Mega Code Archive
Load class from Threads ContextClassLoader, classloader of derived class or the system ClassLoader
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//
// Copyright 2004-2005 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// 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.
//
import java.net.URL;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
/* ------------------------------------------------------------ */
/** ClassLoader Helper.
* This helper class allows classes to be loaded either from the
* Thread's ContextClassLoader, the classloader of the derived class
* or the system ClassLoader.
*
* <B>Usage:</B><PRE>
* public class MyClass {
* void myMethod() {
* ...
* Class c=Loader.loadClass(this.getClass(),classname);
* ...
* }
* </PRE>
* @author Greg Wilkins (gregw)
*/
public class Loader
{
/* ------------------------------------------------------------ */
public static URL getResource(Class loadClass,String name, boolean checkParents)
throws ClassNotFoundException
{
URL url =null;
ClassLoader loader=Thread.currentThread().getContextClassLoader();
while (url==null && loader!=null )
{
url=loader.getResource(name);
loader=(url==null&&checkParents)?loader.getParent():null;
}
loader=loadClass==null?null:loadClass.getClassLoader();
while (url==null && loader!=null )
{
url=loader.getResource(name);
loader=(url==null&&checkParents)?loader.getParent():null;
}
if (url==null)
{
url=ClassLoader.getSystemResource(name);
}
return url;
}
/* ------------------------------------------------------------ */
public static Class loadClass(Class loadClass,String name)
throws ClassNotFoundException
{
return loadClass(loadClass,name,false);
}
/* ------------------------------------------------------------ */
/** Load a class.
*
* @param loadClass
* @param name
* @param checkParents If true, try loading directly from parent classloaders.
* @return Class
* @throws ClassNotFoundException
*/
public static Class loadClass(Class loadClass,String name,boolean checkParents)
throws ClassNotFoundException
{
ClassNotFoundException ex=null;
Class c =null;
ClassLoader loader=Thread.currentThread().getContextClassLoader();
while (c==null && loader!=null )
{
try { c=loader.loadClass(name); }
catch (ClassNotFoundException e) {if(ex==null)ex=e;}
loader=(c==null&&checkParents)?loader.getParent():null;
}
loader=loadClass==null?null:loadClass.getClassLoader();
while (c==null && loader!=null )
{
try { c=loader.loadClass(name); }
catch (ClassNotFoundException e) {if(ex==null)ex=e;}
loader=(c==null&&checkParents)?loader.getParent():null;
}
if (c==null)
{
try { c=Class.forName(name); }
catch (ClassNotFoundException e) {if(ex==null)ex=e;}
}
if (c!=null)
return c;
throw ex;
}
public static ResourceBundle getResourceBundle(Class loadClass,String name,boolean checkParents, Locale locale)
throws MissingResourceException
{
MissingResourceException ex=null;
ResourceBundle bundle =null;
ClassLoader loader=Thread.currentThread().getContextClassLoader();
while (bundle==null && loader!=null )
{
try { bundle=ResourceBundle.getBundle(name, locale, loader); }
catch (MissingResourceException e) {if(ex==null)ex=e;}
loader=(bundle==null&&checkParents)?loader.getParent():null;
}
loader=loadClass==null?null:loadClass.getClassLoader();
while (bundle==null && loader!=null )
{
try { bundle=ResourceBundle.getBundle(name, locale, loader); }
catch (MissingResourceException e) {if(ex==null)ex=e;}
loader=(bundle==null&&checkParents)?loader.getParent():null;
}
if (bundle==null)
{
try { bundle=ResourceBundle.getBundle(name, locale); }
catch (MissingResourceException e) {if(ex==null)ex=e;}
}
if (bundle!=null)
return bundle;
throw ex;
}
}
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