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Posted to user-java@ibatis.apache.org by Nathan Maves <Na...@Sun.COM> on 2005/05/27 22:17:31 UTC
Support for generics
Since apple is taking then sweet time I just got Java 1.5. I am
diving in head first but I am curious about what the plans for
Generics are.
Will I batis support them?
Could there be a way to specify the list type instead of Object?
i.e.
return a List<Student> back based on the result class of the query?
Nathan
Re: Support for generics
Posted by Brandon Goodin <br...@gmail.com>.
Possibly the new early binding functionality (in the TRUNK) will allow
for you to use generic typing for your lists then you wouldn't need to
cast them. But, that is an untested suggestion.
Brandon
On 5/27/05, Larry Meadors <la...@gmail.com> wrote:
> I have done that with my DAO layer.
>
> SqlMap returns it as List, but you can cast it.
>
> Worked great. :)
>
> Larry
>
>
> On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> > Since apple is taking then sweet time I just got Java 1.5. I am
> > diving in head first but I am curious about what the plans for
> > Generics are.
> >
> > Will I batis support them?
> > Could there be a way to specify the list type instead of Object?
> >
> > i.e.
> > return a List<Student> back based on the result class of the query?
> >
> > Nathan
> >
> >
>
Re: Support for generics
Posted by Gilles Bayon <ib...@gmail.com>.
See page on Wiki
http://opensource.atlassian.com/confluence/oss/pages/viewpage.action?pageId=70
Re: Support for generics
Posted by Clinton Begin <cl...@gmail.com>.
Or if you have VirtualPC, I suppose you could use TortoiseSVN:
http://tortoisesvn.tigris.org/
Clinton
On 5/28/05, Clinton Begin <cl...@gmail.com> wrote:
>
>
> Oh....mac boy. :-) No tortoise for you. Here's a couple of clients for
> you:
>
>
> http://www.lachoseinteractive.net/en/community/subversion/svnx/features/?tk=dhpdtufrfdifnuroa9fqd351h2
> http://smartcvs.com/smartsvn/index.html
>
> Our public Subversion URL is
> http://svn.apache.org/repos/asf/incubator/ibatis/trunk/site
>
> **URL will change soon, once we're out of the incubator.
>
> Other than that, from a client perspective it's pretty much like CVS, but
> with way better version control.
>
> Cheers,
> Clinton
>
> Cheers,
> Clinton
>
>
> On 5/28/05, Nathan Maves <Na...@sun.com> wrote:
> >
> > Hate to be the rookie, only CVS experience, but do we have a page the
> > explains how to get the source from subversion?
> >
> >
> > On May 27, 2005, at 9:09 PM, Brandon Goodin wrote:
> >
> > > yes, build it from the trunk.
> > >
> > > On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> > >> Of course!
> > >>
> > >> Do I need to build it from the trunk?
> > >>
> > >> Nathan
> > >>
> > >> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
> > >>
> > >>>
> > >>> I believe the new Mapper binding functionality would resolve
> > >>> this....
> > >>>
> > >>> Nathan, are you up for trying it out?
> > >>>
> > >>> Cheers,
> > >>> Clinton
> > >>>
> > >>>
> > >>> On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> > >>>> gets to the DAO layer.
> > >>>>
> > >>>> You can cast the List but you will always get the warning for and
> > >>>> unchecked assignment when the List is returned from the sqlmap.
> > >>>>
> > >>>> List<Student> students = (List<Student>)executeQueryForList
> > >>>> ("getStudents",null);
> > >>>>
> > >>>> Looks good but does not resolve the warnings.
> > >>>>
> > >>>> Nathan
> > >>>>
> > >>>>
> > >>>> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> > >>>>
> > >>>>> I have done that with my DAO layer.
> > >>>>>
> > >>>>> SqlMap returns it as List, but you can cast it.
> > >>>>>
> > >>>>> Worked great. :)
> > >>>>>
> > >>>>> Larry
> > >>>>>
> > >>>>>
> > >>>>> On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> > >>>>>
> > >>>>>> Since apple is taking then sweet time I just got Java 1.5.I am
> > >>>>>> diving in head first but I am curious about what the plans for
> > >>>>>> Generics are.
