package com.mrfeinberg;

import java.text.*;

/**
 * @author jdf
 */
public class TimeRegionMatches
{
	private static final String A = "absofreakinlutely";
	private static final String B = "absoLUTEly";

	private static final int ITERS = 1000000;

	static long foo = 0;

	static interface Strategy
	{
		void compare(String a, String b);
	}

	static class NullStrategy implements Strategy
	{
		public void compare(String a, String b)
		{
			foo++;
		}
	}

	static class RegionStrategy implements Strategy
	{
		public void compare(String a, String b)
		{
			if (a.regionMatches(true, 11, b, 4, 6))
				foo++;
		}
	}

	static class NewStringStrategy implements Strategy
	{
		public void compare(String a, String b)
		{
			if (a.substring(11).equalsIgnoreCase(b.substring(4)))
				foo++;
		}
	}

	static NumberFormat F = new DecimalFormat("#.00ms");

	static void time(Strategy s)
	{
		long oldFoo = foo;
		System.gc();
		long startTime = System.nanoTime();
		long startMem = Runtime.getRuntime().freeMemory();
		for (int i = 0; i < ITERS; i++)
			s.compare(A, B);
		long deltaT = System.nanoTime() - startTime;
		long deltaMem = startMem - Runtime.getRuntime().freeMemory();
		assert foo - oldFoo == ITERS;
		System.out.printf("%17s %8s %s bytes allocated\n", s.getClass().getSimpleName(), F.format(deltaT / 1000000.0), deltaMem);
	}

	public static void main(String[] args)
	{
		Strategy[] sts = new Strategy[] {
				new NullStrategy(), new RegionStrategy(), new NewStringStrategy() };
		for (Strategy s : sts)
			time(s);
		System.out.println("-----------------------");
		for (Strategy s : sts)
			time(s);
		System.out.println("-----------------------");
		for (Strategy s : sts)
			time(s);
	}
}