content: /**
   * Copyright (c) 2005-2012 springside.org.cn
   */
  package com.jeespring.common.utils;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.lang.reflect.ParameterizedType;
  import java.lang.reflect.Type;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.lang3.Validate;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.util.Assert;
  
  /**
   * 反射工具类.
   * 提供调用getter/setter方法, 访问私有变量, 调用私有方法, 获取泛型类型Class, 被AOP过的真实类等工具函数.
   * @author calvin
   * @version 2013-01-15
   */
  @SuppressWarnings("rawtypes")
  public class Reflections {
  	
  	private static final String SETTER_PREFIX = "set";
  
  	private static final String GETTER_PREFIX = "get";
  
  	private static final String CGLIB_CLASS_SEPARATOR = "$$";
  	
  	private static Logger logger = LoggerFactory.getLogger(Reflections.class);
  
  	/**
  	 * 调用Getter方法.
  	 * 支持多级，如：对象名.对象名.方法
  	 */
  	public static Object invokeGetter(Object obj, String propertyName) {
  		Object object = obj;
  		for (String name : StringUtils.split(propertyName, ".")){
  			String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(name);
  			object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});
  		}
  		return object;
  	}
  
  	/**
  	 * 调用Setter方法, 仅匹配方法名。
  	 * 支持多级，如：对象名.对象名.方法
  	 */
  	public static void invokeSetter(Object obj, String propertyName, Object value) {
  		Object object = obj;
  		String[] names = StringUtils.split(propertyName, ".");
  		for (int i=0; i<names.length; i++){
  			if(i<names.length-1){
  				String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(names[i]);
  				object = invokeMethod(object, getterMethodName, new Class[] {}, new Object[] {});
  			}else{
  				String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(names[i]);
  				invokeMethodByName(object, setterMethodName, new Object[] { value });
  			}
  		}
  	}
  
  	/**
  	 * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
  	 */
  	public static Object getFieldValue(final Object obj, final String fieldName) {
  		Field field = getAccessibleField(obj, fieldName);
  
  		if (field == null) {
  			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
  		}
  
  		Object result = null;
  		try {
  			result = field.get(obj);
  		} catch (IllegalAccessException e) {
  			logger.error("不可能抛出的异常{}", e.getMessage());
  		}
  		return result;
  	}
  
  	/**
  	 * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
  	 */
  	public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
  		Field field = getAccessibleField(obj, fieldName);
  
  		if (field == null) {
  			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
  		}
  
  		try {
  			field.set(obj, value);
  		} catch (IllegalAccessException e) {
  			logger.error("不可能抛出的异常:{}", e.getMessage());
  		}
  	}
  
  	/**
  	 * 直接调用对象方法, 无视private/protected修饰符.
  	 * 用于一次性调用的情况，否则应使用getAccessibleMethod()函数获得Method后反复调用.
  	 * 同时匹配方法名+参数类型，
  	 */
  	public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes,
  			final Object[] args) {
  		Method method = getAccessibleMethod(obj, methodName, parameterTypes);
  		if (method == null) {
  			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
  		}
  
  		try {
  			return method.invoke(obj, args);
  		} catch (Exception e) {
  			throw convertReflectionExceptionToUnchecked(e);
  		}
  	}
  
  	/**
  	 * 直接调用对象方法, 无视private/protected修饰符，
  	 * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
  	 * 只匹配函数名，如果有多个同名函数调用第一个。
  	 */
  	public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {
  		Method method = getAccessibleMethodByName(obj, methodName);
  		if (method == null) {
  			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
  		}
  
  		try {
  			return method.invoke(obj, args);
  		} catch (Exception e) {
  			throw convertReflectionExceptionToUnchecked(e);
  		}
  	}
  
  	/**
  	 * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问.
  	 * 
  	 * 如向上转型到Object仍无法找到, 返回null.
  	 */
  	public static Field getAccessibleField(final Object obj, final String fieldName) {
  		Validate.notNull(obj, "object can't be null");
  		Validate.notBlank(fieldName, "fieldName can't be blank");
  		for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
  			try {
  				Field field = superClass.getDeclaredField(fieldName);
  				makeAccessible(field);
  				return field;
  			} catch (NoSuchFieldException e) {//NOSONAR
  				// Field不在当前类定义,继续向上转型
  				continue;// new add
  			}
  		}
  		return null;
  	}
  
