ingo@100: /*
ingo@100:  * Copyright (c) 2010 by Intevation GmbH
ingo@100:  *
ingo@100:  * This program is free software under the LGPL (>=v2.1)
ingo@100:  * Read the file LGPL.txt coming with the software for details
ingo@100:  * or visit http://www.gnu.org/licenses/ if it does not exist.
ingo@100:  */
ingo@100: 
sascha@5: package de.intevation.artifactdatabase;
sascha@5: 
sascha@5: import java.io.File;
sascha@5: import java.io.IOException;
sascha@5: 
sascha@93: import javax.xml.namespace.QName;
sascha@5: 
sascha@5: import javax.xml.parsers.DocumentBuilderFactory;
sascha@5: import javax.xml.parsers.ParserConfigurationException;
sascha@5: 
sascha@5: import javax.xml.xpath.XPathConstants;
sascha@5: 
sascha@17: import org.apache.log4j.Logger;
sascha@17: 
sascha@93: import org.w3c.dom.Document;
sascha@93: import org.w3c.dom.Node;
sascha@93: import org.w3c.dom.NodeList;
sascha@93: 
sascha@93: import org.xml.sax.SAXException;
sascha@93: 
sascha@10: /**
sascha@91:  * The central access to the configuration of the artifact database.
sascha@91:  * This class provides some static methods to access the central
sascha@91:  * configuration XML file via XPath.
sascha@91:  *
ingo@80:  * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
sascha@10:  */
sascha@5: public final class Config
sascha@5: {
sascha@17:     private static Logger logger = Logger.getLogger(Config.class);
sascha@17: 
sascha@91:     /**
sascha@91:      * System property name where to find the configuration directory.
sascha@91:      */
sascha@19:     public static final String CONFIG_DIR = "artifact.database.dir";
sascha@5: 
sascha@91:     /**
sascha@91:      * Default path to the configuration directory if none
sascha@91:      * was specified by the CONFIG_DIR system property.
sascha@91:      */
sascha@19:     public static final File CONFIG_DIR_DEFAULT =
sascha@19:         new File(new File(System.getProperty("user.home",
sascha@19:             System.getProperty("user.dir", "."))), ".artifactdb");
sascha@19: 
sascha@91:     /**
sascha@91:      * Name of the central configuration XML file.
sascha@91:      */
sascha@19:     public static final String CONFIG_FILE  = "conf.xml";
sascha@5: 
sascha@91:     /**
sascha@91:      * Name of the configuration filename alias to be use
sascha@91:      * within the configuration. This alias is replaced by
sascha@91:      * the real path.
sascha@91:      */
sascha@91:     public static final String CONFIG_DIR_PLACEHOLDER =
sascha@91:         "${artifacts.config.dir}";
tim@54: 
sascha@5:     private static Document config;
sascha@5: 
sascha@5:     private Config() {
sascha@5:     }
sascha@5: 
sascha@91:     /**
sascha@91:      * Singleton access to the central XML configuration document.
sascha@91:      * @return The central XML configuration document.
sascha@91:      */
sascha@5:     public static synchronized final Document getConfig() {
sascha@5:         if (config == null) {
ingo@61:             config = loadConfig();
sascha@5:         }
sascha@5:         return config;
sascha@5:     }
sascha@5: 
sascha@91:     /**
sascha@91:      * Returns the path to the configuartion directory. If a path
sascha@91:      * was specified via the CONFIG_DIR system property this one
sascha@91:      * is used. Else it falls back to default configuration path.
sascha@91:      * @return The path to the configuartion directory.
sascha@91:      */
sascha@19:     public static File getConfigDirectory() {
sascha@19:         String configDirString = System.getProperty(CONFIG_DIR);
sascha@19: 
sascha@19:         File configDir = configDirString != null
sascha@19:             ? new File(configDirString)
sascha@19:             : CONFIG_DIR_DEFAULT;
sascha@19: 
sascha@19:         if (!configDir.isDirectory()) {
sascha@19:             logger.warn("'" + configDir + "' is not a directory.");
sascha@19:             configDir = CONFIG_DIR_DEFAULT;
sascha@19:         }
sascha@19: 
sascha@19:         return configDir;
sascha@19:     }
sascha@19: 
sascha@91:     /**
sascha@91:      * Replaces the CONFIG_DIR_PLACEHOLDER alias with the real path
sascha@91:      * of the configuration directory.
sascha@91:      * @param path The path containing the CONFIG_DIR_PLACEHOLDER placeholder.
sascha@91:      * @return The path where the CONFIG_DIR_PLACEHOLDER placeholders are
sascha@91:      * replaced by the real path name.
