Mercurial > dive4elements > framework

comparison artifacts-common/src/main/java/org/dive4elements/artifacts/common/utils/Config.java @ 472:783cc1b6b615

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Moved directories to org.dive4elements
author Sascha L. Teichmann <teichmann@intevation.de>
date Thu, 25 Apr 2013 10:53:15 +0200
parents artifacts-common/src/main/java/de/intevation/artifacts/common/utils/Config.java@33f58a847fc4
children 415df0fc4fa1
comparison
equal deleted inserted replaced
471:1a87cb24a446 472:783cc1b6b615
1 /*
2 * Copyright (c) 2010 by Intevation GmbH
3 *
4 * This program is free software under the LGPL (>=v2.1)
5 * Read the file LGPL.txt coming with the software for details
6 * or visit http://www.gnu.org/licenses/ if it does not exist.
7 */
8
9 package de.intevation.artifacts.common.utils;
10
11 import java.io.File;
12 import java.io.IOException;
13
14 import javax.xml.namespace.QName;
15
16 import javax.xml.parsers.DocumentBuilderFactory;
17 import javax.xml.parsers.ParserConfigurationException;
18
19 import javax.xml.xpath.XPathConstants;
20
21 import org.apache.log4j.Logger;
22
23 import org.w3c.dom.Document;
24 import org.w3c.dom.Node;
25 import org.w3c.dom.NodeList;
26
27 import org.xml.sax.SAXException;
28
29 /**
30 * The central access to the configuration of the artifact database.
31 * This class provides some static methods to access the central
32 * configuration XML file via XPath.
33 *
34 * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
35 */
36 public final class Config
37 {
38 private static Logger logger = Logger.getLogger(Config.class);
39
40 /**
41 * System property name where to find the configuration directory.
42 */
43 public static final String CONFIG_DIR = "artifact.database.dir";
44
45 /**
46 * Default path to the configuration directory if none
47 * was specified by the CONFIG_DIR system property.
48 */
49 public static final File CONFIG_DIR_DEFAULT =
50 new File(new File(System.getProperty("user.home",
51 System.getProperty("user.dir", "."))), ".artifactdb");
52
53 /**
54 * Name of the central configuration XML file.
55 */
56 public static final String CONFIG_FILE = "conf.xml";
57
58 /**
59 * Name of the configuration filename alias to be use
60 * within the configuration. This alias is replaced by
61 * the real path.
62 */
63 public static final String CONFIG_DIR_PLACEHOLDER =
64 "${artifacts.config.dir}";
65
66 private static Document config;
67
68 private Config() {
69 }
70
71 /**
72 * Singleton access to the central XML configuration document.
73 * @return The central XML configuration document.
74 */
75 public static synchronized final Document getConfig() {
76 if (config == null) {
77 config = loadConfig();
78 }
79 return config;
80 }
81
82 /**
83 * Returns the path to the configuartion directory. If a path
84 * was specified via the CONFIG_DIR system property this one
85 * is used. Else it falls back to default configuration path.
86 * @return The path to the configuartion directory.
87 */
88 public static File getConfigDirectory() {
89 String configDirString = System.getProperty(CONFIG_DIR);
90
91 File configDir = configDirString != null
92 ? new File(configDirString)
93 : CONFIG_DIR_DEFAULT;
94
95 if (!configDir.isDirectory()) {
96 logger.warn("'" + configDir + "' is not a directory.");
97 configDir = CONFIG_DIR_DEFAULT;
98 }
99
100 return configDir;
101 }
102
103 /**
104 * Replaces the CONFIG_DIR_PLACEHOLDER alias with the real path
105 * of the configuration directory.
106 * @param path The path containing the CONFIG_DIR_PLACEHOLDER placeholder.
107 * @return The path where the CONFIG_DIR_PLACEHOLDER placeholders are
108 * replaced by the real path name.
109 */
110 public static String replaceConfigDir(String path) {
111 String configDir = getConfigDirectory().getAbsolutePath();
112 return path.replace(CONFIG_DIR_PLACEHOLDER, configDir);
113 }
114
115 private static Document loadConfig() {
116
117 File configDir = getConfigDirectory();
118
119 File file = new File(configDir, CONFIG_FILE);
120
121 if (!file.canRead() && !file.isFile()) {
122 logger.error("Cannot read config file '"
123 + file + "'.");
124 return null;
125 }
126
127 try {
128 DocumentBuilderFactory factory =
129 DocumentBuilderFactory.newInstance();
130 factory.setValidating(false); // XXX: This may change in future.
