content: /*
   * Copyright (c) 2010-2018 Nathan Rajlich
   *
   *  Permission is hereby granted, free of charge, to any person
   *  obtaining a copy of this software and associated documentation
   *  files (the "Software"), to deal in the Software without
   *  restriction, including without limitation the rights to use,
   *  copy, modify, merge, publish, distribute, sublicense, and/or sell
   *  copies of the Software, and to permit persons to whom the
   *  Software is furnished to do so, subject to the following
   *  conditions:
   *
   *  The above copyright notice and this permission notice shall be
   *  included in all copies or substantial portions of the Software.
   *
   *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   *  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
   *  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   *  OTHER DEALINGS IN THE SOFTWARE.
   */
  
  package com.alipay.api.java_websocket.extensions;
  
  import com.alipay.api.java_websocket.exceptions.InvalidDataException;
  import com.alipay.api.java_websocket.framing.Framedata;
  
  /**
   * Interface which specifies all required methods to develop a websocket extension.
   *
   * @since 1.3.5
   */
  public interface IExtension {
  
      /**
       * Decode a frame with a extension specific algorithm. The algorithm is subject to be implemented by the specific extension. The
       * resulting frame will be used in the application
       *
       * @param inputFrame the frame, which has do be decoded to be used in the application
       * @throws InvalidDataException Throw InvalidDataException if the received frame is not correctly implemented by the other endpoint or
       *                              there are other protocol errors/decoding errors
       * @since 1.3.5
       */
      void decodeFrame(Framedata inputFrame) throws InvalidDataException;
  
      /**
       * Encode a frame with a extension specific algorithm. The algorithm is subject to be implemented by the specific extension. The
       * resulting frame will be send to the other endpoint.
       *
       * @param inputFrame the frame, which has do be encoded to be used on the other endpoint
       * @since 1.3.5
       */
      void encodeFrame(Framedata inputFrame);
  
      /**
       * Check if the received Sec-WebSocket-Extensions header field contains a offer for the specific extension if the endpoint is in the
       * role of a server
       *
       * @param inputExtensionHeader the received Sec-WebSocket-Extensions header field offered by the other endpoint
       * @return true, if the offer does fit to this specific extension
       * @since 1.3.5
       */
      boolean acceptProvidedExtensionAsServer(String inputExtensionHeader);
  
      /**
       * Check if the received Sec-WebSocket-Extensions header field contains a offer for the specific extension if the endpoint is in the
       * role of a client
       *
       * @param inputExtensionHeader the received Sec-WebSocket-Extensions header field offered by the other endpoint
       * @return true, if the offer does fit to this specific extension
       * @since 1.3.5
       */
      boolean acceptProvidedExtensionAsClient(String inputExtensionHeader);
  
      /**
       * Check if the received frame is correctly implemented by the other endpoint and there are no specification errors (like wrongly set
       * RSV)
       *
       * @param inputFrame the received frame
       * @throws InvalidDataException Throw InvalidDataException if the received frame is not correctly implementing the specification for the
       *                              specific extension
       * @since 1.3.5
       */
      void isFrameValid(Framedata inputFrame) throws InvalidDataException;
  
      /**
       * Return the specific Sec-WebSocket-Extensions header offer for this extension if the endpoint is in the role of a client. If the
       * extension returns an empty string (""), the offer will not be included in the handshake.
       *
       * @return the specific Sec-WebSocket-Extensions header for this extension
       * @since 1.3.5
       */
      String getProvidedExtensionAsClient();
  
      /**
       * Return the specific Sec-WebSocket-Extensions header offer for this extension if the endpoint is in the role of a server. If the
       * extension returns an empty string (""), the offer will not be included in the handshake.
       *
       * @return the specific Sec-WebSocket-Extensions header for this extension
       * @since 1.3.5
       */
      String getProvidedExtensionAsServer();
  
      /**
       * Extensions must only be by one websocket at all. To prevent extensions to be used more than once the Websocket implementation should
       * call this method in order to create a new usable version of a given extension instance.<br> The copy can be safely used in
       * conjunction with a new websocket connection.
       *
       * @return a copy of the extension
       * @since 1.3.5
       */
      IExtension copyInstance();
  
      /**
       * Cleaning up internal stats when the draft gets reset.
       *
       * @since 1.3.5
       */
      void reset();
  
      /**
       * Return a string which should contain the class name as well as additional information about the current configurations for this
       * extension (DEBUG purposes)
       *
       * @return a string containing the class name as well as additional information
       * @since 1.3.5
       */
      String toString();
  }
  