclable.valueOf(currentPosition.getAckSet());
+            if (otherAckSet.equals(thisAckSet)) {
+                return result;
+            }
+            otherAckSet.and(thisAckSet);
+            boolean flag = otherAckSet.equals(thisAckSet);
+            thisAckSet.recycle();
+            otherAckSet.recycle();
+            return flag ? 1 : 0;
+        }
+        return result;
+    }
+
+    public boolean isAckSetRepeated(PositionImpl currentPosition, PositionImpl 
otherPosition) {
+        if (currentPosition.getAckSet() == null || otherPosition.getAckSet() 
== null) {
+            return false;
+        }
+
+        BitSetRecyclable thisAckSet = 
BitSetRecyclable.valueOf(currentPosition.getAckSet());
+        BitSetRecyclable otherAckSet = 
BitSetRecyclable.valueOf(otherPosition.getAckSet());
+        if (otherAckSet.size() < thisAckSet.size()) {
+            otherAckSet.set(otherAckSet.size(), thisAckSet.size());
+        }
+        thisAckSet.flip(0, thisAckSet.size());
+        otherAckSet.flip(0, otherAckSet.size());
+        thisAckSet.and(otherAckSet);
+        boolean isAckSetRepeated = !thisAckSet.isEmpty();
+        thisAckSet.recycle();
+        otherAckSet.recycle();
+        return isAckSetRepeated;
+    }
+
+    public void andAckSet(PositionImpl currentPosition, PositionImpl 
otherPosition) {
+        BitSetRecyclable thisAckSet = 
BitSetRecyclable.valueOf(currentPosition.getAckSet());

Review comment:
       Add check to ensure the ledger Id and the entry Id of the current 
position equals to the other position
   
   And add a unit test for this method.
   
   Is the method can be static?




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
[email protected]


Reply via email to