source: trunk/gsdl3/src/java/org/greenstone/gsdl3/service/ServiceRack.java@ 9426

Last change on this file since 9426 was 9426, checked in by kjdon, 19 years ago

changed the collection specific stuff slightly - instead of the single collection.properties file, now we need the correct class name.properties to be in collection/resources - otherwise services with the same key names will get mixed up.
  • Property svn:keywords set to Author Date Id Revision
File size: 13.0 KB
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1/*
2 * ServiceRack.java
3 * Copyright (C) 2002 New Zealand Digital Library, http://www.nzdl.org
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19package org.greenstone.gsdl3.service;
20
21// greenstone classes
22import org.greenstone.gsdl3.util.*;
23import org.greenstone.gsdl3.core.*;
24
25// xml classes
26import org.w3c.dom.Node;
27import org.w3c.dom.NodeList;
28import org.w3c.dom.Element;
29import org.w3c.dom.Document;
30import org.xml.sax.InputSource;
31import javax.xml.parsers.*;
32import org.apache.xpath.XPathAPI;
33
34// general java classes
35import java.io.Reader;
36import java.io.StringReader;
37import java.io.File;
38import java.util.HashMap;
39import java.util.ResourceBundle;
40import java.util.Locale;
41import java.lang.reflect.Method;
42
43/**
44 * ServiceRack - abstract base class for services
45 *
46 * A ServiceRack provides one or more Services.
47 * This base class implements the process method.
48 *Each service is invoked
49 * by a method called process<service name> which takes one parameter - the xml request Element, and returns an XML response Element.
50 * for example, the TextQuery service would be invoked by
51 * processTextQuery(Element request)
52 *
53 * @author <a href="mailto:[email protected]">Katherine Don</a>
54 * @version $Revision: 9426 $
55 */
56public abstract class ServiceRack
57 implements ModuleInterface
58{
59
60 /** the absolute address of the site home */
61 protected String site_home =null;
62 /** the http address of the site home */
63 protected String site_http_address =null;
64
65 /** the name of the cluster (or collection) that this service
66 belongs to - if any */
67 protected String cluster_name = null;
68
69 /** some services can talk back to the message router */
70 protected ModuleInterface router = null;
71
72 /** a converter class to create Documents etc */
73 protected XMLConverter converter = null;
74
75 /** the original config info - if need to store it */
76 protected Element config_info = null;
77
78 /** XML element for describe requests - the container doc */
79 protected Document doc = null;
80
81 /** XML element for describe requests - list of supported services
82 - this is static */
83 protected Element short_service_info = null;
84
85 /** XML element for stylesheet requests - map of service name to format
86 elem */
87 protected HashMap format_info_map = null;
88
89 /** sets the cluster name */
90 public void setClusterName(String cluster_name) {
91 this.cluster_name = cluster_name;
92 }
93 /** sets the collect name */
94 public void setCollectionName(String coll_name) {
95 setClusterName(coll_name);
96 }
97
98 /** sets the site home */
99 public void setSiteHome(String site_home) {
100 this.site_home = site_home;
101 }
102 /** sets the site http address */
103 public void setSiteAddress(String site_address) {
104 this.site_http_address = site_address;
105 }
106
107 /** sets the message router */
108 public void setMessageRouter(ModuleInterface m) {
109 this.router = m;
110 }
111
112 /** the no-args constructor */
113 public ServiceRack() {
114 this.converter = new XMLConverter();
115 this.doc = this.converter.newDOM();
116 this.short_service_info = this.doc.createElement(GSXML.SERVICE_ELEM+GSXML.LIST_MODIFIER);
117 this.format_info_map = new HashMap();
118 }
119
120
121 /** configure the service module
122 *
123 * @param info the XML node <serviceRack name="XXX"/> with name equal
124 * to the class name (of the subclass)
125 *
126 * must configure short_service_info_ and service_info_map_
127 * @return true if configured ok
128 * must be implemented in subclasses
129 */
130 public boolean configure(Element info) {
131 return configure(info, null);
132 }
133
134 abstract public boolean configure(Element info, Element extra_info);
135
136 /**
137 * Process an XML document - convenience method that uses Strings rather than Elements. just calls process(Element).
