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Merging ClassLoader fixes from the tck-jaxp-1_2_0 branch.

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I had almost forgotten these. Will re-tag the main branch.


git-svn-id: https://svn.apache.org/repos/asf/xml/commons/trunk@226252 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
mrglavas 2005-06-22 02:13:56 +00:00
parent a8a58328eb
commit e37ca1b076
1 changed files with 48 additions and 22 deletions
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68
java/external/src/org/xml/sax/helpers/NewInstance.java vendored
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@ -7,9 +7,6 @@
package org.xml.sax.helpers;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
/**
* Create a new instance of a class by name.
*
@ -23,16 +20,27 @@ import java.lang.reflect.InvocationTargetException;
* <p>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).</p>
* Class.forName(String). It also takes into account JDK 1.2+'s
* AccessController mechanism for performing its actions. </p>
*
* <p>This code is designed to compile and run on JDK version 1.1 and later
* including versions of Java 2.</p>
*
* <p>This is <strong>not</strong> the NewInstance accompanying SAX 2.0.2; it
* represents many fixes to that code.
*
* @author Edwin Goei, David Brownell
* @version 2.0.1 (sax2r2)
*/
class NewInstance {
// constants
// governs whether, if we fail in finding a class even
// when given a classloader, we'll make a last-ditch attempt
// to use the current classloader.
private static final boolean DO_FALLBACK = true;
/**
* Creates a new instance of the specified class name
*
@ -44,11 +52,36 @@ class NewInstance {
{
Class driverClass;
if (classLoader == null) {
// XXX Use the bootstrap ClassLoader. There is no way to
// load a class using the bootstrap ClassLoader that works
// in both JDK 1.1 and Java 2. However, this should still
// work b/c the following should be true:
//
// (cl == null) iff current ClassLoader == null
//
// Thus Class.forName(String) will use the current
// ClassLoader which will be the bootstrap ClassLoader.
driverClass = Class.forName(className);
} else {
try {
driverClass = classLoader.loadClass(className);
} catch (ClassNotFoundException x) {
if (DO_FALLBACK) {
// Fall back to current classloader
classLoader = NewInstance.class.getClassLoader();
if (classLoader != null) {
driverClass = classLoader.loadClass(className);
}
return driverClass.newInstance();
else {
driverClass = Class.forName(className);
}
} else {
throw x;
}
}
}
Object instance = driverClass.newInstance();
return instance;
}
/**
@ -57,23 +90,16 @@ class NewInstance {
*/
static ClassLoader getClassLoader ()
{
Method m = null;
SecuritySupport ss = SecuritySupport.getInstance();
try {
m = Thread.class.getMethod("getContextClassLoader", (Class[]) null);
} 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(), (Object[]) null);
} catch (IllegalAccessException e) {
// assert(false)
throw new UnknownError(e.getMessage());
} catch (InvocationTargetException e) {
// assert(e.getTargetException() instanceof SecurityException)
throw new UnknownError(e.getMessage());
// Figure out which ClassLoader to use for loading the provider
// class. If there is a Context ClassLoader then use it.
ClassLoader cl = ss.getContextClassLoader();
if (cl == null) {
// Assert: we are on JDK 1.1 or we have no Context ClassLoader
// so use the current ClassLoader
cl = NewInstance.class.getClassLoader();
}
return cl;
}
}