Java tutorial
/* * Copyright 2008 Pavel Syrtsov * * 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.sf.ddao.crud.param; import com.sf.ddao.chain.CtxHelper; import com.sf.ddao.chain.MethodCallCtx; import com.sf.ddao.crud.CRUDDao; import com.sf.ddao.factory.param.DefaultParameter; import com.sf.ddao.factory.param.ParameterFactory; import com.sf.ddao.factory.param.ParameterHandler; import com.sf.ddao.factory.param.ParameterService; import org.apache.commons.chain.Context; import java.lang.reflect.AnnotatedElement; import java.lang.reflect.Method; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; import java.util.HashMap; import java.util.Map; /** * Date: Oct 27, 2009 * Time: 3:34:24 PM */ public class CRUDParameterService implements ParameterService { public static final Map<String, Class<? extends ParameterHandler>> classMap = new HashMap<String, Class<? extends ParameterHandler>>() { { put(CRUDBeanPropsParameter.CRUD_BEAN_PROPS, CRUDBeanPropsParameter.class); put(CRUDTableNameParameter.CRUD_TABLE_NAME, CRUDTableNameParameter.class); } }; public static final int USE_GENERICS = -2; public static final int GENERICS_ARG_NUM = 0; public void register(ParameterFactory parameterFactory) { for (String name : classMap.keySet()) { parameterFactory.register(name, this); } } public ParameterHandler create(AnnotatedElement element, String funcName, String paramName, boolean isRef) { final Class<? extends ParameterHandler> aClass = classMap.get(funcName); final ParameterHandler res; try { res = aClass.newInstance(); } catch (Exception e) { throw new RuntimeException(e); } res.init(element, paramName, isRef); return res; } public static Class<?> getCRUDDaoBean(Context ctx, int idx) { final MethodCallCtx callCtx = CtxHelper.get(ctx, MethodCallCtx.class); final Method method = callCtx.getMethod(); if (idx != USE_GENERICS) { Type beanClass; if (idx == DefaultParameter.RETURN_ARG_IDX) { beanClass = method.getGenericReturnType(); } else { beanClass = method.getGenericParameterTypes()[idx]; } if (beanClass instanceof Class) { return (Class) beanClass; } } Class<?> iFace = callCtx.getSubjClass(); for (Type type : iFace.getGenericInterfaces()) { final ParameterizedType parameterizedType = (ParameterizedType) type; if (parameterizedType.getRawType().equals(method.getDeclaringClass())) { final Type[] typeArguments = parameterizedType.getActualTypeArguments(); return (Class<?>) typeArguments[GENERICS_ARG_NUM]; } } throw new RuntimeException(iFace + " expected to extend " + CRUDDao.class); } }