100 lines
4.2 KiB
Java
100 lines
4.2 KiB
Java
/*
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* Copyright (c) 2002, 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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* @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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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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import static org.testng.Assert.fail;
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import static org.testng.Assert.assertSame;
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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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// 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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@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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@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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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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}
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