sascha@5: package de.intevation.artifactdatabase;
sascha@5: 
sascha@5: import java.io.File;
sascha@5: import java.io.IOException;
sascha@5: 
sascha@5: import org.w3c.dom.Document;
sascha@5: import org.w3c.dom.NodeList;
sascha@5: 
sascha@5: import org.xml.sax.SAXException;
sascha@5: 
sascha@5: import javax.xml.parsers.DocumentBuilderFactory;
sascha@5: 
sascha@5: import javax.xml.parsers.ParserConfigurationException;
sascha@5: 
sascha@5: import javax.xml.namespace.QName;
sascha@5: 
sascha@5: import javax.xml.xpath.XPathFactory;
sascha@5: import javax.xml.xpath.XPath;
sascha@5: import javax.xml.xpath.XPathExpressionException;
sascha@5: import javax.xml.xpath.XPathConstants;
sascha@5: 
sascha@5: public final class Config
sascha@5: {
sascha@5:     public static final String CONFIG_PROPERTY = "artifact.database.config";
sascha@5: 
sascha@5:     public static final String CONFIG_DEFAULT  = "artifactdb-conf.xml";
sascha@5: 
sascha@5:     private static Document config;
sascha@5: 
sascha@5:     private Config() {
sascha@5:     }
sascha@5: 
sascha@5:     public static synchronized final Document getConfig() {
sascha@5:         if (config == null) {
sascha@5:             config = loadConfig();
sascha@5:         }
sascha@5:         return config;
sascha@5:     }
sascha@5: 
sascha@5:     private static Document loadConfig() {
sascha@5:         File file = new File(
sascha@5:             System.getProperty(CONFIG_PROPERTY, CONFIG_DEFAULT));
sascha@5: 
sascha@5:         if (!file.canRead() && !file.isFile()) {
sascha@5:             System.err.println("ERROR: cannot read config file '"
sascha@5:                 + file + "'.");
sascha@5:             return null;
sascha@5:         }
sascha@5: 
sascha@5:         try {
sascha@5:             DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
sascha@5:             factory.setValidating(false); // XXX: This may change in future.
sascha@5:             return factory.newDocumentBuilder().parse(file);
sascha@5:         }
sascha@5:         catch (SAXException se) {
sascha@5:             System.err.println("ERROR: while processing XML file '"
sascha@5:                 + file + "'");
sascha@5:             se.printStackTrace(System.err);
sascha@5:         }
sascha@5:         catch (ParserConfigurationException pce) {
sascha@5:             System.err.println("ERROR: with XML configuration");
sascha@5:             pce.printStackTrace(System.err);
sascha@5:         }
sascha@5:         catch (IOException ioe) {
sascha@5:             System.err.println("ERROR: I/O while processing file '"
sascha@5:                 + file + "'");
sascha@5:             ioe.printStackTrace(System.err);
sascha@5:         }
sascha@5: 
sascha@5:         return null;
sascha@5:     }
sascha@5: 
sascha@5:     public static final String getStringXPath(String xpath) {
sascha@5:         return getStringXPath(xpath, null);
sascha@5:     }
sascha@5: 
sascha@5:     public static final String getStringXPath(String query, String def) {
sascha@5:         String s = (String)getXPath(query, XPathConstants.STRING);
sascha@5:         return s == null || s.length() == 0
sascha@5:             ? def
sascha@5:             : s;
sascha@5:     }
sascha@5: 
sascha@5:     public static final Object getXPath(String query, QName returnType) {
sascha@5:         Document document = getConfig();
sascha@5:         if (document == null) {
sascha@5:             return null;
sascha@5:         }
sascha@5: 
sascha@5:         XPathFactory factory = XPathFactory.newInstance();
sascha@5:         XPath        xpath   = factory.newXPath();
sascha@5: 
sascha@5:         try {
sascha@5:             return xpath.evaluate(query, document, returnType);
sascha@5:         }
sascha@5:         catch (XPathExpressionException xpee) {
sascha@5:             xpee.printStackTrace(System.err);
sascha@5:         }
sascha@5: 
sascha@5:         return null;
sascha@5:     }
sascha@5: 
sascha@5:     public static final NodeList getNodeSetXPath(String query) {
sascha@5:         return (NodeList)getXPath(query, XPathConstants.NODESET);
sascha@5:     }
sascha@5: }
sascha@5: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8:
sascha@5: