/*
 *  Copyright 2008 biaoping.yin
 *
 *  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 org.frameworkset.util;

import java.beans.Introspector;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Proxy;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * <p>
 * Title: ClassUtils.java
 * </p>
 * <p>
 * Description:
 * </p>
 * <p>
 * bboss workgroup
 * </p>
 * <p>
 * Copyright (c) 2008
 * </p>
 * 
 * @Date 2010-9-24
 * @author biaoping.yin
 * @version 1.0
 */
public class ClassUtils
{

	/** Suffix for array class names: "[]" */
	public static final String	ARRAY_SUFFIX			= "[]";

	/** Prefix for internal array class names: "[L" */
	private static final String	INTERNAL_ARRAY_PREFIX	= "[L";

	/** The package separator character '.' */
	private static final char	PACKAGE_SEPARATOR		= '.';

	/** The inner class separator character '$' */
	private static final char	INNER_CLASS_SEPARATOR	= '$';

	/** The CGLIB class separator character "$$" */
	public static final String	CGLIB_CLASS_SEPARATOR	= "$$";

	/** The ".class" file suffix */
	public static final String	CLASS_FILE_SUFFIX		= ".class";

	/**
	 * Map with primitive wrapper type as key and corresponding primitive type
	 * as value, for example: Integer.class -> int.class.
	 */
	private static final Map	primitiveWrapperTypeMap	= new HashMap(8);

	/**
	 * Map with primitive type name as key and corresponding primitive type as
	 * value, for example: "int" -> "int.class".
	 */
	private static final Map	primitiveTypeNameMap	= new HashMap(16);

	static
	{
		primitiveWrapperTypeMap.put(Boolean.class, boolean.class);
		primitiveWrapperTypeMap.put(Byte.class, byte.class);
		primitiveWrapperTypeMap.put(Character.class, char.class);
		primitiveWrapperTypeMap.put(Double.class, double.class);
		primitiveWrapperTypeMap.put(Float.class, float.class);
		primitiveWrapperTypeMap.put(Integer.class, int.class);
		primitiveWrapperTypeMap.put(Long.class, long.class);
		primitiveWrapperTypeMap.put(Short.class, short.class);

		Set primitiveTypeNames = new HashSet(16);
		primitiveTypeNames.addAll(primitiveWrapperTypeMap.values());
		primitiveTypeNames.addAll(Arrays.asList(new Class[] { boolean[].class,
			byte[].class, char[].class, double[].class, float[].class,
			int[].class, long[].class, short[].class }));
		for (Iterator it = primitiveTypeNames.iterator(); it.hasNext();)
		{
			Class primitiveClass = (Class) it.next();
			primitiveTypeNameMap.put(primitiveClass.getName(), primitiveClass);
		}
	}

	/**
	 * Return the default ClassLoader to use: typically the thread context
	 * ClassLoader, if available; the ClassLoader that loaded the ClassUtils
	 * class will be used as fallback.
	 * <p>
	 * Call this method if you intend to use the thread context ClassLoader in a
	 * scenario where you absolutely need a non-null ClassLoader reference: for
	 * example, for class path resource loading (but not necessarily for
	 * <code>Class.forName</code>, which accepts a <code>null</code> ClassLoader
	 * reference as well).
	 * 
	 * @return the default ClassLoader (never <code>null</code>)
	 * @see java.lang.Thread#getContextClassLoader()
	 */
	public static ClassLoader getDefaultClassLoader()
	{

		ClassLoader cl = null;
		try
		{
			cl = Thread.currentThread().getContextClassLoader();
		}
		catch (Throwable ex)
		{
			// Cannot access thread context ClassLoader - falling back to system
			// class loader...
		}
		if (cl == null)
		{
			// No thread context class loader -> use class loader of this class.
			cl = ClassUtils.class.getClassLoader();
		}
		return cl;
	}

	/**
	 * Override the thread context ClassLoader with the environment's bean
	 * ClassLoader if necessary, i.e. if the bean ClassLoader is not equivalent
	 * to the thread context ClassLoader already.
	 * 
	 * @param classLoaderToUse
	 *            the actual ClassLoader to use for the thread context
	 * @return the original thread context ClassLoader, or <code>null</code> if
	 *         not overridden
	 */
	public static ClassLoader overrideThreadContextClassLoader(
			ClassLoader classLoaderToUse)
	{

		Thread currentThread = Thread.currentThread();
		ClassLoader threadContextClassLoader = currentThread
				.getContextClassLoader();
		if (classLoaderToUse != null
				&& !classLoaderToUse.equals(threadContextClassLoader))
		{
			currentThread.setContextClassLoader(classLoaderToUse);
			return threadContextClassLoader;
		}
		else
		{
			return null;
		}
	}

