Question

Below I am trying to replace exact search strings with a replace string xxx. I have string original which resembles a java log message. As you can see if the search string is “variable” I am able to successfully replace it with xxx but when the search string is “variable.method()” or “variable.method2()” I am not able to replace it. Am I doing something wrong here?

val original = """variable+ " is in " + variable.method() + " and " + variable.method2()"""
val replaceStr = "xxx"
val searchStr = "variable.method()" // This can change like in the output below
val variableExtracter = ("(?<=^|\\s|\\+)"+searchStr+"(?=\\s|$|\\+)").r
print("Search string : " + searchStr + "\n")
print("Original :" + original + "\n")
val formatted = variableExtracter.replaceAllIn(original, replaceStr)
print("Formatted :" + formatted + "\n")

Output:

Search string : variable //CORRECT OUTPUT
Original :variable+ " is in " + variable.method() + " and " + variable.method2()
Formatted :xxx+ " is in " + variable.method() + " and " + variable.method2()
---
Search string : variable.method()
Original :variable+ " is in " + variable.method() + " and " + variable.method2()
Formatted :variable+ " is in " + variable.method() + " and " + variable.method2()
//EXPECTED OUTPUT: variable+ " is in " + xxx + " and " + variable.method2()
---
Search string : variable.method2()
Original :variable+ " is in " + variable.method() + " and " + variable.method2()
Formatted :variable+ " is in " + variable.method() + " and " + variable.method2()
//EXPECTED OUTPUT:variable+ " is in " + variable.method() + " and " + xxx 
---
Search string : variable.method()
Original :variable.method()+ " has " + variable + " and " + variable.method2()
Formatted :variable.method()+ " has " + variable + " and " + variable.method2()
//EXPECTED OUTPUT:xxx+ " has " + variable + " and " + variable.method2()

Answer 1

Edit:

You can use the Java Pattern quote method Pattern.quote(searchStr) to wrap your string with the \Q and \E.

scala> import java.util.regex.Pattern
import java.util.regex.Pattern

scala> val variableExtracter = ("(?<=^|\\s|\\+)"+Pattern.quote(searchStr)+"(?=\\s|$|\\+)").r
variableExtracter: scala.util.matching.Regex = (?<=^|\s|\+)\Qvariable.method2()\E(?=\s|$|\+)

scala> print("Search string : " + searchStr + "\n")
Search string : variable.method2()

scala> print("Original :" + original + "\n")
Original :variable+ " is in " + variable.method() + " and " + variable.method2()

scala> val formatted = variableExtracter.replaceAllIn(original, replaceStr)
formatted: String = variable+ " is in " + variable.method() + " and " + xxx

scala> print("Formatted :" + formatted + "\n")
Formatted :variable+ " is in " + variable.method() + " and " + xxx

scala> val searchStr = "variable.method()"
searchStr: java.lang.String = variable.method()

scala> val variableExtracter = ("(?<=^|\\s|\\+)"+Pattern.quote(searchStr)+"(?=\\s|$|\\+)").r
variableExtracter: scala.util.matching.Regex = (?<=^|\s|\+)\Qvariable.method()\E(?=\s|$|\+)

scala> val formatted = variableExtracter.replaceAllIn(original, replaceStr)
formatted: String = variable+ " is in " + xxx + " and " + variable.method2()