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package org.openide.util;

import java.lang.ref.Reference;

import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import java.util.Set;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import org.netbeans.junit.NbTestCase;

import org.netbeans.junit.RandomlyFails;

public class WeakSetTest extends NbTestCase {

    public WeakSetTest(String testName) {

        super(testName);

    }

    public void testToArrayMayContainNullsIssue42271 () {

        class R implements Runnable {

            Object[] arr;

            Object last;

            public R () {

                int cnt = 10;

                arr = new Object[cnt];

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

                    arr[i] = new Integer(i); // autoboxing makes test fail!

                }

            }

            public void run () {

                Reference<?> r = new WeakReference<Object>(last);

                for (int i = 0; i < arr.length; i++) {

                    arr[i] = null;

                }

                arr = null;

                last = null;

                assertGC ("Last item has to disappear", r);

            }

            public void putToSet (NotifyWhenIteratedSet s) {

                for (int i = 0; i < arr.length; i++) {

                    s.add (arr[i]);

                }

                assertEquals (arr.length, s.size ());

                Iterator<Object> it = s.superIterator();

                Object prev = it.next ();

                while (it.hasNext ()) {

                    prev = it.next ();

                }

                last = prev;

            }

        }

        R r = new R ();

        NotifyWhenIteratedSet ws = new NotifyWhenIteratedSet (r, 1);

        r.putToSet (ws);

        Object[] arr = ws.toArray ();

        for (int i = 0; i < arr.length; i++) {

            assertNotNull (i + "th index should not be null", arr[i]);

        }

    }

    private static final class NotifyWhenIteratedSet extends WeakSet<Object> {

        private Runnable run;

        private int cnt;

        public NotifyWhenIteratedSet (Runnable run, int cnt) {

            this.run = run;

            this.cnt = cnt;

        }

        public Iterator<Object> superIterator() {

            return super.iterator ();

        }

        @Override

        public Iterator<Object> iterator() {

            final Iterator<Object> it = super.iterator();

            class I implements Iterator<Object> {

                public boolean hasNext() {

                    return it.hasNext ();

                }

                public Object next() {

                    if (--cnt == 0) {

                        run.run ();

                    }

                    return it.next ();

                }

                public void remove() {

                    it.remove();

                }

            }

            return new I ();

        }

    }

    private final static class TestObj {

        static final Set<TestObj> testObjs = new WeakSet<TestObj>();

        private final String name;

        TestObj(String name) {

            this.name = name;

            synchronized (testObjs) {

                testObjs.add(this);

            }

        }

        @Override

        public String toString() {

            return name;

        }

    }

    private final static class GC implements Runnable {

        public void run() {

            try {

                for (int i = 0; i < 5; i++) {

                    gc();

                }

            } catch (InterruptedException ex) {

                // ignore

            }

        }

        static void gc() throws InterruptedException {

            List<byte[]> alloc = new ArrayList<byte[]>();

            int size = 100000;

            for (int i = 0; i < 50; i++) {

                System.gc();

                System.runFinalization();

                try {

                    alloc.add(new byte[size]);

                    size = (int) (((double) size) * 1.3);

                } catch (OutOfMemoryError error) {

                    size = size / 2;

                }

                if (i % 3 == 0) {

                    Thread.sleep(100);

                }

            }

        }

    }

    /**

     * test for issue #106218

     * @throws java.lang.Exception

     */

    @RandomlyFails // OOME in NB-Core-Build #1908

    public void testWeakSetIntegrity() throws Exception {

        //CharSequence log = Log.enable(WeakSet.class.getName(), Level.FINE);

        ArrayList<WeakReference<TestObj>> awr = new ArrayList<WeakReference<TestObj>>();

        ExecutorService exec = Executors.newFixedThreadPool(5);

        exec.execute(new GC());

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

            TestObj to = new TestObj("T" + i);

            awr.add(new WeakReference<TestObj>(to));

            Thread.yield();

            for (WeakReference<TestObj> wro : awr) {

                TestObj wroo = wro.get();

                if (wroo != null) {

                    synchronized (TestObj.testObjs) {

                        boolean found = false;

                        for (TestObj o : TestObj.testObjs) {

                            if (o == wroo) {

                                found = true;

                            }

                        }

                        if (found != TestObj.testObjs.contains(wroo)) {

                            //System.out.println(log.toString());

                            fail("Inconsistency of iterator chain and hash map");

                        }

                    }

                }

            }

        }

        exec.shutdownNow();

    }    

}