public void removeAttribute(String attributeName) {
   Dictionary<String, Object> attributes = proxyContext.getContextAttributes(httpContext);
   attributes.remove(attributeName);
 }
 public Enumeration<String> getAttributeNames() {
   Dictionary<String, Object> attributes = proxyContext.getContextAttributes(httpContext);
   return attributes.keys();
 }
 public void setAttribute(String attributeName, Object attributeValue) {
   Dictionary<String, Object> attributes = proxyContext.getContextAttributes(httpContext);
   attributes.put(attributeName, attributeValue);
 }
 public Object getAttribute(String attributeName) {
   Dictionary<String, Object> attributes = proxyContext.getContextAttributes(httpContext);
   return attributes.get(attributeName);
 }