org.springframework.web.socket.WebSocketHandler Maven / Gradle / Ivy
/*
* Copyright 2002-2013 the original author or authors.
*
* Licensed 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
*
* https://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.springframework.web.socket;
/**
* A handler for WebSocket messages and lifecycle events.
*
* Implementations of this interface are encouraged to handle exceptions locally where
* it makes sense or alternatively let the exception bubble up in which case by default
* the exception is logged and the session closed with
* {@link CloseStatus#SERVER_ERROR SERVER_ERROR(1011)}. The exception handling
* strategy is provided by
* {@link org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator
* ExceptionWebSocketHandlerDecorator} and it can be customized or replaced by decorating
* the {@link WebSocketHandler} with a different decorator.
*
* @author Rossen Stoyanchev
* @author Phillip Webb
* @since 4.0
*/
public interface WebSocketHandler {
/**
* Invoked after WebSocket negotiation has succeeded and the WebSocket connection is
* opened and ready for use.
* @throws Exception this method can handle or propagate exceptions; see class-level
* Javadoc for details.
*/
void afterConnectionEstablished(WebSocketSession session) throws Exception;
/**
* Invoked when a new WebSocket message arrives.
* @throws Exception this method can handle or propagate exceptions; see class-level
* Javadoc for details.
*/
void handleMessage(WebSocketSession session, WebSocketMessage message) throws Exception;
/**
* Handle an error from the underlying WebSocket message transport.
* @throws Exception this method can handle or propagate exceptions; see class-level
* Javadoc for details.
*/
void handleTransportError(WebSocketSession session, Throwable exception) throws Exception;
/**
* Invoked after the WebSocket connection has been closed by either side, or after a
* transport error has occurred. Although the session may technically still be open,
* depending on the underlying implementation, sending messages at this point is
* discouraged and most likely will not succeed.
* @throws Exception this method can handle or propagate exceptions; see class-level
* Javadoc for details.
*/
void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception;
/**
* Whether the WebSocketHandler handles partial messages. If this flag is set to
* {@code true} and the underlying WebSocket server supports partial messages,
* then a large WebSocket message, or one of an unknown size may be split and
* maybe received over multiple calls to
* {@link #handleMessage(WebSocketSession, WebSocketMessage)}. The flag
* {@link org.springframework.web.socket.WebSocketMessage#isLast()} indicates if
* the message is partial and whether it is the last part.
*/
boolean supportsPartialMessages();
}