001/* 002 * Copyright 2002-2018 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.messaging.simp; 018 019import org.springframework.core.NamedThreadLocal; 020import org.springframework.lang.Nullable; 021import org.springframework.messaging.Message; 022 023/** 024 * Holder class to expose SiMP attributes associated with a session (e.g. WebSocket) 025 * in the form of a thread-bound {@link SimpAttributes} object. 026 * 027 * @author Rossen Stoyanchev 028 * @since 4.1 029 */ 030public abstract class SimpAttributesContextHolder { 031 032 private static final ThreadLocal<SimpAttributes> attributesHolder = 033 new NamedThreadLocal<>("SiMP session attributes"); 034 035 036 /** 037 * Reset the SimpAttributes for the current thread. 038 */ 039 public static void resetAttributes() { 040 attributesHolder.remove(); 041 } 042 043 /** 044 * Bind the given SimpAttributes to the current thread. 045 * @param attributes the RequestAttributes to expose 046 */ 047 public static void setAttributes(@Nullable SimpAttributes attributes) { 048 if (attributes != null) { 049 attributesHolder.set(attributes); 050 } 051 else { 052 resetAttributes(); 053 } 054 } 055 056 /** 057 * Extract the SiMP session attributes from the given message, wrap them in 058 * a {@link SimpAttributes} instance and bind it to the current thread. 059 * @param message the message to extract session attributes from 060 */ 061 public static void setAttributesFromMessage(Message<?> message) { 062 setAttributes(SimpAttributes.fromMessage(message)); 063 } 064 065 /** 066 * Return the SimpAttributes currently bound to the thread. 067 * @return the attributes or {@code null} if not bound 068 */ 069 @Nullable 070 public static SimpAttributes getAttributes() { 071 return attributesHolder.get(); 072 } 073 074 /** 075 * Return the SimpAttributes currently bound to the thread or raise an 076 * {@link java.lang.IllegalStateException} if none are bound. 077 * @return the attributes, never {@code null} 078 * @throws java.lang.IllegalStateException if attributes are not bound 079 */ 080 public static SimpAttributes currentAttributes() throws IllegalStateException { 081 SimpAttributes attributes = getAttributes(); 082 if (attributes == null) { 083 throw new IllegalStateException("No thread-bound SimpAttributes found. " + 084 "Your code is probably not processing a client message and executing in " + 085 "message-handling methods invoked by the SimpAnnotationMethodMessageHandler?"); 086 } 087 return attributes; 088 } 089 090}