OnJava8-Examples/strings/TestRegularExpression.java

// strings/TestRegularExpression.java
// <20>2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
// Easily try out regular expressions.
// {Args: abcabcabcdefabc "abc+" "(abc)+" "(abc){2,}" }
import java.util.regex.*;

public class TestRegularExpression {
  public static void main(String[] args) {
    if(args.length < 2) {
      System.out.println("Usage:\njava TestRegularExpression " +
        "characterSequence regularExpression+");
      System.exit(0);
    }
    System.out.println("Input: \"" + args[0] + "\"");
    for(String arg : args) {
      System.out.println("Regular expression: \"" + arg + "\"");
      Pattern p = Pattern.compile(arg);
      Matcher m = p.matcher(args[0]);
      while(m.find()) {
        System.out.println("Match \"" + m.group() + "\" at positions " +
          m.start() + "-" + (m.end() - 1));
      }
    }
  }
}
/* Output:
Input: "abcabcabcdefabc"
Regular expression: "abcabcabcdefabc"
Match "abcabcabcdefabc" at positions 0-14
Regular expression: "abc+"
Match "abc" at positions 0-2
Match "abc" at positions 3-5
Match "abc" at positions 6-8
Match "abc" at positions 12-14
Regular expression: "(abc)+"
Match "abcabcabc" at positions 0-8
Match "abc" at positions 12-14
Regular expression: "(abc){2,}"
Match "abcabcabc" at positions 0-8
*/