com.manpowergroup.cn.core.utils.ReflectionUtils.java Source code

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Here is the source code for com.manpowergroup.cn.core.utils.ReflectionUtils.java

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/**
 * Copyright (c) 2005-2009 springside.org.cn Licensed under the Apache License,
 * Version 2.0 (the "License"); $Id: ReflectionUtils.java,v 1.1 2010/07/15
 * 01:29:09 alan Exp $
 */
package com.manpowergroup.cn.core.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 java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;

import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.beanutils.converters.DateConverter;

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

/**
 * ??Utils?.
 * 
 * ?????,?Class,????Utils.
 * 
 * @author calvin
 */
public class ReflectionUtils {

    private static Logger logger = LoggerFactory.getLogger(ReflectionUtils.class);

    /**
     * ?,private/protected,??getter.
     */
    public static Object getFieldValue(final Object object, final String fieldName) {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException(
                    "Could not find field [" + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        Object result = null;
        try {
            result = field.get(object);
        } catch (IllegalAccessException e) {
            logger.error("??{}", e.getMessage());
        }
        return result;
    }

    /**
     * ,private/protected,??setter.
     */
    public static void setFieldValue(final Object object, final String fieldName, final Object value) {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException(
                    "Could not find field [" + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        try {
            field.set(object, value);
        } catch (IllegalAccessException e) {
            logger.error("??:{}", e.getMessage());
        }
    }

    /**
     * ,private/protected.
     */
    public static Object invokeMethod(final Object object, final String methodName, final Class<?>[] parameterTypes,
            final Object[] parameters) throws InvocationTargetException {
        Method method = getDeclaredMethod(object, methodName, parameterTypes);
        if (method == null)
            throw new IllegalArgumentException(
                    "Could not find method [" + methodName + "] on target [" + object + "]");

        method.setAccessible(true);

        try {
            return method.invoke(object, parameters);
        } catch (IllegalAccessException e) {
            logger.error("??:{}", e.getMessage());
        }

        return null;
    }

    /**
     * ?,?DeclaredField.
     */
    protected static Field getDeclaredField(final Object object, final String fieldName) {
        Assert.notNull(object, "object?");
        Assert.hasText(fieldName, "fieldName");
        for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
                .getSuperclass()) {
            try {
                return superClass.getDeclaredField(fieldName);
            } catch (NoSuchFieldException e) {
                // Field??,?
            }
        }
        return null;
    }

    /**
     * ?,?DeclaredField.
     */
    protected static void makeAccessible(final Field field) {
        if (!Modifier.isPublic(field.getModifiers())
                || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
            field.setAccessible(true);
        }
    }

    /**
     * ?,?DeclaredMethod.
     */
    protected static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes) {
        Assert.notNull(object, "object?");

        for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
                .getSuperclass()) {
            try {
                return superClass.getDeclaredMethod(methodName, parameterTypes);
            } catch (NoSuchMethodException e) {
                // Method??,?
            }
        }
        return null;
    }

    /**
     * ??,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> getSuperClassGenricType(final Class clazz) {
        return getSuperClassGenricType(clazz, 0);
    }

    /**
     * ??,Class?.
     * 
     * 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
     */

    @SuppressWarnings({ "rawtypes" })
    public static Class getSuperClassGenricType(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];
    }

    /**
     * ????(getter),??List.
     * 
     * @param collection ???.
     * @param propertyName ??????.
     */
    @SuppressWarnings("unchecked")
    public static List fetchElementPropertyToList(final Collection collection, final String propertyName) {
        List list = new ArrayList();

        try {
            for (Object obj : collection) {
                list.add(PropertyUtils.getProperty(obj, propertyName));
            }
        } catch (Exception e) {
            convertToUncheckedException(e);
        }

        return list;
    }

    /**
     * ????(getter),??.
     * 
     * @param collection ???.
     * @param propertyName ??????.
     * @param separator .
     */
    @SuppressWarnings("unchecked")
    public static String fetchElementPropertyToString(final Collection collection, final String propertyName,
            final String separator) {
        List list = fetchElementPropertyToList(collection, propertyName);
        return StringUtils.join(list, separator);
    }

    /**
     * ?clazzproperty.
     * 
     * @param value ?
     * @param clazz ???Class
     * @param propertyName ???Class.
     */
    public static Object convertValue(Object value, Class<?> toType) {
        try {
            DateConverter dc = new DateConverter();
            dc.setUseLocaleFormat(true);
            dc.setPatterns(new String[] { "yyyy-MM-dd", "yyyy-MM-dd HH:mm:ss" });
            ConvertUtils.register(dc, Date.class);
            return ConvertUtils.convert(value, toType);
        } catch (Exception e) {
            throw convertToUncheckedException(e);
        }
    }

    /**
     * ??checked exception?unchecked exception.
     */
    public static IllegalArgumentException convertToUncheckedException(Exception e) {
        if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
                || e instanceof NoSuchMethodException)
            return new IllegalArgumentException("Refelction Exception.", e);
        else
            return new IllegalArgumentException(e);
    }
}