java-topology/test/jdk/java/lang/StringBuilder/HugeCapacity.java

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 *
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * version 2 for more details (a copy is included in the LICENSE file that
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 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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import jdk.internal.util.ArraysSupport;

import java.util.Arrays;

/**
 * @test
 * @bug 8149330 8218227 8351443
 * @summary Capacity should not get close to Integer.MAX_VALUE unless
 *          necessary
 * @modules java.base/jdk.internal.util
 * @requires (sun.arch.data.model == "64" & os.maxMemory >= 8G)
 * @run main/othervm -Xms8G -Xmx8G -XX:-CompactStrings -Xlog:gc HugeCapacity false
 * @run main/othervm -Xms8G -Xmx8G -XX:+CompactStrings -Xlog:gc HugeCapacity true
 */

public class HugeCapacity {
    private static int failures = 0;

    public static void main(String[] args) {
        if (args.length == 0) {
           throw new IllegalArgumentException("Need the argument");
        }
        boolean isCompact = Boolean.parseBoolean(args[0]);

        testLatin1(isCompact);
        testUtf16();
        testHugeInitialString();
        testHugeInitialCharSequence();
        testHugePlus(isCompact);
        if (failures > 0) {
            throw new RuntimeException(failures + " tests failed");
        }
    }

    private static void testLatin1(boolean isCompact) {
        try {
            int divisor = isCompact ? 2 : 4;
            StringBuilder sb = new StringBuilder();
            sb.ensureCapacity(Integer.MAX_VALUE / divisor);
            sb.ensureCapacity(Integer.MAX_VALUE / divisor + 1);
        } catch (OutOfMemoryError oom) {
            oom.printStackTrace();
            failures++;
        }
    }

    private static void testUtf16() {
        try {
            StringBuilder sb = new StringBuilder();
            sb.append('\u042b');
            sb.ensureCapacity(Integer.MAX_VALUE / 4);
            sb.ensureCapacity(Integer.MAX_VALUE / 4 + 1);
        } catch (OutOfMemoryError oom) {
            oom.printStackTrace();
            failures++;
        }
    }

    private static void testHugeInitialString() {
        try {
            String str = "Z".repeat(ArraysSupport.SOFT_MAX_ARRAY_LENGTH);
            StringBuilder sb = new StringBuilder(str);
        } catch (OutOfMemoryError ignore) {
        } catch (Throwable unexpected) {
            unexpected.printStackTrace();
            failures++;
        }
    }

    private static void testHugeInitialCharSequence() {
        try {
            CharSequence seq = new MyHugeCharSeq();
            StringBuilder sb = new StringBuilder(seq);
        } catch (OutOfMemoryError ignore) {
        } catch (Throwable unexpected) {
            unexpected.printStackTrace();
            failures++;
        }
    }

    private static class MyHugeCharSeq implements CharSequence {
        public char charAt(int i) {
            throw new UnsupportedOperationException();
        }
        public int length() { return Integer.MAX_VALUE; }
        public CharSequence subSequence(int st, int e) {
            throw new UnsupportedOperationException();
        }
        public String toString() { return ""; }
    }

    // Test creating and appending the max size string for -XX:+CompactStrings and -XX:-CompactStrings
    private static void testHugePlus(boolean isCompact) {
        int repeatCount = (isCompact) ? Integer.MAX_VALUE / 2 - 1 : Integer.MAX_VALUE / 4 - 1;
        char[] chars = new char[repeatCount];
        char[] aChar = {'A', '\uff21'};
        for (char ch : aChar) {
            try {
                int size = (ch > 0xff) ? repeatCount / 2 : repeatCount;
                Arrays.fill(chars, 0, size, ch);
                StringBuilder b = new StringBuilder(0);
                b.append(chars, 0, size);
                b.append(chars, 0, size);
            } catch (Throwable unexpected) {
                unexpected.printStackTrace();
                failures++;
            }
        }
    }
}