138 *
139 * @param xml_in the Document to process - a string
140 * @return the resultant document as a string - contains any error messages
141 * @see String
142 */
143 public String process(String xml_in) {
144
145 Document doc = this.converter.getDOM(xml_in);
146
147 Element res = process(doc.getDocumentElement());
148 return this.converter.getString(res);
149
150 }
151
152 /** process an XML request in DOM form
153 *
154 * @param xml_in the Element node containing the request
155 * should be <message>
156 * @return an Element with the result XML
157 * @see Element
158 */
159 public Element process(Element message) {
160
161 NodeList requests = message.getElementsByTagName(GSXML.REQUEST_ELEM);
162 Document mess_doc = message.getOwnerDocument();
163 Element mainResult = this.doc.createElement(GSXML.MESSAGE_ELEM);
164 if (requests.getLength()==0) {
165 // no requests
166 return mainResult; // empty message for now
167 }
168
169 for (int i=0; i<requests.getLength(); i++) {
170 Element request = (Element)requests.item(i);
171
172 String type = request.getAttribute(GSXML.TYPE_ATT);
173 if (type.equals(GSXML.REQUEST_TYPE_DESCRIBE)) {
174 Element response = processDescribe(request);
175 if (response !=null) {
176 mainResult.appendChild(this.doc.importNode(response, true));
177 }
178
179 } else if (type.equals(GSXML.REQUEST_TYPE_FORMAT)) {
180 Element response = processFormat(request);
181 mainResult.appendChild(this.doc.importNode(response, true));
182
183
184 } else {
185 // other type of request, must be processed by the subclass -
186 // send to the service method
187 StringBuffer error_string = new StringBuffer();
188 String to = GSPath.getFirstLink(request.getAttribute(GSXML.TO_ATT));
189 Element response = null;
190 try {
191 Class c = this.getClass();
192 Class []params = {Class.forName("org.w3c.dom.Element")};
193
194 String method_name = "process"+to;
195 Method m = null;
196 while (c != null) {
197
198 try {
199 m = c.getDeclaredMethod(method_name, params);
200 // if this has worked, break
201 break;
202 } catch (NoSuchMethodException e) {
203 c = c.getSuperclass();
204 } catch (SecurityException e) {
205 System.err.println("ServiceRack.process: security exception for finding method "+method_name);
206 error_string.append("ServiceRack.process: security exception for finding method "+method_name);
207 }
208 } // while
209 if (m != null) {
210 Object []args = {request};
211 try {
212 response = (Element)m.invoke(this, args);
213
214 } catch (Exception e) {
215 System.err.println("ServiceRack.process: Trying to call a processService type method (process"+to+") on a subclass("+this.getClass().getName()+"), but an exception happened:"+e.toString());
216 error_string.append("ServiceRack.process: Trying to call a processService type method (process"+to+") on a subclass("+this.getClass().getName()+"), but an exception happened:"+e.toString());
217 }
218 } else {
219 System.err.println("ServiceRack.process: method "+method_name+" not found for class "+this.getClass().getName());
220 error_string.append("ServiceRack.process: method "+method_name+" not found for class "+this.getClass().getName());
221 }
222
223 } catch (ClassNotFoundException e) {
224 System.err.println("ServiceRack error: Element class not found");
225 error_string.append("ServiceRack error: Element class not found");
226 }
227 if (response !=null) {
228 mainResult.appendChild(this.doc.importNode(response, true));
229 } else {
230 // add in a dummy response
231 System.err.println("adding in an error element\n");
232 response = this.doc.createElement(GSXML.RESPONSE_ELEM);
233 GSXML.addError(this.doc, response, error_string.toString());
234 mainResult.appendChild(response);
235
236 }
237
238 } // else process request
239 } // for each request
240
241 return mainResult;
242
243 }
244
245
246
247 /** process method for describe requests
248 */
249 protected Element processDescribe(Element request) {
250
251 Element response = this.doc.createElement(GSXML.RESPONSE_ELEM);
252 response.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_DESCRIBE);
253
254 String lang = request.getAttribute(GSXML.LANG_ATT);
255 String to = GSPath.getFirstLink(request.getAttribute(GSXML.TO_ATT));
256 if (to.equals("")) { // return the service list
257 response.appendChild(getServiceList(lang));
258 return response;
259 }
260 response.setAttribute(GSXML.FROM_ATT, to);
261 Element param_list = (Element)GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
262 Element description = null;
263 if (param_list == null) {
264 description = getServiceDescription(to, lang, null);
265 } else {
266 NodeList params = param_list.getElementsByTagName(GSXML.PARAM_ELEM);
267 for (int i=0; i<params.getLength(); i++) {
268
269 Element param = (Element)params.item(i);
270 // Identify the structure information desired
271 if (param.getAttribute(GSXML.NAME_ATT).equals(GSXML.SUBSET_PARAM )) {
272 String info = param.getAttribute(GSXML.VALUE_ATT);
273 if (description == null) {
274 description = getServiceDescription(to, lang, info);
275 } else {
276 Element temp = getServiceDescription(to, lang, info);
277 GSXML.mergeElements(description, temp);
278 }
279 }
280 }
281 }
282 if (description != null) { // may be null if non-existant service
283 response.appendChild(description);
284 }
285 return response;
286
287 }
288
289 /** process method for stylesheet requests
290 */
291 protected Element processFormat(Element request) {
292 Element response = this.doc.createElement(GSXML.RESPONSE_ELEM);
293 response.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_FORMAT);
294
295 String to = GSPath.getFirstLink(request.getAttribute(GSXML.TO_ATT));
296
297 if (to.equals("")) { // serviceRack query - is this appropriate??