	/**
	 * Replacement for <code>Class.forName()</code> that also returns Class
	 * instances for primitives (like "int") and array class names (like
	 * "String[]").
	 * <p>
	 * Always uses the default class loader: that is, preferably the thread
	 * context class loader, or the ClassLoader that loaded the ClassUtils class
	 * as fallback.
	 * 
	 * @param name
	 *            the name of the Class
	 * @return Class instance for the supplied name
	 * @throws ClassNotFoundException
	 *             if the class was not found
	 * @throws LinkageError
	 *             if the class file could not be loaded
	 * @see Class#forName(String, boolean, ClassLoader)
	 * @see #getDefaultClassLoader()
	 */
	public static Class forName(String name) throws ClassNotFoundException,
			LinkageError
	{

		return forName(name, getDefaultClassLoader());
	}

	/**
	 * Replacement for <code>Class.forName()</code> that also returns Class
	 * instances for primitives (like "int") and array class names (like
	 * "String[]").
	 * 
	 * @param name
	 *            the name of the Class
	 * @param classLoader
	 *            the class loader to use (may be <code>null</code>, which
	 *            indicates the default class loader)
	 * @return Class instance for the supplied name
	 * @throws ClassNotFoundException
	 *             if the class was not found
	 * @throws LinkageError
	 *             if the class file could not be loaded
	 * @see Class#forName(String, boolean, ClassLoader)
	 */
	public static Class forName(String name, ClassLoader classLoader)
			throws ClassNotFoundException, LinkageError
	{

		Assert.notNull(name, "Name must not be null");

		Class clazz = resolvePrimitiveClassName(name);
		if (clazz != null)
		{
			return clazz;
		}

		// "java.lang.String[]" style arrays
		if (name.endsWith(ARRAY_SUFFIX))
		{
			String elementClassName = name.substring(0, name.length()
					- ARRAY_SUFFIX.length());
			Class elementClass = forName(elementClassName, classLoader);
			return Array.newInstance(elementClass, 0).getClass();
		}

		// "[Ljava.lang.String;" style arrays
		int internalArrayMarker = name.indexOf(INTERNAL_ARRAY_PREFIX);
		if (internalArrayMarker != -1 && name.endsWith(";"))
		{
			String elementClassName = null;
			if (internalArrayMarker == 0)
			{
				elementClassName = name.substring(INTERNAL_ARRAY_PREFIX
						.length(), name.length() - 1);
			}
			else if (name.startsWith("["))
			{
				elementClassName = name.substring(1);
			}
			Class elementClass = forName(elementClassName, classLoader);
			return Array.newInstance(elementClass, 0).getClass();
		}

		ClassLoader classLoaderToUse = classLoader;
		if (classLoaderToUse == null)
		{
			classLoaderToUse = getDefaultClassLoader();
		}
		return classLoaderToUse.loadClass(name);
	}

	/**
	 * Resolve the given class name into a Class instance. Supports primitives
	 * (like "int") and array class names (like "String[]").
	 * <p>
	 * This is effectively equivalent to the <code>forName</code> method with
	 * the same arguments, with the only difference being the exceptions thrown
	 * in case of class loading failure.
	 * 
	 * @param className
	 *            the name of the Class
	 * @param classLoader
	 *            the class loader to use (may be <code>null</code>, which
	 *            indicates the default class loader)
	 * @return Class instance for the supplied name
	 * @throws IllegalArgumentException
	 *             if the class name was not resolvable (that is, the class
	 *             could not be found or the class file could not be loaded)
	 * @see #forName(String, ClassLoader)
	 */
	public static Class resolveClassName(String className,
			ClassLoader classLoader) throws IllegalArgumentException
	{

		try
		{
			return forName(className, classLoader);
		}
		catch (ClassNotFoundException ex)
		{
			IllegalArgumentException iae = new IllegalArgumentException(
					"Cannot find class [" + className + "]");
			iae.initCause(ex);
			throw iae;
		}
		catch (LinkageError ex)
		{
			IllegalArgumentException iae = new IllegalArgumentException(
					"Error loading class [" + className
							+ "]: problem with class file or dependent class.");
			iae.initCause(ex);
			throw iae;
		}
	}

	/**
	 * Resolve the given class name as primitive class, if appropriate,
	 * according to the JVM's naming rules for primitive classes.
	 * <p>
	 * Also supports the JVM's internal class names for primitive arrays. Does
	 * <i>not</i> support the "[]" suffix notation for primitive arrays; this is
	 * only supported by {@link #forName}.
	 * 
	 * @param name
	 *            the name of the potentially primitive class
	 * @return the primitive class, or <code>null</code> if the name does not
	 *         denote a primitive class or primitive array class
	 */
	public static Class resolvePrimitiveClassName(String name)
	{

		Class result = null;
		// Most class names will be quite long, considering that they
		// SHOULD sit in a package, so a length check is worthwhile.
		if (name != null && name.length() <= 8)
		{
			// Could be a primitive - likely.
			result = (Class) primitiveTypeNameMap.get(name);
		}
		return result;
	}

	/**
	 * Determine whether the {@link Class} identified by the supplied name is
	 * present and can be loaded. Will return <code>false</code> if either the
	 * class or one of its dependencies is not present or cannot be loaded.
	 * 
	 * @param className
	 *            the name of the class to check
	 * @return whether the specified class is present
	 * @deprecated as of Bboss 2.5, in favor of
	 *             {@link #isPresent(String, ClassLoader)}
	 */
	public static boolean isPresent(String className)
	{

		return isPresent(className, getDefaultClassLoader());
	}

	/**
	 * Determine whether the {@link Class} identified by the supplied name is
	 * present and can be loaded. Will return <code>false</code> if either the
	 * class or one of its dependencies is not present or cannot be loaded.
	 * 
	 * @param className
	 *            the name of the class to check
	 * @param classLoader
	 *            the class loader to use (may be <code>null</code>, which
	 *            indicates the default class loader)
	 * @return whether the specified class is present
	 */
	public static boolean isPresent(String className, ClassLoader classLoader)
	{

		try
		{
			forName(className, classLoader);
			return true;
		}
		catch (Throwable ex)
		{
			// Class or one of its dependencies is not present...
			return false;
		}
	}

