package jython;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.TreeMap;

public class ClassReloader extends ClassLoader {
	static TreeMap<String, Class> classes = new TreeMap<String, Class>();
	public static String dir = "bin";

	synchronized public static Class gc(String name) {
		for (String key : classes.keySet()) {
			if (key.equals(name))
				return classes.get(key);
		}
		Class rclass = null;
		try {
			rclass = Class.forName(name);
		} catch (ClassNotFoundException e) {
		}
		return rclass;
	}

	synchronized public static Class rc(String name) {
		Class oldclass = gc(name), nclass = null;
		File file = new File(dir + File.separator
				+ name.replace(".", File.separator) + ".class");
		try {
			if (!file.exists()) {
				System.out.println("Class wasn't found!");
			}
			byte[] b = new byte[(int) file.length()];
			new FileInputStream(file).read(b);
			nclass = new ClassReloader().defineClass(name, b, 0, (int) file
					.length());
			if (nclass != null) {
				if (oldclass != null) {
					for (Field field : nclass.getFields()) {
						try {
							if (Modifier.isStatic(field.getModifiers())
									&& oldclass.getField(field.getName()) != null)
								field.set(nclass, oldclass.getField(
										field.getName()).get(oldclass));
						} catch (SecurityException e) {
						} catch (IllegalArgumentException e) {
						} catch (NoSuchFieldException e) {
						} catch (IllegalAccessException e) {
						}
					}
				}
				classes.put(name, nclass);
			}
		} catch (FileNotFoundException e) {
		} catch (IOException e) {
		}
		return nclass;
	}

/*	public static void main(String[] args) {
		Class c1 = ClassReloader.gc("jython.My");
		for (Field f : c1.getDeclaredFields()) {
			System.out.println(f.getName());
		}
		//change class file  
		Class c2 = ClassReloader.rc("jython.My");
		for (Field f : c2.getDeclaredFields()) {
			System.out.println(f.getName());
		}
	}*/
}