/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.apache.commons.logging;
  
  import java.lang.ref.WeakReference;
  import java.lang.reflect.Field;
  
  import junit.framework.TestCase;
  
  public class LogFactoryWeakReferenceTestCase extends TestCase {
      private static final long MAX_WAIT_FOR_REF_NULLED_BY_GC = 15_000;
  
      public void testNotLeakingThisClassLoader() throws Exception {
          // create an isolated loader
          PathableClassLoader loader = new PathableClassLoader(null);
          loader.addLogicalLib("commons-logging");
  
          // load the LogFactory class through this loader
          Class<?> logFactoryClass = loader.loadClass(LogFactory.class.getName());
  
          // reflection hacks to obtain the weak reference
          Field field = logFactoryClass.getDeclaredField("thisClassLoaderRef");
          field.setAccessible(true);
          final WeakReference thisClassLoaderRef = (WeakReference) field.get(null);
  
          // the ref should at this point contain the loader
          assertSame(loader, thisClassLoaderRef.get());
  
          // null out the hard refs
          field = null;
          logFactoryClass = null;
          loader.close();
          loader = null;
  
          final GarbageCollectionHelper gcHelper = new GarbageCollectionHelper();
          gcHelper.run();
          try {
              final long start = System.currentTimeMillis();
              while (thisClassLoaderRef.get() != null) {
                  if (System.currentTimeMillis() - start > MAX_WAIT_FOR_REF_NULLED_BY_GC) {
                      fail("After waiting " + MAX_WAIT_FOR_REF_NULLED_BY_GC + "ms, the weak ref still yields a non-null value.");
                  }
                  Thread.sleep(100);
              }
          } finally {
              gcHelper.close();
          }
      }
  }