	/**
	 * Return the user-defined class for the given instance: usually simply the
	 * class of the given instance, but the original class in case of a
	 * CGLIB-generated subclass.
	 * 
	 * @param instance
	 *            the instance to check
	 * @return the user-defined class
	 */
	public static Class getUserClass(Object instance)
	{

		Assert.notNull(instance, "Instance must not be null");
		return getUserClass(instance.getClass());
	}

	/**
	 * Return the user-defined class for the given class: usually simply the
	 * given class, but the original class in case of a CGLIB-generated
	 * subclass.
	 * 
	 * @param clazz
	 *            the class to check
	 * @return the user-defined class
	 */
	public static Class getUserClass(Class clazz)
	{

		return (clazz != null
				&& clazz.getName().indexOf(CGLIB_CLASS_SEPARATOR) != -1 ? clazz
				.getSuperclass() : clazz);
	}

	/**
	 * Check whether the given class is cache-safe in the given context, i.e.
	 * whether it is loaded by the given ClassLoader or a parent of it.
	 * 
	 * @param clazz
	 *            the class to analyze
	 * @param classLoader
	 *            the ClassLoader to potentially cache metadata in
	 */
	public static boolean isCacheSafe(Class clazz, ClassLoader classLoader)
	{

		Assert.notNull(clazz, "Class must not be null");
		ClassLoader target = clazz.getClassLoader();
		if (target == null)
		{
			return false;
		}
		ClassLoader cur = classLoader;
		if (cur == target)
		{
			return true;
		}
		while (cur != null)
		{
			cur = cur.getParent();
			if (cur == target)
			{
				return true;
			}
		}
		return false;
	}

	/**
	 * Get the class name without the qualified package name.
	 * 
	 * @param className
	 *            the className to get the short name for
	 * @return the class name of the class without the package name
	 * @throws IllegalArgumentException
	 *             if the className is empty
	 */
	public static String getShortName(String className)
	{

		Assert.hasLength(className, "Class name must not be empty");
		int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
		int nameEndIndex = className.indexOf(CGLIB_CLASS_SEPARATOR);
		if (nameEndIndex == -1)
		{
			nameEndIndex = className.length();
		}
		String shortName = className.substring(lastDotIndex + 1, nameEndIndex);
		shortName = shortName.replace(INNER_CLASS_SEPARATOR, PACKAGE_SEPARATOR);
		return shortName;
	}

	/**
	 * Get the class name without the qualified package name.
	 * 
	 * @param clazz
	 *            the class to get the short name for
	 * @return the class name of the class without the package name
	 */
	public static String getShortName(Class clazz)
	{

		return getShortName(getQualifiedName(clazz));
	}

	/**
	 * Return the short string name of a Java class in decapitalized JavaBeans
	 * property format. Strips the outer class name in case of an inner class.
	 * 
	 * @param clazz
	 *            the class
	 * @return the short name rendered in a standard JavaBeans property format
	 * @see java.beans.Introspector#decapitalize(String)
	 */
	public static String getShortNameAsProperty(Class clazz)
	{

		String shortName = ClassUtils.getShortName(clazz);
		int dotIndex = shortName.lastIndexOf('.');
		shortName = (dotIndex != -1 ? shortName.substring(dotIndex + 1)
				: shortName);
		return Introspector.decapitalize(shortName);
	}

	/**
	 * Determine the name of the class file, relative to the containing package:
	 * e.g. "String.class"
	 * 
	 * @param clazz
	 *            the class
	 * @return the file name of the ".class" file
	 */
	public static String getClassFileName(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		String className = clazz.getName();
		int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
		return className.substring(lastDotIndex + 1) + CLASS_FILE_SUFFIX;
	}

	/**
	 * Determine the name of the package of the given class: e.g. "java.lang"
	 * for the <code>java.lang.String</code> class.
	 * 
	 * @param clazz
	 *            the class
	 * @return the package name, or the empty String if the class is defined in
	 *         the default package
	 */
	public static String getPackageName(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		String className = clazz.getName();
		int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
		return (lastDotIndex != -1 ? className.substring(0, lastDotIndex) : "");
	}

	/**
	 * Return the qualified name of the given class: usually simply the class
	 * name, but component type class name + "[]" for arrays.
	 * 
	 * @param clazz
	 *            the class
	 * @return the qualified name of the class
	 */
	public static String getQualifiedName(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		if (clazz.isArray())
		{
			return getQualifiedNameForArray(clazz);
		}
		else
		{
			return clazz.getName();
		}
	}

	/**
	 * Build a nice qualified name for an array: component type class name +
	 * "[]".
	 * 
	 * @param clazz
	 *            the array class
	 * @return a qualified name for the array class
	 */
	private static String getQualifiedNameForArray(Class clazz)
	{

