JSONPath array length validation

[Imran Raza Khan]

I am parsing an json and verify array length like below

  from("direct:parseJson")
        .setHeader("numberOfBooks").jsonpath("$..books.length()", int.class)
        .choice()
                .when( simple("${header.numberOfBooks} == '1'"))
                         .log("One book")
                 .otherwise()
                         .log("multiple");

Above Code works, but i am looking for option if we can avoid line 2 with
below

 .when( simple("${jsonpath(' $..books.length() ', int.class)} == 1") )

its throwing error

Caused by:
org.apache.camel.language.simple.types.SimpleIllegalSyntaxException:
Unknown function: jsonpath(' $..books.length() ', int.class) == 1 at
location 0
${jsonpath(' $..books.length() ', int.class)} == 1