/*
 * @author                 : Mark Drake
 * @version                : 1.0
 * Development Environment : Oracle9i JDeveloper
 * Name of the File        : BaseApplication.java

 * Creation / Modification History :
 *  Shefali Bansal    25-Jan-2003      Modified
 *  Modifications Made:
 *  1. Provided for getting the Table Name and Logging mode from the connection.xml file
 *  2. Removed methods related to OCI Pooling
 *  3. Renamed the doSomething() method as doBulkLoad() method
 *  4. Removed the Main() method

 */

//Package name
package oracle.otnsamples.xmldb.simplebulkloader.common.baseApp;


// IO Imports
import java.io.File;

import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;


//JDBC imports
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

// Import 'Alert' class
import oracle.otnsamples.xmldb.simplebulkloader.common.trace.Alert;

// Oracle SQL Imports
import oracle.sql.CLOB;


// XML Parser Imports
import oracle.xml.parser.v2.DOMParser;
import oracle.xml.parser.v2.XMLDocument;

// W3C DOM Imports
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;

//ORG XML Imports

import org.xml.sax.SAXException;

/**
 * 'BaseApplication' class is part of the Simple Bulk Loader application. This
 * class provides base methods for bulk loading of XML files into the XML DB
 * database.
 */
public class BaseApplication extends Object {
  // Declare the static variables required
  public static final boolean DEBUG = true;

  // Static variables handling connection parameters

  public static final String CONNECTION = "Connection";
  public static final String DRIVER = "Driver";
  public static final String HOSTNAME = "Hostname";
  public static final String PORT = "Port";
  public static final String SID = "SID";
  public static final String SERVICENAME = "ServiceName";
  public static final String SERVERMODE = "Server";
  public static final String SCHEMA = "Schema";
  public static final String PASSWORD = "Password";
  public static final String THIN_DRIVER = "thin";
  public static final String OCI_DRIVER = "oci8";
  public static final String TABLE = "Table";
  public static final String LOGGER = "Logger";

  public static final String DEFAULT_CONNECTION_SETTINGS = "c:\\temp\\connection.xml"; // Please mention the directory path according to the OS
  public static final String DEFAULT_DRIVER = OCI_DRIVER;
  public static final String DEFAULT_HOSTNAME = "localhost";
  public static final String DEFAULT_PORT = "1521";
  public static final String DEFAULT_SID = "ORCL";
  public static final String DEFAULT_SERVICENAME = "ORCL";
  public static final String DEFAULT_SERVERMODE = "DEDICATED";
  public static final String DEFAULT_SCHEMA = "scott";
  public static final String DEFAULT_PASSWORD = "tiger";
  public static final String DEFAULT_TABLE = "UserTable";
  public static final String DEFAULT_LOGGER = "CONSOLE";

  // Declare the member variables required
  protected Connection m_Connection; // Holds the db connection object

  protected XMLDocument m_ConnectionSettings; // Holds the XML Document giving db connection information

  /*
   * Setter method for connection parameters from the XML file
   *
   * @param doc The connection.xml XMLDocument
   */
  private void setConnectionSettings( XMLDocument doc ) {
    m_ConnectionSettings = doc;
  }

  /**
   * Setter method for connection object
   *
   * @param conn Database connection object

   */
  private void setConnection( Connection conn ) {
    m_Connection = conn;
  }

  /**
   * Displays the connection parameters information on the system console and
   * in logger file
   *
   * @throws IOException
   */
  private void dumpConnectionSettings(  ) throws IOException {
    StringWriter sw = new StringWriter(  );
    PrintWriter pw = new PrintWriter( sw );
    m_ConnectionSettings.print( pw );
    pw.close(  );

    Alert.log( "Connection Settings = " );
    Alert.log( sw.toString(  ) );
    Alert.log( DRIVER + " = " + getDriver(  ) );
    Alert.log( HOSTNAME + " = " + getHostname(  ) );
    Alert.log( PORT + " = " + getPort(  ) );
    Alert.log( SERVICENAME + " = " + getServiceName(  ) );
    Alert.log( SERVERMODE + " = " + getServerMode(  ) );
    Alert.log( SCHEMA + " = " + getSchema(  ) );
    Alert.log( PASSWORD + " = " + getPassword(  ) );
    Alert.log( TABLE + " = " + getTable(  ) );
    Alert.log( LOGGER + " = " + getLoggerMode(  ) );
    Alert.log( "Database URL = " + getDatabaseURL(  ) );
  }

  /**
   * Returns the Connection object
   *

   * @return Connection
   *
   * @exception Exception
   */
  public Connection getConnection(  ) throws Exception {
    return m_Connection;
  }

