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/* |
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* Copyright (c) 2007, 2014, 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 5017904 6356890 8004928 |
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* @summary Test empty iterators, enumerations, and collections |
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*/ |
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|
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import java.util.Collection; |
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import java.util.Collections; |
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import java.util.Enumeration; |
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import java.util.Hashtable; |
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import java.util.Iterator; |
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import java.util.List; |
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import java.util.Map; |
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import java.util.NoSuchElementException; |
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import java.util.concurrent.SynchronousQueue; |
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|
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import static java.util.Collections.emptyEnumeration; |
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import static java.util.Collections.emptyIterator; |
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import static java.util.Collections.emptyList; |
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import static java.util.Collections.emptyListIterator; |
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import static java.util.Collections.emptyMap; |
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import static java.util.Collections.emptySet; |
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import static java.util.Collections.nCopies; |
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import static java.util.Collections.unmodifiableMap; |
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|
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public class EmptyIterator { |
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|
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void test(String[] args) throws Throwable { |
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testEmptyCollection(emptyList()); |
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testEmptyCollection(emptySet()); |
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testEmptyCollection(new SynchronousQueue<Object>()); |
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testEmptyMap(emptyMap()); |
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|
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Hashtable<?,?> emptyTable = new Hashtable<>(); |
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testEmptyEnumeration(emptyTable.keys()); |
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testEmptyEnumeration(emptyTable.elements()); |
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testEmptyIterator(emptyTable.keySet().iterator()); |
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testEmptyIterator(emptyTable.values().iterator()); |
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testEmptyIterator(emptyTable.entrySet().iterator()); |
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|
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final Enumeration<EmptyIterator> finalEmptyTyped = emptyEnumeration(); |
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testEmptyEnumeration(finalEmptyTyped); |
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|
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final Enumeration<?> finalEmptyAbstract = emptyEnumeration(); |
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testEmptyEnumeration(finalEmptyAbstract); |
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|
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testEmptyIterator(emptyIterator()); |
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} |
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|
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void testEmptyEnumeration(final Enumeration<?> e) { |
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check(e == emptyEnumeration()); |
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check(!e.hasMoreElements()); |
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THROWS(NoSuchElementException.class, |
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new F(){void f(){ e.nextElement(); }}); |
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} |
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|
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void testEmptyIterator(final Iterator<?> it) { |
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check(it == emptyIterator()); |
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check(! it.hasNext()); |
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THROWS(NoSuchElementException.class, |
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new F(){void f(){ it.next(); }}); |
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THROWS(IllegalStateException.class, |
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new F(){void f(){ it.remove(); }}); |
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} |
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|
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void testEmptyMap(Map<?,?> m) { |
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check(m == emptyMap()); |
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check(m.entrySet().iterator() == |
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Collections.<Map.Entry<?,?>>emptyIterator()); |
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check(m.values().iterator() == emptyIterator()); |
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check(m.keySet().iterator() == emptyIterator()); |
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equal(m, unmodifiableMap(m)); |
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|
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testEmptyCollection(m.keySet()); |
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testEmptyCollection(m.entrySet()); |
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testEmptyCollection(m.values()); |
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} |
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|
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void testToArray(final Collection<?> c) { |
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Object[] a = c.toArray(); |
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equal(a.length, 0); |
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equal(a.getClass().getComponentType(), Object.class); |
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THROWS(NullPointerException.class, |
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new F(){void f(){ c.toArray((Object[])null); }}); |
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|
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{ |
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String[] t = new String[0]; |
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check(c.toArray(t) == t); |
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} |
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|
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{ |
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String[] t = nCopies(10, "").toArray(new String[0]); |
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check(c.toArray(t) == t); |
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check(t[0] == null); |
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for (int i=1; i<t.length; i++) |
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check(t[i] == ""); |
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} |
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} |
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|
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void testEmptyCollection(final Collection<?> c) { |
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testEmptyIterator(c.iterator()); |
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|
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check(c.iterator() == emptyIterator()); |
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if (c instanceof List) |
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check(((List<?>)c).listIterator() == emptyListIterator()); |
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|
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testToArray(c); |
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} |
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|
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//--------------------- Infrastructure --------------------------- |
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volatile int passed = 0, failed = 0; |
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void pass() {passed++;} |
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void fail() {failed++; Thread.dumpStack();} |
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void fail(String msg) {System.err.println(msg); fail();} |
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void unexpected(Throwable t) {failed++; t.printStackTrace();} |
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void check(boolean cond) {if (cond) pass(); else fail();} |
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void equal(Object x, Object y) { |
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if (x == null ? y == null : x.equals(y)) pass(); |
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else fail(x + " not equal to " + y);} |
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public static void main(String[] args) throws Throwable { |
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new EmptyIterator().instanceMain(args);} |
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void instanceMain(String[] args) throws Throwable { |
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try {test(args);} catch (Throwable t) {unexpected(t);} |
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System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); |
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if (failed > 0) throw new AssertionError("Some tests failed");} |
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abstract class F {abstract void f() throws Throwable;} |
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void THROWS(Class<? extends Throwable> k, F... fs) { |
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for (F f : fs) |
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try {f.f(); fail("Expected " + k.getName() + " not thrown");} |
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catch (Throwable t) { |
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if (k.isAssignableFrom(t.getClass())) pass(); |
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else unexpected(t);}} |
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} |