		StringBuffer buffer = new StringBuffer();
		while (clazz.isArray())
		{
			clazz = clazz.getComponentType();
			buffer.append(ClassUtils.ARRAY_SUFFIX);
		}
		buffer.insert(0, clazz.getName());
		return buffer.toString();
	}

	/**
	 * Return the qualified name of the given method, consisting of fully
	 * qualified interface/class name + "." + method name.
	 * 
	 * @param method
	 *            the method
	 * @return the qualified name of the method
	 */
	public static String getQualifiedMethodName(Method method)
	{

		Assert.notNull(method, "Method must not be null");
		return method.getDeclaringClass().getName() + "." + method.getName();
	}

	/**
	 * Return a descriptive name for the given object's type: usually simply the
	 * class name, but component type class name + "[]" for arrays, and an
	 * appended list of implemented interfaces for JDK proxies.
	 * 
	 * @param value
	 *            the value to introspect
	 * @return the qualified name of the class
	 */
	public static String getDescriptiveType(Object value)
	{

		if (value == null)
		{
			return null;
		}
		Class clazz = value.getClass();
		if (Proxy.isProxyClass(clazz))
		{
			StringBuffer buf = new StringBuffer(clazz.getName());
			buf.append(" implementing ");
			Class[] ifcs = clazz.getInterfaces();
			for (int i = 0; i < ifcs.length; i++)
			{
				buf.append(ifcs[i].getName());
				if (i < ifcs.length - 1)
				{
					buf.append(',');
				}
			}
			return buf.toString();
		}
		else if (clazz.isArray())
		{
			return getQualifiedNameForArray(clazz);
		}
		else
		{
			return clazz.getName();
		}
	}

	/**
	 * Determine whether the given class has a constructor with the given
	 * signature.
	 * <p>
	 * Essentially translates <code>NoSuchMethodException</code> to "false".
	 * 
	 * @param clazz
	 *            the clazz to analyze
	 * @param paramTypes
	 *            the parameter types of the method
	 * @return whether the class has a corresponding constructor
	 * @see java.lang.Class#getMethod
	 */
	public static boolean hasConstructor(Class clazz, Class[] paramTypes)
	{

		return (getConstructorIfAvailable(clazz, paramTypes) != null);
	}

	/**
	 * Determine whether the given class has a constructor with the given
	 * signature, and return it if available (else return <code>null</code>).
	 * <p>
	 * Essentially translates <code>NoSuchMethodException</code> to
	 * <code>null</code>.
	 * 
	 * @param clazz
	 *            the clazz to analyze
	 * @param paramTypes
	 *            the parameter types of the method
	 * @return the constructor, or <code>null</code> if not found
	 * @see java.lang.Class#getConstructor
	 */
	public static Constructor getConstructorIfAvailable(Class clazz,
			Class[] paramTypes)
	{

		Assert.notNull(clazz, "Class must not be null");
		try
		{
			return clazz.getConstructor(paramTypes);
		}
		catch (NoSuchMethodException ex)
		{
			return null;
		}
	}

	/**
	 * Determine whether the given class has a method with the given signature.
	 * <p>
	 * Essentially translates <code>NoSuchMethodException</code> to "false".
	 * 
	 * @param clazz
	 *            the clazz to analyze
	 * @param methodName
	 *            the name of the method
	 * @param paramTypes
	 *            the parameter types of the method
	 * @return whether the class has a corresponding method
	 * @see java.lang.Class#getMethod
	 */
	public static boolean hasMethod(Class clazz, String methodName,
			Class... paramTypes)
	{

		return (getMethodIfAvailable(clazz, methodName, paramTypes) != null);
	}

	/**
	 * Determine whether the given class has a method with the given signature,
	 * and return it if available (else return <code>null</code>).
	 * <p>
	 * Essentially translates <code>NoSuchMethodException</code> to
	 * <code>null</code>.
	 * 
	 * @param clazz
	 *            the clazz to analyze
	 * @param methodName
	 *            the name of the method
	 * @param paramTypes
	 *            the parameter types of the method
	 * @return the method, or <code>null</code> if not found
	 * @see java.lang.Class#getMethod
	 */
	public static Method getMethodIfAvailable(Class clazz, String methodName,
			Class... paramTypes)
	{

		Assert.notNull(clazz, "Class must not be null");
		Assert.notNull(methodName, "Method name must not be null");
		try
		{
			return clazz.getMethod(methodName, paramTypes);
		}
		catch (NoSuchMethodException ex)
		{
			return null;
		}
	}

	/**
	 * Return the number of methods with a given name (with any argument types),
	 * for the given class and/or its superclasses. Includes non-public methods.
	 * 
	 * @param clazz
	 *            the clazz to check
	 * @param methodName
	 *            the name of the method
	 * @return the number of methods with the given name
	 */
	public static int getMethodCountForName(Class clazz, String methodName)
	{

		Assert.notNull(clazz, "Class must not be null");
		Assert.notNull(methodName, "Method name must not be null");
		int count = 0;
		Method[] declaredMethods = clazz.getDeclaredMethods();
		for (int i = 0; i < declaredMethods.length; i++)
		{
			Method method = declaredMethods[i];
			if (methodName.equals(method.getName()))
			{
				count++;
			}
		}
		Class[] ifcs = clazz.getInterfaces();
		for (int i = 0; i < ifcs.length; i++)
		{
			count += getMethodCountForName(ifcs[i], methodName);
		}
		if (clazz.getSuperclass() != null)
		{
			count += getMethodCountForName(clazz.getSuperclass(), methodName);
		}
		return count;
	}

