package org.apache.http.protocol;

import org.apache.http.annotation.Contract;
import org.apache.http.annotation.ThreadingBehavior;
import org.apache.http.util.Args;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

@Contract(
   threading = ThreadingBehavior.SAFE_CONDITIONAL
)
public class BasicHttpContext implements HttpContext {
   private final HttpContext parentContext;
   private final Map<String, Object> map;

   public BasicHttpContext() {
      this((HttpContext)null);
   }

   public BasicHttpContext(HttpContext parentContext) {
      this.map = new ConcurrentHashMap();
      this.parentContext = parentContext;
   }

   public Object getAttribute(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;
   }

   public void setAttribute(String id, Object obj) {
      Args.notNull(id, "Id");
      if (obj != null) {
         this.map.put(id, obj);
      } else {
         this.map.remove(id);
      }

   }

   public Object removeAttribute(String id) {
      Args.notNull(id, "Id");
      return this.map.remove(id);
   }

   public void clear() {
      this.map.clear();
   }

   public String toString() {
      return this.map.toString();
   }
}
