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/**

 * @test TestSoftReferencesBehaviorOnOOME

 * @key gc

 * @summary Tests that all SoftReferences has been cleared at time of OOM.

 * @library /test/lib

 * @modules java.base/jdk.internal.misc

 * @run main/othervm -Xmx128m TestSoftReferencesBehaviorOnOOME 512 2k

 * @run main/othervm -Xmx128m TestSoftReferencesBehaviorOnOOME 128k 256k

 * @run main/othervm -Xmx128m TestSoftReferencesBehaviorOnOOME 2k 32k

 */

import jdk.test.lib.Utils;

import jdk.test.lib.Asserts;

import java.lang.ref.SoftReference;

import java.util.LinkedList;

import java.util.Random;

public class TestSoftReferencesBehaviorOnOOME {

    /**

     * Test generates a lot of soft references to objects with random payloads.

     * Then it provokes OOME and checks that all SoftReferences has been gone

     * @param args - [minSize] [maxSize] [freq]

     *  where

     *  - minSize - min size of random objects

     *  - maxSize - max size of random objects

     */

    public static void main(String[] args) {

        long minSize = DEFAULT_MIN_SIZE;

        long maxSize = DEFAULT_MAX_SIZE;

        if ( args.length >= 2) {

            maxSize = getBytesCount(args[1]);

        }

        if ( args.length >= 1) {

            minSize = getBytesCount(args[0]);

        }

        new TestSoftReferencesBehaviorOnOOME().softReferencesOom(minSize, maxSize);

    }

    /**

     * Test that all SoftReferences has been cleared at time of OOM.

     */

    void softReferencesOom(long minSize, long maxSize) {

        System.out.format( "minSize = %d, maxSize = %d%n", minSize, maxSize );

        LinkedList<SoftReference> arrSoftRefs = new LinkedList();

        staticRef = arrSoftRefs;

        LinkedList arrObjects = new LinkedList();

        staticRef = arrObjects;

        long multiplier = maxSize - minSize;

        long numberOfNotNulledObjects = 0;

        try {

            // Lets allocate as many as we can - taking size of all SoftRerefences

            // by minimum. So it can provoke some GC but we surely will allocate enough.

            long numSofts = (long) ((0.95 * Runtime.getRuntime().totalMemory()) / minSize);

            System.out.println("num Soft: " + numSofts);

            while (numSofts-- > 0) {

                int allocationSize = ((int) (RND_GENERATOR.nextDouble() * multiplier))

                            + (int)minSize;

                arrSoftRefs.add(new SoftReference(new byte[allocationSize]));

            }

            System.out.println("free: " + Runtime.getRuntime().freeMemory());

            // provoke OOME.

            while (true) {

                arrObjects.add(new byte[(int) Runtime.getRuntime().totalMemory()]);

            }

        } catch (OutOfMemoryError oome) {

            // Clear allocated ballast, so we don't get another OOM.

            staticRef = null;

            arrObjects = null;

            long oomSoftArraySize = arrSoftRefs.size();

            for (SoftReference sr : arrSoftRefs) {

                Object o = sr.get();

                if (o != null) {

                    numberOfNotNulledObjects++;

                }

            }

            // Make sure we clear all refs before we return failure

            arrSoftRefs = null;

            Asserts.assertFalse(numberOfNotNulledObjects > 0,

                    "" + numberOfNotNulledObjects + " out of "

                    + oomSoftArraySize + " SoftReferences was not "

                    + "null at time of OutOfMemoryError"

            );

        } finally {

            Asserts.assertTrue(arrObjects == null, "OOME hasn't been provoked");

            Asserts.assertTrue(arrSoftRefs == null, "OOME hasn't been provoked");

        }

    }

    private static final long getBytesCount(String arg) {

        String postfixes = "kMGT";

        long mod = 1;

        if (arg.trim().length() >= 2) {

            mod = postfixes.indexOf(arg.trim().charAt(arg.length() - 1));

            if (mod != -1) {

                mod = (long) Math.pow(1024, mod+1);

                arg = arg.substring(0, arg.length() - 1);

            } else {

                mod = 1; // 10^0

            }

        }

        return Long.parseLong(arg) * mod;

    }

    private static final Random RND_GENERATOR = Utils.getRandomInstance();

    private static final long DEFAULT_MIN_SIZE = 512;

    private static final long DEFAULT_MAX_SIZE = 1024;

    private static Object staticRef; // to prevent compile optimisations

}