--- a/artifact-database/src/main/java/de/intevation/artifactdatabase/Config.java	Fri Mar 26 17:59:50 2010 +0000
+++ b/artifact-database/src/main/java/de/intevation/artifactdatabase/Config.java	Sun Mar 28 10:01:03 2010 +0000
@@ -19,27 +19,51 @@
 import org.apache.log4j.Logger;
 
 /**
+ * The central access to the configuration of the artifact database.
+ * This class provides some static methods to access the central
+ * configuration XML file via XPath.
+ *
  * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
  */
 public final class Config
 {
     private static Logger logger = Logger.getLogger(Config.class);
 
+    /**
+     * System property name where to find the configuration directory.
+     */
     public static final String CONFIG_DIR = "artifact.database.dir";
 
+    /**
+     * Default path to the configuration directory if none
+     * was specified by the CONFIG_DIR system property.
+     */
     public static final File CONFIG_DIR_DEFAULT =
         new File(new File(System.getProperty("user.home",
             System.getProperty("user.dir", "."))), ".artifactdb");
 
+    /**
+     * Name of the central configuration XML file.
+     */
     public static final String CONFIG_FILE  = "conf.xml";
 
-    public static final String CONFIG_DIR_PLACEHOLDER = "${artifacts.config.dir}";
+    /**
+     * Name of the configuration filename alias to be use
+     * within the configuration. This alias is replaced by
+     * the real path.
+     */
+    public static final String CONFIG_DIR_PLACEHOLDER =
+        "${artifacts.config.dir}";
 
     private static Document config;
 
     private Config() {
     }
 
+    /**
+     * Singleton access to the central XML configuration document.
+     * @return The central XML configuration document.
+     */
     public static synchronized final Document getConfig() {
         if (config == null) {
             config = loadConfig();
@@ -47,6 +71,12 @@
         return config;
     }
 
+    /**
+     * Returns the path to the configuartion directory. If a path
+     * was specified via the CONFIG_DIR system property this one
+     * is used. Else it falls back to default configuration path.
+     * @return The path to the configuartion directory.
+     */
     public static File getConfigDirectory() {
         String configDirString = System.getProperty(CONFIG_DIR);
 
@@ -62,6 +92,13 @@
         return configDir;
     }
 
+    /**
+     * Replaces the CONFIG_DIR_PLACEHOLDER alias with the real path
+     * of the configuration directory.
+     * @param path The path containing the CONFIG_DIR_PLACEHOLDER placeholder.
+     * @return The path where the CONFIG_DIR_PLACEHOLDER placeholders are
+     * replaced by the real path name.
+     */
     public static String replaceConfigDir(String path) {
         String configDir = getConfigDirectory().getAbsolutePath();
         return path.replace(CONFIG_DIR_PLACEHOLDER, configDir);
@@ -80,7 +117,8 @@
         }
 
         try {
-            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+            DocumentBuilderFactory factory =
+                DocumentBuilderFactory.newInstance();
             factory.setValidating(false); // XXX: This may change in future.
             return factory.newDocumentBuilder().parse(file);
         }
@@ -97,28 +135,75 @@
         return null;
     }
 
+    /**
+     * Convenience method to search within a given document tree via XPath.
+     * See {@link XMLUtils#xpath(Object, String, QName) } for details.
+     * @param root The object which is used as the root of the tree to
+     * be searched in.
+     * @param query The XPath query.
+     * @param returnType The type of the result.
+     * @return The result of type 'returnTyp' or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final Object getXPath(
         Object root, String query, QName returnType
     ) {
         return XMLUtils.xpath(root, query, returnType);
     }
 
+    /**
+     * Convenience method to search within the central configuration via XPath.
+     * See {@link XMLUtils#xpath(Object, String, QName) } for details.
+     * @param query The XPath query.
+     * @param returnType The type of the result.
+     * @return The result of type 'returnTyp' or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final Object getXPath(String query, QName returnType) {
         return XMLUtils.xpath(getConfig(), query, returnType);
     }
 
+    /**
+     * Convenience method to search for a node list within the central
+     * configuation document via XPath.
+     * @param query The XPath query.
+     * @return The queried node list or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final NodeList getNodeSetXPath(String query) {
         return (NodeList)getXPath(query, XPathConstants.NODESET);
     }
 
+    /**
+     * Convenience method to search for a node within the central
+     * configuation document via XPath.
+     * @param query The XPath query.
+     * @return The queried node or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final Node getNodeXPath(String query) {
         return (Node)getXPath(query, XPathConstants.NODE);
     }
 
+    /**
+     * Convenience method to search for a string within the central
+     * configuation document via XPath.
+     * @param xpath The XPath query.
+     * @return The queried string or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final String getStringXPath(String xpath) {
         return getStringXPath(xpath, null);
     }
 
+    /**
+     * Convenience method to search for a string within the central
+     * configuation document via XPath.
+     * @param query The XPath query.
+     * @param def The string to be returned if the search has no results.
+     * @return The queried string or the default value if something went
+     * wrong during XPath evaluation.
+     */
     public static final String getStringXPath(String query, String def) {
         String s = (String)getXPath(query, XPathConstants.STRING);
         return s == null || s.length() == 0
@@ -126,18 +211,51 @@
             : s;
     }
 
+    /**
+     * Convenience method to search for a node list within a given tree
+     * via XPath.
+     * @param root The root of the tree to be searched in.
+     * @param query The XPath query.
+     * @return The queried node list or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final NodeList getNodeSetXPath(Object root, String query) {
         return (NodeList)getXPath(root, query, XPathConstants.NODESET);
     }
 
+    /**
+     * Convenience method to search for a node within a given tree
+     * via XPath.
+     * @param root The root of the tree to be searched in.
+     * @param query The XPath query.
+     * @return The queried node or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final Node getNodeXPath(Object root, String query) {
         return (Node)getXPath(root, query, XPathConstants.NODE);
     }
 
+    /**
+     * Convenience method to search for a string within a given tree
+     * via XPath.
+     * @param root The root of the tree to be searched in.
+     * @param xpath The XPath query.
+     * @return The queried string or null if something went
+     * wrong during XPath evaluation.
+     */
     public static final String getStringXPath(Object root, String xpath) {
         return getStringXPath(root, xpath, null);
     }
 
+    /**
+     * Convenience method to search for a string within a given tree
+     * via XPath.
+     * @param root The root of the tree to be searched in.
+     * @param query xpath The XPath query.
+     * @param def The string to be returned if the search has no results.
+     * @return The queried string or the default value if something went
+     * wrong during XPath evaluation.
+     */
     public static final String getStringXPath(
         Object root, String query, String def
     ) {
@@ -147,4 +265,4 @@
             : s;
     }
 }
-// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8:
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
\ No newline at end of file