Merge pull request #2734 from gabrywu/removeUnnecessaryLock

remove unnecessary lock & fix syncWorkerHostWeight variable reference

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/master/dispatch/host/LowerWeightHostManager.java

@@ -36,8 +36,6 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
 
 import static org.apache.dolphinscheduler.common.Constants.COMMA;
 
@@ -70,11 +68,6 @@ public class LowerWeightHostManager extends CommonHostManager {
      */
     private ConcurrentHashMap<String, Set<HostWeight>> workerHostWeights;
 
-    /**
-     * worker group host lock
-     */
-    private Lock lock;
-
     /**
      * executor service
      */
@@ -84,7 +77,6 @@ public class LowerWeightHostManager extends CommonHostManager {
     public void init(){
         this.selector = new LowerWeightRoundRobin();
         this.workerHostWeights = new ConcurrentHashMap<>();
-        this.lock = new ReentrantLock();
         this.executorService = Executors.newSingleThreadScheduledExecutor(new NamedThreadFactory("LowerWeightHostManagerExecutor"));
         this.executorService.scheduleWithFixedDelay(new RefreshResourceTask(),35, 40, TimeUnit.SECONDS);
         this.roundRobinHostManager = new RoundRobinHostManager();
@@ -116,23 +108,13 @@ public class LowerWeightHostManager extends CommonHostManager {
         throw new UnsupportedOperationException("not support");
     }
 
-    private void syncWorkerHostWeight(Map<String, Set<HostWeight>> workerHostWeights){
-        lock.lock();
-        try {
-            workerHostWeights.clear();
-            workerHostWeights.putAll(workerHostWeights);
-        } finally {
-            lock.unlock();
-        }
+    private void syncWorkerHostWeight(Map<String, Set<HostWeight>> workerHostWeights) {
+        this.workerHostWeights.clear();
+        this.workerHostWeights.putAll(workerHostWeights);
     }
 
-    private Set<HostWeight> getWorkerHostWeights(String workerGroup){
-        lock.lock();
-        try {
-            return workerHostWeights.get(workerGroup);
-        } finally {
-            lock.unlock();
-        }
+    private Set<HostWeight> getWorkerHostWeights(String workerGroup) {
+        return workerHostWeights.get(workerGroup);
     }
 
     class RefreshResourceTask implements Runnable{