sascha@91:      */
tim@54:     public static String replaceConfigDir(String path) {
tim@54:         String configDir = getConfigDirectory().getAbsolutePath();
tim@54:         return path.replace(CONFIG_DIR_PLACEHOLDER, configDir);
tim@54:     }
tim@54: 
ingo@61:     private static Document loadConfig() {
sascha@19: 
sascha@19:         File configDir = getConfigDirectory();
sascha@19: 
ingo@61:         File file = new File(configDir, CONFIG_FILE);
sascha@5: 
sascha@5:         if (!file.canRead() && !file.isFile()) {
sascha@17:             logger.error("Cannot read config file '"
sascha@5:                 + file + "'.");
sascha@5:             return null;
sascha@5:         }
sascha@5: 
sascha@5:         try {
sascha@91:             DocumentBuilderFactory factory =
sascha@91:                 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@17:             logger.error(se.getLocalizedMessage(), se);
sascha@5:         }
sascha@5:         catch (ParserConfigurationException pce) {
sascha@17:             logger.error(pce.getLocalizedMessage(), pce);
sascha@5:         }
sascha@5:         catch (IOException ioe) {
sascha@17:             logger.error(ioe.getLocalizedMessage());
sascha@5:         }
sascha@5: 
sascha@5:         return null;
sascha@5:     }
sascha@5: 
sascha@91:     /**
sascha@91:      * Convenience method to search within a given document tree via XPath.
sascha@91:      * See {@link XMLUtils#xpath(Object, String, QName) } for details.
sascha@91:      * @param root The object which is used as the root of the tree to
sascha@91:      * be searched in.
sascha@91:      * @param query The XPath query.
sascha@91:      * @param returnType The type of the result.
sascha@91:      * @return The result of type 'returnTyp' or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final Object getXPath(
sascha@10:         Object root, String query, QName returnType
sascha@10:     ) {
sascha@25:         return XMLUtils.xpath(root, query, returnType);
sascha@10:     }
sascha@10: 
sascha@91:     /**
sascha@91:      * Convenience method to search within the central configuration via XPath.
sascha@91:      * See {@link XMLUtils#xpath(Object, String, QName) } for details.
sascha@91:      * @param query The XPath query.
sascha@91:      * @param returnType The type of the result.
sascha@91:      * @return The result of type 'returnTyp' or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final Object getXPath(String query, QName returnType) {
sascha@25:         return XMLUtils.xpath(getConfig(), query, returnType);
sascha@10:     }
sascha@10: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a node list within the central
sascha@91:      * configuation document via XPath.
sascha@91:      * @param query The XPath query.
sascha@91:      * @return The queried node list or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final NodeList getNodeSetXPath(String query) {
sascha@10:         return (NodeList)getXPath(query, XPathConstants.NODESET);
sascha@10:     }
sascha@10: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a node within the central
sascha@91:      * configuation document via XPath.
sascha@91:      * @param query The XPath query.
sascha@91:      * @return The queried node or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final Node getNodeXPath(String query) {
sascha@10:         return (Node)getXPath(query, XPathConstants.NODE);
sascha@10:     }
sascha@10: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a string within the central
sascha@91:      * configuation document via XPath.
sascha@91:      * @param xpath The XPath query.
sascha@91:      * @return The queried string or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@5:     public static final String getStringXPath(String xpath) {
sascha@5:         return getStringXPath(xpath, null);
sascha@5:     }
sascha@5: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a string within the central
sascha@91:      * configuation document via XPath.
sascha@91:      * @param query The XPath query.
sascha@91:      * @param def The string to be returned if the search has no results.
sascha@91:      * @return The queried string or the default value if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
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@91:     /**
sascha@91:      * Convenience method to search for a node list within a given tree
sascha@91:      * via XPath.
sascha@91:      * @param root The root of the tree to be searched in.
sascha@91:      * @param query The XPath query.
sascha@91:      * @return The queried node list or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final NodeList getNodeSetXPath(Object root, String query) {
sascha@10:         return (NodeList)getXPath(root, query, XPathConstants.NODESET);
sascha@5:     }
sascha@5: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a node within a given tree
sascha@91:      * via XPath.
sascha@91:      * @param root The root of the tree to be searched in.
sascha@91:      * @param query The XPath query.
sascha@91:      * @return The queried node or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final Node getNodeXPath(Object root, String query) {
sascha@10:         return (Node)getXPath(root, query, XPathConstants.NODE);
sascha@5:     }
sascha@9: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a string within a given tree
sascha@91:      * via XPath.
sascha@91:      * @param root The root of the tree to be searched in.
sascha@91:      * @param xpath The XPath query.
sascha@91:      * @return The queried string or null if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final String getStringXPath(Object root, String xpath) {
sascha@10:         return getStringXPath(root, xpath, null);
sascha@10:     }
sascha@10: 
sascha@91:     /**
sascha@91:      * Convenience method to search for a string within a given tree
sascha@91:      * via XPath.
sascha@91:      * @param root The root of the tree to be searched in.
sascha@91:      * @param query xpath The XPath query.
sascha@91:      * @param def The string to be returned if the search has no results.
sascha@91:      * @return The queried string or the default value if something went
sascha@91:      * wrong during XPath evaluation.
sascha@91:      */
sascha@10:     public static final String getStringXPath(
sascha@10:         Object root, String query, String def
sascha@10:     ) {
sascha@10:         String s = (String)getXPath(root, query, XPathConstants.STRING);
sascha@10:         return s == null || s.length() == 0
sascha@10:             ? def
sascha@10:             : s;
sascha@9:     }
sascha@5: }
sascha@93: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :