import java.util.regex.*;
public class JavaBenchmark {
 public static void main(String [] args)
 {
   Matcher regex1 = Pattern.compile("^(a|b|c|d|e|f|g)+$").matcher("");
   Matcher regex2 = Pattern.compile("^[a-g]+$").matcher("");
   long timesToDo = 1000;

   StringBuffer temp = new StringBuffer();
   for (int i = 1000; i > 0; i--)
           temp.append("abababdedfg");
   String testString = temp.toString();

   // Time first one . . . 
   long count = timesToDo;
   long startTime = System.currentTimeMillis();
   while (--count > 0)
         regex1.reset(testString).find();
   double seconds = (System.currentTimeMillis() - startTime)/1000.0;
   System.out.println("Alternation takes " + seconds + " seconds");

   // Time second one . . . 
   count = timesToDo;
   startTime = System.currentTimeMillis();
   while (--count > 0)
         regex2.reset(testString).find();
   seconds = (System.currentTimeMillis() - startTime)/1000.0;
   System.out.println("Character class takes " + seconds + " seconds");
 }
}




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Copyright 1997-2024 Jeffrey Friedl