sascha@10: package de.intevation.artifactdatabase;
sascha@10: 
sascha@93: import java.io.File;
sascha@93: 
sascha@93: import java.sql.SQLException;
sascha@93: 
sascha@10: import javax.sql.DataSource;
sascha@10: 
sascha@10: import org.apache.commons.dbcp.BasicDataSource;
sascha@10: 
sascha@38: import org.apache.log4j.Logger;
sascha@38: 
sascha@10: /**
sascha@87:  * This class encapsulate the creation and pooling of database connections used
sascha@87:  * by the artifact database. The credential to open the database connections
sascha@87:  * are taken from the global configuratiion.
sascha@87:  * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
sascha@10:  */
sascha@10: public class DBConnection
sascha@10: {
sascha@38:     private static Logger logger = Logger.getLogger(DBConnection.class);
sascha@38: 
sascha@87:     /**
sascha@87:      * XPath to access the database driver within the global configuration.
sascha@87:      */
sascha@10:     public static final String DB_DRIVER =
sascha@38:         "/artifact-database/database/driver/text()";
sascha@87:     /**
sascha@87:      * XPath to access the database URL within the global configuration.
sascha@87:      */
sascha@10:     public static final String DB_URL =
sascha@38:         "/artifact-database/database/url/text()";
sascha@87:     /**
sascha@87:      * XPath to access the database use within the global configuration.
sascha@87:      */
sascha@10:     public static final String DB_USER =
sascha@38:         "/artifact-database/database/user/text()";
sascha@87:     /**
sascha@87:      * XPath to access the database password within the global configuration.
sascha@87:      */
sascha@10:     public static final String DB_PASSWORD =
sascha@38:         "/artifact-database/database/password/text()";
sascha@10: 
sascha@87:     /**
sascha@87:      * The default database driver: H2
sascha@87:      */
sascha@10:     public static final String DEFAULT_DRIVER =
sascha@10:         "org.h2.Driver";
sascha@10: 
sascha@87:     /**
sascha@87:      * The default database name: artifacts.db
sascha@87:      */
sascha@19:     public static final String DEFAULT_DATABASE_FILE =
sascha@19:         "artifacts.db";
sascha@19: 
sascha@87:     /**
sascha@87:      * The default database URL: This is created once by #getDefaultURL()
sascha@87:      */
sascha@19:     public static final String DEFAULT_URL = getDefaultURL();
sascha@10: 
sascha@87:     /**
sascha@87:      * The default database user: ""
sascha@87:      */
sascha@10:     public static final String DEFAULT_USER     = "";
sascha@87: 
sascha@87:     /**
sascha@87:      * The default database password: ""
sascha@87:      */
sascha@10:     public static final String DEFAULT_PASSWORD = "";
sascha@10: 
sascha@10:     private DBConnection() {
sascha@10:     }
sascha@10: 
sascha@87:     /**
sascha@87:      * Constructs the default databse URL. It concats the
sascha@87:      * config directory and the #DEFAULT_DATABASE_FILE
sascha@87:      * to the string with is needed to access H2 databases.
sascha@89:      * @return The default URL.
sascha@87:      */
sascha@19:     public static final String getDefaultURL() {
sascha@19:         File configDir = Config.getConfigDirectory();
sascha@19:         File databaseFile = new File(configDir, DEFAULT_DATABASE_FILE);
sascha@19:         return "jdbc:h2:" + databaseFile;
sascha@19:     }
sascha@19: 
sascha@10:     private static BasicDataSource dataSource;
sascha@10: 
sascha@10:     private static final void addShutdownHook() {
sascha@10:         Runtime.getRuntime().addShutdownHook(new Thread() {
sascha@87:             @Override
sascha@10:             public void run() {
sascha@10:                 if (dataSource != null) {
sascha@10:                     try {
sascha@10:                         dataSource.close();
sascha@10:                     }
sascha@10:                     catch (SQLException sqle) {
sascha@10:                     }
sascha@10:                     dataSource = null;
sascha@10:                 }
sascha@10:             }
sascha@10:         });
sascha@10:     }
sascha@10: 
sascha@87:     /**
sascha@87:      * Static method to fetch a database connection.
sascha@87:      * @return a DataSource to access the database connection.
sascha@87:      */
sascha@10:     public static synchronized DataSource getDataSource() {
sascha@10:         if (dataSource == null) {
sascha@10:             dataSource = new BasicDataSource();
sascha@10: 
sascha@10:             String driver = Config.getStringXPath(
sascha@10:                 DB_DRIVER, DEFAULT_DRIVER);
sascha@10: 
sascha@10:             String url = Config.getStringXPath(
sascha@10:                 DB_URL, DEFAULT_URL);
sascha@10: 
sascha@10:             String user = Config.getStringXPath(
sascha@10:                 DB_USER, DEFAULT_USER);
sascha@10: 
sascha@10:             String password = Config.getStringXPath(
sascha@10:                 DB_PASSWORD, DEFAULT_PASSWORD);
sascha@10: 
sascha@38:             logger.info("database driver: " + driver);
sascha@38:             logger.info("database url: " + url);
sascha@38: 
sascha@10:             dataSource.setDriverClassName(driver);
sascha@10:             dataSource.setUsername(user);
sascha@10:             dataSource.setPassword(password);
sascha@10:             dataSource.setUrl(url);
sascha@10:             addShutdownHook();
sascha@10:         }
sascha@10: 
sascha@10:         return dataSource;
sascha@10:     }
sascha@10: }
sascha@91: //  vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :