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From Mark Payne <marka...@hotmail.com>
Subject Re: use attributed defined in the same UpdateAttribute processor
Date Fri, 17 May 2019 01:21:32 GMT
We could probably handle this without the user interface changing. The processor could be smart
enough to determine the proper ordering to evaluate the properties based on whether or not
it references another property. For example if properties are:

first.name = John
last.name = Doe
greeting = Hello, ${full.name}
full.name = ${first.name} ${last.name}

The processor does not currently order these in any ways. But it could be improved to determine
that full.name must be evaluated before greeting and both first.name and last.name must be
evaluated before full.name.

That way users wouldn’t have to manually order anything. If there were a circular reference
then the order could remain indeterminate and 2 processors could be used.

-Mark

Sent from my iPhone

On May 16, 2019, at 8:03 PM, Andy LoPresto <alopresto@apache.org<mailto:alopresto@apache.org>>
wrote:

You have to do this in two subsequent UpdateAttribute instances because the order of attribute
definition (within an instance) is not deterministic. We have gotten a lot of questions about
this, so perhaps it makes sense to investigate as a new feature. However, if that decision
is made, I think substantial changes to the interface would need to be made to allow for manual
reordering of property descriptors, which is not currently supported, and the transmission
of that data via the DTOs in the API would need to be changed as well, because JSON keys are
not ordered.

Andy LoPresto
alopresto@apache.org<mailto:alopresto@apache.org>
alopresto.apache@gmail.com<mailto:alopresto.apache@gmail.com>
PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4  BACE 3C6E F65B 2F7D EF69

On May 16, 2019, at 2:08 PM, Boris Tyukin <boris@boristyukin.com<mailto:boris@boristyukin.com>>
wrote:

Hi guys,

is it possible to reuse just defined attribute in another attribute in the same instance of
UpdateAttribute processor or I really have to use two separate UpdateAttribute processors?

For example, I define name=boris and then I want to add another attribute greetings=Hi ${name}

If I do it in NiFi 1.9, greetings attribute is set to "Hi "

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