You asked how i would do this with Template method. Here is an example how you could do it:
public class AbstractDAO<T> {
private String table;
private String id_field;
public AbstractDAO(String table, String id_field){
this.table = table;
...
}
public T read(int id){
try
{
T user = run.query("SELECT * FROM "+ table + " WHERE "+id_field +" = ? ", id);
return user;
}
catch (SQLException ex)
{
Log.logException(ex);
return null;
}
}
This one looks easy, how about Create?
public boolean Create(T user){
QueryRunner run = new QueryRunner(dataSource);
try
{
run.update("INSERT INTO "+table+ getFields() +
"VALUES " + getParameters(user));
}
catch (SQLException ex)
{
Log.logException(ex);
return false;
}
return true;
}
protected abstract String getFields();
protected abstract String getParameters(T user);
Ugly, and insecure, but okay for transmitting the idea.