org.xml.sax.helpers.NewInstance Maven / Gradle / Ivy
// NewInstance.java - create a new instance of a class by name.
// http://www.saxproject.org
// Written by Edwin Goei, [email protected]
// and by David Brownell, [email protected]
// NO WARRANTY! This class is in the Public Domain.
// $Id: NewInstance.java,v 1.4 2002/01/30 20:52:27 dbrownell Exp $
package org.xml.sax.helpers;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* Create a new instance of a class by name.
*
*
* This module, both source code and documentation, is in the
* Public Domain, and comes with NO WARRANTY.
* See http://www.saxproject.org
* for further information.
*
*
* This class contains a static method for creating an instance of a
* class from an explicit class name. It tries to use the thread's context
* ClassLoader if possible and falls back to using
* Class.forName(String).
*
* This code is designed to compile and run on JDK version 1.1 and later
* including versions of Java 2.
*
* @author Edwin Goei, David Brownell
* @version 2.0.1 (sax2r2)
*/
class NewInstance {
/**
* Creates a new instance of the specified class name
*
* Package private so this code is not exposed at the API level.
*/
static Object newInstance (ClassLoader classLoader, String className)
throws ClassNotFoundException, IllegalAccessException,
InstantiationException
{
Class driverClass;
if (classLoader == null) {
driverClass = Class.forName(className);
} else {
driverClass = classLoader.loadClass(className);
}
return driverClass.newInstance();
}
/**
* Figure out which ClassLoader to use. For JDK 1.2 and later use
* the context ClassLoader.
*/
static ClassLoader getClassLoader ()
{
Method m = null;
try {
m = Thread.class.getMethod("getContextClassLoader");
} catch (NoSuchMethodException e) {
// Assume that we are running JDK 1.1, use the current ClassLoader
return NewInstance.class.getClassLoader();
}
try {
return (ClassLoader) m.invoke(Thread.currentThread());
} catch (IllegalAccessException e) {
// assert(false)
throw new UnknownError(e.getMessage());
} catch (InvocationTargetException e) {
// assert(e.getTargetException() instanceof SecurityException)
throw new UnknownError(e.getMessage());
}
}
}