	/**
	 * Does the given class and/or its superclasses at least have one or more
	 * methods (with any argument types)? Includes non-public methods.
	 * 
	 * @param clazz
	 *            the clazz to check
	 * @param methodName
	 *            the name of the method
	 * @return whether there is at least one method with the given name
	 */
	public static boolean hasAtLeastOneMethodWithName(Class clazz,
			String methodName)
	{

		Assert.notNull(clazz, "Class must not be null");
		Assert.notNull(methodName, "Method name must not be null");
		Method[] declaredMethods = clazz.getDeclaredMethods();
		for (int i = 0; i < declaredMethods.length; i++)
		{
			Method method = declaredMethods[i];
			if (method.getName().equals(methodName))
			{
				return true;
			}
		}
		Class[] ifcs = clazz.getInterfaces();
		for (int i = 0; i < ifcs.length; i++)
		{
			if (hasAtLeastOneMethodWithName(ifcs[i], methodName))
			{
				return true;
			}
		}
		return (clazz.getSuperclass() != null && hasAtLeastOneMethodWithName(
																				clazz
																						.getSuperclass(),
																				methodName));
	}

	/**
	 * Given a method, which may come from an interface, and a target class used
	 * in the current reflective invocation, find the corresponding target
	 * method if there is one. E.g. the method may be <code>IFoo.bar()</code>
	 * and the target class may be <code>DefaultFoo</code>. In this case, the
	 * method may be <code>DefaultFoo.bar()</code>. This enables attributes on
	 * that method to be found.
	 * 
	 * this method does <i>not</i> resolve Java 5 bridge methods automatically.
	 * 
	 * if bridge method resolution is desirable (e.g. for obtaining metadata
	 * from the original method definition).
	 * 
	 * @param method
	 *            the method to be invoked, which may come from an interface
	 * @param targetClass
	 *            the target class for the current invocation. May be
	 *            <code>null</code> or may not even implement the method.
	 * @return the specific target method, or the original method if the
	 *         <code>targetClass</code> doesn't implement it or is
	 *         <code>null</code>
	 */
	public static Method getMostSpecificMethod(Method method, Class targetClass)
	{

		if (method != null && targetClass != null
				&& !targetClass.equals(method.getDeclaringClass()))
		{
			try
			{
				method = targetClass.getMethod(method.getName(), method
						.getParameterTypes());
			}
			catch (NoSuchMethodException ex)
			{
				// Perhaps the target class doesn't implement this method:
				// that's fine, just use the original method.
			}
		}
		return method;
	}

	/**
	 * Return a static method of a class.
	 * 
	 * @param methodName
	 *            the static method name
	 * @param clazz
	 *            the class which defines the method
	 * @param args
	 *            the parameter types to the method
	 * @return the static method, or <code>null</code> if no static method was
	 *         found
	 * @throws IllegalArgumentException
	 *             if the method name is blank or the clazz is null
	 */
	public static Method getStaticMethod(Class clazz, String methodName,
			Class[] args)
	{

		Assert.notNull(clazz, "Class must not be null");
		Assert.notNull(methodName, "Method name must not be null");
		try
		{
			Method method = clazz.getDeclaredMethod(methodName, args);
			if ((method.getModifiers() & Modifier.STATIC) != 0)
			{
				return method;
			}
		}
		catch (NoSuchMethodException ex)
		{
		}
		return null;
	}

	/**
	 * Check if the given class represents a primitive wrapper, i.e. Boolean,
	 * Byte, Character, Short, Integer, Long, Float, or Double.
	 * 
	 * @param clazz
	 *            the class to check
	 * @return whether the given class is a primitive wrapper class
	 */
	public static boolean isPrimitiveWrapper(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		return primitiveWrapperTypeMap.containsKey(clazz);
	}

	/**
	 * Check if the given class represents a primitive (i.e. boolean, byte,
	 * char, short, int, long, float, or double) or a primitive wrapper (i.e.
	 * Boolean, Byte, Character, Short, Integer, Long, Float, or Double).
	 * 
	 * @param clazz
	 *            the class to check
	 * @return whether the given class is a primitive or primitive wrapper class
	 */
	public static boolean isPrimitiveOrWrapper(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		return (clazz.isPrimitive() || isPrimitiveWrapper(clazz));
	}

	/**
	 * Check if the given class represents an array of primitives, i.e. boolean,
	 * byte, char, short, int, long, float, or double.
	 * 
	 * @param clazz
	 *            the class to check
	 * @return whether the given class is a primitive array class
	 */
	public static boolean isPrimitiveArray(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		return (clazz.isArray() && clazz.getComponentType().isPrimitive());
	}

	/**
	 * Check if the given class represents an array of primitive wrappers, i.e.
	 * Boolean, Byte, Character, Short, Integer, Long, Float, or Double.
	 * 
	 * @param clazz
	 *            the class to check
	 * @return whether the given class is a primitive wrapper array class
	 */
	public static boolean isPrimitiveWrapperArray(Class clazz)
	{

		Assert.notNull(clazz, "Class must not be null");
		return (clazz.isArray() && isPrimitiveWrapper(clazz.getComponentType()));
	}

