Package org.apache.velocity.tools

Class ClassUtils

java.lang.Object

org.apache.velocity.tools.ClassUtils

public class ClassUtils
extends Object

Repository for common class and reflection methods.

Version:

$Id: ClassUtils.java 511959 2007-02-26 19:24:39Z nbubna $

Author:

Nathan Bubna

Field Summary

Fields

Modifier and Type	Field	Description
static ClassUtils	INSTANCE

Method Summary

Modifier and Type	Method	Description
static Method	findDeclaredMethod(Class clazz, String name, Class[] params)
static Method	findMethod(Class clazz, String name, Class[] params)
static Class	getClass(String name)	Load a class with a given name.
static Object	getFieldValue(Class clazz, String fieldname)
static Object	getFieldValue(String fieldPath)
ClassUtils	getInstance()
static Object	getInstance(String classname)
static Iterator	getIterator(Object obj)	Retrieves an Iterator from or creates and Iterator for the specified object.
static URL	getResource(String name, Object caller)	Load a given resource.
static InputStream	getResourceAsStream(String name, Object caller)	This is a convenience method to load a resource as a stream.
static List<URL>	getResources(String name, Object caller)	Load all resources with the specified name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final ClassUtils INSTANCE

Method Detail

getInstance

public ClassUtils getInstance()

getClass

public static Class getClass(String name)
                      throws ClassNotFoundException

Load a class with a given name.

It will try to load the class in the following order:

• From Thread.currentThread().getContextClassLoader()
• Using the basic Class.forName(java.lang.String)
• From ClassUtils.class.getClassLoader()

Parameters:

name - Fully qualified class name to be loaded

Returns:

Class object

Throws:

ClassNotFoundException - if the class cannot be found

getInstance

public static Object getInstance(String classname)
                          throws ClassNotFoundException,
                                 IllegalAccessException,
                                 InstantiationException

Throws:

ClassNotFoundException

IllegalAccessException

InstantiationException

getResources

public static List<URL> getResources(String name,
                                     Object caller)

Load all resources with the specified name. If none are found, we prepend the name with '/' and try again. This will attempt to load the resources from the following methods (in order):

• Thread.currentThread().getContextClassLoader().getResources(name)
• ClassUtils.class.getClassLoader().getResources(name)
• ClassUtils.class.getResource(name)
• getCallerLoader(Object caller).getResources(name)
• caller.getClass().getResource(name)

Parameters:

name - The name of the resources to load

caller - The instance or Class calling this method

getResource

public static URL getResource(String name,
                              Object caller)

Load a given resource.

This method will try to load the resource using the following methods (in order):

• Thread.currentThread().getContextClassLoader().getResource(name)
• ClassUtils.class.getClassLoader().getResource(name)
• ClassUtils.class.getResource(name)
• caller.getClass().getResource(name) or, if caller is a Class, caller.getResource(name)

Parameters:

name - The name of the resource to load

caller - The instance or Class calling this method

getResourceAsStream

public static InputStream getResourceAsStream(String name,
                                              Object caller)

This is a convenience method to load a resource as a stream.

The algorithm used to find the resource is given in getResource()

Parameters:

name - The name of the resource to load

caller - The instance or Class calling this method

findMethod

public static Method findMethod(Class clazz,
                                String name,
                                Class[] params)
                         throws SecurityException

Throws:

SecurityException

findDeclaredMethod

public static Method findDeclaredMethod(Class clazz,
                                        String name,
                                        Class[] params)
                                 throws SecurityException

Throws:

SecurityException

getFieldValue

public static Object getFieldValue(String fieldPath)
                            throws ClassNotFoundException,
                                   NoSuchFieldException,
                                   SecurityException,
                                   IllegalAccessException

Throws:

ClassNotFoundException

NoSuchFieldException

SecurityException

IllegalAccessException

getFieldValue

public static Object getFieldValue(Class clazz,
                                   String fieldname)
                            throws NoSuchFieldException,
                                   SecurityException,
                                   IllegalAccessException

Throws:

NoSuchFieldException

SecurityException

IllegalAccessException

getIterator

public static Iterator getIterator(Object obj)
                            throws NoSuchMethodException,
                                   IllegalAccessException,
                                   InvocationTargetException

Retrieves an Iterator from or creates and Iterator for the specified object. This method is almost entirely copied from Engine's UberspectImpl class.

Throws:

NoSuchMethodException

IllegalAccessException

InvocationTargetException