org.apache.eventmesh.spi.EventMeshExtensionFactory Maven / Gradle / Ivy
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* 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.eventmesh.common.config.ConfigService;
import org.apache.eventmesh.spi.loader.ExtensionClassLoader;
import org.apache.eventmesh.spi.loader.JarExtensionClassLoader;
import org.apache.eventmesh.spi.loader.MetaInfExtensionClassLoader;
import org.apache.commons.lang3.StringUtils;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import lombok.extern.slf4j.Slf4j;
/**
* The extension fetching factory, all extension plugins should be fetched by this factory. And all the extension plugins defined in eventmesh should
* have {@link EventMeshSPI} annotation.
*/
@Slf4j
public class EventMeshExtensionFactory {
private static final List EXTENSION_CLASS_LOADERS = new ArrayList<>();
private static final ConcurrentHashMap EXTENSION_INSTANCE_CACHE = new ConcurrentHashMap<>(16);
static {
EXTENSION_CLASS_LOADERS.add(MetaInfExtensionClassLoader.getInstance());
EXTENSION_CLASS_LOADERS.add(JarExtensionClassLoader.getInstance());
}
private EventMeshExtensionFactory() {
}
/**
* Get an instance of an extension plugin.
*
* @param extensionClass extension plugin class type
* @param extensionName extension instance name
* @param the type of the plugin
* @return plugin instance
*/
public static T getExtension(Class extensionClass, String extensionName) {
if (extensionClass == null) {
throw new ExtensionException("extensionClass is null");
}
if (StringUtils.isEmpty(extensionName)) {
throw new ExtensionException("extensionName is null");
}
if (!extensionClass.isInterface() || !extensionClass.isAnnotationPresent(EventMeshSPI.class)) {
throw new ExtensionException(String.format("extensionClass:%s is invalided", extensionClass));
}
EventMeshSPI eventMeshSPIAnnotation = extensionClass.getAnnotation(EventMeshSPI.class);
if (eventMeshSPIAnnotation.isSingleton()) {
return getSingletonExtension(extensionClass, eventMeshSPIAnnotation, extensionName);
}
return getPrototypeExtension(extensionClass, extensionName);
}
/**
* Get a singleton instance of an extension plugin.
*
* @param extensionClass the type of the extension plugin
* @param spi the type of the spi
* @param extensionInstanceName the name of the extension instance
* @param the type of the extension plugin
* @return a singleton instance of the extension plugin
*/
@SuppressWarnings("unchecked")
private static T getSingletonExtension(Class extensionClass, EventMeshSPI spi, String extensionInstanceName) {
return (T) EXTENSION_INSTANCE_CACHE.computeIfAbsent(new Extension(spi, extensionInstanceName), name -> {
Class extensionInstanceClass = getExtensionInstanceClass(extensionClass, extensionInstanceName);
if (extensionInstanceClass == null) {
log.warn("Get extension instance class {} is null", extensionClass.getName());
return null;
}
try {
T extensionInstance = extensionInstanceClass.getDeclaredConstructor().newInstance();
ConfigService.getInstance().populateConfigForObject(extensionInstance);
log.info("initialize extension instance success, extensionClass: {}, extensionInstanceName: {}",
extensionClass, extensionInstanceName);
return extensionInstance;
} catch (NoSuchMethodException | InstantiationException | IllegalAccessException | InvocationTargetException e) {
throw new ExtensionException("Extension initialize error", e);
} catch (NoSuchFieldException | IOException e) {
log.error("initialize extension instance config failed, extensionClass: {}, extensionInstanceName: {}",
extensionClass, extensionInstanceName, e);
throw new ExtensionException("Extension initialize error", e);
}
});
}
/**
* Get a new instance of an extension plugin.
*
* @param extensionType the type of the extension plugin
* @param extensionInstanceName the name of the extension instance
* @param the type of the extension plugin
* @return a new instance of the extension plugin
*/
private static T getPrototypeExtension(Class extensionType, String extensionInstanceName) {
Class extensionInstanceClass = getExtensionInstanceClass(extensionType, extensionInstanceName);
if (extensionInstanceClass == null) {
return null;
}
try {
T extensionInstance = extensionInstanceClass.getDeclaredConstructor().newInstance();
ConfigService.getInstance().populateConfigForObject(extensionInstance);
log.info("initialize extension instance success, extensionType: {}, extensionName: {}",
extensionType, extensionInstanceName);
return extensionInstance;
} catch (NoSuchMethodException | InstantiationException | IllegalAccessException | InvocationTargetException e) {
throw new ExtensionException("Extension initialize error", e);
} catch (NoSuchFieldException | IOException e) {
log.error("initialize extension instance config failed, extensionType: {}, extensionInstanceName: {}",
extensionType, extensionInstanceName, e);
throw new ExtensionException("Extension initialize error", e);
}
}
/**
* Get the class of an extension instance.
*
* @param extensionType the type of the extension instance
* @param extensionInstanceName the name of the extension instance
* @param the type of the extension instance
* @return the class of the extension instance
*/
@SuppressWarnings("unchecked")
private static Class getExtensionInstanceClass(Class extensionType, String extensionInstanceName) {
for (ExtensionClassLoader extensionClassLoader : EXTENSION_CLASS_LOADERS) {
Map> extensionInstanceClassMap = extensionClassLoader.loadExtensionClass(extensionType, extensionInstanceName);
Class instanceClass = extensionInstanceClassMap.get(extensionInstanceName);
if (instanceClass != null) {
return (Class) instanceClass;
}
}
return null;
}
private static class Extension {
private EventMeshSPI spi;
private String extensionInstanceName;
public Extension(EventMeshSPI spi, String extensionInstanceName) {
this.spi = spi;
this.extensionInstanceName = extensionInstanceName;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof Extension)) {
return false;
}
Extension extension = (Extension) o;
return Objects.equals(spi, extension.spi) && Objects.equals(extensionInstanceName, extension.extensionInstanceName);
}
@Override
public int hashCode() {
return Objects.hash(spi, extensionInstanceName);
}
}
}
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