[ISSUE apache#367] Support prototype spi instance

  change producer and consumer spi to prototype

eventmesh-connector-api/src/main/java/org/apache/eventmesh/api/consumer/MeshMQPushConsumer.java

@@ -27,7 +27,7 @@
 import org.apache.eventmesh.api.AbstractContext;
 import org.apache.eventmesh.spi.EventMeshSPI;
 
-@EventMeshSPI
+@EventMeshSPI(isSingleton = false)
 public interface MeshMQPushConsumer extends Consumer {
 
     void init(Properties keyValue) throws Exception;

eventmesh-connector-api/src/main/java/org/apache/eventmesh/api/producer/MeshMQProducer.java

@@ -26,7 +26,7 @@
 import org.apache.eventmesh.api.RRCallback;
 import org.apache.eventmesh.spi.EventMeshSPI;
 
-@EventMeshSPI
+@EventMeshSPI(isSingleton = false)
 public interface MeshMQProducer extends Producer {
 
     void init(Properties properties) throws Exception;

eventmesh-spi/src/main/java/org/apache/eventmesh/spi/EventMeshExtensionLoader.java

@@ -44,12 +44,18 @@ public static <T> T getExtension(Class<T> extensionType, String extensionName) {
             loadExtensionClass(extensionType);
         }
         if (!hasInitializeExtension(extensionName)) {
-            initializeExtension(extensionType, extensionName);
+            T instance = initializeExtension(extensionType, extensionName);
+            EventMeshSPI spiAnnotation = extensionType.getAnnotation(EventMeshSPI.class);
+            if (!spiAnnotation.isSingleton()) {
+                return instance;
+            }
+            EXTENSION_INSTANCE_CACHE.put(extensionName, instance);
         }
         return (T) EXTENSION_INSTANCE_CACHE.get(extensionName);
     }
 
-    private static <T> void initializeExtension(Class<T> extensionType, String extensionName) {
+    @SuppressWarnings("unchecked")
+    private static <T> T initializeExtension(Class<T> extensionType, String extensionName) {
         ConcurrentHashMap<String, Class<?>> extensionClassMap = EXTENSION_CLASS_LOAD_CACHE.get(extensionType);
         if (extensionClassMap == null) {
             throw new ExtensionException(String.format("Extension type:%s has not been loaded", extensionType));
@@ -61,7 +67,7 @@ private static <T> void initializeExtension(Class<T> extensionType, String exten
         try {
             Object extensionObj = aClass.newInstance();
             logger.info("initialize extension instance success, extensionType: {}, extensionName: {}", extensionType, extensionName);
-            EXTENSION_INSTANCE_CACHE.put(extensionName, extensionObj);
+            return (T) extensionObj;
         } catch (InstantiationException | IllegalAccessException e) {
             throw new ExtensionException("Extension initialize error", e);
         }

eventmesh-spi/src/main/java/org/apache/eventmesh/spi/EventMeshSPI.java

@@ -31,5 +31,10 @@
 @Target({ElementType.TYPE})
 public @interface EventMeshSPI {
 
+    /**
+     * If true, the spi instance is singleton
+     */
+    boolean isSingleton() default false;
+
 }
 

eventmesh-spi/src/test/java/org/apache/eventmesh/spi/EventMeshExtensionFactoryTest.java

@@ -17,13 +17,24 @@
 
 package org.apache.eventmesh.spi;
 
+import org.apache.eventmesh.spi.example.TestPrototypeExtension;
+import org.apache.eventmesh.spi.example.TestSingletonExtension;
+import org.junit.Assert;
 import org.junit.Test;
 
 public class EventMeshExtensionFactoryTest {
 
     @Test
-    public void getExtension() {
-        TestExtension extensionA = EventMeshExtensionFactory.getExtension(TestExtension.class, "extensionA");
-        extensionA.hello();
+    public void getSingletonExtensionTest() {
+        TestSingletonExtension extensionA = EventMeshExtensionFactory.getExtension(TestSingletonExtension.class, "singletonExtension");
+        TestSingletonExtension extensionB = EventMeshExtensionFactory.getExtension(TestSingletonExtension.class, "singletonExtension");
+        Assert.assertSame(extensionA, extensionB);
+    }
+
+    @Test
+    public void getPrototypeExtensionTest() {
+        TestPrototypeExtension prototypeExtensionA = EventMeshExtensionFactory.getExtension(TestPrototypeExtension.class, "prototypeExtension");
+        TestPrototypeExtension prototypeExtensionB = EventMeshExtensionFactory.getExtension(TestPrototypeExtension.class, "prototypeExtension");
+        Assert.assertNotSame(prototypeExtensionA, prototypeExtensionB);
     }
 }

eventmesh-spi/src/test/java/org/apache/eventmesh/spi/example/PrototypeExtension.java

@@ -0,0 +1,8 @@
+package org.apache.eventmesh.spi.example;
+
+public class PrototypeExtension implements TestPrototypeExtension {
+    @Override
+    public void hello() {
+        System.out.println("I am PrototypeExtension");
+    }
+}

eventmesh-spi/src/test/java/org/apache/eventmesh/spi/ExtensionA.java → eventmesh-spi/src/test/java/org/apache/eventmesh/spi/example/SingletonExtension.java

@@ -15,12 +15,12 @@
  * limitations under the License.
  */
 
-package org.apache.eventmesh.spi;
+package org.apache.eventmesh.spi.example;
 
-public class ExtensionA implements TestExtension {
+public class SingletonExtension implements TestSingletonExtension {
 
     @Override
     public void hello() {
-        System.out.println("I am ExtensionA");
+        System.out.println("I am SingletonExtension");
     }
 }

eventmesh-spi/src/test/java/org/apache/eventmesh/spi/example/TestPrototypeExtension.java

@@ -0,0 +1,9 @@
+package org.apache.eventmesh.spi.example;
+
+import org.apache.eventmesh.spi.EventMeshSPI;
+
+@EventMeshSPI(isSingleton = false)
+public interface TestPrototypeExtension {
+
+    void hello();
+}

eventmesh-spi/src/test/java/org/apache/eventmesh/spi/TestExtension.java → eventmesh-spi/src/test/java/org/apache/eventmesh/spi/example/TestSingletonExtension.java

@@ -15,10 +15,12 @@
  * limitations under the License.
  */
 
-package org.apache.eventmesh.spi;
+package org.apache.eventmesh.spi.example;
 
-@EventMeshSPI
-public interface TestExtension {
+import org.apache.eventmesh.spi.EventMeshSPI;
+
+@EventMeshSPI(isSingleton = true)
+public interface TestSingletonExtension {
 
     void hello();
 }

eventmesh-spi/src/test/resources/META-INF/eventmesh/org.apache.eventmesh.spi.TestExtension → eventmesh-spi/src/test/resources/META-INF/eventmesh/org.apache.eventmesh.spi.example.TestPrototypeExtension

@@ -14,4 +14,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-extensionA=org.apache.eventmesh.spi.ExtensionA
+prototypeExtension=org.apache.eventmesh.spi.example.PrototypeExtension

eventmesh-spi/src/test/resources/META-INF/eventmesh/org.apache.eventmesh.spi.example.TestSingletonExtension

@@ -0,0 +1,17 @@
+#
+# 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.
+
+singletonExtension=org.apache.eventmesh.spi.example.SingletonExtension