  /**
   * Returns the connection object for the schema name and password passed
   *
   * @param schema String specifying the database schema name
   * @param passwd String specifying the database schema password
   *
   * @return Connection
   *
   * @throws Exception
   */

  public Connection getConnection( String schema, String passwd )
                           throws Exception {
    return m_Connection;
  }

  /**
   * This is the method that will perform the actual loading of the XML files
   * into the XML DB. This method is overridden by the doBulkLoad() method in
   * SimpleBulkLoader class to implement the required behavior.
   *
   * @param args array
   *
   * @throws Exception
   */
  public void doBulkLoad( String[] args ) throws Exception {
  }

  /**
   * Creates a temporary CLOB to hold the input stream content. Once the

   * temporary CLOB is created the contents of the input stream are read and
   * copied into this CLOB
   *
   * @param conn object containing DB connection info
   * @param is InputStream specifying the content of the XML files
   *
   * @return CLOB
   *
   * @throws SQLException
   * @throws IOException
   */
  public CLOB createCLOB( Connection conn, InputStream is )
                  throws SQLException, IOException {
    // If the temporary CLOB has not yet been created, create a new one
    CLOB clob = CLOB.createTemporary( conn, false, CLOB.DURATION_SESSION );

    // Write the contents into this temporary CLOB
    writeToClob( clob, is );

    // Return the temporary CLOB object

    return clob;
  }

  /**
   * Writes the content of the input stream to the temporary CLOB object passed
   * to it and returns the data containing the CLOB object
   *
   * @param clob CLOB object to hold the input stream content
   * @param is XML data containing stream
   *
   * @return CLOB
   *
   * @throws SQLException
   * @throws IOException This exception is thrown if the xml file is not found
   */
  public CLOB writeToClob( CLOB clob, InputStream is )
                   throws SQLException, IOException {
    InputStreamReader reader = new InputStreamReader( is );

    // Get the output stream to write
    Writer writer = clob.getCharacterOutputStream(  );


    // Read the input stream
    char[] buffer = new char[clob.getChunkSize(  )];

    for ( int charsRead = reader.read( buffer ); charsRead > -1;
              charsRead = reader.read( buffer ) ) {
      // Write the data into the temporary CLOB
      writer.write( buffer, 0, charsRead );
    }

    // Close the stream
    writer.close(  );

    // Return the XML content containing CLOB Object
    return clob;
  }

  /**
   * Getter method for getting the text value of a node given the node name
   * from  the XML document contained in "connection.xml" file.
   *
   * @param nodeName String specifying the nodename whose text value is to be

   *        retrieved
   *
   * @return String the text value of the node name passed
   */
  public String getTextNode( String nodeName ) {
    return getTextNode( nodeName, null );
  }

  /**
   * Getter method for getting the text value of a node given the node name
   * from  the XML document contained in "connection.xml" file.
   *
   * @param nodeName specifying the node name
   * @param defaultValue default text value of the node, if node name specified
   *        is not found in the DOM
   *
   * @return String the text value of the node name passed
   */
  public String getTextNode( String nodeName, String defaultValue ) {
    String textValue = null;

    // Get the DOM element for the XML document
    Element root = m_ConnectionSettings.getDocumentElement(  );


    // Get the list of nodes having the same name as the Node name passed
    NodeList children = root.getElementsByTagName( nodeName );

    // If the nodes with name matching as the node name exists then
    if ( children.getLength(  ) != 0 ) {
      // Get the details of the first node from the list
      Element element = (Element) children.item( 0 );
      Text text = (Text) element.getFirstChild(  );

      // Get the text value of the node
      if ( text != null ) {
        return text.getData(  );
      }

      // If there are no nodes matching the node name specified then
      else {
        return defaultValue;
      }
    }
    else {
      return defaultValue;
    }
  }


  /**
   * Getter method for Driver information
   *
   * @return the driver information
   */
  protected String getDriver(  ) {
    return getTextNode( DRIVER, DEFAULT_DRIVER );
  }

  /**
   * Getter method for Hostname information
   *
   * @return the host name
   */
  protected String getHostname(  ) {
    return getTextNode( HOSTNAME, DEFAULT_HOSTNAME );
  }

  /**
   * Getter method for Port information
   *
   * @return the port number
   */
  protected String getPort(  ) {

    return getTextNode( PORT, DEFAULT_PORT );
  }

  /**
   * Getter method for database Table information
   *
   * @return the table
   */
  protected String getTable(  ) {
    return getTextNode( TABLE, DEFAULT_TABLE );
  }

  /**
   * Getter method for Service Name information
   *
   * @return the service name
   */
  protected String getServiceName(  ) {
    return getTextNode( SERVICENAME, DEFAULT_SERVICENAME );
  }

