How to concate Two ValueProvider and assign it to new ValueProvider?

Question

I want to concatenate the value of two ValueProvider<String> and assign it to a new ValueProvider<String> How I can achieve it?

ValueProvider<String> A; //if A = Nikhil;
ValueProvider<String> B; //if B = Suthar;
ValueProvider<String> C = A + B; //Then C = Nikhil Suthar;

I am aware about get and that will not work, I want ValueProvider not String — Nikhil Suthar, Jan 09 '23 at 13:05

score 2 · Accepted Answer · answered Jan 09 '23 at 17:33

2

You can combine different providers into one, see this as an example: https://github.com/GoogleCloudPlatform/DataflowTemplates/blob/main/v1/src/main/java/com/google/cloud/teleport/util/DualInputNestedValueProvider.java.

answered Jan 09 '23 at 17:33

Bruno Volpato

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Thanks, I am also working with this and trying to understand the logic. – Nikhil Suthar Jan 10 '23 at 05:45

score 0 · Answer 2 · answered Jan 08 '23 at 14:23

0

The ValueProvider provides a get() method (see Apache Beam). So you can do sth like this:

ValueProvider<String> a; 
ValueProvider<String> b; 
String c = a.get() + b.get();

answered Jan 08 '23 at 14:23

Roland J.

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4

I can not use get() first of all and secondly I don't want data as String Type. – Nikhil Suthar Jan 09 '23 at 13:04
@NikhilSuthar - Can you add a bit more detail on why you need the combined value as a ValueProvider? I'm guessing that you need to pass it into a built-in transform that take a ValueProvider, but would be good to specify. Roland's solution would work in runtime contexts such as in the body of a DoFn. – Jeff Klukas Jan 09 '23 at 15:01

score 0 · Answer 3 · answered Jan 09 '23 at 14:58

0

This question comes up from time to time (see Dataflow. ValueProvider. How to create from several options? for example) but there is not currently support for combining ValueProviders in the Beam Java SDK. NestedValueProvider is available for transforming a runtime parameter, but it doesn't support multiple inputs.

answered Jan 09 '23 at 14:58

Jeff Klukas

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yes, I had asked this question because of this limitation of NestedValueProvider. I am working on GCP Provided Method do DualNestedProvider, it should work. – Nikhil Suthar Jan 10 '23 at 05:46

score 0 · Answer 4 · answered Jan 12 '23 at 23:28

0

You could also look into using flex templates instead, which avoid having to worry about ValueProviders at all.

answered Jan 12 '23 at 23:28

robertwb

4,891
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How to concate Two ValueProvider and assign it to new ValueProvider?

4 Answers4