Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
AbstractPoemApp |
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| 3.0;3 | ||||
AbstractPoemApp$1 |
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| 3.0;3 |
1 | /* | |
2 | * $Source: /usr/cvsroot/melati/melati/src/site/resources/withWebmacro/org.melati.app.AbstractPoemApp.html,v $ | |
3 | * $Revision: 1.1 $ | |
4 | * | |
5 | * Copyright (C) 2005 Tim Pizey | |
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 Pizey <timp At paneris.org> | |
42 | * http://paneris.org/~timp | |
43 | */ | |
44 | ||
45 | package org.melati.app; | |
46 | ||
47 | ||
48 | import java.io.IOException; | |
49 | ||
50 | import org.melati.Melati; | |
51 | import org.melati.PoemContext; | |
52 | import org.melati.poem.AccessPoemException; | |
53 | import org.melati.poem.PoemDatabaseFactory; | |
54 | import org.melati.poem.PoemThread; | |
55 | import org.melati.poem.PoemTask; | |
56 | import org.melati.poem.AccessToken; | |
57 | import org.melati.poem.util.ArrayUtils; | |
58 | import org.melati.util.ConfigException; | |
59 | import org.melati.util.MelatiException; | |
60 | import org.melati.util.UnexpectedExceptionException; | |
61 | ||
62 | /** | |
63 | * Base class to use Poem as an application. | |
64 | * | |
65 | * <p> | |
66 | * Simply extend this class and override the {@link #doPoemRequest} method. | |
67 | * If you are going to use a template engine look at {@link AbstractTemplateApp}. | |
68 | * </p> | |
69 | * | |
70 | * <UL> | |
71 | * <LI> | |
72 | * The command line arguments are expected in the following order: | |
73 | * <BLOCKQUOTE><TT> | |
74 | * <BR>db | |
75 | * <BR>db method | |
76 | * <BR>db table method | |
77 | * <BR>db table troid method | |
78 | * </TT></BLOCKQUOTE> | |
79 | * | |
80 | * these components are broken out of the command line arguments and passed to | |
81 | * your application code in the {@link Melati} parameter. | |
82 | * | |
83 | * <TABLE> | |
84 | * <TR> | |
85 | * <TD><TT><I>db</I></TT></TD> | |
86 | * <TD> | |
87 | * The first argument is taken to be the `logical name' | |
88 | * of the POEM database to which the servlet should connect. It | |
89 | * is mapped onto JDBC connection details via the config file | |
90 | * <TT>org.melati.LogicalDatabase.properties</TT>, of which there is an | |
91 | * example in the source tree. This is automatically made available in | |
92 | * templates as <TT>$melati.Database</TT>. | |
93 | * </TD> | |
94 | * <TR> | |
95 | * <TD><TT><I>table</I></TT></TD> | |
96 | * <TD> | |
97 | * The name of a table to work on: | |
98 | * perhaps it is meant to list its contents. This is automatically | |
99 | * made available in templates as <TT>$melati.Table</TT>. | |
100 | * </TD> | |
101 | * </TR> | |
102 | * <TR> | |
103 | * <TD><TT><I>troid</I></TT></TD> | |
104 | * <TD> | |
105 | * The POEM `troid' (table row identifier, or row-unique integer) of a | |
106 | * row within a <TT><I>table</I></TT>. | |
107 | * This is automatically made | |
108 | * available in templates as <TT>$melati.Object</TT>. | |
109 | * </TD> | |
110 | * </TR> | |
111 | * <TR> | |
112 | * <TD><TT><I>method</I></TT></TD> | |
113 | * <TD> | |
114 | * A freeform string telling your servlet what it is meant to do. This | |
115 | * is automatically made available in templates as | |
116 | * <TT>$melati.Method</TT>. | |
117 | * </TD> | |
118 | * </TR> | |
119 | * </TABLE> | |
120 | * | |
121 | * <LI> | |
122 | * You can change the way these things are determined by overriding | |
123 | * {@link #poemContext}. | |
124 | * | |
125 | * <LI> | |
126 | * Any POEM database operations you perform will be done with the access | |
127 | * rights of the POEM <TT>User</TT> associated with the POEM session. If | |
128 | * there is no established session, the current user will be set to | |
129 | * the default `guest' user. If this method terminates with an | |
130 | * <TT>AccessPoemException</TT>, indicating that you have attempted something | |
131 | * which you aren't entitled to do, the user will be prompted to log in, and | |
132 | * the original request will be retried. The precise mechanism used for | |
133 | * login is <A HREF=#loginmechanism>configurable</A>. | |
134 | * | |
135 | * <LI> | |
136 | * No changes made to the database by other concurrently executing threads | |
137 | * will be visible to you (in the sense that once you have seen a particular | |
138 | * version of a record, you will always subsequently see the same one), and | |
