Developer Notes - ITwelzel.biz

The DAO Implementation
A DAO interface has at least one concrete class that implements the interface for a
specific type of data source. The following is an implementation of the Contacts
DAO interface for an hsqldb data source:
public class HSQLDBContactsDAO implements ContactsDAO
{
public static String GET_PERSON_STATEMENT =
"select * from person where personID = ?";
public static String GET_ADDRESS_STATEMENT =
"select * from address where addressID = ?";
public static String GET_COMPANY_STATEMENT =
"select * from company where companyID = ?";
public HSQLDBContactsDAO()
{
}
protected PersonDAO getPerson(String personID)
throws DAOException
{
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
PersonDAO ret = null;
try
{
conn = getDataSource().getConnection();
ps = conn.prepareStatement(GET_PERSON_STATEMENT,
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
ps.setString(1, personID);
rs = ps.executeQuery();
if (rs.first())
{
ret = new HSQLDBPersonDAO(personID, rs);
}
Developer Notes
}
rs.close();
ps.close();
conn.close();
return ret;
}
catch (SQLException se)
{
throw new DAOException("SQLException: " + se.getMessage());
}
protected AddressDAO getAddress(String addressID)
throws DAOException
{
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
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