  /**
   * Getter method for Server Mode information
   *
   * @return the Server Mode
   */

  protected String getServerMode(  ) {
    return getTextNode( SERVERMODE, DEFAULT_SERVERMODE );
  }

  /**
   * Getter method for SID information
   *
   * @return the SID
   */
  protected String getSID(  ) {
    return getTextNode( SID, DEFAULT_SID );
  }

  /**
   * Getter method for Schema information
   *
   * @return Schema Name information
   */
  protected String getSchema(  ) {
    return getTextNode( SCHEMA, DEFAULT_SCHEMA );
  }

  /**
   * Getter method for Schema password information
   *
   * @return Schema password information
   */

  protected String getPassword(  ) {
    return getTextNode( PASSWORD, DEFAULT_PASSWORD );
  }

  /**
   * Getter method for Logger mode information
   *
   * @return Logger mode information
   */
  protected String getLoggerMode(  ) {
    return getTextNode( LOGGER, DEFAULT_LOGGER );
  }

  /**
     * Gets the connection information from connection.xml file
     *
     * @throws IOException
     * @throws SAXException
     */
    public void getConnectionSettings(  ) throws IOException, SAXException {
      // Get the name of the Connection File
      String filename = DEFAULT_CONNECTION_SETTINGS;

      try {
        // Create a Reader on the Connection File
        File file = new File( filename );

        // Check for the existence of the file

        if ( file.exists(  ) ) {
          Reader reader = new FileReader( new File( filename ) );

          DOMParser parser = new DOMParser(  );

          // Parse the Connection File
          parser.parse( reader );

          // Obtain the DOM
          XMLDocument doc = parser.getDocument(  );

          setConnectionSettings( doc );

          // Get the logger mode entered in the config XML file by the user
          String mode = getLoggerMode(  );

          // Based on the logger mode entered by the user, set the same in the Alert class
          Alert alert = new Alert(  );
          alert.setLoggerMode( mode );

          if ( DEBUG ) {
            dumpConnectionSettings(  );
          }
        }
        else {
          throw new NullPointerException(  );
        }
      } catch ( NullPointerException ex ) {
        System.out.println( "BaseApplication.getConnectionSettings:The system cannot find configuration XML file -connection.xml- in the directory location specified : FileNotFound Exception" );

        throw ex;
      } catch ( IOException ex ) {
        Alert.log( "BaseApplication.getConnectionSettings:The system cannot find the configuration XML file in the directory location specified : IO Exception" );
      }
  }

  /**
   * Getter method for the database Connection URL based on the driver type
   *
   * @return Database connection URL
   */
  protected String getDatabaseURL(  ) {
    // Based on the driver return the database URL information
    if ( getDriver(  ) != null ) {
      if ( getDriver(  ).equalsIgnoreCase( THIN_DRIVER ) ) {
        // Return the database connection URL information
        return "jdbc:oracle:thin:@" + getHostname(  ) + ":" + getPort(  ) +
               ":" + getSID(  );
      }
      else {
        // Return the database connection URL information
        return "jdbc:oracle:oci8:@(description=(address=(host=" +
               getHostname(  ) + ")(protocol=tcp)(port=" + getPort(  ) +
               "))(connect_data=(service_name=" + getServiceName(  ) +
               ")(server=" + getServerMode(  ) + ")))";
      }
    }
    else {
      return null;
    }

  }

  /**
   * Opens the DB connection once the DB connection parameters are available
   *
   * @return Connection
   *
   * @throws Exception
   */
  public Connection openConnection(  ) throws Exception {
    String user = getSchema(  );
    String password = getPassword(  );
    String connectionString = user + "/" + password + "@" + getDatabaseURL(  );
    Connection conn = null;

    if ( DEBUG ) {
      Alert.log( "BaseApplication.getConnection(): Connecting as " +
                 connectionString );
    }

    //Load the Oracle JDBC Driver and register it.
    DriverManager.registerDriver( new oracle.jdbc.driver.OracleDriver(  ) );

    try {
      //The following statement creates a database connection object using the
      //DriverManager.getConnection method.
      conn = DriverManager.getConnection( getDatabaseURL(  ), user, password );

      if ( DEBUG ) {
        Alert.log( "BaseApplication.getConnection(): Database Connection Established" );
      }

    }
     catch ( SQLException sqle ) {
      // Get the error code for the SQL Exception
      int err = sqle.getErrorCode(  );
      Alert.log( "BaseApplication.getConnection(): Failed to connect using " +
                 connectionString );

      // Display in the log, the exception that has occurred
      Alert.log( sqle );
      throw sqle;
    }

    // Return the database connection object
    return conn;
  }

  /**
   * Creates a DB connection
   *
   * @throws Exception
   */
  public void createConnection(  ) throws Exception {
    getConnectionSettings(  );
    setConnection( openConnection(  ) );
  }
}