298 return response;
299 }
300
301
302 // describe a particular service
303 if (this.format_info_map.containsKey(to)) {
304 response.appendChild(getServiceFormat(to));
305 response.setAttribute(GSXML.FROM_ATT, to);
306 return response;
307 }
308 // else no format info
309 System.err.println("ServiceRack describe request: no format info for "+to+".");
310 return response;
311 }
312
313 /** returns the service list for the subclass */
314 protected Element getServiceList(String lang) {
315 // for now, it is static and has no language stuff
316 return (Element) this.short_service_info.cloneNode(true);
317 }
318
319 /** returns a specific service description */
320 abstract protected Element getServiceDescription(String service, String lang, String subset);
321
322 protected Element getServiceFormat(String service) {
323 Element format = (Element)((Element)this.format_info_map.get(service)).cloneNode(true);
324 return format;
325 }
326
327 /** overloaded version for no args case */
328 protected String getTextString(String key, String lang) {
329 return getTextString(key, lang, null, null);
330 }
331
332 protected String getTextString(String key, String lang, String dictionary) {
333 return getTextString(key, lang, dictionary, null);
334 }
335 protected String getTextString(String key, String lang, String [] args) {
336 return getTextString(key, lang, null, args);
337 }
338
339 /** getTextString - retrieves a language specific text string for the given
340key and locale, from the specified resource_bundle (dictionary)
341 */
342 protected String getTextString(String key, String lang, String dictionary, String[] args) {
343
344 // we want to use the collection class loader in case there are coll specific files
345 CollectionClassLoader class_loader = new CollectionClassLoader(this.site_home, this.cluster_name);
346
347 if (dictionary != null) {
348 // just try the one specified dictionary
349 Dictionary dict = new Dictionary(dictionary, lang, class_loader);
350 String result = dict.get(key, args);
351 if (result == null) { // not found
352 return "_"+key+"_";
353 }
354 return result;
355 }
356
357 // now we try class names for dictionary names
358 String class_name = this.getClass().getName();
359 class_name = class_name.substring(class_name.lastIndexOf('.')+1);
360 Dictionary dict = new Dictionary(class_name, lang, class_loader);
361 String result = dict.get(key, args);
362 if (result != null) {
363 return result;
364 }
365
366 // we have to try super classes
367 Class c = this.getClass().getSuperclass();
368 while (result == null && c != null) {
369 class_name = c.getName();
370 class_name = class_name.substring(class_name.lastIndexOf('.')+1);
371 if (class_name.equals("ServiceRack")) {
372 // this is as far as we go
373 break;
374 }
375 dict = new Dictionary(class_name, lang, class_loader);
376 result = dict.get(key, args);
377 c = c.getSuperclass();
378 }
379 if (result == null) {
380 return "_"+key+"_";
381 }
382 return result;
383
384 }
385
386 protected String getMetadataNameText(String key, String lang) {
387
388 String properties_name = "metadata_names";
389 Dictionary dict = new Dictionary(properties_name, lang);
390
391 String result = dict.get(key);
392 if (result == null) { // not found
393 return null;
394 }
395 return result;
396 }
397}
398
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