Add protect logic to TopN's topNWorkerReportCycle (#9599)

Author: wu-sheng

Diff for: oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/worker/TopNStreamProcessor.java

@@ -54,7 +54,6 @@ public class TopNStreamProcessor implements StreamProcessor<TopN> {
     @Getter
     private List<TopNWorker> persistentWorkers = new ArrayList<>();
     private Map<Class<? extends Record>, TopNWorker> workers = new HashMap<>();
-    @Setter
     @Getter
     private int topNWorkerReportCycle = 10;
     @Setter
@@ -65,6 +64,13 @@ public static TopNStreamProcessor getInstance() {
         return PROCESSOR;
     }
 
+    public void setTopNWorkerReportCycle(final int topNWorkerReportCycle) {
+        if (topNWorkerReportCycle < 1) {
+            return;
+        }
+        this.topNWorkerReportCycle = topNWorkerReportCycle;
+    }
+
     @Override
     @SuppressWarnings("unchecked")
     public void create(ModuleDefineHolder moduleDefineHolder,
@@ -79,7 +85,8 @@ public void create(ModuleDefineHolder moduleDefineHolder,
         IRecordDAO recordDAO;
         try {
             recordDAO = storageDAO.newRecordDao(builder.getDeclaredConstructor().newInstance());
-        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
+        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException |
+                 InvocationTargetException e) {
             throw new UnexpectedException(
                 "Create " + stream.builder().getSimpleName() + " top n record DAO failure.", e);
         }