util/Collections/EmptyCollectionSerialization.java

/*
 * Copyright (c) 2002, 2013, 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     4684279 7129185
 * @summary Empty utility collections should be singletons
 * @author  Josh Bloch
 * @run testng EmptyCollectionSerialization
 */

import java.util.*;
import java.util.function.Supplier;
import java.io.*;
import org.testng.annotations.Test;
import org.testng.annotations.DataProvider;

import static org.testng.Assert.fail;
import static org.testng.Assert.assertSame;

public class EmptyCollectionSerialization {
    private static Object patheticDeepCopy(Object o) throws Exception {
        // Serialize
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(o);
        byte[] serializedForm = bos.toByteArray();

        // Deserialize
        InputStream is = new ByteArrayInputStream(serializedForm);
        ObjectInputStream ois = new ObjectInputStream(is);
        return ois.readObject();
    }

    @Test(dataProvider="SerializableSingletons")
    public static void serializableSingletons(String description, Supplier<Object> o) {
        try {
            Object singleton = o.get();
            assertSame(o.get(), singleton, description + ": broken Supplier not returning singleton");
            Object copy = patheticDeepCopy(singleton);
            assertSame( copy, singleton, description + ": " +
                copy.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(copy)) +
                " is not the singleton " +
                singleton.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(singleton)));
        } catch (Exception all) {
            fail(description + ": Unexpected Exception", all);
        }
    }

    @DataProvider(name = "SerializableSingletons", parallel = true)
    public static Iterator<Object[]> navigableMapProvider() {
        return makeSingletons().iterator();
    }

    public static Collection<Object[]> makeSingletons() {
        return Arrays.asList(
            new Object[]{"Collections.EMPTY_LIST",
                (Supplier) () -> {return Collections.EMPTY_LIST;}},
            new Object[]{"Collections.EMPTY_MAP",
                (Supplier) () -> {return Collections.EMPTY_MAP;}},
            new Object[]{"Collections.EMPTY_SET",
                (Supplier) () -> {return Collections.EMPTY_SET;}},
            new Object[]{"Collections.singletonMap()",
                (Supplier) () -> {return Collections.emptyList();}},
            new Object[]{"Collections.emptyMap()",
                (Supplier) () -> {return Collections.emptyMap();}},
            new Object[]{"Collections.emptySet()",
                (Supplier) () -> {return Collections.emptySet();}},
            new Object[]{"Collections.emptySortedSet()",
                (Supplier) () -> {return Collections.emptySortedSet();}},
            new Object[]{"Collections.emptySortedMap()",
                (Supplier) () -> {return Collections.emptySortedMap();}},
            new Object[]{"Collections.emptyNavigableSet()",
                (Supplier) () -> {return Collections.emptyNavigableSet();}},
            new Object[]{"Collections.emptyNavigableMap()",
                (Supplier) () -> {return Collections.emptyNavigableMap();}}
            );
    }
}
Revision:	1.3
Committed:	Wed Sep 9 22:05:28 2015 UTC (8 years, 8 months ago) by jsr166
Branch:	MAIN
Changes since 1.2:	+50 -11 lines
Log Message:	merge upstream changes
#	User	Rev	Content
1	jsr166	1.1	/*
2	jsr166	1.3	* Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
3	jsr166	1.1	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4			*
5			* This code is free software; you can redistribute it and/or modify it
6			* under the terms of the GNU General Public License version 2 only, as
7			* published by the Free Software Foundation.
8			*
9			* This code is distributed in the hope that it will be useful, but WITHOUT
10			* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11			* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12			* version 2 for more details (a copy is included in the LICENSE file that
13			* accompanied this code).
14			*
15			* You should have received a copy of the GNU General Public License version
16			* 2 along with this work; if not, write to the Free Software Foundation,
17			* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18			*
19	jsr166	1.2	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20			* or visit www.oracle.com if you need additional information or have any
21			* questions.
22	jsr166	1.1	*/
23
24			/*
25			* @test
26	jsr166	1.3	* @bug 4684279 7129185
27	jsr166	1.1	* @summary Empty utility collections should be singletons
28			* @author Josh Bloch
29	jsr166	1.3	* @run testng EmptyCollectionSerialization
30	jsr166	1.1	*/
31
32			import java.util.*;
33	jsr166	1.3	import java.util.function.Supplier;
34	jsr166	1.1	import java.io.*;
35	jsr166	1.3	import org.testng.annotations.Test;
36			import org.testng.annotations.DataProvider;
37
38			import static org.testng.Assert.fail;
39			import static org.testng.Assert.assertSame;
40	jsr166	1.1
41			public class EmptyCollectionSerialization {
42			private static Object patheticDeepCopy(Object o) throws Exception {
43			// Serialize
44			ByteArrayOutputStream bos = new ByteArrayOutputStream();
45			ObjectOutputStream oos = new ObjectOutputStream(bos);
46			oos.writeObject(o);
47			byte[] serializedForm = bos.toByteArray();
48
49			// Deserialize
50			InputStream is = new ByteArrayInputStream(serializedForm);
51			ObjectInputStream ois = new ObjectInputStream(is);
52			return ois.readObject();
53			}
54
55	jsr166	1.3	@Test(dataProvider="SerializableSingletons")
56			public static void serializableSingletons(String description, Supplier<Object> o) {
57			try {
58			Object singleton = o.get();
59			assertSame(o.get(), singleton, description + ": broken Supplier not returning singleton");
60			Object copy = patheticDeepCopy(singleton);
61			assertSame( copy, singleton, description + ": " +
62			copy.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(copy)) +
63			" is not the singleton " +
64			singleton.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(singleton)));
65			} catch (Exception all) {
66			fail(description + ": Unexpected Exception", all);
67			}
68			}
69
70			@DataProvider(name = "SerializableSingletons", parallel = true)
71			public static Iterator<Object[]> navigableMapProvider() {
72			return makeSingletons().iterator();
73	jsr166	1.1	}
74
75	jsr166	1.3	public static Collection<Object[]> makeSingletons() {
76			return Arrays.asList(
77			new Object[]{"Collections.EMPTY_LIST",
78			(Supplier) () -> {return Collections.EMPTY_LIST;}},
79			new Object[]{"Collections.EMPTY_MAP",
80			(Supplier) () -> {return Collections.EMPTY_MAP;}},
81			new Object[]{"Collections.EMPTY_SET",
82			(Supplier) () -> {return Collections.EMPTY_SET;}},
83			new Object[]{"Collections.singletonMap()",
84			(Supplier) () -> {return Collections.emptyList();}},
85			new Object[]{"Collections.emptyMap()",
86			(Supplier) () -> {return Collections.emptyMap();}},
87			new Object[]{"Collections.emptySet()",
88			(Supplier) () -> {return Collections.emptySet();}},
89			new Object[]{"Collections.emptySortedSet()",
90			(Supplier) () -> {return Collections.emptySortedSet();}},
91			new Object[]{"Collections.emptySortedMap()",
92			(Supplier) () -> {return Collections.emptySortedMap();}},
93			new Object[]{"Collections.emptyNavigableSet()",
94			(Supplier) () -> {return Collections.emptyNavigableSet();}},
95			new Object[]{"Collections.emptyNavigableMap()",
96			(Supplier) () -> {return Collections.emptyNavigableMap();}}
97			);
98	jsr166	1.1	}
99			}