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jeremybenn |
// NewInstance.java - create a new instance of a class by name.
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// http://www.saxproject.org
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// Written by Edwin Goei, edwingo@apache.org
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// and by David Brownell, dbrownell@users.sourceforge.net
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// NO WARRANTY! This class is in the Public Domain.
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// $Id: NewInstance.java,v 1.1 2004/12/23 22:38:42 mark Exp $
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package org.xml.sax.helpers;
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import java.lang.reflect.Method;
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import java.lang.reflect.InvocationTargetException;
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/**
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* Create a new instance of a class by name.
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*
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* <blockquote>
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* <em>This module, both source code and documentation, is in the
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* Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
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* See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
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* for further information.
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* </blockquote>
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*
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* <p>This class contains a static method for creating an instance of a
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* class from an explicit class name. It tries to use the thread's context
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* ClassLoader if possible and falls back to using
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* Class.forName(String).</p>
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*
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* <p>This code is designed to compile and run on JDK version 1.1 and later
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* including versions of Java 2.</p>
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*
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* @author Edwin Goei, David Brownell
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* @version 2.0.1 (sax2r2)
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*/
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class NewInstance {
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/**
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* Creates a new instance of the specified class name
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*
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* Package private so this code is not exposed at the API level.
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*/
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static Object newInstance (ClassLoader classLoader, String className)
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throws ClassNotFoundException, IllegalAccessException,
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InstantiationException
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{
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Class driverClass;
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if (classLoader == null) {
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driverClass = Class.forName(className);
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} else {
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driverClass = classLoader.loadClass(className);
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}
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return driverClass.newInstance();
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}
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/**
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* Figure out which ClassLoader to use. For JDK 1.2 and later use
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* the context ClassLoader.
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*/
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static ClassLoader getClassLoader ()
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{
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Method m = null;
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try {
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m = Thread.class.getMethod("getContextClassLoader", null);
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} catch (NoSuchMethodException e) {
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// Assume that we are running JDK 1.1, use the current ClassLoader
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return NewInstance.class.getClassLoader();
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}
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try {
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return (ClassLoader) m.invoke(Thread.currentThread(), null);
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} catch (IllegalAccessException e) {
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// assert(false)
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throw new UnknownError(e.getMessage());
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} catch (InvocationTargetException e) {
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// assert(e.getTargetException() instanceof SecurityException)
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throw new UnknownError(e.getMessage());
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}
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}
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}
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