/*

  * 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.johnzon.websocket.internal.mapper;

 import org.apache.johnzon.mapper.Mapper;

 import org.apache.johnzon.mapper.MapperBuilder;

 import java.util.Map;

 import java.util.concurrent.ConcurrentHashMap;

 import javax.servlet.ServletContextEvent;

 import javax.servlet.ServletContextListener;

 import javax.servlet.annotation.WebListener;

 @WebListener

 public class MapperLocator implements ServletContextListener {

     private static final Map<ClassLoader, Mapper> MAPPER_BY_LOADER = new ConcurrentHashMap<ClassLoader, Mapper>();

     private static final String ATTRIBUTE = MapperLocator.class.getName() + ".mapper";

     @Override

     public void contextInitialized(final ServletContextEvent servletContextEvent) {

         final Mapper build = newMapper();

         MAPPER_BY_LOADER.put(servletContextEvent.getServletContext().getClassLoader(), build);

         servletContextEvent.getServletContext().setAttribute(ATTRIBUTE, build);

     }

     @Override

     public void contextDestroyed(final ServletContextEvent servletContextEvent) {

         MAPPER_BY_LOADER.remove(servletContextEvent.getServletContext().getClassLoader());

     }

     public static Mapper locate() {

         ClassLoader loader = Thread.currentThread().getContextClassLoader();

         if (loader == null) {

             loader = MapperLocator.class.getClassLoader();

         }

         final Mapper mapper = MAPPER_BY_LOADER.get(loader);

         if (mapper == null) {

             return newMapper();

         }

         return mapper;

     }

     private static Mapper newMapper() {

         return new MapperBuilder().build();

     }

 }