	/**
	 * Check if the right-hand side type may be assigned to the left-hand side
	 * type, assuming setting by reflection. Considers primitive wrapper classes
	 * as assignable to the corresponding primitive types.
	 * 
	 * @param lhsType
	 *            the target type
	 * @param rhsType
	 *            the value type that should be assigned to the target type
	 * @return if the target type is assignable from the value type
	 * @see TypeUtils#isAssignable
	 */
	public static boolean isAssignable(Class lhsType, Class rhsType)
	{

		Assert.notNull(lhsType, "Left-hand side type must not be null");
		Assert.notNull(rhsType, "Right-hand side type must not be null");
		return (lhsType.isAssignableFrom(rhsType) || lhsType
				.equals(primitiveWrapperTypeMap.get(rhsType)));
	}

	/**
	 * Determine if the given type is assignable from the given value, assuming
	 * setting by reflection. Considers primitive wrapper classes as assignable
	 * to the corresponding primitive types.
	 * 
	 * @param type
	 *            the target type
	 * @param value
	 *            the value that should be assigned to the type
	 * @return if the type is assignable from the value
	 */
	public static boolean isAssignableValue(Class type, Object value)
	{

		Assert.notNull(type, "Type must not be null");
		return (value != null ? isAssignable(type, value.getClass()) : !type
				.isPrimitive());
	}

	/**
	 * Convert a "/"-based resource path to a "."-based fully qualified class
	 * name.
	 * 
	 * @param resourcePath
	 *            the resource path pointing to a class
	 * @return the corresponding fully qualified class name
	 */
	public static String convertResourcePathToClassName(String resourcePath)
	{

		return resourcePath.replace('/', '.');
	}

	/**
	 * Convert a "."-based fully qualified class name to a "/"-based resource
	 * path.
	 * 
	 * @param className
	 *            the fully qualified class name
	 * @return the corresponding resource path, pointing to the class
	 */
	public static String convertClassNameToResourcePath(String className)
	{

		return className.replace('.', '/');
	}

	/**
	 * Return a path suitable for use with <code>ClassLoader.getResource</code>
	 * (also suitable for use with <code>Class.getResource</code> by prepending
	 * a slash ('/') to the return value. Built by taking the package of the
	 * specified class file, converting all dots ('.') to slashes ('/'), adding
	 * a trailing slash if necesssary, and concatenating the specified resource
	 * name to this. <br/>
	 * As such, this function may be used to build a path suitable for loading a
	 * resource file that is in the same package as a class file,
	 * 
	 * even more convenient.
	 * 
	 * @param clazz
	 *            the Class whose package will be used as the base
	 * @param resourceName
	 *            the resource name to append. A leading slash is optional.
	 * @return the built-up resource path
	 * @see java.lang.ClassLoader#getResource
	 * @see java.lang.Class#getResource
	 */
	public static String addResourcePathToPackagePath(Class clazz,
			String resourceName)
	{

		Assert.notNull(resourceName, "Resource name must not be null");
		if (!resourceName.startsWith("/"))
		{
			return classPackageAsResourcePath(clazz) + "/" + resourceName;
		}
		return classPackageAsResourcePath(clazz) + resourceName;
	}

	/**
	 * Given an input class object, return a string which consists of the
	 * class's package name as a pathname, i.e., all dots ('.') are replaced by
	 * slashes ('/'). Neither a leading nor trailing slash is added. The result
	 * could be concatenated with a slash and the name of a resource, and fed
	 * directly to <code>ClassLoader.getResource()</code>. For it to be fed to
	 * <code>Class.getResource</code> instead, a leading slash would also have
	 * to be prepended to the returned value.
	 * 
	 * @param clazz
	 *            the input class. A <code>null</code> value or the default
	 *            (empty) package will result in an empty string ("") being
	 *            returned.
	 * @return a path which represents the package name
	 * @see ClassLoader#getResource
	 * @see Class#getResource
	 */
	public static String classPackageAsResourcePath(Class clazz)
	{

		if (clazz == null)
		{
			return "";
		}
		String className = clazz.getName();
		int packageEndIndex = className.lastIndexOf('.');
		if (packageEndIndex == -1)
		{
			return "";
		}
		String packageName = className.substring(0, packageEndIndex);
		return packageName.replace('.', '/');
	}

	/**
	 * Build a String that consists of the names of the classes/interfaces in
	 * the given array.
	 * <p>
	 * Basically like <code>AbstractCollection.toString()</code>, but stripping
	 * the "class "/"interface " prefix before every class name.
	 * 
	 * @param classes
	 *            a Collection of Class objects (may be <code>null</code>)
	 * @return a String of form "[com.foo.Bar, com.foo.Baz]"
	 * @see java.util.AbstractCollection#toString()
	 */
	public static String classNamesToString(Class[] classes)
	{

		return classNamesToString(Arrays.asList(classes));
	}

	/**
	 * Build a String that consists of the names of the classes/interfaces in
	 * the given collection.
	 * <p>
	 * Basically like <code>AbstractCollection.toString()</code>, but stripping
	 * the "class "/"interface " prefix before every class name.
	 * 
	 * @param classes
	 *            a Collection of Class objects (may be <code>null</code>)
	 * @return a String of form "[com.foo.Bar, com.foo.Baz]"
	 * @see java.util.AbstractCollection#toString()
	 */
	public static String classNamesToString(Collection classes)
	{

		if (CollectionUtils.isEmpty(classes))
		{
			return "[]";
		}
		StringBuffer sb = new StringBuffer("[");
		for (Iterator it = classes.iterator(); it.hasNext();)
		{
			Class clazz = (Class) it.next();
			sb.append(clazz.getName());
			if (it.hasNext())
			{
				sb.append(", ");
			}
		}
		sb.append("]");
		return sb.toString();
	}

