org.mc4j.ems.connection.support.classloader.ChildFirstClassloader.java Source code

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Here is the source code for org.mc4j.ems.connection.support.classloader.ChildFirstClassloader.java

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/*
 * Copyright 2002-2004 Greg Hinkle
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.mc4j.ems.connection.support.classloader;

import java.net.URL;
import java.net.URLClassLoader;

/**
 * WARNING: GH - DISGUSTING HACK
 * This is an aweful little hack that allows us to execute under jdk 1.5 (which includes jmx)
 * while utilizing the jmx classes we load from somewhere else. We just override the classloader
 * delegation for cases of the "javax.management" classes.
 *
 * @author Greg Hinkle (ghinkle@users.sourceforge.net), Apr 5, 2005
 * @version $Revision: 589 $($Author: ghinkl $ / $Date: 2008-04-10 21:52:05 +0200 (Do, 10 Apr 2008) $)
 */
public class ChildFirstClassloader extends URLClassLoader {

    public ChildFirstClassloader(URL[] urls, ClassLoader parent) {
        super(urls, parent);
    }

    protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
        Class c = findLoadedClass(name);
        if (c == null) {
            if (name.indexOf("org.mc4j") == -1 || name.indexOf("org.apache.commons.logging") == -1) { //true) {//name.indexOf("javax.management") >= 0) {
                //                   if (name.contains("log4j.xml"))
                //                      System.out.println("Looking for " + name);
                try {
                    try {
                        c = findClass(name);
                    } catch (SecurityException se) {
                        int i = name.lastIndexOf('.');
                        String pkgname = name.substring(0, i);
                        // Check if package already loaded.
                        Package pkg = getPackage(pkgname);
                        if (pkg == null) {
                            definePackage(pkgname, null, null, null, null, null, null, null);
                        }
                    }
                    if (resolve) {
                        resolveClass(c);
                    }
                } catch (ClassNotFoundException cnfe) {
                    c = super.loadClass(name, resolve);
                }
            } else {
                c = super.loadClass(name, resolve);
            }
        }
        return c;
    }

    @Override
    public URL getResource(String name) {
        URL res = findResource(name);
        if (res == null)
            res = super.getResource(name);
        return res;
    }

    /*
    private Class defineClass(String name, Resource res) throws IOException {
       int i = name.lastIndexOf('.');
       URL url = res.getCodeSourceURL();
       if (i != -1) {
           String pkgname = name.substring(0, i);
           // Check if package already loaded.
           Package pkg = getPackage(pkgname);
           Manifest man = res.getManifest();
           if (pkg != null) {
          // Package found, so check package sealing.
          if (pkg.isSealed()) {
      // Verify that code source URL is the same.
      if (!pkg.isSealed(url)) {
     throw new SecurityException(
         "sealing violation: package " + pkgname + " is sealed");
      }
        
          } else {
      // Make sure we are not attempting to seal the package
      // at this code source URL.
      if ((man != null) && isSealed(pkgname, man)) {
     throw new SecurityException(
         "sealing violation: can't seal package " + pkgname +
         ": already loaded");
      }
          }
           } else {
          if (man != null) {
      definePackage(pkgname, man, url);
          } else {
                definePackage(pkgname, null, null, null, null, null, null, null);
            }
           }
       }*/

}