> > >>>>>>
> > >>>>>> Will I batis support them?
> > >>>>>> Could there be a way to specify the list type instead of Object?
> > >>>>>>
> > >>>>>> i.e.
> > >>>>>> return a List<Student> back based on the result class of the
> > >>>>>> query?
> > >>>>>>
> > >>>>>> Nathan
> > >>>>>>
> > >>>>>>
> > >>>>>
> > >>>>
> > >>
> > >>
> >
> >
>
Re: Support for generics
Posted by Clinton Begin <cl...@gmail.com>.
Oh....mac boy. :-) No tortoise for you. Here's a couple of clients for you:
http://www.lachoseinteractive.net/en/community/subversion/svnx/features/?tk=dhpdtufrfdifnuroa9fqd351h2
http://smartcvs.com/smartsvn/index.html
Our public Subversion URL is
http://svn.apache.org/repos/asf/incubator/ibatis/trunk/site
**URL will change soon, once we're out of the incubator.
Other than that, from a client perspective it's pretty much like CVS, but
with way better version control.
Cheers,
Clinton
Cheers,
Clinton
On 5/28/05, Nathan Maves <Na...@sun.com> wrote:
>
> Hate to be the rookie, only CVS experience, but do we have a page the
> explains how to get the source from subversion?
>
>
> On May 27, 2005, at 9:09 PM, Brandon Goodin wrote:
>
> > yes, build it from the trunk.
> >
> > On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> >> Of course!
> >>
> >> Do I need to build it from the trunk?
> >>
> >> Nathan
> >>
> >> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
> >>
> >>>
> >>> I believe the new Mapper binding functionality would resolve
> >>> this....
> >>>
> >>> Nathan, are you up for trying it out?
> >>>
> >>> Cheers,
> >>> Clinton
> >>>
> >>>
> >>> On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> >>>> gets to the DAO layer.
> >>>>
> >>>> You can cast the List but you will always get the warning for and
> >>>> unchecked assignment when the List is returned from the sqlmap.
> >>>>
> >>>> List<Student> students = (List<Student>)executeQueryForList
> >>>> ("getStudents",null);
> >>>>
> >>>> Looks good but does not resolve the warnings.
> >>>>
> >>>> Nathan
> >>>>
> >>>>
> >>>> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> >>>>
> >>>>> I have done that with my DAO layer.
> >>>>>
> >>>>> SqlMap returns it as List, but you can cast it.
> >>>>>
> >>>>> Worked great. :)
> >>>>>
> >>>>> Larry
> >>>>>
> >>>>>
> >>>>> On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> >>>>>
> >>>>>> Since apple is taking then sweet time I just got Java 1.5.I am
> >>>>>> diving in head first but I am curious about what the plans for
> >>>>>> Generics are.
> >>>>>>
> >>>>>> Will I batis support them?
> >>>>>> Could there be a way to specify the list type instead of Object?
> >>>>>>
> >>>>>> i.e.
> >>>>>> return a List<Student> back based on the result class of the
> >>>>>> query?
> >>>>>>
> >>>>>> Nathan
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>
> >>
>
>
Re: Support for generics
Posted by Nathan Maves <Na...@Sun.COM>.
Hate to be the rookie, only CVS experience, but do we have a page the
explains how to get the source from subversion?
On May 27, 2005, at 9:09 PM, Brandon Goodin wrote:
> yes, build it from the trunk.
>
> On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
>> Of course!
>>
>> Do I need to build it from the trunk?
>>
>> Nathan
>>
>> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
>>
>>>
>>> I believe the new Mapper binding functionality would resolve
>>> this....
>>>
>>> Nathan, are you up for trying it out?
>>>
>>> Cheers,
>>> Clinton
>>>
>>>
>>> On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
>>>> gets to the DAO layer.
