等效于IEnumerable的Java <char>

Question

This is the C# code that I have to convert:

static readonly IEnumerable<char> BigAlphas = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();

So far I've tried the following:

static final Iterable<Character> BigAlphas = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();

This gives me the error:

incompatible types

required: java.lang.Iterable

found: char[]

I know I'm getting this error because I'm trying to set an Iterable<Character> to a char array but I'm not sure what else can be done to translate it.

Answer 1

Would a simple String work?

 static final String BigAlphas = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

String implements CharSequence, which seems to be what you need, and it also has loads of methods to check membership and such.

Answer 2

static final Iterable<Character> alphabet() {
  return new Iterable<Character>() {

    public final Iterator<Character> iterator() {
      return new Iterator<Character>() {

        private char cursor = 'A';

        public boolean hasNext() {
          return cursor <= 'Z';
        }

        public Character next() {
          return cursor++;
        }

        public void remove() {
          throw new UnsupportedOperationException("cannot remove from stream");
        }
      };
    }
  };
}

Usage:

for (final char ch : alphabet()) {
  /* ch in interval [A,Z] */
}

---

Here's a more generic form.

static final Iterable<Character> iterable(final CharSequence seq) {
  return new Iterable<Character>() {

    public final Iterator<Character> iterator() {
      return new Iterator<Character>() {

        private int cursor;

        public boolean hasNext() {
          return cursor < seq.length();
        }

        public Character next() {
          return seq.charAt(cursor++);
        }

        public void remove() {
          throw new UnsupportedOperationException("cannot remove from stream");
        }
      };
    }
  };
}
/* ... */
for (final char ch : iterable("qwertyuiop")) {
  /* ... */
}

Answer 3

好吧， 随心所欲 ...如果您不介意使用Guava ：

Iterable<Character> BigAlphas = Chars.asList("ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray());