org.nerve.utils.reflection.ReflectionUtils.java Source code

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/**
 *  Copyright (c) 2012-2014 http://www.eryansky.com
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 */
package org.nerve.utils.reflection;

import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;
import org.nerve.utils.Assert;

import java.lang.annotation.Annotation;
import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.List;

/**
 * ??.
 *
 * ??getter/setter, ???, ?, ?Class, AOP.
 *
 */
public class ReflectionUtils {
    private static final String SETTER_PREFIX = "set";

    private static final String GETTER_PREFIX = "get";

    private static final String CGLIB_CLASS_SEPARATOR = "$$";

    /**
     * Getter.
     *
     * @param target  Object
     * @param propertyName ??
     * @param <T>   
     * @return Object
     */
    public static <T> T invokeGetter(Object target, String propertyName) {
        String getterMethodName = "get" + StringUtils.capitalize(propertyName);
        return (T) invokeMethod(target, getterMethodName, new Class[] {}, new Object[] {});
    }

    /**
      * Setter, ???
      * @param obj           
      * @param propertyName  ??
      * @param value         
      */
    public static void invokeSetter(Object obj, String propertyName, Object value) {
        String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(propertyName);
        invokeMethodByName(obj, setterMethodName, new Object[] { value });
    }

    /**
      * Getter.???.??.
      * @param obj               
      * @param propertyName      ??
      * @return                  
      */
    public static Object invokeGetter2(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;
    }

    /**
      * Setter, ??????.??.
      * @param obj           
      * @param propertyName  ??
      * @param value         
      */
    public static void invokeSetter2(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 });
            }
        }
    }

    /**
     * ?, private/protected, ??getter.
     *
     * @param target
     *            Object
     * @param fieldName
     *            ??
     * @param <T>   
     * @return Object
     */
    public static <T> T getFieldValue(final Object target, final String fieldName) {
        Assert.notNull(target, "target?");
        Assert.notNull(fieldName, "fieldName?");

        Field field = getAccessibleField(target, fieldName);

        if (field == null) {
            throw new IllegalArgumentException(
                    "? [" + fieldName + "]   [" + target + "] ");
        }

        Object result = null;
        try {
            result = field.get(target);
        } catch (IllegalAccessException e) {
        }
        return (T) result;
    }

    /**
      * , private/protected, ??setter.
      * @param obj           
      * @param fieldName     ??
      * @param value         
      */
    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) {
            e.printStackTrace();
        }
    }

    /**
      * , private/protected.
      * ?getAccessibleMethod()Method????.
      * ????+?
      * @param obj               
      * @param methodName        ??
      * @param parameterTypes    ?
      * @param args              ?
      * @return                  object
      */
    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);
        }
    }

    /**
     * , private/protected
      * ?getAccessibleMethodByName()Method????.
      * ???????
      * @param obj           
      * @param methodName    ??
      * @param args          ?
      * @return              object
      */
    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);
        }
    }

    /**
      * ?, ?DeclaredField, ?.
      *
      * ?Object?, null.
      * @param obj       
      * @param fieldName ??
      * @return          Field
      */
    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??,?
            }
        }
        return null;
    }

    /**
      * ?, ?DeclaredMethod,?.
      * ?Object?, null.
      * ???+?
      *
      * ?. ?Method,?Method.invoke(Object obj, Object... args)
      * @param obj               
      * @param methodName        ??
      * @param parameterTypes    ?
      * @return                  Method
      */
    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??,?
            }
        }
        return null;
    }

    /**
      * ?, ?DeclaredMethod,?.
      * ?Object?, null.
      * ????
      *
      * ?. ?Method,?Method.invoke(Object obj, Object... args)
      * @param obj           
      * @param methodName    ??
      * @return              Method
      */
    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;
    }

