package de.spieleck.util;
import java.util.HashMap;
public class FastClassForName
{
private FastClassForName() { }
protected static HashMap classCache = new HashMap(15);
public static Object newInstance(String className, Class require)
{
return newInstance(className, null, require);
}
public static Object newInstance(String className, String defaultPackage,
Class require)
{
return newInstance(className, defaultPackage, require, require);
}
public static Object newInstance(String className, String defaultPackage,
Class require, Class context)
{
if (className == null)
return null;
try
{
Class clazz = null;
String classIndex;
if (defaultPackage != null)
classIndex = defaultPackage + className;
else
classIndex = className;
clazz = (Class)classCache.get(classIndex);
if (clazz == null)
{
try
{
clazz = contextClassForName(className, context);
}
catch (Exception oneMoreTrial)
{
if (defaultPackage != null)
clazz = contextClassForName(classIndex, context);
}
if (clazz != null)
classCache.put(classIndex, clazz);
}
if ( clazz == null )
{
System.err.println("?no Class '"+className
+"@"+defaultPackage+"' found.");
}
else if ( require.isAssignableFrom(clazz))
return clazz.newInstance();
else
{
System.err.println("?'"+clazz+"' not assignable to '"
+require+"'!");
}
}
catch (Exception help)
{
System.err.println("?no Class '" + className + "' found." + help);
help.printStackTrace();
}
return null;
}
public static Class contextClassForName(String className, Class context)
throws ClassNotFoundException
{
try
{
ClassLoader loader = context.getClassLoader();
return Class.forName(className, false, loader);
}
catch (NoSuchMethodError ignore)
{
return Class.forName(className);
}
catch ( ClassNotFoundException e )
{
ClassLoader loader = Thread.currentThread().getContextClassLoader();
return Class.forName(className, false, loader);
}
}
}