[jira] [Commented] (SCB-360) make guava eventbus simpler and faster

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SCB-360?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16387405#comment-16387405 ] 

ASF GitHub Bot commented on SCB-360:
------------------------------------

liubao68 commented on a change in pull request #570: SCB-360 write simpler eventBus to optimize performance
URL: https://github.com/apache/incubator-servicecomb-java-chassis/pull/570#discussion_r172426922
 
 

 ##########
 File path: foundations/foundation-common/src/main/java/com/google/common/eventbus/SimpleEventBus.java
 ##########
 @@ -0,0 +1,84 @@
+/*
+ * 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 com.google.common.eventbus;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import org.apache.servicecomb.foundation.common.concurrent.ConcurrentHashMapEx;
+
+import com.google.common.collect.Multimap;
+
+// EventBus has performance problem, we create a new simpler eventBus
+//
+// extend from EventBus is not necessary
+// but EventManager has a public EventBus field, we need to make compatible
+//
+// different between this class and EventBus:
+// 1. not support cycle trigger:
+//   subscribe a, when handle a, trigger event b
+//   subscribe b, when handle b, trigger event a
+public class SimpleEventBus extends com.google.common.eventbus.EventBus {
+  private AnnotatedSubscriberFinder finder = new AnnotatedSubscriberFinder();
+
+  // key is event type
+  // value is CopyOnWriteArrayList
+  private Map<Class<?>, List<EventSubscriber>> subscribersByType = new ConcurrentHashMapEx<>();
+
+  @Override
+  public void register(Object listener) {
+    Multimap<Class<?>, EventSubscriber> methodsInListener = finder.findAllSubscribers(listener);
+
+    for (Entry<Class<?>, Collection<EventSubscriber>> entry : methodsInListener.asMap().entrySet()) {
+      List<EventSubscriber> exists = subscribersByType.computeIfAbsent(entry.getKey(), cls -> {
+        return new CopyOnWriteArrayList<>();
+      });
+      exists.addAll(entry.getValue());
+    }
+  }
+
+  @Override
+  public void unregister(Object listener) {
+    Multimap<Class<?>, EventSubscriber> methodsInListener = finder.findAllSubscribers(listener);
+
+    for (Entry<Class<?>, Collection<EventSubscriber>> entry : methodsInListener.asMap().entrySet()) {
+      List<EventSubscriber> exists = subscribersByType.get(entry.getKey());
+      if (exists == null) {
+        continue;
+      }
+
+      exists.removeAll(entry.getValue());
+    }
+  }
+
+  @Override
+  public void post(Object event) {
 
 Review comment:
   OK.  This will just make events out of order when trigger events in events handling logic.

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> make guava eventbus simpler and faster
> --------------------------------------
>
>                 Key: SCB-360
>                 URL: https://issues.apache.org/jira/browse/SCB-360
>             Project: Apache ServiceComb
>          Issue Type: Sub-task
>          Components: Java-Chassis
>            Reporter: wujimin
>            Assignee: wujimin
>            Priority: Major
>




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