content: package org.apache.archiva.metadata.repository;
  
  /*
   * 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.
   */
  
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * Implements just the open/close methods in a concurrent safe manner.
   */
  public abstract class AbstractRepositorySessionFactory implements RepositorySessionFactory {
  
      AtomicBoolean open = new AtomicBoolean();
  
      protected abstract void initialize();
  
      protected abstract void shutdown();
  
      @Override
      public void open() {
          if (open.compareAndSet(false,true)) {
              initialize();
          }
      }
  
      @Override
      public boolean isOpen() {
          return open.get();
      }
  
      @Override
      public void close() {
          if(open.compareAndSet(true,false)) {
              shutdown();
          }
      }
  }
  