OnJava8-Examples/strings/StartEnd.java

// strings/StartEnd.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
import java.util.regex.*;

public class StartEnd {
  public static String input =
    "As long as there is injustice, whenever a\n" +
    "Targathian baby cries out, wherever a distress\n" +
    "signal sounds among the stars ... We'll be there.\n"+
    "This fine ship, and this fine crew ...\n" +
    "Never give up! Never surrender!";
  private static class Display {
    private boolean regexPrinted = false;
    private String regex;
    Display(String regex) { this.regex = regex; }
    void display(String message) {
      if(!regexPrinted) {
        System.out.println(regex);
        regexPrinted = true;
      }
      System.out.println(message);
    }
  }
  static void examine(String s, String regex) {
    Display d = new Display(regex);
    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher(s);
    while(m.find())
      d.display("find() '" + m.group() +
        "' start = "+ m.start() + " end = " + m.end());
    if(m.lookingAt()) // No reset() necessary
      d.display("lookingAt() start = "
        + m.start() + " end = " + m.end());
    if(m.matches()) // No reset() necessary
      d.display("matches() start = "
        + m.start() + " end = " + m.end());
  }
  public static void main(String[] args) {
    for(String in : input.split("\n")) {
      System.out.println("input : " + in);
      for(String regex : new String[]{"\\w*ere\\w*",
        "\\w*ever", "T\\w+", "Never.*?!"})
        examine(in, regex);
    }
  }
}
/* Output:
input : As long as there is injustice, whenever a
\w*ere\w*
find() 'there' start = 11 end = 16
\w*ever
find() 'whenever' start = 31 end = 39
input : Targathian baby cries out, wherever a distress
\w*ere\w*
find() 'wherever' start = 27 end = 35
\w*ever
find() 'wherever' start = 27 end = 35
T\w+
find() 'Targathian' start = 0 end = 10
lookingAt() start = 0 end = 10
input : signal sounds among the stars ... We'll be there.
\w*ere\w*
find() 'there' start = 43 end = 48
input : This fine ship, and this fine crew ...
T\w+
find() 'This' start = 0 end = 4
lookingAt() start = 0 end = 4
input : Never give up! Never surrender!
\w*ever
find() 'Never' start = 0 end = 5
find() 'Never' start = 15 end = 20
lookingAt() start = 0 end = 5
Never.*?!
find() 'Never give up!' start = 0 end = 14
find() 'Never surrender!' start = 15 end = 31
lookingAt() start = 0 end = 14
matches() start = 0 end = 31
*/