1 /*
2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/define/DynamicTagLibrary.java,v 1.6 2002/08/01 09:53:18 jstrachan Exp $
3 * $Revision: 1.6 $
4 * $Date: 2002/08/01 09:53:18 $
5 *
6 * ====================================================================
7 *
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 *
25 * 3. The end-user documentation included with the redistribution, if
26 * any, must include the following acknowlegement:
27 * "This product includes software developed by the
28 * Apache Software Foundation (http://www.apache.org/)."
29 * Alternately, this acknowlegement may appear in the software itself,
30 * if and wherever such third-party acknowlegements normally appear.
31 *
32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
33 * Foundation" must not be used to endorse or promote products derived
34 * from this software without prior written permission. For written
35 * permission, please contact apache@apache.org.
36 *
37 * 5. Products derived from this software may not be called "Apache"
38 * nor may "Apache" appear in their names without prior written
39 * permission of the Apache Group.
40 *
41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * SUCH DAMAGE.
53 * ====================================================================
54 *
55 * This software consists of voluntary contributions made by many
56 * individuals on behalf of the Apache Software Foundation. For more
57 * information on the Apache Software Foundation, please see
58 * <http://www.apache.org/>.
59 *
60 * $Id: DynamicTagLibrary.java,v 1.6 2002/08/01 09:53:18 jstrachan Exp $
61 */
62 package org.apache.commons.jelly.impl;
63
64 import java.util.HashMap;
65 import java.util.Map;
66
67 import org.apache.commons.jelly.DynaTag;
68 import org.apache.commons.jelly.Script;
69 import org.apache.commons.jelly.Tag;
70 import org.apache.commons.jelly.TagLibrary;
71 import org.apache.commons.jelly.impl.DynaTagScript;
72 import org.apache.commons.jelly.impl.TagFactory;
73 import org.apache.commons.jelly.impl.TagScript;
74
75 import org.xml.sax.Attributes;
76
77 /***
78 * <p><code>DynamicTagLibrary</code> represents a TagLibrary which
79 * gets created by running a Jelly script.</p>
80 *
81 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
82 * @version $Revision: 1.6 $
83 */
84 public class DynamicTagLibrary extends TagLibrary {
85
86 private String uri;
87 private Map templates = new HashMap();
88 private TagLibrary parent;
89
90 public DynamicTagLibrary() {
91 }
92
93 public DynamicTagLibrary(String uri) {
94 this.uri = uri;
95 }
96
97 /*** Creates a new script to execute the given tag name and attributes */
98 public TagScript createTagScript(final String name, final Attributes attributes)
99 throws Exception {
100
101 return new DynaTagScript(
102 new TagFactory() {
103 public Tag createTag() throws Exception {
104 Tag answer = DynamicTagLibrary.this.createTag(name);
105
106 // delegate to my parent instead
107 if ( answer == null && parent != null ) {
108 return parent.createTag(name, attributes);
109 }
110 return answer;
111 }
112 }
113 );
114 }
115
116 /*** Creates a new Tag for the given tag name if it exists */
117 public Tag createTag(String name)
118 throws Exception {
119
120 Object value = templates.get(name);
121 if ( value instanceof Script ) {
122 Script template = (Script) value;
123 return new DynamicTag(template);
124 }
125 else if ( value instanceof TagFactory ) {
126 TagFactory factory = (TagFactory) value;
127 return factory.createTag();
128 }
129 return null;
130 }
131
132 /***
133 * Creates a new tag with the given name and template
134 */
135 public void registerDynamicTag(String name, Script template) {
136 templates.put(name, template);
137 }
138
139 /***
140 * Creates a new Jelly Bean Tag with the given name
141 */
142 public void registerBeanTag(String name, TagFactory factory) {
143 templates.put(name, factory);
144 }
145
146 // Properties
147 //-------------------------------------------------------------------------
148 public String getUri() {
149 return uri;
150 }
151
152 public void setUri(String uri) {
153 this.uri = uri;
154 }
155
156
157 /***
158 * Returns the parent library which will be used to resolve unknown tags.
159 * @return TagLibrary
160 */
161 public TagLibrary getParent() {
162 return parent;
163 }
164
165 /***
166 * Sets the parent to inherit tags from that are not defined in this library.
167 * @param parent The parent to set
168 */
169 public void setParent(TagLibrary parent) {
170 this.parent = parent;
171 }
172
173 }
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