>>>>
>>>> You can cast the List but you will always get the warning for and
>>>> unchecked assignment when the List is returned from the sqlmap.
>>>>
>>>> List<Student> students = (List<Student>)executeQueryForList
>>>> ("getStudents",null);
>>>>
>>>> Looks good but does not resolve the warnings.
>>>>
>>>> Nathan
>>>>
>>>>
>>>> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
>>>>
>>>>> I have done that with my DAO layer.
>>>>>
>>>>> SqlMap returns it as List, but you can cast it.
>>>>>
>>>>> Worked great. :)
>>>>>
>>>>> Larry
>>>>>
>>>>>
>>>>> On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
>>>>>
>>>>>> Since apple is taking then sweet time I just got Java 1.5.I am
>>>>>> diving in head first but I am curious about what the plans for
>>>>>> Generics are.
>>>>>>
>>>>>> Will I batis support them?
>>>>>> Could there be a way to specify the list type instead of Object?
>>>>>>
>>>>>> i.e.
>>>>>> return a List<Student> back based on the result class of the
>>>>>> query?
>>>>>>
>>>>>> Nathan
>>>>>>
>>>>>>
>>>>>
>>>>
>>
>>
Re: Support for generics
Posted by Brandon Goodin <br...@gmail.com>.
yes, build it from the trunk.
On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> Of course!
>
> Do I need to build it from the trunk?
>
> Nathan
>
> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
>
> >
> > I believe the new Mapper binding functionality would resolve this....
> >
> > Nathan, are you up for trying it out?
> >
> > Cheers,
> > Clinton
> >
> >
> > On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> >> gets to the DAO layer.
> >>
> >> You can cast the List but you will always get the warning for and
> >> unchecked assignment when the List is returned from the sqlmap.
> >>
> >> List<Student> students = (List<Student>)executeQueryForList
> >> ("getStudents",null);
> >>
> >> Looks good but does not resolve the warnings.
> >>
> >> Nathan
> >>
> >>
> >> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> >>
> >> > I have done that with my DAO layer.
> >> >
> >> > SqlMap returns it as List, but you can cast it.
> >> >
> >> > Worked great. :)
> >> >
> >> > Larry
> >> >
> >> >
> >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> >> >
> >> >> Since apple is taking then sweet time I just got Java 1.5.I am
> >> >> diving in head first but I am curious about what the plans for
> >> >> Generics are.
> >> >>
> >> >> Will I batis support them?
> >> >> Could there be a way to specify the list type instead of Object?
> >> >>
> >> >> i.e.
> >> >> return a List<Student> back based on the result class of the query?
> >> >>
> >> >> Nathan
> >> >>
> >> >>
> >> >
> >>
>
>
Re: Support for generics
Posted by Nathan Maves <Na...@Sun.COM>.
Of course!
Do I need to build it from the trunk?
Nathan
On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
>
> I believe the new Mapper binding functionality would resolve this....
>
> Nathan, are you up for trying it out?
>
> Cheers,
> Clinton
>
>
> On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
>> gets to the DAO layer.
>>
>> You can cast the List but you will always get the warning for and
>> unchecked assignment when the List is returned from the sqlmap.
>>
>> List<Student> students = (List<Student>)executeQueryForList
>> ("getStudents",null);
>>
>> Looks good but does not resolve the warnings.
>>
>> Nathan
>>
>>
>> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
>>
>> > I have done that with my DAO layer.
>> >
>> > SqlMap returns it as List, but you can cast it.
>> >
>> > Worked great. :)
>> >
>> > Larry
>> >
>> >
>> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
>> >
>> >> Since apple is taking then sweet time I just got Java 1.5. I am
>> >> diving in head first but I am curious about what the plans for
>> >> Generics are.
>> >>
>> >> Will I batis support them?
>> >> Could there be a way to specify the list type instead of Object?
>> >>
>> >> i.e.
>> >> return a List<Student> back based on the result class of the query?
>> >>
>> >> Nathan
>> >>
>> >>
>> >
>>
Re: Support for generics
Posted by Brandon Goodin <br...@gmail.com>.
