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19
20
21 package org.apache.james.util;
22
23 import org.apache.oro.text.perl.MalformedPerl5PatternException;
24 import org.apache.oro.text.perl.Perl5Util;
25 import org.w3c.dom.Attr;
26 import org.w3c.dom.Document;
27 import org.w3c.dom.Element;
28 import org.w3c.dom.NamedNodeMap;
29 import org.w3c.dom.NodeList;
30
31 import javax.xml.parsers.DocumentBuilder;
32 import javax.xml.parsers.DocumentBuilderFactory;
33 import java.io.File;
34 import java.util.HashMap;
35 import java.util.Iterator;
36 import java.util.Map;
37
38 /*
39 * This is derived from the SQLResources.java class that we have been
40 * using to provide SQL strings based upon the particular drive being
41 * used.
42 *
43 * The format is indentical to the format used by SQLResources. The
44 * only difference are the names of the elements and attributes. A
45 * mapping is as follows:
46 *
47 * sqlResources xmlResources
48 * ------------ ------------
49 * sqlResources resources
50 * dbMatchers matchers
51 * dbMatcher matcher
52 * db for
53 * databaseProductName match
54 * sqlDefs group
55 * sql resource
56 *
57 * This class provides String resources defined in XML. Resources are
58 * organized into groups, and identified by name. For each resource
59 * there can be a standard value, and custom values matched by regular
60 * expression.
61 *
62 * The structure of the XML file is:
63 *
64 * <resources>
65 * <matchers>
66 * <matcher for="<i>label</i>" match="<i>regular expression</i>"/>
67 * ...
68 * </matchers>
69 * <group name="<i>group name</i>">
70 * <resource name="<i>resouce name</i>" [for="<i>match label</i>"]><i>text, including ${placeholders}, which will be replaced at runtime.</i></resource>
71 * ...
72 * </group>
73 * <i>... more <group> elements ...</i>
74 * </resources>
75 *
76 */
77 public class XMLResources
78 {
79 /**
80 * A map of statement types to resource strings
81 */
82 private Map m_resource = new HashMap();
83
84 /**
85 * A set of all used String values
86 */
87 static private Map stringTable = java.util.Collections.synchronizedMap(new HashMap());
88
89 /**
90 * A Perl5 regexp matching helper class
91 */
92 private Perl5Util m_perl5Util = new Perl5Util();
93
94 /**
95 * Configures an XMLResources object to provide string statements from a file.
96 *
97 * Parameters encoded as $(parameter} in the input file are
98 * replace by values from the parameters Map, if the named parameter exists.
99 * Parameter values may also be specified in the resourceSection element.
100 *
101 * @param xmlFile the input file containing the string definitions
102 * @param group xml element containing the strings to be used
103 * @param select if customized elements exist for this value, use them instead of the default
104 * @param configParameters a map of parameters (name-value string pairs) which are
105 * replaced where found in the input strings
106 */
107 public void init(File xmlFile, String group,
108 String select, Map configParameters)
109 throws Exception
110 {
111 // Parse the xmlFile as an XML document.
112 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
113 DocumentBuilder builder = factory.newDocumentBuilder();
114 Document doc = builder.parse(xmlFile);
115
116 // First process the matchers, to select the statements to use.
117 Element matcherElement =
118 (Element)(doc.getElementsByTagName("matchers").item(0));
119 String selectTag = null;
120 if ( matcherElement != null ) {
121 selectTag = match(select, matcherElement);
122 m_perl5Util = null; // release the PERL matcher!
123 }
124
125 // Now get the section defining strings for the group required.