131 return factory.newDocumentBuilder().parse(file);
132 }
133 catch (SAXException se) {
134 logger.error(se.getLocalizedMessage(), se);
135 }
136 catch (ParserConfigurationException pce) {
137 logger.error(pce.getLocalizedMessage(), pce);
138 }
139 catch (IOException ioe) {
140 logger.error(ioe.getLocalizedMessage());
141 }
142
143 return null;
144 }
145
146 /**
147 * Convenience method to search within a given document tree via XPath.
148 * See {@link XMLUtils#xpath(Object, String, QName) } for details.
149 * @param root The object which is used as the root of the tree to
150 * be searched in.
151 * @param query The XPath query.
152 * @param returnType The type of the result.
153 * @return The result of type 'returnTyp' or null if something went
154 * wrong during XPath evaluation.
155 */
156 public static final Object getXPath(
157 Object root, String query, QName returnType
158 ) {
159 return XMLUtils.xpath(root, query, returnType);
160 }
161
162 /**
163 * Convenience method to search within the central configuration via XPath.
164 * See {@link XMLUtils#xpath(Object, String, QName) } for details.
165 * @param query The XPath query.
166 * @param returnType The type of the result.
167 * @return The result of type 'returnTyp' or null if something went
168 * wrong during XPath evaluation.
169 */
170 public static final Object getXPath(String query, QName returnType) {
171 return XMLUtils.xpath(getConfig(), query, returnType);
172 }
173
174 /**
175 * Convenience method to search for a node list within the central
176 * configuation document via XPath.
177 * @param query The XPath query.
178 * @return The queried node list or null if something went
179 * wrong during XPath evaluation.
180 */
181 public static final NodeList getNodeSetXPath(String query) {
182 return (NodeList)getXPath(query, XPathConstants.NODESET);
183 }
184
185 /**
186 * Convenience method to search for a node within the central
187 * configuation document via XPath.
188 * @param query The XPath query.
189 * @return The queried node or null if something went
190 * wrong during XPath evaluation.
191 */
192 public static final Node getNodeXPath(String query) {
193 return (Node)getXPath(query, XPathConstants.NODE);
194 }
195
196 /**
197 * Convenience method to search for a string within the central
198 * configuation document via XPath.
199 * @param xpath The XPath query.
200 * @return The queried string or null if something went
201 * wrong during XPath evaluation.
202 */
203 public static final String getStringXPath(String xpath) {
204 return getStringXPath(xpath, null);
205 }
206
207 /**
208 * Convenience method to search for a string within the central
209 * configuation document via XPath.
210 * @param query The XPath query.
211 * @param def The string to be returned if the search has no results.
212 * @return The queried string or the default value if something went
213 * wrong during XPath evaluation.
214 */
215 public static final String getStringXPath(String query, String def) {
216 String s = (String)getXPath(query, XPathConstants.STRING);
217 return s == null || s.length() == 0
218 ? def
219 : s;
220 }
221
222 /**
223 * Convenience method to search for a node list within a given tree
224 * via XPath.
225 * @param root The root of the tree to be searched in.
226 * @param query The XPath query.
227 * @return The queried node list or null if something went
228 * wrong during XPath evaluation.
229 */
230 public static final NodeList getNodeSetXPath(Object root, String query) {
231 return (NodeList)getXPath(root, query, XPathConstants.NODESET);
232 }
233
234 /**
235 * Convenience method to search for a node within a given tree
236 * via XPath.
237 * @param root The root of the tree to be searched in.
238 * @param query The XPath query.
239 * @return The queried node or null if something went
240 * wrong during XPath evaluation.
241 */
242 public static final Node getNodeXPath(Object root, String query) {
243 return (Node)getXPath(root, query, XPathConstants.NODE);
244 }
245
246 /**
247 * Convenience method to search for a string within a given tree
248 * via XPath.
249 * @param root The root of the tree to be searched in.
250 * @param xpath The XPath query.
251 * @return The queried string or null if something went
252 * wrong during XPath evaluation.
253 */
254 public static final String getStringXPath(Object root, String xpath) {
255 return getStringXPath(root, xpath, null);
256 }
257
258 /**
259 * Convenience method to search for a string within a given tree
260 * via XPath.
261 * @param root The root of the tree to be searched in.
262 * @param query xpath The XPath query.
263 * @param def The string to be returned if the search has no results.
264 * @return The queried string or the default value if something went
265 * wrong during XPath evaluation.
266 */
267 public static final String getStringXPath(
268 Object root, String query, String def
269 ) {
270 String s = (String)getXPath(root, query, XPathConstants.STRING);
271 return s == null || s.length() == 0
272 ? def
273 : s;
274 }
275 }
276 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
http://dive4elements.wald.intevation.org