org.jolokia.util

Class ClassUtil

java.lang.Object

org.jolokia.util.ClassUtil

public final class ClassUtil
extends Object

Utility for class lookup.

Since:

19.04.11

Author:

roland

Method Summary

Modifier and Type	Method and Description
static Object	applyMethod(Object pObject, String pMethod, Object... pArgs) Apply a method to a given object with optional arguments.
static boolean	checkForClass(String pClassName) Check for the existence of a given class
static <T> Class<T>	classForName(String pClassName, boolean pInitialize, ClassLoader... pClassLoaders) Load a certain class.
static <T> Class<T>	classForName(String pClassName, ClassLoader... pClassLoaders) Lookup a class.
static InputStream	getResourceAsStream(String pPath) Get the given path as an input stream or return null if not found
static Set<String>	getResources(String pResource) Get all resources from the classpath which are specified by the given path.
static <T> T	newInstance(Class<T> pClass, Object... pArguments) Instantiate an instance of the given class with its default constructor
static <T> T	newInstance(String pClassName, Object... pArguments) Instantiate an instance of the given class with its default constructor.

Methods inherited from class java.lang.Object

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

Method Detail

classForName

public static <T> Class<T> classForName(String pClassName,
                                        ClassLoader... pClassLoaders)

Lookup a class. See classForName(String, boolean,ClassLoader[]) for details. The class gets initialized during lookup.

Parameters:

pClassName - name to lookup.

Returns:

the class found or null if no class could be found.

classForName

public static <T> Class<T> classForName(String pClassName,
                                        boolean pInitialize,
                                        ClassLoader... pClassLoaders)

Load a certain class. Several class loader are tried: Fires the current thread's context class loader, then its parents. If this doesn't work, the class loader which loaded this class is used (and its parents)

Parameters:

pClassName - class name to load

pInitialize - whether the class must be initialized

pClassLoaders - optional class loaders which are tried as well

Returns:

the class class found or null if no class could be loaded

getResourceAsStream

public static InputStream getResourceAsStream(String pPath)

Get the given path as an input stream or return null if not found

Parameters:

pPath - path to lookup

Returns:

input stream or null if not found.

checkForClass

public static boolean checkForClass(String pClassName)

Check for the existence of a given class

Parameters:

pClassName - class name to check

Returns:

true if the class could be loaded by the thread's conext class loader, false otherwise

newInstance

public static <T> T newInstance(String pClassName,
                                Object... pArguments)

Instantiate an instance of the given class with its default constructor. The context class loader is used to lookup the class

Type Parameters:

T - type object type

Parameters:

pClassName - name of class to instantiate

pArguments - optional constructor arguments. Works only for objects with the same class as declared in the constructor types (no subclasses)

Returns:

instantiated object

Throws:

IllegalArgumentException - if the class could not be found or instantiated

newInstance

public static <T> T newInstance(Class<T> pClass,
                                Object... pArguments)

Instantiate an instance of the given class with its default constructor

Type Parameters:

T - type object type

Parameters:

pClass - class to instantiate

pArguments - optional constructor arguments. Works only for objects with the same class as declared in the constructor types (no subclasses)

Returns:

instantiated object

Throws:

IllegalArgumentException - if the class could not be found or instantiated

applyMethod

public static Object applyMethod(Object pObject,
                                 String pMethod,
                                 Object... pArgs)

Apply a method to a given object with optional arguments. The method is looked up the whole class hierarchy.

Parameters:

pObject - object on which to apply the method

pMethod - the method name

pArgs - optional arguments

Returns:

return value (if any)

getResources

public static Set<String> getResources(String pResource)
                                throws IOException

Get all resources from the classpath which are specified by the given path.

Parameters:

pResource - resource specification to use for lookup

Returns:

the list or URLs to loookup

Throws:

IOException