gistfile1.java

public class Main {
	public static void main(final String[] args) {
		final long[] values = new long[250000];
		final Random random = new Random();
		for (int i = 0; i < 250000; i++) {
			values[i] = random.nextLong();
		}
		
		final Derived1 derived1 = new Derived1();
		final Derived2 derived2 = new Derived2();
		final Derived3 derived3 = new Derived3();
		
		System.out.println("Java v" + System.getProperty("java.runtime.version"));
		
                //
                // monomorphic case using derived1 only
                //
		benchmark1("monomorphic (1)", derived1, values);
		benchmark1("monomorphic (2)", derived1, values);
		benchmark1("monomorphic (3)", derived1, values);

                //
                // first call using derived2 makes base.accumulate(...) call site in benchmark1 bimorphic		
                //
		benchmark1("bimorphic (1)", derived2, values);
		benchmark1("bimorphic (2)", derived1, values);
		benchmark1("bimorphic (3)", derived2, values);
		
                //
                // call using derived3 makes base.accumulate(...) call site in benchmark1 megamorphic
                //
		benchmark1("megamorphic (1)", derived3, values);
		benchmark1("megamorphic (2)", derived2, values);
		benchmark1("megamorphic (3)", derived1, values);
		
                //
                // monomorphic case at a different call site
                //
		benchmark2("monomorphic (call site 2)", derived3, values);
	}
	
	private static void benchmark1(final String name, final Base base, final long[] values) {
		final long iterations = values.length * 1000l;
		System.out.print(MessageFormat.format("{0} {1} calls: ", iterations, name));
		final long before = System.currentTimeMillis();
		for (long i = 0; i < iterations; i++) {
			base.accumulate(values[(int) (i % values.length)]);
		}
		final long result = System.currentTimeMillis() - before;
		System.out.println(MessageFormat.format("{0}", result));
	}
	
        //
        // copy/paste of benchmark1 to show *morphisms are specific to a particular call site
        //
	private static void benchmark2(final String name, final Base base, final long[] values) {
		final long iterations = values.length * 1000l;
		System.out.print(MessageFormat.format("{0} {1} calls: ", iterations, name));
		final long before = System.currentTimeMillis();
		for (long i = 0; i < iterations; i++) {
			base.accumulate(values[(int) (i % values.length)]);
		}
		final long result = System.currentTimeMillis() - before;
		System.out.println(MessageFormat.format("{0}", result));
	}
}