	/**
	 * Return all interfaces that the given instance implements as array,
	 * including ones implemented by superclasses.
	 * 
	 * @param instance
	 *            the instance to analyse for interfaces
	 * @return all interfaces that the given instance implements as array
	 */
	public static Class[] getAllInterfaces(Object instance)
	{

		Assert.notNull(instance, "Instance must not be null");
		return getAllInterfacesForClass(instance.getClass());
	}

	/**
	 * Return all interfaces that the given class implements as array, including
	 * ones implemented by superclasses.
	 * <p>
	 * If the class itself is an interface, it gets returned as sole interface.
	 * 
	 * @param clazz
	 *            the class to analyse for interfaces
	 * @return all interfaces that the given object implements as array
	 */
	public static Class[] getAllInterfacesForClass(Class clazz)
	{

		return getAllInterfacesForClass(clazz, null);
	}

	/**
	 * Return all interfaces that the given class implements as array, including
	 * ones implemented by superclasses.
	 * <p>
	 * If the class itself is an interface, it gets returned as sole interface.
	 * 
	 * @param clazz
	 *            the class to analyse for interfaces
	 * @param classLoader
	 *            the ClassLoader that the interfaces need to be visible in (may
	 *            be <code>null</code> when accepting all declared interfaces)
	 * @return all interfaces that the given object implements as array
	 */
	public static Class[] getAllInterfacesForClass(Class clazz,
			ClassLoader classLoader)
	{

		Assert.notNull(clazz, "Class must not be null");
		if (clazz.isInterface())
		{
			return new Class[] { clazz };
		}
		List interfaces = new ArrayList();
		while (clazz != null)
		{
			for (int i = 0; i < clazz.getInterfaces().length; i++)
			{
				Class ifc = clazz.getInterfaces()[i];
				if (!interfaces.contains(ifc)
						&& (classLoader == null || isVisible(ifc, classLoader)))
				{
					interfaces.add(ifc);
				}
			}
			clazz = clazz.getSuperclass();
		}
		return (Class[]) interfaces.toArray(new Class[interfaces.size()]);
	}

	/**
	 * Return all interfaces that the given instance implements as Set,
	 * including ones implemented by superclasses.
	 * 
	 * @param instance
	 *            the instance to analyse for interfaces
	 * @return all interfaces that the given instance implements as Set
	 */
	public static Set getAllInterfacesAsSet(Object instance)
	{

		Assert.notNull(instance, "Instance must not be null");
		return getAllInterfacesForClassAsSet(instance.getClass());
	}

	/**
	 * Return all interfaces that the given class implements as Set, including
	 * ones implemented by superclasses.
	 * <p>
	 * If the class itself is an interface, it gets returned as sole interface.
	 * 
	 * @param clazz
	 *            the class to analyse for interfaces
	 * @return all interfaces that the given object implements as Set
	 */
	public static Set getAllInterfacesForClassAsSet(Class clazz)
	{

		return getAllInterfacesForClassAsSet(clazz, null);
	}

	/**
	 * Return all interfaces that the given class implements as Set, including
	 * ones implemented by superclasses.
	 * <p>
	 * If the class itself is an interface, it gets returned as sole interface.
	 * 
	 * @param clazz
	 *            the class to analyse for interfaces
	 * @param classLoader
	 *            the ClassLoader that the interfaces need to be visible in (may
	 *            be <code>null</code> when accepting all declared interfaces)
	 * @return all interfaces that the given object implements as Set
	 */
	public static Set getAllInterfacesForClassAsSet(Class clazz,
			ClassLoader classLoader)
	{

		Assert.notNull(clazz, "Class must not be null");
		if (clazz.isInterface())
		{
			return Collections.singleton(clazz);
		}
		Set interfaces = new LinkedHashSet();
		while (clazz != null)
		{
			for (int i = 0; i < clazz.getInterfaces().length; i++)
			{
				Class ifc = clazz.getInterfaces()[i];
				if (classLoader == null || isVisible(ifc, classLoader))
				{
					interfaces.add(ifc);
				}
			}
			clazz = clazz.getSuperclass();
		}
		return interfaces;
	}

	/**
	 * Create a composite interface Class for the given interfaces, implementing
	 * the given interfaces in one single Class.
	 * <p>
	 * This implementation builds a JDK proxy class for the given interfaces.
	 * 
	 * @param interfaces
	 *            the interfaces to merge
	 * @param classLoader
	 *            the ClassLoader to create the composite Class in
	 * @return the merged interface as Class
	 * @see java.lang.reflect.Proxy#getProxyClass
	 */
	public static Class createCompositeInterface(Class[] interfaces,
			ClassLoader classLoader)
	{