"If I were to ditch a layer in this 5 layer cake, I'd ditch the DAOs. :-)"
Well, i wounldn't say ditch the DAO layer. I'd say make the Mapping
interface your DAO layer.
"I'm personally not a fan of code generation at all."
I believe it would be possible to create a tool that makes the
creation and maintenance of the mapping interface easier. Currently I
have begun prototyping an iBatis GUI tool. I do not like build time
code generation with Ant. But, I DO like incremental and intentional
code generation that cuts down on keystrokes. I think we can all
appreciate the setter/getter code generation in each of our favorite
IDEs. The iBatis GUI looks to be that kind of tool for iBatis
development.
Brandon
On 5/29/05, Clinton Begin <cl...@gmail.com> wrote:
> Sorry, I accidentally replied to Nathan only.
>
> ---------- Forwarded message ----------
> From: Clinton Begin <clinton.begin@gmail.com >
> Date: May 29, 2005 9:56 AM
> Subject: Re: Support for generics
> To: Nathan Maves <Na...@sun.com>
>
>
> I understand that that is possible. I'm personally not a fan of code
> generation at all. In this case I think it would be especially impractical.
> I've never just sat down and coded all of my SQL mapping files up front,
> which would be necessary if we were to generate the interface. I suppose we
> could regenerate it after each change, but what a yucky programming
> paradigm. By the time we've set up the Ant build, the SQL Mapper interface
> generator task, and all of our SQL Maps, I could have typed a lot of
> interfaces!
>
> I think one of the best benefits of this approach is that you can very
> easily test drive your persistence layer.
>
> You can start with a test:
>
> public void testShouldGetDocumentWithIDofOne () {
> DocumentMapper mapper = new MockDocumentMapper(); //or use your
> favourite mocking framework
> Document doc = mapper.getDocument(i);
> assertNotNull (doc);
> assertEquals (1, doc.getId());
> }
>
> You can create the interface and the mock:
>
> public interface DocumentMapper {
> Document getDocument (int id);
> }
>
> public class MockDocumentMapper implements DocumentMapper {
> public Document getDocument (int id) {
> return new Document (id);
> }
> }
>
> All without an SqlMapClient. Of course all we're really testing in this
> example is an interface, but what this allows you to do is more easily test
> of consumers of the mapping layer (DAOs). For example, if you have a DAO
> that depends on a Mapper, you can more easily test the DAO without an
> SqlMapClient instance (or any persistence related mocks):
>
> public class SqlMapDocumentDao extends SqlMapDaoTemplate {
>
> private DocumentMapper documentMapper;
>
> // Used by the DAO framework
> public SqlMapDocumentDao (DaoManager daoManager) {
> super(daoManager);
> // this next method isn't part of the DAO template yet
> documentMapper = (DocumentMapper) getMapper(DocumentMapper.class);
> }
>
> // Used by unit tests
> public SqlMapDocumentDao (DocumentMapper documentMapper) {
> this.documentMapper = documentMapper;
> }
>
> }
>
> I know it looks like a lot of code, and indeed we'd want to question the
> value of using both DAO and Mapper interfaces (too much abstraction). The
> testing approach described above works just as well at the service layer
> (i.e. without DAOs), or even at the presentation layer (i.e. without a
> service layer -spank!). I think this gives us a cleaner alternative model
> for when we don't use DAOs, and a more layered model if we want maximum
> abstraction (limited value, but it's there).
>
> If I were to ditch a layer in this 5 layer cake, I'd ditch the DAOs. :-)
>
>
> Cheers,
> Clinton
>
>
> On 5/28/05, Nathan Maves <Nathan.Maves@sun.com > wrote:
> > Clinton,
> >
> > First off thanks. I will get it a go this week.
> >
> > As per Fabrizio response to the email below, I agree that this process
> > of creating interfaces is too programatic. By that it would seem to me
> > that these interfaces could be created automatically when parsing the
> > sql map files. All you would need to do is create a method based on
> > the id, resultClass and the parameterClass.