139 | * your own changes will not be made permanent until this method completes | |
140 | * successfully or you perform an explicit <TT>PoemThread.commit()</TT>. If | |
141 | * it terminates with an exception or you issue a | |
142 | * <TT>PoemThread.rollback()</TT>, your changes will be lost. | |
143 | * | |
144 | * <LI> | |
145 | * <A NAME=loginmechanism></A>It is possible to configure how your | |
146 | * <TT>PoemApp</TT>-derived applications implement user login. If the | |
147 | * properties file <TT>org.melati.MelatiApp.properties</TT> | |
148 | * exists and contains a setting | |
149 | * <TT>org.melati.MelatiApp.accessHandler=<I>foo</I></TT>, then | |
150 | * <TT><I>foo</I></TT> is taken to be the name of a class implementing the | |
151 | * <TT>AccessHandler</TT> interface. | |
152 | * </UL> | |
153 | * | |
154 | * If you do not need access handling then set your accessHandler to | |
155 | * <tt>org.melati.login.OpenAccessHandler</tt>. | |
156 | * If you do need access handling then set your accessHandler to | |
157 | * <tt>org.melati.login.CommandLineAccessHandler</tt>. | |
158 | * However this is not extremely secure, as the user could potentially | |
159 | * change this seting to <tt>OpenAccessHandler</tt> as they are on the same machine. | |
160 | * | |
161 | * You can specify the username and password to use by adding command line parameters: | |
162 | * <pre> | |
163 | * <tt>-username user -password password</tt> | |
164 | * </pre> | |
165 | * | |
166 | * | |
167 | * @see org.melati.poem.Database#guestAccessToken | |
168 | * @see org.melati.poem.PoemThread#commit | |
169 | * @see org.melati.poem.PoemThread#rollback | |
170 | * @see #poemContext | |
171 | * @see org.melati.login.AccessHandler | |
172 | * @see org.melati.login.HttpSessionAccessHandler | |
173 | * @see org.melati.login.Login | |
174 | * @see org.melati.login.OpenAccessHandler | |
175 | * @see org.melati.login.CommandLineAccessHandler | |
176 | */ | |
177 | ||
178 | 100 | public abstract class AbstractPoemApp extends AbstractConfigApp implements App { |
179 | ||
180 | 2 | private static Boolean taskPerformedOrLoggedInAndTaskAttempted = Boolean.FALSE; |
181 | ||
182 | /** | |
183 | * Initialise. | |
184 | * | |
185 | * @param args the command line arguments | |
186 | * @return a configured Melati | |
187 | * {@inheritDoc} | |
188 | * @see org.melati.app.AbstractConfigApp#init(java.lang.String[]) | |
189 | */ | |
190 | public Melati init(String[] args) throws MelatiException { | |
191 | 56 | Melati m = super.init(args); |
192 | 54 | if (m.getDatabase() == null) { |
193 | try { | |
194 | 2 | super.term(m); |
195 | 0 | } catch (IOException e) { |
196 | 0 | e = null; |
197 | 2 | } |
198 | 2 | throw new ConfigException("No database configured"); |
199 | } | |
200 | 52 | return m; |
201 | } | |
202 | ||
203 | /** | |
204 | * Clean up at end of run. | |
205 | * | |
206 | * @param melati the melati | |
207 | * @throws IOException | |
208 | */ | |
209 | public void term(Melati melati) throws IOException { | |
210 | 56 | super.term(melati); |
211 | 56 | if (melati.getDatabase() != null) |
212 | 56 | PoemDatabaseFactory.disconnectDatabase(melati.getDatabase().getName()); |
213 | 56 | } |
214 | ||
215 | /** | |
216 | * A place holder for things you might want to do before | |
217 | * setting up a <code>PoemSession</code>. | |
218 | * | |
219 | * @param melati the current Melati | |
220 | * @throws Exception if anything goes wrong | |
221 | */ | |
222 | protected void prePoemSession(Melati melati) throws Exception { | |
223 | 44 | Melati foolEclipse = melati; |
224 | 44 | melati = foolEclipse; |
225 | 44 | } |
226 | ||
227 | protected void doConfiguredRequest(final Melati melati) { | |
228 | // Do something outside of the PoemSession | |
229 | try { | |
230 | 46 | melati.getConfig().getAccessHandler().buildRequest(melati); |
231 | 46 | prePoemSession(melati); |
232 | 2 | } catch (Exception e) { |
233 | 2 | throw new UnexpectedExceptionException(e); |
234 | 44 | } |
235 | ||
236 | // Login loop | |
237 | // If not logged-in when required then an exception is thrown. | |
238 | // The exception is handled and the task revisited | |
239 | // The flag is reset to allow this to be run again. | |
240 | 44 | synchronized(taskPerformedOrLoggedInAndTaskAttempted) { |
241 | 44 | taskPerformedOrLoggedInAndTaskAttempted = Boolean.FALSE; |
242 | //int goes = 0; | |
243 | 84 | while (taskPerformedOrLoggedInAndTaskAttempted.equals(Boolean.FALSE)) { |
244 | //goes ++; | |
245 | //if (goes > 2) | |
