optimize: mark the lockholder of branchsession as final (apache#5487)

changes/en-us/2.0.0.md

@@ -77,6 +77,7 @@ The version is updated as follows:
 - [[#5471](https://github.com/seata/seata/pull/5471)] optimize transaction log on client side
 - [[#5485](https://github.com/seata/seata/pull/5485)] optimize server log output
 - [[#4907](https://github.com/seata/seata/pull/4907)] optimize thread scheduling and code
+- [[#5487](https://github.com/seata/seata/pull/5487)] mark the lockholder of branchsession as final
 
 ### test:
 - [[#5308](https://github.com/seata/seata/pull/5308)] add unit test [FileLoader, ObjectHolder, StringUtils]

changes/zh-cn/2.0.0.md

@@ -76,6 +76,7 @@ Seata 是一款开源的分布式事务解决方案，提供高性能和简单
 - [[#5471](https://github.com/seata/seata/pull/5471)] 优化客户侧事务日志
 - [[#5485](https://github.com/seata/seata/pull/5485)] 优化Server日志输出
 - [[#4907](https://github.com/seata/seata/pull/4907)] 调整二阶段result线程池大小及优化代码
+- [[#5487](https://github.com/seata/seata/pull/5487)] 将branchsession中的lockholder增加final修饰
 
 ### security:
 - [[#5172](https://github.com/seata/seata/pull/5172)] 修复一些安全漏洞的版本

server/src/main/java/io/seata/server/session/BranchSession.java

@@ -20,6 +20,9 @@
 import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+import io.seata.common.util.CollectionUtils;
 import io.seata.common.util.CompressUtil;
 import io.seata.core.exception.TransactionException;
 import io.seata.core.model.BranchStatus;
@@ -33,7 +36,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-
 import static io.seata.core.model.LockStatus.Locked;
 
 /**
@@ -72,11 +74,19 @@ public class BranchSession implements Lockable, Comparable<BranchSession>, Sessi
 
     private LockStatus lockStatus = Locked;
 
-    private Map<FileLocker.BucketLockMap, Set<String>> lockHolder
-        = Collections.emptyMap();
+    private final Map<FileLocker.BucketLockMap, Set<String>> lockHolder;
 
     private final LockManager lockManager = LockerManagerFactory.getLockManager();
 
+    public BranchSession() {
+        lockHolder = new ConcurrentHashMap<>(2);
+    }
+
+    public BranchSession(BranchType branchType) {
+        this.branchType = branchType;
+        this.lockHolder = branchType == BranchType.AT ? new ConcurrentHashMap<>(8) : Collections.emptyMap();
+    }
+
     /**
      * Gets application data.
      *
@@ -280,14 +290,6 @@ public Map<FileLocker.BucketLockMap, Set<String>> getLockHolder() {
         return lockHolder;
     }
 
-    /**
-     * Set lock holder.
-     *
-     */
-    public void setLockHolder(Map<FileLocker.BucketLockMap, Set<String>> lockHolder) {
-        this.lockHolder = lockHolder;
-    }
-
     @Override
     public boolean lock() throws TransactionException {
         return this.lock(true, false);
@@ -302,7 +304,7 @@ public boolean lock(boolean autoCommit, boolean skipCheckLock) throws Transactio
 
     @Override
     public boolean unlock() throws TransactionException {
-        if (this.branchType == BranchType.AT) {
+        if (this.branchType == BranchType.AT && CollectionUtils.isNotEmpty(this.lockHolder)) {
             return lockManager.releaseLock(this);
         }
         return true;

server/src/main/java/io/seata/server/session/SessionHelper.java

@@ -88,12 +88,11 @@ public static BranchSession newBranchByGlobal(GlobalSession globalSession, Branc
      */
     public static BranchSession newBranchByGlobal(GlobalSession globalSession, BranchType branchType, String resourceId,
             String applicationData, String lockKeys, String clientId) {
-        BranchSession branchSession = new BranchSession();
+        BranchSession branchSession = new BranchSession(branchType);
 
         branchSession.setXid(globalSession.getXid());
         branchSession.setTransactionId(globalSession.getTransactionId());
         branchSession.setBranchId(UUIDGenerator.generateUUID());
-        branchSession.setBranchType(branchType);
         branchSession.setResourceId(resourceId);
         branchSession.setLockKey(lockKeys);
         branchSession.setClientId(clientId);

server/src/main/java/io/seata/server/storage/file/lock/FileLocker.java

@@ -75,7 +75,7 @@ public boolean acquireLock(List<RowLock> rowLocks, boolean autoCommit, boolean s
         String resourceId = branchSession.getResourceId();
         long transactionId = branchSession.getTransactionId();
 
-        Map<BucketLockMap, Set<String>> bucketHolder = new ConcurrentHashMap<>(8);
+        Map<BucketLockMap, Set<String>> bucketHolder = branchSession.getLockHolder();
         Map<String, ConcurrentMap<Integer, BucketLockMap>> dbLockMap = CollectionUtils.computeIfAbsent(
             LOCK_MAP, resourceId, key -> new ConcurrentHashMap<>(8));
         boolean failFast = false;
@@ -100,11 +100,8 @@ public boolean acquireLock(List<RowLock> rowLocks, boolean autoCommit, boolean s
             } else {
                 LOGGER.info("Global lock on [" + tableName + ":" + pk + "] is holding by " + previousLockBranchSession.getBranchId());
                 try {
-                    if (CollectionUtils.isNotEmpty(bucketHolder)) {
-                        branchSession.setLockHolder(bucketHolder);
-                        // Release all acquired locks.
-                        branchSession.unlock();
-                    }
+                    // Release all acquired locks.
+                    branchSession.unlock();
                 } catch (TransactionException e) {
                     throw new FrameworkException(e);
                 }
@@ -123,9 +120,6 @@ public boolean acquireLock(List<RowLock> rowLocks, boolean autoCommit, boolean s
         if (failFast) {
             throw new StoreException(new BranchTransactionException(LockKeyConflictFailFast));
         }
-        if (CollectionUtils.isNotEmpty(bucketHolder)) {
-            branchSession.setLockHolder(bucketHolder);
-        }
         return canLock;
     }