// Example 122 from page 97 of Java Precisely second edition (The MIT Press 2005)
// Author: Peter Sestoft (sestoft@itu.dk)

import java.util.*;

// The HashSet is 2 to 5 times faster than Arrays.binarySearch, even
// for this list of strings of only 52 elements:

class Example122 {
  final static String[] keywordarray = 
  { "abstract", "assert", "boolean", "break", "byte", "case", "catch", 
    "char", "class", "const", "continue", "default", "do", "double", "else", 
    "enum", "extends", "false", "final", "finally", "float", "for", "goto", 
    "if", "implements", "import", "instanceof", "int", "interface", "long", 
    "native", "new", "null", "package", "private", "protected", "public", 
    "return", "short", "static", "strictfp", "super", "switch", 
    "synchronized", "this", "throw", "throws", "transient", "true", 
    "try", "void", "volatile", "while" };

  final static Set<String> keywords 
    = new HashSet<String>(Arrays.asList(keywordarray));  

  static boolean isKeyword1(String id) 
  { return keywords.contains(id); }

  static boolean isKeyword2(String id) 
  { return Arrays.binarySearch(keywordarray, id) >= 0; }
      
  public static void main(String[] args) {
    if (args.length != 2) 
      System.out.println("Usage: java Example122 <iterations> <word>");
    else {
      final int count = Integer.parseInt(args[0]);
      final String id = args[1];
      for (int i=0; i<keywordarray.length; i++)
        if (isKeyword1(keywordarray[i]) != isKeyword2(keywordarray[i]))
          System.out.println("Error at i = " + i);
      if (isKeyword1(id) != isKeyword2(id))
        System.out.println("Error at id = " + id);
      
      System.out.print("HashSet.contains    ");
      Timer t1 = new Timer();
      for (int i=0; i<count; i++)
        isKeyword1(id);
      System.out.println(t1.check());      
      
      System.out.print("Arrays.binarySearch ");
      Timer t2 = new Timer();
      for (int i=0; i<count; i++)
        isKeyword2(id);
      System.out.println(t2.check());
    }
  }

  private final static class Timer {
    private long starttime;
    
    public Timer() { starttime = System.currentTimeMillis(); }
    
    double check() {
      return (System.currentTimeMillis()-starttime)/1000.0;
    }
  }
}