classutils.java

EasyDBO是一个超轻量级对象-关系映射（Object/Relation Mapping

			clazz.getMethod(methodName, paramTypes);
			return true;
		}
		catch (NoSuchMethodException ex) {
			return false;
		}
	}

	/**
	 * 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;
		do {
			for (int i = 0; i < clazz.getDeclaredMethods().length; i++) {
				Method method = clazz.getDeclaredMethods()[i];
				if (methodName.equals(method.getName())) {
					count++;
				}
			}
			clazz = clazz.getSuperclass();
		}
		while (clazz != null);
		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");
		do {
			for (int i = 0; i < clazz.getDeclaredMethods().length; i++) {
				Method method = clazz.getDeclaredMethods()[i];
				if (method.getName().equals(methodName)) {
					return true;
				}
			}
			clazz = clazz.getSuperclass();
		}
		while (clazz != null);
		return false;
	}

	/**
	 * 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.
	 */
	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).
	 */
	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.
	 */
	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.
	 */
	public static boolean isPrimitiveWrapperArray(Class clazz) {
		Assert.notNull(clazz, "Class must not be null");
		return (clazz.isArray() && isPrimitiveWrapper(clazz.getComponentType()));
	}

	/**
	 * Determine if the given target type is assignable from the given value
	 * type, assuming setting by reflection. Considers primitive wrapper
	 * classes as assignable to the corresponding primitive types.
	 * @param targetType the target type
	 * @param valueType	the value type that should be assigned to the target type
	 * @return if the target type is assignable from the value type
	 */
	public static boolean isAssignable(Class targetType, Class valueType) {
		Assert.notNull(targetType, "Target type must not be null");
		Assert.notNull(valueType, "Value type must not be null");
		return (targetType.isAssignableFrom(valueType) ||
						targetType.equals(primitiveWrapperTypeMap.get(valueType)));
	}

	/**
	 * 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());
	}


	/**
	 * 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,
	 * although {@link org.springframework.core.io.ClassPathResource} is usually
	 * 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 ClassLoader#getResource
	 * @see 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 ClassLoader.getResource(). For it to be fed to Class.getResource,
	 * a leading slash would also have to be prepended to the return value.
	 * @param clazz the input class. A null 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 || clazz.getPackage() == null) {
			return "";
		}
		return clazz.getPackage().getName().replace('.', '/');
	}

	/**
	 * Return all interfaces that the given object implements as array,
	 * including ones implemented by superclasses.
	 * @param object the object to analyse for interfaces
	 * @return all interfaces that the given object implements as array
	 */
	public static Class[] getAllInterfaces(Object object) {
		Set interfaces = getAllInterfacesAsSet(object);
		return (Class[]) interfaces.toArray(new Class[interfaces.size()]);
	}

	/**
	 * 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) {
		Set interfaces = getAllInterfacesForClassAsSet(clazz);
		return (Class[]) interfaces.toArray(new Class[interfaces.size()]);
	}

	/**
	 * Return all interfaces that the given object implements as List,
	 * including ones implemented by superclasses.
	 * @param object the object to analyse for interfaces
	 * @return all interfaces that the given object implements as List
	 */
	public static Set getAllInterfacesAsSet(Object object) {
		return getAllInterfacesForClassAsSet(object.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) {
		if (clazz.isInterface()) {
			return Collections.singleton(clazz);
		}
		Set interfaces = new HashSet();
		while (clazz != null) {
			for (int i = 0; i < clazz.getInterfaces().length; i++) {
				Class ifc = clazz.getInterfaces()[i];
				interfaces.add(ifc);
			}
			clazz = clazz.getSuperclass();
		}
		return interfaces;
	}


	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();
	}

}