126 NodeList sections = doc.getElementsByTagName("group");
127 int sectionsCount = sections.getLength();
128 Element sectionElement = null;
129 for (int i = 0; i < sectionsCount; i++ ) {
130 sectionElement = (Element)(sections.item(i));
131 String sectionName = sectionElement.getAttribute("name");
132 if ( sectionName != null && sectionName.equals(group) ) {
133 break;
134 }
135
136 }
137 if ( sectionElement == null ) {
138 StringBuffer exceptionBuffer =
139 new StringBuffer(64)
140 .append("Error loading string definition file. ")
141 .append("The element named \'")
142 .append(group)
143 .append("\' does not exist.");
144 throw new RuntimeException(exceptionBuffer.toString());
145 }
146
147 // Get parameters defined within the file as defaults,
148 // and use supplied parameters as overrides.
149 Map parameters = new HashMap();
150 // First read from the <params> element, if it exists.
151 Element parametersElement =
152 (Element)(sectionElement.getElementsByTagName("parameters").item(0));
153 if ( parametersElement != null ) {
154 NamedNodeMap params = parametersElement.getAttributes();
155 int paramCount = params.getLength();
156 for (int i = 0; i < paramCount; i++ ) {
157 Attr param = (Attr)params.item(i);
158 String paramName = param.getName();
159 String paramValue = param.getValue();
160 parameters.put(paramName, paramValue);
161 }
162 }
163 // Then copy in the parameters supplied with the call.
164 parameters.putAll(configParameters);
165
166 // 2 maps - one for storing default statements,
167 // the other for statements with a "for" attribute matching this
168 // connection.
169 Map defaultStrings = new HashMap();
170 Map selectTagStrings = new HashMap();
171
172 // Process each string resource, replacing string parameters,
173 // and adding to the appropriate map..
174 NodeList resDefs = sectionElement.getElementsByTagName("resource");
175 int resCount = resDefs.getLength();
176 for ( int i = 0; i < resCount; i++ ) {
177 // See if this needs to be processed (is default or product specific)
178 Element resElement = (Element)(resDefs.item(i));
179 String resSelect = resElement.getAttribute("for");
180 Map resMap;
181 if ( resSelect.equals("")) {
182 // default
183 resMap = defaultStrings;
184 }
185 else if (resSelect.equals(selectTag) ) {
186 // Specific to this product
187 resMap = selectTagStrings;
188 }
189 else {
190 // for a different product
191 continue;
192 }
193
194 // Get the key and value for this string resource.
195 String resKey = resElement.getAttribute("name");
196 if ( resKey == null ) {
197 // ignore elements without a "name" attribute.
198 continue;
199 }
200 String resString = resElement.getFirstChild().getNodeValue();
201
202 // Do parameter replacements for this string resource.
203 Iterator paramNames = parameters.keySet().iterator();
204 while ( paramNames.hasNext() ) {
205 String paramName = (String)paramNames.next();
206 String paramValue = (String)parameters.get(paramName);
207
208 StringBuffer replaceBuffer =
209 new StringBuffer(64)
210 .append("${")
211 .append(paramName)
212 .append("}");
213 resString = substituteSubString(resString, replaceBuffer.toString(), paramValue);
214 }
215
216 // See if we already have registered a string of this value
217 String shared = (String) stringTable.get(resString);
218 // If not, register it -- we will use it next time
219 if (shared == null) {
220 stringTable.put(resString, resString);
221 } else {
222 resString = shared;
223 }
224
225 // Add to the resMap - either the "default" or the "product" map
226 resMap.put(resKey, resString);
227 }
228
229 // Copy in default strings, then overwrite product-specific ones.
230 m_resource.putAll(defaultStrings);
231 m_resource.putAll(selectTagStrings);
232 }
233
234 /**
235 * Compares the "select" value against a set of regular expressions
236 * defined in XML. The first successful match defines the name of a
237 * selector tag. This value is then used to choose the specific
238 * expressions to use.
239 *
240 * @param select the String to be checked
241 * @param matchersElement the XML element containing selector patterns
242 *
243 * @return the selector tag that will be used to select custom resources
244 *
245 */
246 private String match(String select, Element matchersElement)
247 throws MalformedPerl5PatternException
248 {
249 String selectTagName = select;
250
251 NodeList matchers = matchersElement.getElementsByTagName("matcher");
252 for ( int i = 0; i < matchers.getLength(); i++ ) {
253 // Get the values for this matcher element.
