1 /*
   2  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 import java.io.IOException;
  25 import java.net.URL;
  26 import java.util.Enumeration;
  27 import java.lang.System.LoggerFinder;
  28 
  29 /**
  30  * A custom class loader which can hide the registered LoggerProvider
  31  * depending on the value of a test.logger.hidesProvider system property.
  32  * @author danielfuchs
  33  */
  34 public class SystemClassLoader extends ClassLoader {
  35 
  36     final public boolean hidesProvider;
  37 
  38     public SystemClassLoader() {
  39         hidesProvider = Boolean.getBoolean("test.logger.hidesProvider");
  40     }
  41     public SystemClassLoader(ClassLoader parent) {
  42         super(parent);
  43         hidesProvider = Boolean.getBoolean("test.logger.hidesProvider");
  44     }
  45 
  46     boolean accept(String name) {
  47         final boolean res = !name.endsWith(LoggerFinder.class.getName());
  48         if (res == false) {
  49             System.out.println("Hiding " + name);
  50         }
  51         return res;
  52     }
  53 
  54     @Override
  55     public URL getResource(String name) {
  56         if (hidesProvider && !accept(name)) {
  57             return null;
  58         } else {
  59             return super.getResource(name);
  60         }
  61     }
  62 
  63     class Enumerator implements Enumeration<URL> {
  64         final Enumeration<URL> enumeration;
  65         volatile URL next;
  66         Enumerator(Enumeration<URL> enumeration) {
  67             this.enumeration = enumeration;
  68         }
  69 
  70         @Override
  71         public boolean hasMoreElements() {
  72             if (next != null) return true;
  73             if (!enumeration.hasMoreElements()) return false;
  74             if (hidesProvider == false) return true;
  75             next = enumeration.nextElement();
  76             if (accept(next.getPath())) return true;
  77             next = null;
  78             return hasMoreElements();
  79         }
  80 
  81         @Override
  82         public URL nextElement() {
  83             final URL res = next == null ? enumeration.nextElement() : next;
  84             next = null;
  85             if (hidesProvider == false || accept(res.getPath())) return res;
  86             return nextElement();
  87         }
  88     }
  89 
  90     @Override
  91     public Enumeration<URL> getResources(String name) throws IOException {
  92         final Enumeration<URL> enumeration = super.getResources(name);
  93         return hidesProvider ? new Enumerator(enumeration) : enumeration;
  94     }
  95 
  96 
  97 
  98 }