/*
* Copyright 2007-2009 the original author or authors.
*
* 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 net.paoding.rose.web.paramresolver;
import java.lang.reflect.Method;
import net.paoding.rose.web.Invocation;
import net.paoding.rose.web.annotation.DefValue;
import net.paoding.rose.web.annotation.Param;
import net.paoding.rose.web.impl.validation.ParameterBindingResult;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.TypeMismatchException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;
import org.springframework.validation.FieldError;
/**
* @author 王志亮 [qieqie.wang@gmail.com]
*/
public final class MethodParameterResolver {
private static Log logger = LogFactory.getLog(MethodParameterResolver.class);
// ---------------------------------------------------------
private final Method method;
private final String[] parameterNames;
private final ParamResolver[] resolvers;
private final ParamMetaData[] paramMetaDatas;
public MethodParameterResolver(Class<?> controllerClazz, Method method,
ParameterNameDiscovererImpl parameterNameDiscoverer, ResolverFactory resolverFactory) {
this.method = method;
Class<?>[] parameterTypes = method.getParameterTypes();
parameterNames = parameterNameDiscoverer.getParameterNames(method);
resolvers = new ParamResolver[parameterTypes.length];
paramMetaDatas = new ParamMetaData[parameterTypes.length];
//
for (int i = 0; i < parameterTypes.length; i++) {
ParamMetaDataImpl paramMetaData = new ParamMetaDataImpl(controllerClazz, method,
parameterTypes[i], parameterNames[i], i);
paramMetaDatas[i] = paramMetaData;
resolvers[i] = resolverFactory.supports(paramMetaData);
}
}
public ParamMetaData[] getParamMetaDatas() {
return paramMetaDatas;
}
public String[] getParameterNames() {
return parameterNames;
}
public Method getMethod() {
return method;
}
public Param getParamAnnotationAt(int index) {
return this.paramMetaDatas[index].getAnnotation(Param.class);
}
// ---------------------------------------------------------
public Object[] resolve(final Invocation inv,
final ParameterBindingResult parameterBindingResult) throws Exception {
Object[] parameters = new Object[paramMetaDatas.length];
for (int i = 0; i < resolvers.length; i++) {
if (resolvers[i] == null) {
continue;
}
try {
if (logger.isDebugEnabled()) {
logger.debug("Resolves parameter "
+ paramMetaDatas[i].getParamType().getSimpleName() + " using "
+ resolvers[i].getClass().getName());
}
parameters[i] = resolvers[i].resolve(inv, paramMetaDatas[i]);
// afterPropertiesSet
if (parameters[i] instanceof InitializingBean) {
((InitializingBean) parameters[i]).afterPropertiesSet();
}
} catch (TypeMismatchException e) {
// 出现这个错误肯定是解析一般参数失败导致的，而非bean里面的某个属性值的解析失败
logger.debug("", e);
// 对简单类型的参数，设置一个默认值给它以支持对该方法的继续调用
if (paramMetaDatas[i].getParamType().isPrimitive()) {
DefValue defValudeAnnotation = paramMetaDatas[i].getAnnotation(DefValue.class);
if (defValudeAnnotation == null
|| DefValue.NATIVE_DEFAULT.equals(defValudeAnnotation.value())) {
// 对这最常用的类型做一下if-else判断，其他类型就简单使用converter来做吧
if (paramMetaDatas[i].getParamType() == int.class) {
parameters[i] = Integer.valueOf(0);
} else if (paramMetaDatas[i].getParamType() == long.class) {
parameters[i] = Long.valueOf(0);
} else if (paramMetaDatas[i].getParamType() == boolean.class) {
parameters[i] = Boolean.FALSE;
} else if (paramMetaDatas[i].getParamType() == double.class) {
parameters[i] = Double.valueOf(0);
} else if (paramMetaDatas[i].getParamType() == float.class) {
parameters[i] = Float.valueOf(0);
} else {
TypeConverter typeConverter = SafedTypeConverterFactory
.getCurrentConverter();
parameters[i] = typeConverter.convertIfNecessary("0", paramMetaDatas[i]
.getParamType());
}
} else {
TypeConverter typeConverter = SafedTypeConverterFactory
.getCurrentConverter();
parameters[i] = typeConverter.convertIfNecessary(defValudeAnnotation
.value(), paramMetaDatas[i].getParamType());
}
}
//
String paramName = parameterNames[i];
if (paramName == null) {
for (String name : paramMetaDatas[i].getParamNames()) {
if ((paramName = name) != null) {
break;
}
}
}
Assert.isTrue(paramName != null);
FieldError fieldError = new FieldError(//
"method", // 该出错字段所在的对象的名字；对于这类异常我们统一规定名字为method
paramName, // 出错的字段的名字；取其参数名
inv.getParameter(paramName), // 被拒绝的值
true,//whether this error represents a binding failure (like a type mismatch); else, it is a validation failure
new String[] { e.getErrorCode() },// "typeMismatch"
new String[] { inv.getParameter(paramName) }, //the array of arguments to be used to resolve this message
null // the default message to be used to resolve this message
);
parameterBindingResult.addError(fieldError);
} catch (Exception e) {
// 什么错误呢？比如很有可能是构造对象不能成功导致的错误，没有默认构造函数、构造函数执行失败等等
logger.error("", e);
throw e;
}
}
return parameters;
}
}