> >
> > Am I way of in thinking this?
> >
> > Nathan
> >
> > On May 28, 2005, at 10:36 PM, Clinton Begin wrote:
> >
> > >
> > >
> http://www.mail-archive.com/ibatis-user-java@incubator.apache.org/
> > > msg02403.html
> > >
> > > Cheers,
> > > Clinton
> > >
> > > On 5/28/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> > >> to use the Mapper binding functionality.
> > >>
> > >> Nathan
> > >>
> > >> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
> > >>
> > >> >
> > >> >I believe the new Mapper binding functionality would resolve
> > >> this....
> > >> >
> > >> >Nathan, are you up for trying it out?
> > >> >
> > >> >Cheers,
> > >> >Clinton
> > >> >
> > >> >
> > >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> > >> >> gets to the DAO layer.
> > >> >>
> > >> >> You can cast the List but you will always get the warning for and
> > >> >> unchecked assignment when the List is returned from the sqlmap.
> > >> >>
> > >> >> List<Student> students =
> (List<Student>)executeQueryForList
> > >> >> ("getStudents",null);
> > >> >>
> > >> >> Looks good but does not resolve the warnings.
> > >> >>
> > >> >> Nathan
> > >> >>
> > >> >>
> > >> >> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> > >> >>
> > >> >> > I have done that with my DAO layer.
> > >> >> >
> > >> >> > SqlMap returns it as List, but you can cast it.
> > >> >> >
> > >> >> > Worked great. :)
> > >> >> >
> > >> >> > Larry
> > >> >> >
> > >> >> >
> > >> >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com > wrote:
> > >> >> >
> > >> >> >> Since apple is taking then sweet time I just got Java 1.5.I am
> > >> >> >> diving in head first but I am curious about what the plans for
> > >> >> >> Generics are.
> > >> >> >>
> > >> >> >> Will I batis support them?
> > >> >> >> Could there be a way to specify the list type instead of Object?
> > >> >> >>
> > >> >> >> i.e.
> > >> >> >> return a List<Student> back based on the result class of the
> > >> query?
> > >> >> >>
> > >> >> >> Nathan
> > >> >> >>
> > >> >> >>
> > >> >> >
> > >> >>
> > >>
> >
> >
>
>
Fwd: Support for generics
Posted by Clinton Begin <cl...@gmail.com>.
Sorry, I accidentally replied to Nathan only.
---------- Forwarded message ----------
From: Clinton Begin <cl...@gmail.com>
Date: May 29, 2005 9:56 AM
Subject: Re: Support for generics
To: Nathan Maves <Na...@sun.com>
I understand that that is possible. I'm personally not a fan of code
generation at all. In this case I think it would be especially impractical.
I've never just sat down and coded all of my SQL mapping files up front,
which would be necessary if we were to generate the interface. I suppose we
could regenerate it after each change, but what a yucky programming
paradigm. By the time we've set up the Ant build, the SQL Mapper interface
generator task, and all of our SQL Maps, I could have typed a lot of
interfaces!
I think one of the best benefits of this approach is that you can very
easily test drive your persistence layer.
You can start with a test:
public void testShouldGetDocumentWithIDofOne () {
DocumentMapper mapper = new MockDocumentMapper(); //or use your favourite
mocking framework
Document doc = mapper.getDocument(i);
assertNotNull (doc);
assertEquals (1, doc.getId());
}
You can create the interface and the mock:
public interface DocumentMapper {
Document getDocument (int id);
}
public class MockDocumentMapper implements DocumentMapper {
public Document getDocument (int id) {
return new Document (id);
}
}
All without an SqlMapClient. Of course all we're really testing in this
example is an interface, but what this allows you to do is more easily test
of consumers of the mapping layer (DAOs). For example, if you have a DAO
that depends on a Mapper, you can more easily test the DAO without an
SqlMapClient instance (or any persistence related mocks):
public class SqlMapDocumentDao extends SqlMapDaoTemplate {
private DocumentMapper documentMapper;
// Used by the DAO framework
public SqlMapDocumentDao (DaoManager daoManager) {
super(daoManager);
// this next method isn't part of the DAO template yet
documentMapper = (DocumentMapper) getMapper(DocumentMapper.class);
}
// Used by unit tests
public SqlMapDocumentDao (DocumentMapper documentMapper) {
this.documentMapper = documentMapper;
}
}
I know it looks like a lot of code, and indeed we'd want to question the
value of using both DAO and Mapper interfaces (too much abstraction). The
testing approach described above works just as well at the service layer (
i.e. without DAOs), or even at the presentation layer (i.e. without a
service layer -spank!). I think this gives us a cleaner alternative model
for when we don't use DAOs, and a more layered model if we want maximum
abstraction (limited value, but it's there).
