"public Object getObject(int i,
Map map)
throws SQLException"
Doe's somebody tried to use this method ? I am not sure, but looks like it
can be driver specific.
It is trivial to implement converters. It can be something like this:
//delegates convertion for driver
Object getObject( ResultSet rs, int col, int jdbcType ){
switch(){
case Types.INT :
return new Integer(rs.getInt(col));
..................
}
}
and
int [] toJdbcTypes( PropertyDescriptors [] props ) {
int [] result = new int[propTypes.length];
for( int i= 0, len = propTypes.length; i < len; i++ ){
Integer type = (Integer)classToJdbcMap.get(props[i].getType());
if(type == null){
throw new Exception("register mapping for " + props[i].getType());
}
result[i] = type.intValue();
}
}
This kind of implementation must be performant.
----- Original Message -----
From: "David Graham" <[EMAIL PROTECTED]>
To: "Jakarta Commons Developers List" <[EMAIL PROTECTED]>
Sent: Tuesday, November 25, 2003 7:49 PM
Subject: Re: [DbUtils]Improving the BeanHandler
>
> --- Corby Page <[EMAIL PROTECTED]> wrote:
> > Hi, first off I'd like to say thanks for the DbUtils package. It has
> > been
> > very helpful for cleaning up my code in places where I have to do manual
> > persistence.
> >
> > I have had to modify the code in order to use the BeanHandler, and I
> > wanted
> > to offer my modifications as a patch to the codebase.
> >
> > Let me run through a quick use-case: I have a bean with a property
> > called
> > quantity of type double. I tried to populate this bean with a SELECT
> > statement using the BeanHandler.
> >
> > However, the BasicRowProcessor.createBean( ... ) method executes the
> > following code:
> >
> > Object value = rs.getObject(i);
> >
> > The return type from my Sybase JDBC Driver here is BigDecimal. Since
> > this
> > isn't a perfect match for the exposed bean property, it refuses to
> > populate
> > the property.
> >
> > When I code this persistence operation by hand, I use rs.getDouble(i).
> > This
> > way, I make the vendor do the work for me. I tell the vendor I expect a
> > double return type, and he is responsible for performing the
> > BigDecimal.doubleValue() conversion.
> >
> > So, I have created my own custom RowProcessor that replaces the
> > getObject
> > call from above with a method that looks like this:
> >
> > Object value;
> > if ( propType.equals( Double.TYPE ) || propType.equals(
> > Double.class ) )
> > {
> > value = new Double( rs.getDouble( index ) );
> > }
> > ....
> > else
> > {
> > value = rs.getObject( index );
> > }
> >
> > This is implemented for all of the appropriate ResultSet methods of
> > course.
> > Now, we look at the type of the named property, and we call the
> > appropriate
> > method of the JDBC driver to get the vendor to adapt to that type, if
> > possible. This feels a lot more flexible than requiring a bean property
> > to
> > precisely match a (possibly arbitrary) default type used by the JDBC
> > vendor.
>
> The types returned by rs.getObject() are not arbitrary; they are
> explicitly defined in the JDBC specification. Your proposal certainly
> looks more flexible than the current implementation. At least we designed
> with interfaces to make your interim solution possible :-).
>
> >
> > I would be happy to offer this code as a patch to BasicRowProcessor, as
> > an
> > alternate RowProcessor that extends BasicRowProcessor, or leave it up to
> > you guys to implement if you feel this is a good idea.
>
> Please open an enhancement ticket with a patch to BasicRowProcessor and
> test cases attached. We can review it further after we see the exact code
> changes.
>
> David
>
> >
> > Thanks,
> > Corby
> >
> >
> >
> > ---------------------------------------------------------------------
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> >
>
>
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