001/*
002 * Copyright 2002-2013 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.socket.handler;
018
019import org.springframework.util.Assert;
020import org.springframework.web.socket.CloseStatus;
021import org.springframework.web.socket.WebSocketHandler;
022import org.springframework.web.socket.WebSocketMessage;
023import org.springframework.web.socket.WebSocketSession;
024
025/**
026 * Wraps another {@link org.springframework.web.socket.WebSocketHandler}
027 * instance and delegates to it.
028 *
029 * <p>Also provides a {@link #getDelegate()} method to return the decorated
030 * handler as well as a {@link #getLastHandler()} method to go through all nested
031 * delegates and return the "last" handler.
032 *
033 * @author Rossen Stoyanchev
034 * @since 4.0
035 */
036public class WebSocketHandlerDecorator implements WebSocketHandler {
037
038        private final WebSocketHandler delegate;
039
040
041        public WebSocketHandlerDecorator(WebSocketHandler delegate) {
042                Assert.notNull(delegate, "Delegate must not be null");
043                this.delegate = delegate;
044        }
045
046
047        public WebSocketHandler getDelegate() {
048                return this.delegate;
049        }
050
051        public WebSocketHandler getLastHandler() {
052                WebSocketHandler result = this.delegate;
053                while (result instanceof WebSocketHandlerDecorator) {
054                        result = ((WebSocketHandlerDecorator) result).getDelegate();
055                }
056                return result;
057        }
058
059        public static WebSocketHandler unwrap(WebSocketHandler handler) {
060                if (handler instanceof WebSocketHandlerDecorator) {
061                        return ((WebSocketHandlerDecorator) handler).getLastHandler();
062                }
063                else {
064                        return handler;
065                }
066        }
067
068        @Override
069        public void afterConnectionEstablished(WebSocketSession session) throws Exception {
070                this.delegate.afterConnectionEstablished(session);
071        }
072
073        @Override
074        public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
075                this.delegate.handleMessage(session, message);
076        }
077
078        @Override
079        public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
080                this.delegate.handleTransportError(session, exception);
081        }
082
083        @Override
084        public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
085                this.delegate.afterConnectionClosed(session, closeStatus);
086        }
087
088        @Override
089        public boolean supportsPartialMessages() {
090                return this.delegate.supportsPartialMessages();
091        }
092
093        @Override
094        public String toString() {
095                return getClass().getSimpleName() + " [delegate=" + this.delegate + "]";
096        }
097
098}