    /**
      * ?private/protectedpublic?????JDKSecurityManager
      * @param method    
      */
    public static void makeAccessible(Method method) {
        if ((!Modifier.isPublic(method.getModifiers())
                || !Modifier.isPublic(method.getDeclaringClass().getModifiers())) && !method.isAccessible()) {
            method.setAccessible(true);
        }
    }

    /**
      * ?private/protected???public?????JDKSecurityManager
      * @param field 
      */
    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);
        }
    }

    /**
     * ??, Class?, ?
     * , Object.class.
     * eg.
     * public UserDao extends HibernateDao?User
     *
     * @param clazz The class to introspect
     *  @param <T>   
     * @return the first generic declaration, or Object.class if cannot be determined
     */
    public static <T> Class<T> getClassGenricType(final Class clazz) {
        return getClassGenricType(clazz, 0);
    }

    /**
     * ??, Class?.
     * , Object.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
     */
    public static Class getClassGenricType(final Class clazz, final int index) {

        Type genType = clazz.getGenericSuperclass();

        if (!(genType instanceof ParameterizedType)) {
            System.err.println(clazz.getSimpleName() + "'s superclass not ParameterizedType");
            return Object.class;
        }

        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

        if (index >= params.length || index < 0) {
            System.err.println("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
                    + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            System.err.println(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
            return Object.class;
        }

        return (Class) params[index];
    }

    public static Class<?> getTargetClass(Object target) {
        Assert.notNull(target, "target?");
        return getTargetClass(target.getClass());

    }

    /**
     * ?Classcglib AOPCGLIBClass?Class
     *
     * @param targetClass  
     *
     * @return Class
     */
    public static Class<?> getTargetClass(Class<?> targetClass) {

        Assert.notNull(targetClass, "targetClass?");

        Class clazz = targetClass;
        if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
            Class<?> superClass = clazz.getSuperclass();
            if (superClass != null && !Object.class.equals(superClass)) {
                return superClass;
            }
        }
        return clazz;
    }

    /**
      * ??checked exception?unchecked exception.
      * @param e     
      * @return      RuntimeException
      */
    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);
    }

    public static <T> T getAnnotation(Object target, Class annotationClass) {
        Assert.notNull(target, "target?");
        return (T) getAnnotation(target.getClass(), annotationClass);
    }

    public static <T extends Annotation> T getAnnotation(Class targetClass, Class annotationClass) {
        Assert.notNull(targetClass, "targetClass?");
        Assert.notNull(annotationClass, "annotationClass?");

        if (targetClass.isAnnotationPresent(annotationClass)) {
            return (T) targetClass.getAnnotation(annotationClass);
        }

        return null;
    }

    /**
     * ?ObjectannotationClass
     *
     * @param target
     *            Object
     * @param annotationClass
     *            Annotation
     * @param <T>   
     * @return {@link Annotation}
     */
    public static <T extends Annotation> List<T> getAnnotations(Object target, Class annotationClass) {
        Assert.notNull(target, "target?");
        return getAnnotations(getTargetClass(target), annotationClass);
    }

    /**
     * ?annotationClass
      * @param targetClass       Class
      * @param annotationClass   Class
      * @param <T>               
      * @return                  
      */
    public static <T extends Annotation> List<T> getAnnotations(Class targetClass, Class annotationClass) {
        Assert.notNull(targetClass, "targetClass?");
        Assert.notNull(annotationClass, "annotationClass?");

        List<T> result = new ArrayList<T>();
        Annotation annotation = targetClass.getAnnotation(annotationClass);
        if (annotation != null) {
            result.add((T) annotation);
        }
        Constructor[] constructors = targetClass.getDeclaredConstructors();
        // ?
        CollectionUtils.addAll(result, getAnnotations(constructors, annotationClass).iterator());

        Field[] fields = targetClass.getDeclaredFields();
        // ?
        CollectionUtils.addAll(result, getAnnotations(fields, annotationClass).iterator());

