001/* 002 * Copyright 2002-2019 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.context.support; 018 019import java.util.HashMap; 020import java.util.Map; 021 022import org.apache.commons.logging.Log; 023import org.apache.commons.logging.LogFactory; 024 025import org.springframework.beans.factory.ObjectFactory; 026import org.springframework.beans.factory.config.Scope; 027import org.springframework.core.NamedThreadLocal; 028 029/** 030 * A simple thread-backed {@link Scope} implementation. 031 * 032 * <p><b>NOTE:</b> This thread scope is not registered by default in common contexts. 033 * Instead, you need to explicitly assign it to a scope key in your setup, either through 034 * {@link org.springframework.beans.factory.config.ConfigurableBeanFactory#registerScope} 035 * or through a {@link org.springframework.beans.factory.config.CustomScopeConfigurer} bean. 036 * 037 * <p>{@code SimpleThreadScope} <em>does not clean up any objects</em> associated with it. 038 * It is therefore typically preferable to use a request-bound scope implementation such 039 * as {@code org.springframework.web.context.request.RequestScope} in web environments, 040 * implementing the full lifecycle for scoped attributes (including reliable destruction). 041 * 042 * <p>For an implementation of a thread-based {@code Scope} with support for destruction 043 * callbacks, refer to 044 * <a href="https://www.springbyexample.org/examples/custom-thread-scope-module.html">Spring by Example</a>. 045 * 046 * <p>Thanks to Eugene Kuleshov for submitting the original prototype for a thread scope! 047 * 048 * @author Arjen Poutsma 049 * @author Juergen Hoeller 050 * @since 3.0 051 * @see org.springframework.web.context.request.RequestScope 052 */ 053public class SimpleThreadScope implements Scope { 054 055 private static final Log logger = LogFactory.getLog(SimpleThreadScope.class); 056 057 private final ThreadLocal<Map<String, Object>> threadScope = 058 new NamedThreadLocal<Map<String, Object>>("SimpleThreadScope") { 059 @Override 060 protected Map<String, Object> initialValue() { 061 return new HashMap<String, Object>(); 062 } 063 }; 064 065 066 @Override 067 public Object get(String name, ObjectFactory<?> objectFactory) { 068 Map<String, Object> scope = this.threadScope.get(); 069 Object scopedObject = scope.get(name); 070 if (scopedObject == null) { 071 scopedObject = objectFactory.getObject(); 072 scope.put(name, scopedObject); 073 } 074 return scopedObject; 075 } 076 077 @Override 078 public Object remove(String name) { 079 Map<String, Object> scope = this.threadScope.get(); 080 return scope.remove(name); 081 } 082 083 @Override 084 public void registerDestructionCallback(String name, Runnable callback) { 085 logger.warn("SimpleThreadScope does not support destruction callbacks. " + 086 "Consider using RequestScope in a web environment."); 087 } 088 089 @Override 090 public Object resolveContextualObject(String key) { 091 return null; 092 } 093 094 @Override 095 public String getConversationId() { 096 return Thread.currentThread().getName(); 097 } 098 099}