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edwardc8281
October 15, 2024
Question

refresh behavior in Interface

  • October 15, 2024
  • 6 replies
  • 0 views

I want to know the internal mechanism of local variable refreshing in an interface. When a local variable is refreshing, what is the underlying logic of the behavior? Is all code re-executed? Can you give me a conclusion and provide a demo to prove the conclusion.

6 replies

shubhama926776
shubhama926776
Brainy
October 15, 2024

This article might solve your all questions as different Local variables that are used within interfaces can refresh their values under a variety of conditions. 





https://docs.appian.com/suite/help/24.3/Local_Variables.html#:~:text=Local%20variables%20are%20a%20specific,data%20within%20a%20particular%20expression.

शुभम्
E
edwardc8281Author
October 16, 2024

I have read this article before I raise this ticket, it can't solve my question, I want to know some more underlying mechanisms or principles. Like when the refresh behavior is occurring whether the code which will be not refreshed will be re-executed?  

mikes0011
mikes0011
Brainy
October 17, 2024
I want to know some more underlying mechanisms or principles.

The underlying mechanics are not public and not published by Appian as far as I know.  We know only what the official docmentation tells us (and what we can infer from experimentation).

What is your use case / what are you trying to accomplish?

somasundaram.d
somasundaram.d
October 16, 2024

Appian had concepts of load() and with(),

If you use load(), the code engulfed by load will get evaluated only once. A local variable's value is only calculated the first time the expression is evaluated and is then loaded back into the expression each time the expression is evaluated again within the same context

If you use with(),it recalculates the local variable values after interactions. This recalculation always happens, even if the interaction's updates could not have impacted the variable's value

localVariables() can implement the functionality of load and with function for each local variable initialized using various refresh options in the a!refreshVariable function.

Please read through this for more related information

docs.appian.com/.../SAIL_Performance.html

E
edwardc8281Author
October 17, 2024

Is there any way to verify the conclusion?

somasundaram.d
somasundaram.d
October 17, 2024

Play around the code to verify

a!localVariables(
  local!counter:0,
  local!randomValue:a!refreshVariable(
    value: rand()
    /*refreshInterval: 0.5*/ /*Refresh every 30 seconds*/
    /*refreshOnReferencedVarChange: local!counter*/  /*Refresh when value of counter changes. Click on Add and see the change*/
    /*refreshAlways: true */  /* Refresh always*/
  ),
  {
    a!linkField(
      links: a!dynamicLink(
        label: "Add",
        saveInto: {
          a!save(
            local!counter,
            local!counter+1
          )
        }
      )
    ),
    a!textField(
      value: local!randomValue
    )
  }
)

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