[ISSUE #367]Enhance SPI plugins

eventmesh-common/gradle.properties

@@ -16,4 +16,4 @@
 #
 group=org.apache.eventmesh
 version=1.2.0-SNAPSHOT
-jdk=1.7
+jdk=1.8

eventmesh-spi/build.gradle

@@ -0,0 +1,16 @@
+/*
+ * 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.
+ */

eventmesh-spi/gradle.properties

@@ -0,0 +1,20 @@
+#
+# 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.
+#
+group=org.apache.eventmesh
+version=1.2.0-SNAPSHOT
+jdk=1.8
+snapshot=false

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

@@ -0,0 +1,37 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+import org.apache.commons.lang3.StringUtils;
+
+public enum EventMeshExtensionFactory {
+    ;
+
+    public static <T> T getExtension(Class<T> extensionType, String extensionName) {
+        if (extensionType == null) {
+            throw new ExtensionException("extensionType is null");
+        }
+        if (StringUtils.isEmpty(extensionName)) {
+            throw new ExtensionException("extensionName is null");
+        }
+        if (!extensionType.isInterface() || !extensionType.isAnnotationPresent(EventMeshSPI.class)) {
+            throw new ExtensionException(String.format("extensionType:%s is invalided", extensionType));
+        }
+        return EventMeshExtensionLoader.getExtension(extensionType, extensionName);
+    }
+}

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

@@ -0,0 +1,110 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Enumeration;
+import java.util.Properties;
+import java.util.concurrent.ConcurrentHashMap;
+
+public enum EventMeshExtensionLoader {
+    ;
+
+    private static final ConcurrentHashMap<Class<?>, ConcurrentHashMap<String, Class<?>>> EXTENSION_CLASS_LOAD_CACHE = new ConcurrentHashMap<>(16);
+
+    private static final ConcurrentHashMap<String, Object> EXTENSION_INSTANCE_CACHE = new ConcurrentHashMap<>(16);
+
+    private static final String EVENTMESH_EXTENSION_DIR = "META-INF/eventmesh/";
+
+    @SuppressWarnings("unchecked")
+    public static <T> T getExtension(Class<T> extensionType, String extensionName) {
+        if (!hasLoadExtensionClass(extensionType)) {
+            loadExtensionClass(extensionType);
+        }
+        if (!hasInitializeExtension(extensionName)) {
+            initializeExtension(extensionType, extensionName);
+        }
+        return (T) EXTENSION_INSTANCE_CACHE.get(extensionName);
+    }
+
+    private static <T> void 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));
+        }
+        if (!extensionClassMap.containsKey(extensionName)) {
+            throw new ExtensionException(String.format("Extension name:%s has not been loaded", extensionName));
+        }
+        Class<?> aClass = extensionClassMap.get(extensionName);
+        try {
+            EXTENSION_INSTANCE_CACHE.put(extensionName, aClass.newInstance());
+        } catch (InstantiationException | IllegalAccessException e) {
+            throw new ExtensionException("Extension initialize error", e);
+        }
+    }
+
+    public static <T> void loadExtensionClass(Class<T> extensionType) {
+        String extensionFileName = EVENTMESH_EXTENSION_DIR + extensionType.getName();
+        ClassLoader classLoader = EventMeshExtensionLoader.class.getClassLoader();
+        try {
+            Enumeration<URL> extensionUrls = classLoader.getResources(extensionFileName);
+            if (extensionUrls != null) {
+                while (extensionUrls.hasMoreElements()) {
+                    URL url = extensionUrls.nextElement();
+                    loadResources(url, extensionType);
+                }
+            }
+        } catch (IOException e) {
+            throw new ExtensionException("load extension class error", e);
+        }
+
+
+    }
+
+    private static <T> void loadResources(URL url, Class<T> extensionType) throws IOException {
+        try (InputStream inputStream = url.openStream()) {
+            Properties properties = new Properties();
+            properties.load(inputStream);
+            properties.forEach((extensionName, extensionClass) -> {
+                String extensionNameStr = (String) extensionName;
+                String extensionClassStr = (String) extensionClass;
+                try {
+                    Class<?> targetClass = Class.forName(extensionClassStr);
+                    if (!extensionType.isAssignableFrom(targetClass)) {
+                        throw new ExtensionException(
+                                String.format("class: %s is not subClass of %s", targetClass, extensionType));
+                    }
+                    EXTENSION_CLASS_LOAD_CACHE.computeIfAbsent(extensionType, k -> new ConcurrentHashMap<>())
+                            .put(extensionNameStr, targetClass);
+                } catch (ClassNotFoundException e) {
+                    throw new ExtensionException("load extension class error", e);
+                }
+            });
+        }
+    }
+
+    private static <T> boolean hasLoadExtensionClass(Class<T> extensionType) {
+        return EXTENSION_CLASS_LOAD_CACHE.containsKey(extensionType);
+    }
+
+    private static boolean hasInitializeExtension(String extensionName) {
+        return EXTENSION_INSTANCE_CACHE.containsKey(extensionName);
+    }
+}

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

@@ -0,0 +1,35 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Just as a marker for SPI
+ */
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.TYPE})
+public @interface EventMeshSPI {
+
+}
+

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

@@ -0,0 +1,33 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+public class ExtensionException extends RuntimeException {
+
+    public ExtensionException(Exception e) {
+        super(e);
+    }
+
+    public ExtensionException(String message) {
+        super(message);
+    }
+
+    public ExtensionException(String message, Exception e) {
+        super(message, e);
+    }
+}

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

@@ -0,0 +1,29 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+import org.junit.Test;
+
+public class EventMeshExtensionFactoryTest {
+
+    @Test
+    public void getExtension() {
+        TestExtension extensionA = EventMeshExtensionFactory.getExtension(TestExtension.class, "extensionA");
+        extensionA.hello();
+    }
+}

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

@@ -0,0 +1,26 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+public class ExtensionA implements TestExtension {
+
+    @Override
+    public void hello() {
+        System.out.println("I am ExtensionA");
+    }
+}

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

@@ -0,0 +1,24 @@
+/*
+ * 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 org.apache.eventmesh.spi;
+
+@EventMeshSPI
+public interface TestExtension {
+
+    void hello();
+}

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

@@ -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.
+
+extensionA=org.apache.eventmesh.spi.ExtensionA

settings.gradle

@@ -17,5 +17,12 @@
 
 rootProject.name = 'EventMesh'
 String jdkVersion = "${jdk}"
-include 'eventmesh-runtime','eventmesh-connector-rocketmq','eventmesh-sdk-java','eventmesh-common','eventmesh-connector-api','eventmesh-starter','eventmesh-test'
+include 'eventmesh-runtime'
+include 'eventmesh-connector-rocketmq'
+include 'eventmesh-sdk-java'
+include 'eventmesh-common'
+include 'eventmesh-connector-api'
+include 'eventmesh-starter'
+include 'eventmesh-test'
+include 'eventmesh-spi'