empire-db-examples/empire-db-example-struts2/src/main/java/org/apache/empire/struts2/websample/web/SampleApplication.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.empire.struts2.websample.web;

import java.sql.Connection;
import java.sql.DriverManager;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.empire.commons.StringUtils;
import org.apache.empire.db.DBCommand;
import org.apache.empire.db.DBDatabaseDriver;
import org.apache.empire.db.DBRecord;
import org.apache.empire.db.DBSQLScript;
import org.apache.empire.db.hsql.DBDatabaseDriverHSql;
import org.apache.empire.db.mysql.DBDatabaseDriverMySQL;
import org.apache.empire.db.oracle.DBDatabaseDriverOracle;
import org.apache.empire.db.postgresql.DBDatabaseDriverPostgreSQL;
import org.apache.empire.db.sqlserver.DBDatabaseDriverMSSQL;
import org.apache.empire.struts2.actionsupport.TextProviderActionSupport;
import org.apache.empire.struts2.html.HtmlTagDictionary;
import org.apache.empire.struts2.web.AppContext;
import org.apache.empire.struts2.web.WebApplication;
import org.apache.empire.struts2.websample.db.SampleDB;


public class SampleApplication implements WebApplication {
	// Logger
	protected static Log log = LogFactory.getLog(SampleApplication.class);

	// must be singleton
	private static SampleApplication application;

    public static SampleApplication getInstance()
    {
        return application;
    }

	// Non-Static
	private SampleDB db = new SampleDB();
	private SampleConfig config = new SampleConfig();

	private Connection conn = null;

	public void init(AppContext servletContext) {
		try {
			
			// Application
			if (application != null) {
				log.fatal("Application has already been initiallized!");
				return;
			}
			application = this;

			// register all controls
			// InputControlManager.registerControl("myType", new
			// MyTypeInputControl());
			config.init(servletContext.getRealPath("WEB-INF/config.xml"));

			// Set Html Dictionary
			HtmlTagDictionary.set(new SampleHtmlTagDictionary());

			// Set Database to Servlet Context
			servletContext.setAttribute("db", db);

			// Get a JDBC Connection
			log.info("*** getJDBCConnection() ***");
			conn = getJDBCConnection(servletContext);

			// Choose a driver
			log.info("*** create DBDatabaseDriverOracle() ***");
			DBDatabaseDriver driver = getDatabaseDriver(config.getDatabaseProvider());

            // Open Database (and create if not existing)
            log.info("*** open database ***");
            try {
                // Open the database
                db.open(driver, conn);
                // Check whether database exists
                databaseExists(conn);
                System.out.println("*** Database already exists. Skipping Step4 ***");
                
            } catch(Exception e) {
                // STEP 4: Create Database
                log.info("*** create Database ***");
                // postgre does not support DDL in transaction
                if(db.getDriver() instanceof DBDatabaseDriverPostgreSQL)
                {
                    conn.setAutoCommit(true);
                }
                createSampleDatabase(driver, conn);
                if(db.getDriver() instanceof DBDatabaseDriverPostgreSQL)
                {
                    conn.setAutoCommit(false);
                }
                // Open again
                if (db.isOpen()==false)
                    db.open(driver, conn);
            }
			
			/*
			// Check Database Definition against Real Database(log differences)
			log.info("*** driver.checkDatabase() ***");
			driver.checkDatabase(db, config.getSchemaName(), conn);
			*/

			// Disable Message caching
			TextProviderActionSupport.setCachingEnabled(false);
			
			// Done
			log.info("Application initialized ");

		} catch (Exception e) {
			// Error
			log.info(e.toString());
			e.printStackTrace();
		}

	}

	public SampleDB getDatabase() {
		return db;
	}

	public Connection getPooledConnection() {
		return conn;
	}

	public void releaseConnection(Connection conn) {
		// Return Connection to Connection Pool
	}

	/*
	 * getJDBCConnection
	 */
	private Connection getJDBCConnection(AppContext appContext) {
		// Establish a new database connection
		Connection conn = null;
		String jdbcURL = config.getJdbcURL();
		if (jdbcURL.indexOf("file:")>0)
			jdbcURL = StringUtils.replace(jdbcURL, "file:", "file:"+appContext.getRealPath("/"));
		// Connect
		log.info("Connecting to Database'" + jdbcURL + "' / User=" + config.getJdbcUser());
		try { // Connect to the databse
			Class.forName(config.getJdbcClass()).newInstance();
			conn = DriverManager.getConnection(jdbcURL, config.getJdbcUser(), config.getJdbcPwd());
			log.info("Connected successfully");
			// set the AutoCommit to false this session. You must commit
			// explicitly now
			conn.setAutoCommit(false);
			log.info("AutoCommit is " + conn.getAutoCommit());

