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/* |
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* Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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|
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/* |
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* @test |
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* @bug 4684279 7129185 |
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* @summary Empty utility collections should be singletons |
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* @author Josh Bloch |
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* @run testng EmptyCollectionSerialization |
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*/ |
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|
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import java.util.*; |
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import java.util.function.Supplier; |
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import java.io.*; |
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import org.testng.annotations.Test; |
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import org.testng.annotations.DataProvider; |
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|
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import static org.testng.Assert.fail; |
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import static org.testng.Assert.assertSame; |
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|
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public class EmptyCollectionSerialization { |
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private static Object patheticDeepCopy(Object o) throws Exception { |
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// Serialize |
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ByteArrayOutputStream bos = new ByteArrayOutputStream(); |
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ObjectOutputStream oos = new ObjectOutputStream(bos); |
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oos.writeObject(o); |
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byte[] serializedForm = bos.toByteArray(); |
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|
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// Deserialize |
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InputStream is = new ByteArrayInputStream(serializedForm); |
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ObjectInputStream ois = new ObjectInputStream(is); |
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return ois.readObject(); |
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} |
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|
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@Test(dataProvider="SerializableSingletons") |
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public static void serializableSingletons(String description, Supplier<Object> o) { |
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try { |
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Object singleton = o.get(); |
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assertSame(o.get(), singleton, description + ": broken Supplier not returning singleton"); |
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Object copy = patheticDeepCopy(singleton); |
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assertSame( copy, singleton, description + ": " + |
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copy.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(copy)) + |
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" is not the singleton " + |
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singleton.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(singleton))); |
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} catch (Exception all) { |
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fail(description + ": Unexpected Exception", all); |
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} |
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} |
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|
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@DataProvider(name = "SerializableSingletons", parallel = true) |
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public static Iterator<Object[]> navigableMapProvider() { |
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return makeSingletons().iterator(); |
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} |
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|
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public static Collection<Object[]> makeSingletons() { |
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return Arrays.asList( |
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new Object[]{"Collections.EMPTY_LIST", |
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(Supplier) () -> {return Collections.EMPTY_LIST;}}, |
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new Object[]{"Collections.EMPTY_MAP", |
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(Supplier) () -> {return Collections.EMPTY_MAP;}}, |
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new Object[]{"Collections.EMPTY_SET", |
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(Supplier) () -> {return Collections.EMPTY_SET;}}, |
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new Object[]{"Collections.singletonMap()", |
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(Supplier) () -> {return Collections.emptyList();}}, |
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new Object[]{"Collections.emptyMap()", |
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(Supplier) () -> {return Collections.emptyMap();}}, |
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new Object[]{"Collections.emptySet()", |
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(Supplier) () -> {return Collections.emptySet();}}, |
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new Object[]{"Collections.emptySortedSet()", |
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(Supplier) () -> {return Collections.emptySortedSet();}}, |
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new Object[]{"Collections.emptySortedMap()", |
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(Supplier) () -> {return Collections.emptySortedMap();}}, |
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new Object[]{"Collections.emptyNavigableSet()", |
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(Supplier) () -> {return Collections.emptyNavigableSet();}}, |
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new Object[]{"Collections.emptyNavigableMap()", |
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(Supplier) () -> {return Collections.emptyNavigableMap();}} |
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); |
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} |
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} |
