import java.util.Arrays;

public class TestConcatSpeed {

    private static final int TEST_SIZE = 500;
    
    private static int avgStringLength = 0;

    private static String thirdString = "";

    private static void setAvgStringLength(int avgStringLength) {
        TestConcatSpeed.avgStringLength = avgStringLength;
        char[] cs = new char[avgStringLength];
        Arrays.fill(cs, 'c');
        thirdString = new String(cs);
    }
    
    public static void main(String[] args) {
        String[] as = new String[TEST_SIZE];
        String[] bs = new String[TEST_SIZE];
        
        
        System.out.println("java version, repetitions, avg length, concat 2, buffer 2, builder 2, buffer 2 (LK), builder 2 (LK), concat 3, buffer 3, builder 3, buffer 3 (LK), builder 3 (LK)");
        for (int i = 0; i <= 100; i += 10) {
            setAvgStringLength(i);
            performTest(as, bs);
        }
        
    }

    private static void performTest(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            char[] cs = new char[i * avgStringLength * 2 / TEST_SIZE];
            Arrays.fill(cs, 'a');
            as[i] = new String(cs);
        }

        for (int i = 0; i < bs.length; i++) {
            char[] cs = new char[i];
            Arrays.fill(cs, 'a');
            bs[i] = new String(cs);
        }
        
        //Timing timing;
        long start, finish;
        final long baseline;

        // 0
        
        start = System.currentTimeMillis();
        testNoop(as, bs);
        baseline = System.currentTimeMillis() - start;

        System.out.print(System.getProperty("java.version") + ", ");

        System.out.print(as.length * bs.length +", ");

        System.out.print(avgStringLength +", ");
        
        // 2
        
        start = System.currentTimeMillis();
        testConcat2(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBuffer2(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBuilder2(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBufferLK2(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBuilderLK2(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        // 3
        
        start = System.currentTimeMillis();
        testConcat3(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBuffer3(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBuilder3(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBufferLK3(as, bs);
        finish = System.currentTimeMillis();
        System.out.print(finish-start-baseline + ", ");

        start = System.currentTimeMillis();
        testBuilderLK3(as, bs);
        finish = System.currentTimeMillis();
        System.out.println(finish-start-baseline);
    }

    private static void testNoop(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                String a = as[i];
                String b = bs[j];
            }
        }
    }

    private static void testConcat2(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                as[i].concat(bs[j]);
            }
        }
    }

    private static void testBuffer2(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                StringBuffer sb = new StringBuffer();
                sb.append(as[i]);
                sb.append(bs[j]);
                sb.toString();
            }
        }
    }
    
    private static void testBuilder2(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                StringBuilder sb = new StringBuilder();
                sb.append(as[i]);
                sb.append(bs[j]);
                sb.toString();
            }
        }
    }

    private static void testBufferLK2(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                String a = as[i];
                String b = bs[j];
                StringBuffer sb = new StringBuffer(a.length() + b.length());
                sb.append(as[i]);
                sb.append(bs[j]);
                sb.toString();
            }
        }
    }
    
    private static void testBuilderLK2(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                String a = as[i];
                String b = bs[j];
                StringBuilder sb = new StringBuilder(a.length() + b.length());
                sb.append(a);
                sb.append(b);
                sb.toString();
            }
        }
    }

    
    
    private static void testConcat3(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                as[i].concat(bs[j]).concat(thirdString);
            }
        }
    }

    private static void testBuffer3(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                StringBuffer sb = new StringBuffer();
                sb.append(as[i]);
                sb.append(bs[j]);
                sb.append(thirdString);
                sb.toString();
            }
        }
    }
    
    private static void testBuilder3(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                StringBuilder sb = new StringBuilder();
                sb.append(as[i]);
                sb.append(bs[j]);
                sb.append(thirdString);
                sb.toString();
            }
        }
    }

    private static void testBufferLK3(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                String a = as[i];
                String b = bs[j];
                StringBuffer sb = new StringBuffer(a.length() + b.length() + thirdString.length());
                sb.append(as[i]);
                sb.append(bs[j]);
                sb.append(thirdString);
                sb.toString();
            }
        }
    }
    
    private static void testBuilderLK3(String[] as, String[] bs) {
        for (int i = 0; i < as.length; i++) {
            for (int j = 0; j < bs.length; j++) {
                String a = as[i];
                String b = bs[j];
                StringBuilder sb = new StringBuilder(a.length() + b.length() + thirdString.length());
                sb.append(a);
                sb.append(b);
                sb.append(thirdString);
                sb.toString();
            }
        }
    }

    
    
}