		Assert.notEmpty(interfaces, "Interfaces must not be empty");
		Assert.notNull(classLoader, "ClassLoader must not be null");
		return Proxy.getProxyClass(classLoader, interfaces);
	}

	/**
	 * Check whether the given class is visible in the given ClassLoader.
	 * 
	 * @param clazz
	 *            the class to check (typically an interface)
	 * @param classLoader
	 *            the ClassLoader to check against (may be <code>null</code>, in
	 *            which case this method will always return <code>true</code>)
	 */
	public static boolean isVisible(Class clazz, ClassLoader classLoader)
	{

		if (classLoader == null)
		{
			return true;
		}
		try
		{
			Class actualClass = classLoader.loadClass(clazz.getName());
			return (clazz == actualClass);
			// Else: different interface class found...
		}
		catch (ClassNotFoundException ex)
		{
			// No interface class found...
			return false;
		}
	}

	public static Class genericParameterType(Method method, int posistion)
	{

		Type[] types = method.getGenericParameterTypes();
		// Class[] pts = method.getParameterTypes();

		if (types == null || types.length == 0)
		{
			return null;
		}

		Type type = types[posistion];
		if (type instanceof ParameterizedType)
		{
			Type[] types_ = ((ParameterizedType) type).getActualTypeArguments();
			if(types_ == null || types_.length == 0)
			{
				return null;
			}
			Type zzz = types_[0];
			return zzz instanceof Class?(Class) zzz:null;

		}

		return null;

	}
	
	
	public static Class genericType(Field field)
	{

		Type type = field.getGenericType();
		// Class[] pts = method.getParameterTypes();

		if (type == null)
		{
			return null;
		}

//		Type type = types[posistion];
		if (type instanceof ParameterizedType)
		{

			Type[] types = ((ParameterizedType) type).getActualTypeArguments();
			if(types == null || types.length == 0)
			{
				return null;
			}
			Type zzz = types[0];
			return zzz instanceof Class?(Class) zzz:null;

		}

		return null;

	}

	public static Class[] genericParameterTypes(Method method, int posistion)
	{

		Type[] types = method.getGenericParameterTypes();
		// Class[] pts = method.getParameterTypes();

		if (types == null || types.length == 0)
		{
			return null;
		}

		// for(int i = 0; i < types.length; i ++)
		 
		Type type = types[posistion];
		if (type instanceof ParameterizedType)
		{

			Type[] ptypes = ((ParameterizedType) type)
					.getActualTypeArguments();

			Class[] genericParameterTypes = new Class[ptypes.length];
			int i = 0;
			for (Type zzz : ptypes)
			{
				if(zzz instanceof Class)
				{
					genericParameterTypes[i] = (Class) zzz;
					i++;
				}
			}
			return resizeClasses(genericParameterTypes,i);

		}
		 
		return null;

	}
	
	public static Class[] genericTypes(Field field)
	{
		if (field == null )
		{
			return null;
		}
		Type type = field.getGenericType();
		// Class[] pts = method.getParameterTypes();

		if (type == null )
		{
			return null;
		}

		
		if (type instanceof ParameterizedType)
		{

			Type[] ptypes = ((ParameterizedType) type)
					.getActualTypeArguments();

			Class[] genericParameterTypes = new Class[ptypes.length];
			int i = 0;
			for (Type zzz : ptypes)
			{
				if(zzz instanceof Class)
				{
				
					genericParameterTypes[i] = (Class) zzz;
					i++;
				}
			}
			return resizeClasses(genericParameterTypes,i);

		}
		
		return null;

	}
	private static Class[] resizeClasses(Class[] clazzes,int i)
	{
		if(i == clazzes.length || i == 0)
			return clazzes;
		Class[] newclazzes = new Class[i];
		for(int j = 0; j < i; j ++)
		{
			newclazzes[j] = clazzes[j];
		}
		return newclazzes;
	}

	public static Class getPropertyGenericType(Method writeMethod)
	{

//		Type[] types = writeMethod.getGenericParameterTypes();
//
//		if (types == null || types.length == 0)
//		{
//			return null;
//		}
//		Class genericParameterType = null;
//		Type type = types[0];
//		if (type instanceof ParameterizedType)
//		{
////			Class listClass = (Class) type;
////			if (List.class.isAssignableFrom(listClass)
////					|| Set.class.isAssignableFrom(listClass))
//			{
//				Type zzz = ((ParameterizedType) type).getActualTypeArguments()[0];
//				genericParameterType = (Class) zzz;
//			}
//		}
//
//		return genericParameterType;
		return ClassUtils.genericParameterType(writeMethod, 0);
	}
	
	public static Class[] getPropertyGenericTypes(Method writeMethod)
	{

//		Type[] types = writeMethod.getGenericParameterTypes();
//
//		if (types == null || types.length == 0)
//		{
//			return null;
//		}
//		Class genericParameterType = null;
//		Type type = types[0];
//		if (type instanceof ParameterizedType)
//		{
////			Class listClass = (Class) type;
////			if (List.class.isAssignableFrom(listClass)
////					|| Set.class.isAssignableFrom(listClass))
//			{
//				Type zzz = ((ParameterizedType) type).getActualTypeArguments()[0];
//				genericParameterType = (Class) zzz;
//			}
//		}

		return ClassUtils.genericParameterTypes(writeMethod, 0);
	}

}
