/*

  * 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.jsr;

 import java.util.Collections;

 import java.util.Map;

 import java.util.concurrent.ConcurrentHashMap;

 import javax.json.Json;

 import javax.json.JsonReaderFactory;

 import javax.json.JsonWriterFactory;

 import javax.servlet.ServletContextEvent;

 import javax.servlet.ServletContextListener;

 import javax.servlet.annotation.WebListener;

 @WebListener

 public class FactoryLocator implements ServletContextListener {

     private static final Map<ClassLoader, JsonReaderFactory> READER_FACTORY_BY_LOADER = new ConcurrentHashMap<ClassLoader, JsonReaderFactory>();

     private static final Map<ClassLoader, JsonWriterFactory> WRITER_FACTORY_BY_LOADER = new ConcurrentHashMap<ClassLoader, JsonWriterFactory>();

     private static final String READER_ATTRIBUTE = FactoryLocator.class.getName() + ".readerFactory";

     private static final String WRITER_ATTRIBUTE = FactoryLocator.class.getName() + ".writerFactory";

     @Override

     public void contextInitialized(final ServletContextEvent servletContextEvent) {

         final ClassLoader classLoader = servletContextEvent.getServletContext().getClassLoader();

         final JsonReaderFactory reader = newReadFactory();

         READER_FACTORY_BY_LOADER.put(classLoader, reader);

         servletContextEvent.getServletContext().setAttribute(READER_ATTRIBUTE, reader);

         final JsonWriterFactory writer = newWriterFactory();

         WRITER_FACTORY_BY_LOADER.put(classLoader, writer);

         servletContextEvent.getServletContext().setAttribute(WRITER_ATTRIBUTE, reader);

     }

     @Override

     public void contextDestroyed(final ServletContextEvent servletContextEvent) {

         final ClassLoader classLoader = servletContextEvent.getServletContext().getClassLoader();

         READER_FACTORY_BY_LOADER.remove(classLoader);

         WRITER_FACTORY_BY_LOADER.remove(classLoader);

     }

     public static JsonReaderFactory readerLocate() {

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

         if (loader == null) {

             loader = FactoryLocator.class.getClassLoader();

         }

         final JsonReaderFactory factory = READER_FACTORY_BY_LOADER.get(loader);

         if (factory == null) {

             return newReadFactory();

         }

         return factory;

     }

     public static JsonWriterFactory writerLocate() {

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

         if (loader == null) {

             loader = FactoryLocator.class.getClassLoader();

         }

         final JsonWriterFactory factory = WRITER_FACTORY_BY_LOADER.get(loader);

         if (factory == null) {

             return newWriterFactory();

         }

         return factory;

     }

     private static JsonReaderFactory newReadFactory() {

         return Json.createReaderFactory(Collections.<String, Object>emptyMap());

     }

     private static JsonWriterFactory newWriterFactory() {

         return Json.createWriterFactory(Collections.<String, Object>emptyMap());

     }

 }