//: c11:SetPerformance.java // {Args: 500} // From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002 // www.BruceEckel.com. See copyright notice in CopyRight.txt. import java.util.*; import com.bruceeckel.util.*; public class SetPerformance { private static int reps = 50000; private abstract static class Tester { String name; Tester(String name) { this.name = name; } abstract void test(Set s, int size); } private static Tester[] tests = { new Tester("add") { void test(Set s, int size) { for(int i = 0; i < reps; i++) { s.clear(); Collections2.fill(s, Collections2.countries.reset(),size); } } }, new Tester("contains") { void test(Set s, int size) { for(int i = 0; i < reps; i++) for(int j = 0; j < size; j++) s.contains(Integer.toString(j)); } }, new Tester("iteration") { void test(Set s, int size) { for(int i = 0; i < reps * 10; i++) { Iterator it = s.iterator(); while(it.hasNext()) it.next(); } } }, }; public static void test(Set s, int size) { // Strip qualifiers from class name: System.out.println("Testing " + s.getClass().getName().replaceAll("\\w+\\.", "") + " size " + size); Collections2.fill(s, Collections2.countries.reset(), size); for(int i = 0; i < tests.length; i++) { System.out.print(tests[i].name); long t1 = System.currentTimeMillis(); tests[i].test(s, size); long t2 = System.currentTimeMillis(); System.out.println(": " + ((double)(t2 - t1)/(double)size)); } } public static void main(String[] args) { // Choose a different number of // repetitions via the command line: if(args.length > 0) reps = Integer.parseInt(args[0]); System.out.println(reps + " repetitions"); // Small: test(new TreeSet(), 10); test(new HashSet(), 10); test(new LinkedHashSet(), 10); // Medium: test(new TreeSet(), 100); test(new HashSet(), 100); test(new LinkedHashSet(), 100); // Large: test(new TreeSet(), 1000); test(new HashSet(), 1000); test(new LinkedHashSet(), 1000); } } ///:~