254 Element matcher = (Element)matchers.item(i);
255 String matchName = matcher.getAttribute("for");
256 StringBuffer selectTagPatternBuffer =
257 new StringBuffer(64)
258 .append("/")
259 .append(matcher.getAttribute("match"))
260 .append("/i");
261
262 // If the select string matches the pattern, use the match
263 // name from this matcher.
264 if ( m_perl5Util.match(selectTagPatternBuffer.toString(), selectTagName) ) {
265 return matchName;
266 }
267 }
268 return null;
269 }
270
271 /**
272 * Replace substrings of one string with another string and return altered string.
273 * @param input input string
274 * @param find the string to replace
275 * @param replace the string to replace with
276 * @return the substituted string
277 */
278 static private String substituteSubString( String input,
279 String find,
280 String replace )
281 {
282 int find_length = find.length();
283 int replace_length = replace.length();
284
285 StringBuffer output = new StringBuffer(input);
286 int index = input.indexOf(find);
287 int outputOffset = 0;
288
289 while ( index > -1 ) {
290 output.replace(index + outputOffset, index + outputOffset + find_length, replace);
291 outputOffset = outputOffset + (replace_length - find_length);
292
293 index = input.indexOf(find, index + find_length);
294 }
295
296 String result = output.toString();
297 return result;
298 }
299
300 /**
301 * Returns a named string for the specified key.
302 *
303 * @param name the name of the String resource required.
304 * @return the requested resource
305 */
306 public String getString(String name)
307 {
308 return (String)m_resource.get(name);
309 }
310
311 /**
312 * Returns a named string for the specified key.
313 *
314 * @param name the name of the String resource required.
315 * @param required true if the resource is required
316 * @return the requested resource
317 */
318 public String getString(String name, boolean required)
319 {
320 String str = getString(name);
321
322 if (str == null && required) {
323 StringBuffer exceptionBuffer =
324 new StringBuffer(64)
325 .append("Required String resource: '")
326 .append(name)
327 .append("' was not found.");
328 throw new IllegalArgumentException(exceptionBuffer.toString());
329 }
330 return str;
331 }
332
333 /**
334 * Returns a named string, replacing parameters with the values set in a Map.
335 *
336 * @param name the name of the String resource required.
337 * @param parameters a map of parameters (name-value string pairs) which are
338 * replaced where found in the input strings
339 * @return the requested resource
340 */
341 public String getString(String name, Map parameters)
342 {
343 return replaceParameters(getString(name), parameters);
344 }
345
346 /**
347 * Returns a named string, replacing parameters with the values set in a Map.
348 *
349 * @param name the name of the String resource required.
350 * @param parameters a map of parameters (name-value string pairs) which are
351 * replaced where found in the input strings
352 * @return the requested resource
353 */
354 public String getString(String name, Map parameters, boolean required)
355 {
356 return replaceParameters(getString(name, required), parameters);
357 }
358
359 /**
360 * Returns a named string, replacing parameters with the values set.
361 *
362 * @param str the name of the String resource required.
363 * @param parameters a map of parameters (name-value string pairs) which are
364 * replaced where found in the input strings
365 * @return the requested resource
366 */
367 static public String replaceParameters(String str, Map parameters)
368 {
369 if (str != null && parameters != null) {
370 // Do parameter replacements for this string resource.
371 Iterator paramNames = parameters.keySet().iterator();
372 StringBuffer replaceBuffer = new StringBuffer(64);
373 while ( paramNames.hasNext() ) {
374 String paramName = (String)paramNames.next();
375 String paramValue = (String)parameters.get(paramName);
376 replaceBuffer.append("${").append(paramName).append("}");
377 str = substituteSubString(str, replaceBuffer.toString(), paramValue);
378 if (paramNames.hasNext()) replaceBuffer.setLength(0);
379 }
380 }
381
382 return str;
383 }
384 }