1 package org.apache.velocity.app.event;
2
3 import org.apache.velocity.context.Context;
4 import org.apache.velocity.util.ContextAware;
5
6 /*
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements. See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership. The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License. You may obtain a copy of the License at
14 *
15 * http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied. See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 */
24
25 /**
26 * Event handler for include type directives (e.g. <code>#include()</code>, <code>#parse()</code>)
27 * Allows the developer to modify the path of the resource returned.
28 *
29 * @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
30 * @version $Id: IncludeEventHandler.java 685685 2008-08-13 21:43:27Z nbubna $
31 * @since 1.5
32 */
33 public interface IncludeEventHandler extends EventHandler
34 {
35 /**
36 * Called when an include-type directive is encountered (
37 * <code>#include</code> or <code>#parse</code>). May modify the path
38 * of the resource to be included or may block the include entirely. All the
39 * registered IncludeEventHandlers are called unless null is returned. If
40 * none are registered the template at the includeResourcePath is retrieved.
41 *
42 * @param includeResourcePath the path as given in the include directive.
43 * @param currentResourcePath the path of the currently rendering template that includes the
44 * include directive.
45 * @param directiveName name of the directive used to include the resource. (With the
46 * standard directives this is either "parse" or "include").
47 *
48 * @return a new resource path for the directive, or null to block the
49 * include from occurring.
50 */
51 public String includeEvent( String includeResourcePath, String currentResourcePath, String directiveName );
52
53
54
55 /**
56 * Defines the execution strategy for includeEvent
57 */
58 static class IncludeEventExecutor implements EventHandlerMethodExecutor
59 {
60 private Context context;
61 private String includeResourcePath;
62 private String currentResourcePath;
63 private String directiveName;
64
65 private boolean executed = false;
66
67 IncludeEventExecutor(
68 Context context,
69 String includeResourcePath,
70 String currentResourcePath,
71 String directiveName)
72 {
73 this.context = context;
74 this.includeResourcePath = includeResourcePath;
75 this.currentResourcePath = currentResourcePath;
76 this.directiveName = directiveName;
77 }
78
79 /**
80 * Call the method includeEvent()
81 *
82 * @param handler call the appropriate method on this handler
83 */
84 public void execute(EventHandler handler)
85 {
86 IncludeEventHandler eh = (IncludeEventHandler) handler;
87
88 if (eh instanceof ContextAware)
89 ((ContextAware) eh).setContext(context);
90
91 executed = true;
92 includeResourcePath = ((IncludeEventHandler) handler)
93 .includeEvent(includeResourcePath, currentResourcePath, directiveName);
94 }
95
96 public Object getReturnValue()
97 {
98 return includeResourcePath;
99 }
100
101 public boolean isDone()
102 {
103 return executed && (includeResourcePath == null);
104 }
105
106
107 }
108
109 }