1 /** 2 * Copyright (C) 2007 Google Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.inject.servlet; 18 19 import com.google.inject.Injector; 20 21 import java.lang.ref.WeakReference; 22 23 import javax.servlet.ServletContext; 24 import javax.servlet.ServletContextEvent; 25 import javax.servlet.ServletContextListener; 26 27 /** 28 * As of Guice 2.0 you can still use (your subclasses of) {@code GuiceServletContextListener} 29 * class as a logical place to create and configure your injector. This will ensure the injector 30 * is created when the web application is deployed. 31 * 32 * @author Kevin Bourrillion (kevinb@google.com) 33 * @since 2.0 34 */ 35 public abstract class GuiceServletContextListener 36 implements ServletContextListener { 37 38 static final String INJECTOR_NAME = Injector.class.getName(); 39 contextInitialized(ServletContextEvent servletContextEvent)40 public void contextInitialized(ServletContextEvent servletContextEvent) { 41 final ServletContext servletContext = servletContextEvent.getServletContext(); 42 43 // Set the Servletcontext early for those people who are using this class. 44 // NOTE(dhanji): This use of the servletContext is deprecated. 45 GuiceFilter.servletContext = new WeakReference<ServletContext>(servletContext); 46 47 Injector injector = getInjector(); 48 injector.getInstance(InternalServletModule.BackwardsCompatibleServletContextProvider.class) 49 .set(servletContext); 50 servletContext.setAttribute(INJECTOR_NAME, injector); 51 } 52 contextDestroyed(ServletContextEvent servletContextEvent)53 public void contextDestroyed(ServletContextEvent servletContextEvent) { 54 ServletContext servletContext = servletContextEvent.getServletContext(); 55 servletContext.removeAttribute(INJECTOR_NAME); 56 } 57 58 /** 59 * Override this method to create (or otherwise obtain a reference to) your 60 * injector. 61 */ getInjector()62 protected abstract Injector getInjector(); 63 } 64