If I were to ditch a layer in this 5 layer cake, I'd ditch the DAOs. :-)
Cheers,
Clinton
On 5/28/05, Nathan Maves <Na...@sun.com> wrote:
>
> Clinton,
>
> First off thanks. I will get it a go this week.
>
> As per Fabrizio response to the email below, I agree that this process
> of creating interfaces is too programatic. By that it would seem to me
> that these interfaces could be created automatically when parsing the
> sql map files. All you would need to do is create a method based on
> the id, resultClass and the parameterClass.
>
> Am I way of in thinking this?
>
> Nathan
>
> On May 28, 2005, at 10:36 PM, Clinton Begin wrote:
>
> >
> > http://www.mail-archive.com/ibatis-user-java@incubator.apache.org/
> > msg02403.html
> >
> > Cheers,
> > Clinton
> >
> > On 5/28/05, Nathan Maves <Na...@sun.com> wrote:
> >> to use the Mapper binding functionality.
> >>
> >> Nathan
> >>
> >> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
> >>
> >> >
> >> >I believe the new Mapper binding functionality would resolve
> >> this....
> >> >
> >> >Nathan, are you up for trying it out?
> >> >
> >> >Cheers,
> >> >Clinton
> >> >
> >> >
> >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> >> >> gets to the DAO layer.
> >> >>
> >> >> You can cast the List but you will always get the warning for and
> >> >> unchecked assignment when the List is returned from the sqlmap.
> >> >>
> >> >> List<Student> students = (List<Student>)executeQueryForList
> >> >> ("getStudents",null);
> >> >>
> >> >> Looks good but does not resolve the warnings.
> >> >>
> >> >> Nathan
> >> >>
> >> >>
> >> >> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> >> >>
> >> >> > I have done that with my DAO layer.
> >> >> >
> >> >> > SqlMap returns it as List, but you can cast it.
> >> >> >
> >> >> > Worked great. :)
> >> >> >
> >> >> > Larry
> >> >> >
> >> >> >
> >> >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> >> >> >
> >> >> >> Since apple is taking then sweet time I just got Java 1.5.I am
> >> >> >> diving in head first but I am curious about what the plans for
> >> >> >> Generics are.
> >> >> >>
> >> >> >> Will I batis support them?
> >> >> >> Could there be a way to specify the list type instead of Object?
> >> >> >>
> >> >> >> i.e.
> >> >> >> return a List<Student> back based on the result class of the
> >> query?
> >> >> >>
> >> >> >> Nathan
> >> >> >>
> >> >> >>
> >> >> >
> >> >>
> >>
>
>
Fwd: Support for generics
Posted by Clinton Begin <cl...@gmail.com>.
Sorry, I accidentally replied to Nathan only.
---------- Forwarded message ----------
From: Clinton Begin <cl...@gmail.com>
Date: May 29, 2005 9:56 AM
Subject: Re: Support for generics
To: Nathan Maves <Na...@sun.com>
I understand that that is possible. I'm personally not a fan of code
generation at all. In this case I think it would be especially impractical.
I've never just sat down and coded all of my SQL mapping files up front,
which would be necessary if we were to generate the interface. I suppose we
could regenerate it after each change, but what a yucky programming
paradigm. By the time we've set up the Ant build, the SQL Mapper interface
generator task, and all of our SQL Maps, I could have typed a lot of
interfaces!
