Dictionary/src/java/org/thdl/lex/LexRepository.java

package org.thdl.lex;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

/**
 * Description of the Class
 * 
 * @author travis
 * @created September 26, 2002
 */
public class LexRepository {
	//attributes
	private static LexRepository instance;

	private DataSource dataSource;

	/**
	 * Sets the dataSource attribute of the LexRepository object
	 * 
	 * @param dataSource
	 *            The new dataSource value
	 */
	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
	}

	/**
	 * Gets the dataSource attribute of the LexRepository object
	 * 
	 * @return The dataSource value
	 */
	public DataSource getDataSource() {
		return dataSource;
	}

	//accessors

	/**
	 * Gets the instance attribute of the LexRepository class
	 * 
	 * @return The instance value
	 * @exception LexRepositoryException
	 *                Description of the Exception
	 * @since
	 */
	public static LexRepository getInstance() throws LexRepositoryException {
		if (instance == null) {
			instance = new LexRepository();
		}
		return instance;
	}

	//helper methods

	/**
	 * doUpdate() performs an INSERT/UPDATE/DROP action
	 * 
	 * @param sql
	 *            Description of the Parameter
	 * @return Description of the Return Value
	 * @exception LexRepositoryException
	 *                Description of the Exception
	 * @since
	 */
	public int doUpdate(String sql) throws LexRepositoryException {
		try {
			Connection con = getDataSource().getConnection();
			int i = con.createStatement().executeUpdate(sql);
			con.close();
			return i;
		} catch (SQLException sqle) {
			throw new LexRepositoryException(sqle);
		}
	}

	/**
	 * doInsert() is a wrapper for doUpdate() that returns the auto_increment
	 * primary key value of the newly inserted row
	 * 
	 * @param sql
	 *            Description of the Parameter
	 * @return Description of the Return Value
	 * @exception LexRepositoryException
	 *                Description of the Exception
	 * @since
	 */
	public int doInsert(String sql) throws LexRepositoryException {
		if (null == sql) {
			throw new LexRepositoryException("SQL String was null");
		}
		if (sql.equals("")) {
			throw new LexRepositoryException("SQL String was empty");
		}
		try {
			ResultSet rs;
			int returnVal = 0;
			int i;
			i = doUpdate(sql);
			if (i > 0) {
				Connection con = getDataSource().getConnection();
				rs = con.createStatement().executeQuery(
						"SELECT LAST_INSERT_ID()");
				while (rs.next()) {
					returnVal = rs.getInt(1);
				}
				con.close();
				return returnVal;
			} else {
				returnVal = i;
			}
			throw new LexRepositoryException(
					"Insert affected 0 rows. Sql String was '" + sql + "'");
		} catch (SQLException sqle) {
			throw new LexRepositoryException(sqle);
		}
	}

	//main
	/**
	 * The main program for the LexRepository class. This method tests all other
	 * methods in this class
	 * 
	 * @param args
	 *            The command line arguments
	 * @since
	 */
	public static void main(String[] args) {
	}

	//constructors
	/**
	 * Default Constructor for the LexRepository object
	 * 
	 * @exception LexRepositoryException
	 *                Description of the Exception
	 * @since
	 */
	private LexRepository() throws LexRepositoryException {
		try {
			Context context = new InitialContext();
			DataSource source = (DataSource) context
					.lookup(LexConstants.DATASOURCE_NAME);
			setDataSource(source);
		} catch (NamingException ne) {
			throw new LexRepositoryException(ne);
		}

	}
}