Scanner Without Separator

Question

I would like to be able to parse strings like the following: "123456abcd9876az45678". BNF is as follows:

number: ? definition of an int ?
word: letter { , letter }
expression: number { , word , number }

However, the java.util.scanner class does not allow me to do the following:

Scanner s = new Scanner("-123456abcd9876az45678");
System.out.println(s.nextInt());
while (s.hasNext("[a-z]+")) {
    System.out.println(s.next("[a-z]+"));
    System.out.println(s.nextInt());
}

Ideally, this should give:

-123456
abcd
987
az
45678

I really hoped that java.util.Scanner would help me, but it looks like I will need to create my own scanner. Is there anything that is already present in the Java API to help me?

---

The question is missing too much information. And so all the answers are valid for the question, but not for my problem.

Answer 1

, AFAIK. , , , findInLine() findWithinHorizon(). findWithinHorizion().

Scanner s = new Scanner("-123456abcd9876az45678");
Pattern num = Pattern.compile("[+-]?\\d+");
Pattern letters = Pattern.compile("[A-Za-z]+");
System.out.println(s.findWithinHorizon(num, 0));
String str;
while ((str = s.findWithinHorizon(letters, 0)) != null) {
    System.out.println(str);
    System.out.println(s.findWithinHorizon(num, 0));
}

Answer 2

, Pattern Matcher. . .

Answer 3

, findWithinHorizon \G (= ).

( ):

Scanner scanner = new Scanner(input);
while (true) {
  String letters = scanner.findWithinHorizon("\\G\\s*\\[a-zA-Z]+", 0);
  if (letters != null) {
    System.out.println("letters: " + letters.trim());
  } else {
    String number = scanner.findWithinHorizon("\\G\\s[+-]?[0-9]+", 0);
    if (number != null) {
      System.out.println("number: " + number.trim());
    } else if (scanner.findWithinHorizon("\\G\\s*\\Z", 0) != null) {
      System.out.println("end");
      break;
    } else {
      System.out.println("unrecognized input");
      break;
    }
  }
}

, , .

Answer 4

You can set a delimiter to a template that cannot match anything, for example.

Scanner s = ...
s.useDelimiter("(?!=a)a");