I think one of the best benefits of this approach is that you can very
easily test drive your persistence layer.
You can start with a test:
public void testShouldGetDocumentWithIDofOne () {
DocumentMapper mapper = new MockDocumentMapper(); //or use your favourite
mocking framework
Document doc = mapper.getDocument(i);
assertNotNull (doc);
assertEquals (1, doc.getId());
}
You can create the interface and the mock:
public interface DocumentMapper {
Document getDocument (int id);
}
public class MockDocumentMapper implements DocumentMapper {
public Document getDocument (int id) {
return new Document (id);
}
}
All without an SqlMapClient. Of course all we're really testing in this
example is an interface, but what this allows you to do is more easily test
of consumers of the mapping layer (DAOs). For example, if you have a DAO
that depends on a Mapper, you can more easily test the DAO without an
SqlMapClient instance (or any persistence related mocks):
public class SqlMapDocumentDao extends SqlMapDaoTemplate {
private DocumentMapper documentMapper;
// Used by the DAO framework
public SqlMapDocumentDao (DaoManager daoManager) {
super(daoManager);
// this next method isn't part of the DAO template yet
documentMapper = (DocumentMapper) getMapper(DocumentMapper.class);
}
// Used by unit tests
public SqlMapDocumentDao (DocumentMapper documentMapper) {
this.documentMapper = documentMapper;
}
}
I know it looks like a lot of code, and indeed we'd want to question the
value of using both DAO and Mapper interfaces (too much abstraction). The
testing approach described above works just as well at the service layer (
i.e. without DAOs), or even at the presentation layer (i.e. without a
service layer -spank!). I think this gives us a cleaner alternative model
for when we don't use DAOs, and a more layered model if we want maximum
abstraction (limited value, but it's there).
If I were to ditch a layer in this 5 layer cake, I'd ditch the DAOs. :-)
Cheers,
Clinton
On 5/28/05, Nathan Maves <Na...@sun.com> wrote:
>
> Clinton,
>
> First off thanks. I will get it a go this week.
>
> As per Fabrizio response to the email below, I agree that this process
> of creating interfaces is too programatic. By that it would seem to me
> that these interfaces could be created automatically when parsing the
> sql map files. All you would need to do is create a method based on
> the id, resultClass and the parameterClass.
>
> Am I way of in thinking this?
>
> Nathan
>
> On May 28, 2005, at 10:36 PM, Clinton Begin wrote:
>
> >
> > http://www.mail-archive.com/ibatis-user-java@incubator.apache.org/
> > msg02403.html
> >
> > Cheers,
> > Clinton
> >
> > On 5/28/05, Nathan Maves <Na...@sun.com> wrote:
> >> to use the Mapper binding functionality.
> >>
> >> Nathan
> >>
> >> On May 27, 2005, at 8:32 PM, Clinton Begin wrote:
> >>
> >> >
> >> >I believe the new Mapper binding functionality would resolve
> >> this....
> >> >
> >> >Nathan, are you up for trying it out?
> >> >
> >> >Cheers,
> >> >Clinton
> >> >
> >> >
> >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> >> >> gets to the DAO layer.
> >> >>
> >> >> You can cast the List but you will always get the warning for and
> >> >> unchecked assignment when the List is returned from the sqlmap.
> >> >>
> >> >> List<Student> students = (List<Student>)executeQueryForList
> >> >> ("getStudents",null);
> >> >>
> >> >> Looks good but does not resolve the warnings.
> >> >>
> >> >> Nathan
> >> >>
> >> >>
> >> >> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> >> >>
> >> >> > I have done that with my DAO layer.
> >> >> >
> >> >> > SqlMap returns it as List, but you can cast it.
> >> >> >
> >> >> > Worked great. :)
> >> >> >
> >> >> > Larry
> >> >> >
> >> >> >
> >> >> > On 5/27/05, Nathan Maves < Nathan.Maves@sun.com> wrote:
> >> >> >
> >> >> >> Since apple is taking then sweet time I just got Java 1.5.I am
> >> >> >> diving in head first but I am curious about what the plans for
> >> >> >> Generics are.
