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Java > Open Source Codes > javax > servlet > jsp > JspPage


1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package javax.servlet.jsp;
18
19 import javax.servlet.*;
20
21 /**
22  * The JspPage interface describes the generic interaction that a JSP Page
23  * Implementation class must satisfy; pages that use the HTTP protocol
24  * are described by the HttpJspPage interface.
25  *
26  * <p><B>Two plus One Methods</B>
27  * <p>
28  * The interface defines a protocol with 3 methods; only two of
29  * them: jspInit() and jspDestroy() are part of this interface as
30  * the signature of the third method: _jspService() depends on
31  * the specific protocol used and cannot be expressed in a generic
32  * way in Java.
33  * <p>
34  * A class implementing this interface is responsible for invoking
35  * the above methods at the appropriate time based on the
36  * corresponding Servlet-based method invocations.
37  * <p>
38  * The jspInit() and jspDestroy() methods can be defined by a JSP
39  * author, but the _jspService() method is defined automatically
40  * by the JSP processor based on the contents of the JSP page.
41  *
42  * <p><B>_jspService()</B>
43  * <p>
44  * The _jspService()method corresponds to the body of the JSP page. This
45  * method is defined automatically by the JSP container and should never
46  * be defined by the JSP page author.
47  * <p>
48  * If a superclass is specified using the extends attribute, that
49  * superclass may choose to perform some actions in its service() method
50  * before or after calling the _jspService() method. See using the extends
51  * attribute in the JSP_Engine chapter of the JSP specification.
52  * <p>
53  * The specific signature depends on the protocol supported by the JSP page.
54  *
55  * <pre>
56  * public void _jspService(<em>ServletRequestSubtype</em> request,
57  * <em>ServletResponseSubtype</em> response)
58  * throws ServletException, IOException;
59  * </pre>
60  */
61
62
63 public interface JspPage extends Servlet {
64
65     /**
66      * The jspInit() method is invoked when the JSP page is initialized. It
67      * is the responsibility of the JSP implementation (and of the class
68      * mentioned by the extends attribute, if present) that at this point
69      * invocations to the getServletConfig() method will return the desired
70      * value.
71      *
72      * A JSP page can override this method by including a definition for it
73      * in a declaration element.
74      *
75      * A JSP page should redefine the init() method from Servlet.
76      */
77     public void jspInit();
78
79     /**
80      * The jspDestroy() method is invoked when the JSP page is about to be
81      * destroyed.
82      *
83      * A JSP page can override this method by including a definition for it
84      * in a declaration element.
85      *
86      * A JSP page should redefine the destroy() method from Servlet.
87      */
88     public void jspDestroy();
89
90 }
91
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