[66] | 1 | /* |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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| 3 | * contributor license agreements. See the NOTICE file distributed with |
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| 4 | * this work for additional information regarding copyright ownership. |
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| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
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| 6 | * (the "License"); you may not use this file except in compliance with |
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| 7 | * the License. You may obtain a copy of the License at |
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| 8 | * |
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| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 10 | * |
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| 11 | * Unless required by applicable law or agreed to in writing, software |
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| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 14 | * See the License for the specific language governing permissions and |
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| 15 | * limitations under the License. |
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| 16 | */ |
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| 17 | |
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| 18 | package listeners; |
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| 19 | |
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| 20 | |
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| 21 | import javax.servlet.ServletContext; |
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| 22 | import javax.servlet.ServletContextAttributeEvent; |
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| 23 | import javax.servlet.ServletContextAttributeListener; |
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| 24 | import javax.servlet.ServletContextEvent; |
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| 25 | import javax.servlet.ServletContextListener; |
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| 26 | |
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| 27 | |
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| 28 | /** |
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| 29 | * Example listener for context-related application events, which were |
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| 30 | * introduced in the 2.3 version of the Servlet API. This listener |
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| 31 | * merely documents the occurrence of such events in the application log |
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| 32 | * associated with our servlet context. |
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| 33 | * |
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| 34 | * @author Craig R. McClanahan |
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| 35 | * @version $Revision: 500674 $ $Date: 2007-01-28 00:15:00 +0100 (Sun, 28 Jan 2007) $ |
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| 36 | */ |
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| 37 | |
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| 38 | public final class ContextListener |
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| 39 | implements ServletContextAttributeListener, ServletContextListener { |
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| 40 | |
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| 41 | |
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| 42 | // ----------------------------------------------------- Instance Variables |
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| 43 | |
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| 44 | |
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| 45 | /** |
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| 46 | * The servlet context with which we are associated. |
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| 47 | */ |
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| 48 | private ServletContext context = null; |
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| 49 | |
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| 50 | |
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| 51 | // --------------------------------------------------------- Public Methods |
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| 52 | |
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| 53 | |
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| 54 | /** |
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| 55 | * Record the fact that a servlet context attribute was added. |
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| 56 | * |
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| 57 | * @param event The servlet context attribute event |
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| 58 | */ |
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| 59 | public void attributeAdded(ServletContextAttributeEvent event) { |
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| 60 | |
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| 61 | log("attributeAdded('" + event.getName() + "', '" + |
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| 62 | event.getValue() + "')"); |
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| 63 | |
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| 64 | } |
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| 65 | |
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| 66 | |
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| 67 | /** |
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| 68 | * Record the fact that a servlet context attribute was removed. |
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| 69 | * |
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| 70 | * @param event The servlet context attribute event |
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| 71 | */ |
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| 72 | public void attributeRemoved(ServletContextAttributeEvent event) { |
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| 73 | |
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| 74 | log("attributeRemoved('" + event.getName() + "', '" + |
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| 75 | event.getValue() + "')"); |
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| 76 | |
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| 77 | } |
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| 78 | |
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| 79 | |
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| 80 | /** |
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| 81 | * Record the fact that a servlet context attribute was replaced. |
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| 82 | * |
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| 83 | * @param event The servlet context attribute event |
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| 84 | */ |
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| 85 | public void attributeReplaced(ServletContextAttributeEvent event) { |
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| 86 | |
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| 87 | log("attributeReplaced('" + event.getName() + "', '" + |
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| 88 | event.getValue() + "')"); |
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| 89 | |
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| 90 | } |
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| 91 | |
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| 92 | |
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| 93 | /** |
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| 94 | * Record the fact that this web application has been destroyed. |
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| 95 | * |
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| 96 | * @param event The servlet context event |
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| 97 | */ |
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| 98 | public void contextDestroyed(ServletContextEvent event) { |
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| 99 | |
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| 100 | log("contextDestroyed()"); |
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| 101 | this.context = null; |
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| 102 | |
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| 103 | } |
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| 104 | |
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| 105 | |
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| 106 | /** |
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| 107 | * Record the fact that this web application has been initialized. |
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| 108 | * |
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| 109 | * @param event The servlet context event |
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| 110 | */ |
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| 111 | public void contextInitialized(ServletContextEvent event) { |
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| 112 | |
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| 113 | this.context = event.getServletContext(); |
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| 114 | log("contextInitialized()"); |
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| 115 | |
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| 116 | } |
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| 117 | |
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| 118 | |
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| 119 | // -------------------------------------------------------- Private Methods |
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| 120 | |
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| 121 | |
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| 122 | /** |
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| 123 | * Log a message to the servlet context application log. |
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| 124 | * |
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| 125 | * @param message Message to be logged |
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| 126 | */ |
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| 127 | private void log(String message) { |
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| 128 | |
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| 129 | if (context != null) |
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| 130 | context.log("ContextListener: " + message); |
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| 131 | else |
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| 132 | System.out.println("ContextListener: " + message); |
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| 133 | |
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| 134 | } |
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| 135 | |
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| 136 | } |
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