		} catch (Exception e) {
			log.error("Failed to connect directly to '" + config.getJdbcURL() + "' / User=" + config.getJdbcUser());
			log.error(e.toString());
			throw new RuntimeException(e);
		}
		return conn;
	}
	
	/*
	 * getDatabaseDriver
	 */
	private DBDatabaseDriver getDatabaseDriver(String provider)
    {
        if (provider.equalsIgnoreCase("mysql"))
        {
            DBDatabaseDriverMySQL driver = new DBDatabaseDriverMySQL();
            // Set Driver specific properties (if any)
            driver.setDatabaseName(config.getSchemaName());
            return driver;
        }
        else if (provider.equalsIgnoreCase("oracle"))
        {
            DBDatabaseDriverOracle driver = new DBDatabaseDriverOracle();
            // Set Driver specific properties (if any)
            return driver;
        }
        else if (provider.equalsIgnoreCase("sqlserver"))
        {
            DBDatabaseDriverMSSQL driver = new DBDatabaseDriverMSSQL();
            // Set Driver specific properties (if any)
            driver.setDatabaseName(config.getSchemaName());
            return driver;
        }
        else if (provider.equalsIgnoreCase("hsqldb"))
        {
            DBDatabaseDriverHSql driver = new DBDatabaseDriverHSql();
            // Set Driver specific properties (if any)
            return driver;
        }
        else
        {   // Unknown Provider
            throw new RuntimeException("Unknown Database Provider " + provider);
        }
    }

	private void databaseExists(Connection conn) {
		// Check wether DB exists
		DBCommand cmd = db.createCommand();
		cmd.select(db.T_DEPARTMENTS.count());
		db.querySingleInt(cmd, -1, conn);
	}
	
	/*
	 * creates a DDL Script for the entire SampleDB Database then checks if the
	 * department table exists by running "select count(*) from DEPARTMENTS" if
	 * the department tables does not exist, the entire dll-script is executed
	 * line by line
	 */
	private void createSampleDatabase(DBDatabaseDriver driver, Connection conn)
	{
        // create DLL for Database Definition
        DBSQLScript script = new DBSQLScript();
        db.getCreateDDLScript(driver, script);
        // Show DLL Statements
        System.out.println(script.toString());
        // Execute Script
        script.executeAll(driver, conn, false);
        db.commit(conn);
        // Open again
        if (db.isOpen()==false)
            db.open(driver, conn);
		// Insert Sample Departments
		int idDevDep = insertDepartmentSampleRecord(conn, "Development", "ITTK");
		int idSalDep = insertDepartmentSampleRecord(conn, "Sales", "ITTK");
		// Insert Sample Employees
		insertEmployeeSampleRecord(conn, "Mr.", "Eugen", "Miller",   "M", idDevDep);
		insertEmployeeSampleRecord(conn, "Mr.", "Max",   "Mc. Callahan",   "M", idDevDep);
		insertEmployeeSampleRecord(conn, "Mrs.", "Anna", "Smith", "F", idSalDep);
		// Commit
		db.commit(conn);
	}

	/*
	 * Insert a department
	 */
	private int insertDepartmentSampleRecord(Connection conn, String department_name, String businessUnit) {
			// Insert a Department
			DBRecord rec = new DBRecord();
			rec.create(db.T_DEPARTMENTS);
			rec.setValue(db.T_DEPARTMENTS.C_NAME, department_name);
			rec.setValue(db.T_DEPARTMENTS.C_BUSINESS_UNIT, businessUnit);
			rec.update(conn);
			// Return Department ID
			return rec.getInt(db.T_DEPARTMENTS.C_DEPARTMENT_ID);
		}

	/*
	 * Insert a person
	 */
	private int insertEmployeeSampleRecord(Connection conn, String salutation, String firstName, String lastName, String gender, int depID) {
		// Insert an Employee
		DBRecord rec = new DBRecord();
		rec.create(db.T_EMPLOYEES);
		rec.setValue(db.T_EMPLOYEES.C_SALUTATION, salutation);
		rec.setValue(db.T_EMPLOYEES.C_FIRSTNAME, firstName);
		rec.setValue(db.T_EMPLOYEES.C_LASTNAME, lastName);
		rec.setValue(db.T_EMPLOYEES.C_GENDER, gender);
		rec.setValue(db.T_EMPLOYEES.C_DEPARTMENT_ID, depID);
		rec.update(conn);
		// Return Employee ID
		return rec.getInt(db.T_EMPLOYEES.C_EMPLOYEE_ID);
	}

}