How to use FindInMap to set property of number type?

Fn.findInMap returns a string token. However, how to use it set a property which is number type?

The following usage will throw Exception in thread "main" java.lang.NumberFormatException: For input string: "${Token[TOKEN.14]}"

Mapping writeCapacityMapping = new Mapping(parent, "TableWriteCapacityMapping", MappingProps.builder()
                .withMapping(ImmutableMap.of(
                        Stage.beta.name(), ImmutableMap.of(
                                "min", 5,
                                "max", 100),
                        Stage.prod.name(), ImmutableMap.of(
                                "min", 400,
                                "max", 1200)))
                .build());

...
String minCapacity = Fn.findInMap("TableWriteCapacityMapping", stageParameter.getValueAsString(), "min");
String maxCapacity = Fn.findInMap("TableWriteCapacityMapping", stageParameter.getValueAsString(), "max");
 
ScalableTargetProps props = ScalableTargetProps.builder()
                .withMinCapacity(Integer.valueOf(minCapacity))
                .withMaxCapacity(Integer.valueOf(maxCapacity))
                .build();

And the expected cloudformation template will be:

Mappings:
  WriteCapacityMap:
    beta:
      min: 5
      max: 100
    prod:
      min: 400
      max: 1200
 
TableWriteCapacityScalableTarget:
    Type: "AWS::ApplicationAutoScaling::ScalableTarget"
    Properties:
      MinCapacity:
        Fn::FindInMap: [WriteCapacityMap, { Ref: "Stage" }, min]
      MaxCapacity:
        Fn::FindInMap: [WriteCapacityMap, { Ref: "Stage" }, max]

[rix0rrr]

Token.asNumber() is the right way to force tokens to the right type.

[skinny85]

@eladb I’m re-opening this one, let me know if you disagree!