> >> >> >>
> >> >> >> Will I batis support them?
> >> >> >> Could there be a way to specify the list type instead of Object?
> >> >> >>
> >> >> >> i.e.
> >> >> >> return a List<Student> back based on the result class of the
> >> query?
> >> >> >>
> >> >> >> Nathan
> >> >> >>
> >> >> >>
> >> >> >
> >> >>
> >>
>
>
Re: Support for generics
Posted by Clinton Begin <cl...@gmail.com>.
I believe the new Mapper binding functionality would resolve this....
Nathan, are you up for trying it out?
Cheers,
Clinton
On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
>
> Yeah, I have used generics everywhere but the missing link is when it
> gets to the DAO layer.
>
> You can cast the List but you will always get the warning for and
> unchecked assignment when the List is returned from the sqlmap.
>
> List<Student> students = (List<Student>)executeQueryForList
> ("getStudents",null);
>
> Looks good but does not resolve the warnings.
>
> Nathan
>
>
> On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
>
> > I have done that with my DAO layer.
> >
> > SqlMap returns it as List, but you can cast it.
> >
> > Worked great. :)
> >
> > Larry
> >
> >
> > On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> >
> >> Since apple is taking then sweet time I just got Java 1.5. I am
> >> diving in head first but I am curious about what the plans for
> >> Generics are.
> >>
> >> Will I batis support them?
> >> Could there be a way to specify the list type instead of Object?
> >>
> >> i.e.
> >> return a List<Student> back based on the result class of the query?
> >>
> >> Nathan
> >>
> >>
> >
>
>
Re: Support for generics
Posted by Nathan Maves <Na...@Sun.COM>.
Yeah, I have used generics everywhere but the missing link is when it
gets to the DAO layer.
You can cast the List but you will always get the warning for and
unchecked assignment when the List is returned from the sqlmap.
List<Student> students = (List<Student>)executeQueryForList
("getStudents",null);
Looks good but does not resolve the warnings.
Nathan
On May 27, 2005, at 2:30 PM, Larry Meadors wrote:
> I have done that with my DAO layer.
>
> SqlMap returns it as List, but you can cast it.
>
> Worked great. :)
>
> Larry
>
>
> On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
>
>> Since apple is taking then sweet time I just got Java 1.5. I am
>> diving in head first but I am curious about what the plans for
>> Generics are.
>>
>> Will I batis support them?
>> Could there be a way to specify the list type instead of Object?
>>
>> i.e.
>> return a List<Student> back based on the result class of the query?
>>
>> Nathan
>>
>>
>
Re: Support for generics
Posted by Larry Meadors <la...@gmail.com>.
I have done that with my DAO layer.
SqlMap returns it as List, but you can cast it.
Worked great. :)
Larry
On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> Since apple is taking then sweet time I just got Java 1.5. I am
> diving in head first but I am curious about what the plans for
> Generics are.
>
> Will I batis support them?
> Could there be a way to specify the list type instead of Object?
>
> i.e.
> return a List<Student> back based on the result class of the query?
>
> Nathan
>
>
Re: Support for generics
Posted by Brandon Goodin <br...@gmail.com>.
This is definitely on our list to do... sometime :-p. But, it is a
matter of compatibility. We have talked about creating a special
ibatis version to take advantage of some of the java 5 features. But,
we haven't really looked into it real deep and don't know what it
would take to accomplish it and if it is something we need to add to
ibatis.
Have you tried to simply use generics with ibatis?
Brandon
On 5/27/05, Nathan Maves <Na...@sun.com> wrote:
> Since apple is taking then sweet time I just got Java 1.5. I am
> diving in head first but I am curious about what the plans for
> Generics are.
>
> Will I batis support them?
> Could there be a way to specify the list type instead of Object?
>
> i.e.
> return a List<Student> back based on the result class of the query?
>
> Nathan
>
>