246 | // throw new MelatiBugMelatiException("Problem with login loop logic, goes = " + goes); | |
247 | 48 | melati.getDatabase().inSession ( |
248 | 48 | AccessToken.root, new PoemTask() { |
249 | public void run () { | |
250 | 48 | melati.getConfig().getAccessHandler().establishUser(melati); |
251 | 48 | melati.loadTableAndObject(); |
252 | try { | |
253 | try { | |
254 | 48 | doPoemRequest(melati); |
255 | 36 | taskPerformedOrLoggedInAndTaskAttempted = Boolean.TRUE; |
256 | 12 | } catch (Exception e) { |
257 | 12 | _handleException (melati, e); |
258 | 36 | } |
259 | 8 | } catch (Exception e) { |
260 | 8 | taskPerformedOrLoggedInAndTaskAttempted = Boolean.TRUE; |
261 | try { | |
262 | 8 | term(melati); |
263 | 0 | } catch (IOException e1) { |
264 | 0 | e1 = null; |
265 | 8 | } |
266 | 8 | throw new UnhandledExceptionException(e); |
267 | 40 | } |
268 | 40 | } |
269 | ||
270 | // Not sure there is any point in this | |
271 | // Cannot find a way of accessing it | |
272 | //public String toString() { | |
273 | // return "PoemApp"; | |
274 | //} | |
275 | } | |
276 | ); | |
277 | } | |
278 | 36 | } |
279 | 36 | } |
280 | ||
281 | /** | |
282 | * Default method to handle an exception. | |
283 | * | |
284 | * @param melati the Melati | |
285 | * @param exception the exception to handle | |
286 | */ | |
287 | protected static void handleException(Melati melati, Exception exception) | |
288 | throws Exception { | |
289 | ||
290 | 12 | if (exception instanceof AccessPoemException) { |
291 | 10 | melati.getConfig().getAccessHandler() |
292 | .handleAccessException(melati,(AccessPoemException)exception); | |
293 | ||
294 | } | |
295 | else | |
296 | 2 | throw exception; |
297 | 4 | } |
298 | ||
299 | protected final void _handleException(Melati melati, Exception exception) | |
300 | throws Exception { | |
301 | try { | |
302 | 12 | handleException(melati, exception); |
303 | } | |
304 | 8 | catch (Exception e) { |
305 | 8 | PoemThread.rollback(); |
306 | 8 | throw e; |
307 | 4 | } |
308 | 4 | } |
309 | ||
310 | ||
311 | protected PoemContext poemContext(Melati melati) | |
312 | throws InvalidArgumentsException { | |
313 | 38 | String[] args = melati.getArguments(); |
314 | ||
315 | 38 | PoemContext pc = new PoemContext(); |
316 | 38 | if (args.length > 0) { |
317 | 36 | pc.setLogicalDatabase(args[0]); |
318 | 36 | setTableTroidMethod(pc, (String[])ArrayUtils.section(args, 1, args.length)); |
319 | } | |
320 | ||
321 | 36 | return pc; |
322 | } | |
323 | ||
324 | protected void setTableTroidMethod(PoemContext pc, String[] args){ | |
325 | 54 | if (args.length == 1) { |
326 | 6 | pc.setMethod(args[0]); |
327 | } | |
328 | 54 | if (args.length == 2) { |
329 | 6 | pc.setTable(args[0]); |
330 | try { | |
331 | 6 | pc.setTroid(new Integer (args[1])); |
332 | } | |
333 | 2 | catch (NumberFormatException e) { |
334 | 2 | pc.setMethod(args[1]); |
335 | 4 | } |
336 | } | |
337 | 54 | if (args.length >= 3) { |
338 | 36 | pc.setTable(args[0]); |
339 | try { | |
340 | 36 | pc.setTroid(new Integer (args[1])); |
341 | } | |
342 | 2 | catch (NumberFormatException e) { |
343 | 2 | throw new UnexpectedExceptionException(new InvalidArgumentsException(args, e)); |
344 | 34 | } |
345 | 34 | pc.setMethod(args[2]); |
346 | } | |
347 | 52 | } |
348 | ||
349 | ||
350 | /** | |
351 | * This is provided for convenience, so you don't have to specify the | |
352 | * logical database in the arguments. This is useful when | |
353 | * writing applications where you are only accessing a single database. | |
354 | * | |
355 | * Simply override {@link #poemContext(Melati melati)} thus: | |
356 | * | |
357 | * <PRE> | |
358 | * protected PoemContext poemContext(Melati melati) | |
359 | * throws InvalidArgumentsException { | |
360 | * return poemContextWithLDB(melati,"<your logical database name>"); | |
361 | * } | |
362 | * </PRE> | |
363 | * | |
364 | */ | |
365 | protected PoemContext poemContextWithLDB(Melati melati, | |
366 | String logicalDatabase) | |
367 | throws InvalidArgumentsException { | |
368 | 18 | PoemContext pc = new PoemContext(); |
369 | 18 | pc.setLogicalDatabase(logicalDatabase); |
370 | 18 | setTableTroidMethod(pc, melati.getArguments()); |
371 | 18 | return pc; |
372 | } | |
373 | ||
374 | /** | |
375 | * Override this method to do your own thing. | |
376 | * | |
377 | * @param melati a {@link Melati} containing POEM and other configuration data | |
378 | */ | |
379 | protected abstract void doPoemRequest(Melati melati) throws Exception; | |
380 | ||
381 | } |