All that you have mentioned is implemented in the TypeExtractor. I just
mean corner cases e.g. if you have a POJO
public class MyPojo {
public Object field1;
public Object field2;
public Tuple2 field3;
}
Where the TypeExtractor can not analyze anything. Then you may want to
provide the TypeInfo manually. TypeInfoParser makes it easy to specify
the types of the fields of POJOs manually (but only as an internal
feature). But as I said this just a corner case.
Timo
On 18.11.2015 18:43, Stephan Ewen wrote:
I think the TypeHints case can cover this:
public class MyPojo<T, R> {
public T field1;
public R field2;
}
If you say '.returns(new TypeHint<MyPojo<String, Double>>() {})' this
creates an anonymous subclass of the TypeHint, which has the types that T
and R bind to, which allows one to construct the POJO type info properly.
(Not sure if all that is implemented in the TypeExtractor, though).
What do you think?
Stephan
On Wed, Nov 18, 2015 at 6:03 PM, Timo Walther <twal...@apache.org> wrote:
If the TypeExtractor is not able to handle the fields of a Pojo correctly,
the String parser is quite useful to say
"org.my.Pojo<field1=Tuple2<String,Long>>". Doing this with TypeInformation
classes is terrible. But I think this a corner case we can ignore. I would
also remove the ".returns(String)" in favor of TypeHints, but let the
TypeInfoParser remain in a typeutils package (internal tool).
Regards,
Timo
On 18.11.2015 16:47, Stephan Ewen wrote:
If we want to drop any of the possible ".returns(...)" methods (like class
or string) we should do that now.
The "class" method is probably redundant anyways, as the hints are only
necessary in generics are involved (where class does not help anyways).
@Timo: What can the String do what the TypeHint cannot do?
On Wed, Nov 11, 2015 at 9:06 PM, Timo Walther <twal...@apache.org> wrote:
+1
It's still hacky but we don't have better alternatives.
I'm not 100% sure if we can get rid of the parser. I think it's still a
nice way for quickly defining the fields of a POJO if the type extractor
fails to analyze it. But actually I don't know an example where it fails.
Regards,
Timo
On 11.11.2015 19:56, Aljoscha Krettek wrote:
Big +1
Of course, we had the initial talk about it… :D
On 11 Nov 2015, at 19:33, Kirschnick, Johannes <
johannes.kirschn...@tu-berlin.de> wrote:
Hi Stephan,
looking at the TypeHint, I got reminded on how Gson (a Json Parser)
handles this situation of parsing generics.
See here for an overview
https://sites.google.com/site/gson/gson-user-guide#TOC-Serializing-and-Deserializing-Generic-Types
Seems like this method was rediscovered :) And maybe there are some
tricks that can be learned from the implementation
I'm all in favor for "hard" types over string literals.
Johannes
P.S.
Apparently GWT uses the same "trick" to handle generics ...
-----Ursprüngliche Nachricht-----
Von: ewenstep...@gmail.com [mailto:ewenstep...@gmail.com] Im Auftrag
von Stephan Ewen
Gesendet: Mittwoch, 11. November 2015 15:53
An: dev@flink.apache.org
Betreff: [DISCUSSION] Type hints versus TypeInfoParser
Hi all!
We discovered a nice way to give TypeHints in the Google Cloud Dataflow
SDK, in a way that would fit Flink perfectly. I created a JIRA for
that:
https://issues.apache.org/jira/browse/FLINK-2788
Since this is more powerful and type safe than the String/Parser way of
giving hints, I was wondering whether we should add this and deprecate
the
String variant. If we do that, 1.0 is the time to do that.
What do you think about this idea?
@Timo Walther Since you worked a lot on types/parser/etc - what is your
take on this?
Greetings,
Stephan
