/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* Licensed 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.alibaba.citrus.service.moduleloader.impl.adapter;
import static com.alibaba.citrus.springext.util.SpringExtUtil.*;
import static com.alibaba.citrus.util.CollectionUtil.*;
import static com.alibaba.citrus.util.StringUtil.*;
import java.lang.reflect.Method;
import java.util.Map;
import com.alibaba.citrus.service.moduleloader.Module;
import com.alibaba.citrus.service.moduleloader.ModuleInfo;
import com.alibaba.citrus.service.moduleloader.ModuleLoaderException;
import net.sf.cglib.reflect.FastClass;
import net.sf.cglib.reflect.FastMethod;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
/**
* 以事件的方式调用module的方法。
* <p>
* 支持绑定参数，参见{@link com.alibaba.citrus.service.dataresolver.DataResolverService}。
* </p>
*/
public abstract class AbstractModuleEventAdapterFactory<A extends AbstractModuleEventAdapter>
extends AbstractDataBindingAdapterFactory implements ApplicationContextAware {
private static final String DEFAULT_EVENT = "perform";
private static final String PRE_HANDLER = "beforeExecution";
private static final String POST_HANDLER = "afterExecution";
private ApplicationContext context;
public void setApplicationContext(ApplicationContext context) {
this.context = context;
}
public Module adapt(String type, String name, Object moduleObject) {
if (!isAdaptableType(type)) {
return null;
}
Class<?> moduleClass = moduleObject.getClass();
Map<String, Method> handlers = getEventHandlers(moduleClass);
if (handlers == null) {
return null;
}
ModuleInfo moduleInfo = new ModuleInfo(type, name);
FastClass fc = FastClass.create(moduleClass);
Map<String, MethodInvoker> fastHandlers = createHashMap(handlers.size());
for (Map.Entry<String, Method> entry : handlers.entrySet()) {
FastMethod fm = fc.getMethod(entry.getValue());
fastHandlers.put(entry.getKey(), getMethodInvoker(fm, moduleInfo, isEventHandlerSkippable()));
}
FastMethod preHandler = getFastMethod(fc, PRE_HANDLER);
FastMethod postHanlder = getFastMethod(fc, POST_HANDLER);
AbstractModuleEventAdapter adapter = createAdapter(moduleObject,
fastHandlers,
getMethodInvoker(preHandler, moduleInfo, false),
getMethodInvoker(postHanlder, moduleInfo, false));
try {
// 注入并初始化adapter（不是注入moduleObject，后者取决于factory的设置）
autowireAndInitialize(adapter, context, AbstractBeanDefinition.AUTOWIRE_AUTODETECT, type + "." + name);
} catch (Exception e) {
throw new ModuleLoaderException("Failed to configure module adapter", e);
}
return adapter;
}
/** 取得事件处理方法。 */
private Map<String, Method> getEventHandlers(Class<?> moduleClass) {
Map<String, Method> handlers = null;
for (Method method : moduleClass.getMethods()) {
if (checkMethod(method)) {
String methodName = method.getName();
// doXyz()
if (methodName.length() > 2 && methodName.startsWith("do")
&& Character.isUpperCase(methodName.charAt(2))) {
String eventName = toCamelCase(methodName.substring(2));
// default handler: doPerform()
if (DEFAULT_EVENT.equals(eventName)) {
eventName = null;
}
if (handlers == null) {
handlers = createHashMap();
}
handlers.put(eventName, method);
}
}
}
return handlers;
}
/** 取得方法，如果不存在或不符合要求，则返回null。 */
private FastMethod getFastMethod(FastClass fc, String methodName) {
Method method = getMethod(fc.getJavaClass(), methodName);
if (method == null) {
return null;
} else {
return fc.getMethod(method);
}
}
/** 判断module type是否可被适配。 */
protected abstract boolean isAdaptableType(String type);
/** 判断方法是否可被跳过。 */
protected abstract boolean isEventHandlerSkippable();
/** 工厂方法，用来创建一个adapter实例。 */
protected abstract A createAdapter(Object moduleObject, Map<String, MethodInvoker> handlers, MethodInvoker preHandler, MethodInvoker postHanlder);
}