Mule 3 DataWeave(1.x) Script To Resolve Wildcard Dynamically

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Mulesoft DataWeave is a simple powerful tool to transform data inside a flow. Numerous core operators and functions are already present to perform various operations such as capitalize, camelize, upper, and lower.

For string operations, there are no core functions present to resolve a wildcard. I hope the DataWeave(DWL 1.0) function below helps you to perform a requirement where you want to resolve a wildcard using a set of parameters.

Steps

Goal To Achieve Below:

Java
  
Input: "This is to test wildcards.1st wildcard {1}, 2nd wildcard {2}, Nth wildcard {n}"
Output: "This is to test wildcards.1st wildcard 1, 2nd wildcard 2, Nth wildcard Wn"
  Assuming passing set of wildcards as [1,2,"Wn"]

DataWeave Code:

TypeScript-JSX
  
%dw 1.0
%output application/json

%var inputString = "This is to test wildcards.1st wildcard {1}, 2nd wildcard {2}, Nth wildcard {n}"
%function reolveParam(unresolvedString,parameters=[]) 
	using(propArr=unresolvedString splitBy /\{\w*\}/)
		((flatten (propArr zip parameters) reduce ($$ ++ $)) when ((sizeOf propArr) > 1 ) otherwise unresolvedString)
---

reolveParam(inputString,[1,2,"Wn"])

Explanation: 

Here in the above resolveParam function, two inputs are needed.  The first one is unresolvedString which is mandatory with a wildcard. In this case "{}" is used as a wildcard pattern, and those are resolved with provided set of parameters (2nd input) as an Array. unresolvedString is split into an array(propArr) of string tokens using the regex for the wildcard. Then, propArr is zipped with parameters array using zip operator. Ultimately flatten and reduce operators help to achieve the resolved string.

Transform Message

The second parameter named parameters is optional. In the case of an input string without a wildcard, there is no need to pass the 2nd parameter. The function could be invoked in this way resolveParam("This is an input without wildcard").

Your requirement might be a bit different, however, and changing a bit in the above code might help you achieve your program's goal. As a learning exercise, you could extend this function with another param with regex. I am leaving it up to you for your learning purposes.

A similar function in Mule 4(DWL 2.0) will also be added soon.

 

 

 

 

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