Are Java 8 streams just not intended to be used with Characters and Strings?

Question

I already read this related post. When it comes to String operations, streams seem to attract a huge amount of ceremony. If you want to parse a String as a stream of chars on which you might want to do some operations, you need to convert them to an IntStream first, map to Object, then cast the int to char, eventually casting the char to String and then return it.

And people say imperative style programming has a ceremony overhead. Please correct me if I am completely doing this wrong. My intention is not to mock around but to understand Java streams better because I generally appreciate them.

// Simple method which encrypts all chars in a string
String input = "Hel!lo";

String result = input.chars()                               // Need to convert into an IntStream
        .mapToObj(e -> Character.toUpperCase((char) e))     // Need to map to Object (!) and then cast to char
        .map(CryptoMath::encryptChar)                       // Calling the encryption
        .map(String::valueOf)                               // Need to cast to String again...
        .collect(joining(""));                              // Finally done

System.out.println(result);

Answer 1

If you can operate on Unicode code points instead of characters, it becomes a bit less cumbersome than operating on char:

String input = "Hel!lo";

String result = input.codePoints()
                     .map( Character::toUpperCase )
                     .collect( StringBuilder::new,
                               StringBuilder::appendCodePoint,
                               StringBuilder::append )
                     .toString();

System.out.println(result);

There's no boxing required, no conversion to string at the point of collection, and you are less likely to be tripped up by surrogate pairs in your input data. One of those nice occasions where it's less painful to implement something that caters for a broader set of inputs.

Answer 2

With Eclipse Collections, you can supplement the missing parts in Java standard library. The following will work using CharAdapter, assuming CryptoMath.encryptChar() returns char.

String result = CharAdapter.adapt(input)
        .collectChar(Character::toUpperCase) 
        .collectChar(CryptoMath::encryptChar)
        .makeString("");

Note: I am a committer for Eclipse Collections.