/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.hc.core5.http.protocol;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.http.HttpVersion;
  import org.apache.hc.core5.http.ProtocolVersion;
  import org.apache.hc.core5.util.Args;
  
  /**
   * Default implementation of {@link HttpContext}.
   * <p>
   * Please note instances of this class can be thread unsafe if the
   * parent context is not thread safe.
   *
   * @since 4.0
   */
  @Contract(threading = ThreadingBehavior.SAFE_CONDITIONAL)
  public class BasicHttpContext implements HttpContext {
  
      private final HttpContext parentContext;
      private final Map<String, Object> map;
  
      private ProtocolVersion version;
  
      public BasicHttpContext() {
          this(null);
      }
  
      public BasicHttpContext(final HttpContext parentContext) {
          super();
          this.map = new ConcurrentHashMap<>();
          this.parentContext = parentContext;
      }
  
      @Override
      public Object getAttribute(final String id) {
          Args.notNull(id, "Id");
          Object obj = this.map.get(id);
          if (obj == null && this.parentContext != null) {
              obj = this.parentContext.getAttribute(id);
          }
          return obj;
      }
  
      @Override
      public Object setAttribute(final String id, final Object obj) {
          Args.notNull(id, "Id");
          if (obj != null) {
              return this.map.put(id, obj);
          }
          return this.map.remove(id);
      }
  
      @Override
      public Object removeAttribute(final String id) {
          Args.notNull(id, "Id");
          return this.map.remove(id);
      }
  
      /**
       * @since 5.0
       */
      @Override
      public ProtocolVersion getProtocolVersion() {
          return this.version != null ? this.version : HttpVersion.DEFAULT;
      }
  
      /**
       * @since 5.0
      */
     @Override
     public void setProtocolVersion(final ProtocolVersion version) {
         this.version = version;
     }
 
     /**
      * @since 4.2
      */
     public void clear() {
         this.map.clear();
     }
 
     @Override
     public String toString() {
         return this.map.toString();
     }
 
 }