Java example source code file (ToArrayTest.java)

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Java - Java tags/keywords

abstractcollection, arraystoreexception, candidate, cap, exception, iterator, not, object, override, string, testcollection, throwable, toarraytest, unsupportedoperationexception, util

The ToArrayTest.java Java example source code

/*
 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
 * 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 7121314
 * @summary AbstractCollection.toArray(T[]) doesn't return the given array
 *           in concurrent modification.
 * @author Ulf Zibis, David Holmes
 */

import java.util.AbstractCollection;
import java.util.Arrays;
import java.util.Iterator;

public class ToArrayTest {

    static class TestCollection<E> extends AbstractCollection {
        private final E[] elements;
        private int[] sizes;
        private int nextSize;

        public TestCollection(E[] elements) {
            this.elements = elements;
            setSizeSequence(new int[] { elements.length });
        }

        /*
         * Sets the values that size() will return on each use. The next
         * call to size will return sizes[0], then sizes[1] etc. This allows us
         * to emulate a concurrent change to the contents of the collection
         * without having to perform concurrent changes. If sizes[n+1] contains
         * a larger value, the collection will appear to have shrunk when
         * iterated; if a smaller value then the collection will appear to have
         * grown when iterated.
         */
        void setSizeSequence(int... sizes) {
            this.sizes = sizes;
            nextSize = 0;
        }

        /* can change collection's size after each invocation */
        @Override
        public int size() {
            return sizes[nextSize == sizes.length - 1 ? nextSize : nextSize++];
        }

        @Override
        public Iterator<E> iterator() {
            return new Iterator<E>() {
                int pos = 0;

                public boolean hasNext() {
                    return pos < sizes[nextSize];
                }
                public E next() {
                    return elements[pos++];
                }
                public void remove() {
                    throw new UnsupportedOperationException(
                            "Not supported yet.");
                }
            };
        }
    }

    static final Object[] OBJECTS = { new Object(), new Object(), new Object() };
    static final TestCollection<?> CANDIDATE = new TestCollection