running listener code in separate thread

Author: l-trotta

java-client/src/main/java/co/elastic/clients/elasticsearch/_helpers/bulk/BulkIngester.java

@@ -36,6 +36,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CompletionStage;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
@@ -58,10 +59,11 @@ public class BulkIngester<Context> implements AutoCloseable {
     private final long maxSize;
     private final int maxOperations;
     private final @Nullable BulkListener<Context> listener;
+    private ExecutorService listenerExecutor = null; // Created only if listener is present
     private final Long flushIntervalMillis;
 
     private @Nullable ScheduledFuture<?> flushTask;
-    private @Nullable ScheduledExecutorService scheduler;
+    private @Nullable ScheduledExecutorService flushScheduler;
 
     // Current state
     private List<BulkOperation> operations = new ArrayList<>();
@@ -98,6 +100,14 @@ private BulkIngester(Builder<Context> builder) {
         this.maxSize = builder.bulkSize < 0 ? Long.MAX_VALUE : builder.bulkSize;
         this.maxOperations = builder.bulkOperations < 0 ? Integer.MAX_VALUE : builder.bulkOperations;
         this.listener = builder.listener;
+        if(listener != null) {
+            this.listenerExecutor = Executors.newSingleThreadScheduledExecutor((r) -> {
+                Thread t = Executors.defaultThreadFactory().newThread(r);
+                t.setName("listener-executor#" + ingesterId);
+                t.setDaemon(true);
+                return t;
+            });
+        }
         this.flushIntervalMillis = builder.flushIntervalMillis;
 
         if (flushIntervalMillis != null) {
@@ -114,7 +124,7 @@ private BulkIngester(Builder<Context> builder) {
                     });
 
                 // Keep it, we'll have to close it.
-                this.scheduler = scheduler;
+                this.flushScheduler = scheduler;
             } else {
                 // It's not ours, we will not close it.
                 scheduler = builder.scheduler;
@@ -291,7 +301,8 @@ public void flush() {
                 long id = sendRequestCondition.invocations();
 
                 if (listener != null) {
-                    listener.beforeBulk(id, request, requestContexts);
+                    BulkRequest finalRequest = request;
+                    listenerExecutor.submit(() -> listener.beforeBulk(id, finalRequest, requestContexts));
                 }
 
                 CompletionStage<BulkResponse> result = client.bulk(request);
@@ -317,12 +328,12 @@ public void flush() {
                 if (resp != null) {
                     // Success
                     if (listener != null) {
-                        listener.afterBulk(exec.id, exec.request, exec.contexts, resp);
+                        listenerExecutor.submit(() -> listener.afterBulk(exec.id, exec.request, exec.contexts, resp));
                     }
                 } else {
                     // Failure
                     if (listener != null) {
-                        listener.afterBulk(exec.id, exec.request, exec.contexts, thr);
+                        listenerExecutor.submit(() -> listener.afterBulk(exec.id, exec.request, exec.contexts, thr));
                     }
                 }
                 return null;
@@ -389,8 +400,12 @@ public void close() {
             flushTask.cancel(false);
         }
 
-        if (scheduler != null) {
-            scheduler.shutdownNow();
+        if (flushScheduler != null) {
+            flushScheduler.shutdownNow();
+        }
+
+        if (listenerExecutor != null){
+            listenerExecutor.shutdownNow();
         }
     }