        Method[] methods = targetClass.getDeclaredMethods();
        // ?
        CollectionUtils.addAll(result, getAnnotations(methods, annotationClass).iterator());

        for (Class<?> superClass = targetClass.getSuperclass(); superClass == null
                || superClass == Object.class; superClass = superClass.getSuperclass()) {
            List<T> temp = (List<T>) getAnnotations(superClass, annotationClass);
            if (CollectionUtils.isNotEmpty(temp)) {
                CollectionUtils.addAll(result, temp.iterator());
            }
        }

        return result;
    }

    /**
     * ?fieldannotationClass
     *
     * @param field
     *            field
     * @param annotationClass
     *            annotationClass
     * @param <T>   
     * @return {@link Annotation}
     */
    public static <T extends Annotation> T getAnnotation(Field field, Class annotationClass) {

        Assert.notNull(field, "field?");
        Assert.notNull(annotationClass, "annotationClass?");

        field.setAccessible(true);
        if (field.isAnnotationPresent(annotationClass)) {
            return (T) field.getAnnotation(annotationClass);
        }
        return null;
    }

    /**
     * ?field?annotationClass
     *
     * @param fields
     *            field
     * @param annotationClass
     *            annotationClass
     * @param <T>   
     * @return List
     */
    public static <T extends Annotation> List<T> getAnnotations(Field[] fields, Class annotationClass) {

        if (ArrayUtils.isEmpty(fields)) {
            return null;
        }

        List<T> result = new ArrayList<T>();

        for (Field field : fields) {
            field.setAccessible(true);
            Annotation annotation = getAnnotation(field, annotationClass);
            if (annotation != null) {
                result.add((T) annotation);
            }
        }

        return result;
    }

    /**
     * ?methodannotationClass
     *
     * @param method
     *            method
     * @param annotationClass
     *            annotationClass
     * @param <T>   
     * @return {@link Annotation}
     */
    public static <T extends Annotation> T getAnnotation(Method method, Class annotationClass) {

        Assert.notNull(method, "method?");
        Assert.notNull(annotationClass, "annotationClass?");

        method.setAccessible(true);
        if (method.isAnnotationPresent(annotationClass)) {
            return (T) method.getAnnotation(annotationClass);
        }
        return null;
    }

    /**
     * ?method?annotationClass
     *
     * @param methods
     *            method
     * @param annotationClass
     *            annotationClass
     * @param <T>   
     * @return List
     */
    public static <T extends Annotation> List<T> getAnnotations(Method[] methods, Class annotationClass) {

        if (ArrayUtils.isEmpty(methods)) {
            return null;
        }

        List<T> result = new ArrayList<T>();

        for (Method method : methods) {

            Annotation annotation = getAnnotation(method, annotationClass);
            if (annotation != null) {
                result.add((T) annotation);
            }
        }

        return result;
    }

    /**
     * ?constructorannotationClass
     *
     * @param constructor
     *            constructor
     * @param annotationClass
     *            annotationClass
     * @param <T>   
     * @return {@link Annotation}
     */
    public static <T extends Annotation> T getAnnotation(Constructor constructor, Class annotationClass) {

        Assert.notNull(constructor, "constructor?");
        Assert.notNull(annotationClass, "annotationClass?");

        constructor.setAccessible(true);

        if (constructor.isAnnotationPresent(annotationClass)) {
            return (T) constructor.getAnnotation(annotationClass);
        }

        return null;
    }

    /**
     * ?constructors?annotationClass
     *
     * @param constructors
     *            constructor
     * @param annotationClass
     *            annotationClass
     * @param <T>   
     * @return List
     */
    public static <T extends Annotation> List<T> getAnnotations(Constructor<T>[] constructors,
            Class annotationClass) {

        if (ArrayUtils.isEmpty(constructors)) {
            return null;
        }

        List<T> result = new ArrayList<T>();

        for (Constructor constructor : constructors) {
            Annotation annotation = getAnnotation(constructor, annotationClass);
            if (annotation != null) {
                result.add((T) annotation);
            }
        }

        return result;
    }
}