test2.java

高质量Java程序设计 源代码

package net.betterjava.design.refactor;

import java.io.FileWriter;
import java.io.IOException;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

/**
 * test Set.add().
 */
public class Test2 {
	private static String data[][];
	private static int rpts[][] = { { 1000, 100 }, {
			100, 2000 }, {
			100, 4000 }, {
			100, 10000 }, {
			100, 20000 }
	}; //the number of outer and inner loop

	/**
	 * record one round test data	 
	 */
	private static void record(int currentTurn, int currentRound, String result) {
		data[currentTurn][currentRound] = result;
	}

	/**
	 * a warming method act as running for JIT warm,
	 * the time of warming can be used to filter peak test
	 */
	private static void warming() {
		long time = System.currentTimeMillis();
		int temp = 0;
		for (int i = 0; i < 8000; i++) {
			temp = 0;
			for (int j = 0; j < 10000; j++) {
				temp++;
			}
		}
		System.out.println("warming time: " + (System.currentTimeMillis() - time));
	}

	/**
	 * generate a csv file conatains each round's test data
	 * @param fw the csv file
	 * @throws IOException
	 */
	private static void genCSV(FileWriter fw) throws IOException {
		for (int i = 0; i < data.length; i++) {
			for (int j = 0; j < data[i].length; j++) {
				fw.write(data[i][j] + ",");
			}
			fw.write("\n");
		}
		fw.flush();
	}

	/**
	 * force garbage collector to run.
	 * @param mb the memory amount that prepare for next test
	 */
	private static void fullGC(int mb) {
		byte[][] memory = new byte[mb * 2][];
		int count = 0;

		try {
			for (int i = 0; i < mb * 2; i++) {
				memory[i] = new byte[1024 * 1024];
			}
		} catch (OutOfMemoryError e) {
			log("out of memeory at " + new Date(System.currentTimeMillis()));
		}

		memory = null;
		Runtime.getRuntime().gc();
		try {
			Thread.currentThread().sleep(1000);
		} catch (InterruptedException e) {
			log(e);
		}
	}

	private static void log(String msg) {
		System.out.println(msg);
	}

	private static void log(Throwable e) {
		e.printStackTrace(System.out);
	}

	/**
	 * contains the code to test.
	 * @param rpts the loop counter of test
	 * @param innerSet the test object
	 * @return long the test code running time
	 */
	private static long runTestBody(int rpts, Set innerSet) {
		long elapse = System.currentTimeMillis();
		for (int j = 0; j < rpts; j++) {
			innerSet.add(String.valueOf(j));
		}
		return System.currentTimeMillis() - elapse;
	}

	public static void main(String[] args) {
		Set hashSet = new HashSet();
		Set treeSet = new TreeSet();

		int turn = 5;
		int round = 1;
		int indexOfRoundRpts = 1;
		data = new String[turn][round];
		warming();

		for (int currentTurn = 0; currentTurn < turn; currentTurn++) {
			for (int currentRound = 0; currentRound < round; currentRound++) {
				Set innerSet = new HashSet();
				long elapse = 0;
				for (int k = 0; k < rpts[currentTurn][currentRound]; k++) {
					elapse += runTestBody(rpts[currentTurn][indexOfRoundRpts], innerSet);
				}
				String result =
					String.valueOf(
						elapse
							* 1.0
							/ (rpts[currentTurn][currentRound]
								* rpts[currentTurn][indexOfRoundRpts]));
				record(currentTurn, currentRound, result);
			}
		}

		FileWriter fw = null;
		try {
			fw = new FileWriter("test.csv");
			genCSV(fw);
		} catch (IOException e) {
			log(e);
		} finally {
			try {
				fw.close();
			} catch (IOException e) {
				log(e);
			}
		}
	}
}