/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */

/* @test

 * @bug 4546734 5007612

 * @summary Test StringBuffer.trimToSize

 */

import java.util.Random;

public class Trim {

    private static Random generator = new Random();

    public static void main(String[] args) throws Exception {

        bash();

        //capacityCheck();

    }

    // Make sure trimToSize is safe to use; it should never cause an

    // exception or mutation

    private static void bash() throws Exception {

        for (int i=0; i<1000; i++) {

            StringBuffer sb1 = generateTestBuffer(0, 100);

            StringBuffer sb2 = new StringBuffer(sb1);

            sb1.trimToSize();

            if (!sb1.toString().equals(sb2.toString()))

                throw new RuntimeException(

                    "trim mutated stringbuffer contents");

            // Append a random sb

            StringBuffer sb3 = generateTestBuffer(0, 100);

            sb1.append(sb3);

            sb2.append(sb3);

            if (generator.nextInt(2) == 0)

                sb1.trimToSize();

            else

                sb2.trimToSize();

            if (!sb1.toString().equals(sb2.toString()))

                throw new RuntimeException(

                    "trim mutated stringbuffer contents");

            // Append sb with lots of extra space

            sb3 = new StringBuffer(100);

            sb3.append("a");

            sb1.append(sb3);

            sb2.append(sb3);

            if (generator.nextInt(2) == 0)

                sb1.trimToSize();

            else

                sb2.trimToSize();

            if (!sb1.toString().equals(sb2.toString()))

                throw new RuntimeException(

                    "trim mutated stringbuffer contents");

        }

    }

    // This test gives some assurance that trimToSize is working but

    // it should not be part of an automated run, and a failure here

    // is not against spec; this method is provided simply to be run

    // by hand and assure the engineer that it is working. The test

    // may stop working at some time in the future depending on

    // how String and StringBuffer are implemented because it depends

    // upon the capacity method.

    private static void capacityCheck() {

        for (int i=0; i<100; i++) {

            int sizeNeeded = generator.nextInt(1000)+1;

            int sizeExtra = generator.nextInt(100) + 1;

            StringBuffer sb = new StringBuffer(sizeNeeded + sizeExtra);

            StringBuffer sb2 = generateTestBuffer(sizeNeeded, sizeNeeded);

            if (sb2.length() != sizeNeeded)

                throw new RuntimeException("sb generated incorrectly");

            sb.append(sb2);

            int oldCapacity = sb.capacity();

            sb.trimToSize();

            int newCapacity = sb.capacity();

            if (oldCapacity == newCapacity)

                throw new RuntimeException("trim failed");

        }

    }

    private static int getRandomIndex(int constraint1, int constraint2) {

        int range = constraint2 - constraint1;

        if (range <= 0)

            return constraint1;

        int x = generator.nextInt(range);

        return constraint1 + x;

    }

    private static StringBuffer generateTestBuffer(int min, int max) {

        StringBuffer aNewStringBuffer = new StringBuffer();

        int aNewLength = getRandomIndex(min, max);

        for(int y=0; y<aNewLength; y++) {

            int achar = generator.nextInt(30)+30;

            char test = (char)(achar);

            aNewStringBuffer.append(test);

        }

        return aNewStringBuffer;

    }

}