If you have a function which given X returns a List<ABC>, you can use FlatMapElements <https://beam.apache.org/documentation/sdks/javadoc/2.4.0/org/apache/beam/sdk/transforms/FlatMapElements.html> transform on PCollection<X> to get a PCollection<ABC>.
On Thu, Jun 7, 2018 at 8:16 AM S. Sahayaraj <[email protected]> wrote: > In case if we could return List<ABC> from DoFn<> then we could use the > code as suggested in section 3.1.2 and mentioned by you below., but the > return type of DoFn<> is always PCollection<> in where I could not have the > list of ABC objects which further will be fed as input for parallel > computation. Is there any possibility to convert List<ABC> to > PCollection<ABC> in DoFn<> itself? OR can DoFn<> return List<ABC> objects? > > > > > > Cheers, > > S. Sahayaraj > > > > *From:* Robert Bradshaw [mailto:[email protected]] > *Sent:* Wednesday, June 6, 2018 9:40 PM > *To:* [email protected] > *Subject:* [EXTERNAL] - Re: Create PCollection<ABC> from List<ABC>in > DoFn<> > > > > You can use the Create transform to do this, e.g. > > > > Pipeline p = ... > > List<ABC> inMemoryObjects = ... > > PCollection<ABC> pcollectionOfObject = p.apply(Create.of( > inMemoryObjects)); > > result = pcollectionOfObject.apply(ParDo.of(SomeDoFn...)); > > > > See section 3.1.2 at > https://beam.apache.org/documentation/programming-guide/#pcollections > > > > On Wed, Jun 6, 2018 at 8:34 AM S. Sahayaraj <[email protected]> wrote: > > Hello, > > I have created a java class which extends DoFn<>, there > are list of objects of type ABC (List<ABC>) populated in > processElement(ProcessContext c) at runtime and would like to generate > respective PCollection<ABC> from List<ABC> so that the subsequent > transformation can do parallel execution on each ABC object in > PCollection<ABC>. How do we create PCollection from in-memory object > created in DoFn<>? OR How do we get pipeline object being in DoFn<>? OR is > there any SDK guidelines to refer? > > > > > > Thanks, > > S. Sahayaraj > >