  	/**
  	 * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
  	 * 如向上转型到Object仍无法找到, 返回null.
  	 * 匹配函数名+参数类型。
  	 * 
  	 * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
  	 */
  	public static Method getAccessibleMethod(final Object obj, final String methodName,
  			final Class<?>... parameterTypes) {
  		Validate.notNull(obj, "object can't be null");
  		Validate.notBlank(methodName, "methodName can't be blank");
  
  		for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
  			try {
  				Method method = searchType.getDeclaredMethod(methodName, parameterTypes);
  				makeAccessible(method);
  				return method;
  			} catch (NoSuchMethodException e) {
  				// Method不在当前类定义,继续向上转型
  				continue;// new add
  			}
  		}
  		return null;
  	}
  
  	/**
  	 * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
  	 * 如向上转型到Object仍无法找到, 返回null.
  	 * 只匹配函数名。
  	 * 
  	 * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
  	 */
  	public static Method getAccessibleMethodByName(final Object obj, final String methodName) {
  		Validate.notNull(obj, "object can't be null");
  		Validate.notBlank(methodName, "methodName can't be blank");
  
  		for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
  			Method[] methods = searchType.getDeclaredMethods();
  			for (Method method : methods) {
  				if (method.getName().equals(methodName)) {
  					makeAccessible(method);
  					return method;
  				}
  			}
  		}
  		return null;
  	}
  
  	/**
  	 * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
  	 */
  	public static void makeAccessible(Method method) {
  		if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))
  				&& !method.isAccessible()) {
  			method.setAccessible(true);
  		}
  	}
  
  	/**
  	 * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
  	 */
  	public static void makeAccessible(Field field) {
  		if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier
  				.isFinal(field.getModifiers())) && !field.isAccessible()) {
  			field.setAccessible(true);
  		}
  	}
  
  	/**
  	 * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处
  	 * 如无法找到, 返回Object.class.
  	 * eg.
  	 * public UserDao extends HibernateDao<User>
  	 *
  	 * @param clazz The class to introspect
  	 * @return the first generic declaration, or Object.class if cannot be determined
  	 */
  	@SuppressWarnings("unchecked")
  	public static <T> Class<T> getClassGenricType(final Class clazz) {
  		return getClassGenricType(clazz, 0);
  	}
  
  	/**
  	 * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
  	 * 如无法找到, 返回Object.class.
  	 * 
  	 * 如public UserDao extends HibernateDao<User,Long>
  	 *
  	 * @param clazz clazz The class to introspect
  	 * @param index the Index of the generic ddeclaration,start from 0.
  	 * @return the index generic declaration, or Object.class if cannot be determined
  	 */
  	public static Class getClassGenricType(final Class clazz, final int index) {
  
  		Type genType = clazz.getGenericSuperclass();
  
  		if (!(genType instanceof ParameterizedType)) {
  			logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
  			return Object.class;
  		}
  
  		Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
  
  		if (index >= params.length || index < 0) {
  			logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
  					+ params.length);
  			return Object.class;
  		}
  		if (!(params[index] instanceof Class)) {
  			logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
  			return Object.class;
  		}
  
  		return (Class) params[index];
  	}
  	
  	public static Class<?> getUserClass(Object instance) {
  		Assert.notNull(instance, "Instance must not be null");
  		Class clazz = instance.getClass();
  		if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
  			Class<?> superClass = clazz.getSuperclass();
  			if (superClass != null && !Object.class.equals(superClass)) {
  				return superClass;
  			}
  		}
  		return clazz;
  
  	}
  	
  	/**
  	 * 将反射时的checked exception转换为unchecked exception.
  	 */
  	public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
  		if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
  				|| e instanceof NoSuchMethodException) {
  			return new IllegalArgumentException(e);
  		} else if (e instanceof InvocationTargetException) {
  			return new RuntimeException(((InvocationTargetException) e).getTargetException());
  		} else if (e instanceof RuntimeException) {
  			return (RuntimeException) e;
  		}
  		return new RuntimeException("Unexpected Checked Exception.", e);
  	}
  }
  