1 /*
2 * $Source$
3 * $Revision$
4 *
5 * Copyright (C) 2000 Tim Joyce
6 *
7 * Part of Melati (http://melati.org), a framework for the rapid
8 * development of clean, maintainable web applications.
9 *
10 * Melati is free software; Permission is granted to copy, distribute
11 * and/or modify this software under the terms either:
12 *
13 * a) the GNU General Public License as published by the Free Software
14 * Foundation; either version 2 of the License, or (at your option)
15 * any later version,
16 *
17 * or
18 *
19 * b) any version of the Melati Software License, as published
20 * at http://melati.org
21 *
22 * You should have received a copy of the GNU General Public License and
23 * the Melati Software License along with this program;
24 * if not, write to the Free Software Foundation, Inc.,
25 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
26 * GNU General Public License and visit http://melati.org to obtain the
27 * Melati Software License.
28 *
29 * Feel free to contact the Developers of Melati (http://melati.org),
30 * if you would like to work out a different arrangement than the options
31 * outlined here. It is our intention to allow Melati to be used by as
32 * wide an audience as possible.
33 *
34 * This program is distributed in the hope that it will be useful,
35 * but WITHOUT ANY WARRANTY; without even the implied warranty of
36 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
37 * GNU General Public License for more details.
38 *
39 * Contact details for copyright holder:
40 *
41 * Tim Joyce <timj At paneris.org>
42 * http://paneris.org/
43 * 68 Sandbanks Rd, Poole, Dorset. BH14 8BY. UK
44 */
45
46 package org.melati.template;
47
48 import java.io.IOException;
49 import java.io.PrintWriter;
50
51 import javax.servlet.http.HttpServletResponse;
52 import javax.servlet.http.HttpServlet;
53
54 import org.melati.Melati;
55 import org.melati.MelatiConfig;
56 import org.melati.util.MelatiIOException;
57 import org.melati.util.MelatiWriter;
58 import org.melati.util.MelatiSimpleWriter;
59 import org.melati.util.MelatiStringWriter;
60 import org.melati.util.MelatiBufferedWriter;
61
62
63 /**
64 * The <code>null</code> {@link ServletTemplateEngine}.
65 *
66 * @author Tim Joyce
67 */
68 public class NoTemplateEngine extends AbstractTemplateEngine implements ServletTemplateEngine {
69
70 private String message =
71 "No Template engine is Configured, please specify an engine in " +
72 "org.melati.MelatiConfig.properties";
73
74 /**
75 * Constructor.
76 */
77 public NoTemplateEngine() {
78 super();
79 }
80
81 /**
82 * Construct a null Engine.
83 *
84 * @param config a {@link MelatiConfig}
85 */
86 public void init(MelatiConfig config) {
87 // we don't throw an exception here as it gets hidden away, rather
88 // it is better to wait until expandTemplate or getParameters, as
89 // that produces a nice
90 // exception to the browser
91 }
92
93 /**
94 * Construct a new Engine for use in a servlet environment.
95 *
96 * @see org.melati.servlet.TemplateServlet
97 * @param melatiConfig a {@link MelatiConfig}
98 * @param servlet the servlet we are within
99 * @throws TemplateEngineException if any problem occurs with the engine
100 */
101 public void init(MelatiConfig melatiConfig, HttpServlet servlet)
102 throws TemplateEngineException {
103 init(melatiConfig);
104 }
105
106 /**
107 * Throw exception.
108 *
109 * @throws TemplateEngineException if any problem occurs with the engine
110 * @return a {@link TemplateContext}
111 */
112 public TemplateContext getTemplateContext()
113 throws TemplateEngineException {
114 throw new TemplateEngineException(message);
115 }
116
117 /**
118 * Throw exception.
119 *
120 * @param melati the {@link Melati}
121 * @throws TemplateEngineException always
122 * @return an exception
123 */
124 public ServletTemplateContext getServletTemplateContext(Melati melati)
125 throws TemplateEngineException {
126 throw new TemplateEngineException(message);
127 }
128
129 /**
130 * The name of the template engine (used to find the templets).
131 * @return the name of the current configured template engine
132 */
133 public String getName() {
134 return "none";
135 }
136
137 /**
138 * @return the extension of the templates used by this template engine
139 */
140 public String templateExtension() {
141 return ".none";
142 }
143
144 /**
145 * Get a template given its name.
146 *
147 * @param templateName the name of the template to find
148 * @return a template
149 */
150 public Template template(String templateName) {
151 throw new TemplateEngineException(
152 "The template " +
153 templateName + " could not be found because you have not configured a template engine.");
154 }
155
156 /**
157 * Expand the Template against the context.
158 *
159 * @param out a {@link MelatiWriter} to output on
160 * @param templateName the name of the template to expand
161 * @param templateContext the {@link ServletTemplateContext} to expand
162 * the template against
163 * @throws TemplateEngineException if invoked
164 */
165 public void expandTemplate(MelatiWriter out, String templateName,
166 TemplateContext templateContext)
167 throws TemplateEngineException {
168 throw new TemplateEngineException(message);
169 }
170
171
172 /**
173 * Expand the Template against the context.
174 *
175 * @param out a {@link MelatiWriter} to output on
176 * @param melatiTemplate the {@link Template} to expand
177 * @param templateContext the {@link ServletTemplateContext} to expand
178 * the template against
179 * @throws TemplateEngineException if invoked
180 */
181 public void expandTemplate(MelatiWriter out, Template melatiTemplate,
182 TemplateContext templateContext)
183 throws TemplateEngineException {
184 throw new TemplateEngineException(message);
185 }
186
187 /**
188 * Expand the Template against the context.
189 *
190 * @param melatiTemplate the {@link Template} to expand
191 * @param templateContext the {@link ServletTemplateContext} to expand
192 * the template against
193 * @throws TemplateEngineException if invoked
194 * {@inheritDoc}
195 * @see org.melati.template.TemplateEngine#expandedTemplate
196 * (org.melati.template.Template, org.melati.template.TemplateContext)
197 */
198 public String expandedTemplate(Template melatiTemplate,
199 TemplateContext templateContext)
200 throws TemplateEngineException {
201 throw new TemplateEngineException(message);
202 }
203
204 /**
205 * @param response the <code>HttpServletResponse</code> that this
206 * writer will be part of
207 * @param buffered whether the writer should be buffered
208 * @return a {@link MelatiWriter}
209 * appropriate for this engine.
210 */
211 public MelatiWriter getServletWriter(HttpServletResponse response,
212 boolean buffered) {
213 PrintWriter printWriter = null;
214 try {
215 printWriter = response.getWriter();
216 } catch (IOException e) {
217 throw new MelatiIOException(e);
218 }
219 if (buffered)
220 return new MelatiBufferedWriter(printWriter);
221 else
222 return new MelatiSimpleWriter(printWriter);
223 }
224
225 /**
226 * Return a {@link MelatiStringWriter}.
227 * {@inheritDoc}
228 * @see org.melati.template.TemplateEngine#getStringWriter()
229 * @see Melati#getStringWriter()
230 */
231 public MelatiStringWriter getStringWriter() {
232 return new MelatiStringWriter();
233 }
234
235 /**
236 * Get the underlying engine.
237 *
238 * @return 'none'
239 */
240 public Object getEngine() {
241 return "none";
242 }
243
244 }