content: /*
   * 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.cassandra;
  
  import java.io.IOException;
  import java.net.URLClassLoader;
  import java.util.function.Predicate;
  
  import org.junit.runners.BlockJUnit4ClassRunner;
  import org.junit.runners.model.InitializationError;
  
  import org.apache.cassandra.distributed.impl.AbstractCluster;
  
  /**
   *
   * This class is usually used to test singletons. It ensure singletons can be unique in each test case.
   *
   */
  public class CassandraIsolatedJunit4ClassRunner extends BlockJUnit4ClassRunner
  {
  
      private static final Predicate<String> isolatedPackage = name ->
                                                               name.startsWith("org.apache.cassandra.") ||
                                                               // YAML could not be shared because
                                                               // org.apache.cassandra.config.Config is loaded by org.yaml.snakeyaml.YAML
                                                               name.startsWith("org.yaml.snakeyaml.");
  
  
      /**
       * Creates a CassandraIsolatedJunit4ClassRunner to run {@code klass}
       *
       * @param clazz
       * @throws InitializationError if the test class is malformed.
       */
      public CassandraIsolatedJunit4ClassRunner(Class<?> clazz) throws InitializationError
      {
          super(createClassLoader(clazz));
      }
  
      private static Class<?> createClassLoader(Class<?> clazz) throws InitializationError {
          try {
              ClassLoader testClassLoader = new CassandraIsolatedClassLoader();
              return Class.forName(clazz.getName(), true, testClassLoader);
          } catch (ClassNotFoundException e) {
              throw new InitializationError(e);
          }
      }
  
      public static class CassandraIsolatedClassLoader extends URLClassLoader
      {
          public CassandraIsolatedClassLoader()
          {
              super(AbstractCluster.CURRENT_VERSION.classpath);
          }
  
          @Override
          public Class<?> loadClass(String name) throws ClassNotFoundException
          {
  
              if (isolatedPackage.test(name))
              {
                  synchronized (getClassLoadingLock(name))
                  {
                      // First, check if the class has already been loaded
                      Class<?> c = findLoadedClass(name);
  
                      if (c == null)
                          c = findClass(name);
  
                      return c;
                  }
              }
              else
              {
                  return super.loadClass(name);
              }
          }
  
          protected void finalize()
          {
              try
              {
                  close();
              }
              catch (IOException e)
              {
                  e.printStackTrace();
              }
          }
      }
  }
  