1 /* 2 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. 3 * 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 * 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 */ 23 24 /* 25 * @test 26 * @bug 5017904 6356890 27 * @summary Test empty iterators, enumerations, and collections 28 */ 29 30 import java.util.*; 31 import static java.util.Collections.*; 32 33 public class EmptyIterator { 34 35 void test(String[] args) throws Throwable { 36 testEmptyCollection(Collections.<Object>emptyList()); 37 testEmptyCollection(Collections.<Object>emptySet()); 38 39 testEmptyMap(Collections.<Object, Object>emptyMap()); 40 41 Hashtable<Object, Object> emptyTable = new Hashtable<Object, Object>(); 42 testEmptyEnumeration(emptyTable.keys()); 43 testEmptyEnumeration(emptyTable.elements()); 44 testEmptyIterator(emptyTable.keySet().iterator()); 45 testEmptyIterator(emptyTable.values().iterator()); 46 testEmptyIterator(emptyTable.entrySet().iterator()); 47 48 testEmptyEnumeration(javax.swing.tree.DefaultMutableTreeNode 49 .EMPTY_ENUMERATION); 50 testEmptyEnumeration(javax.swing.text.SimpleAttributeSet 51 .EMPTY.getAttributeNames()); 52 53 @SuppressWarnings("unchecked") Iterator<?> x = 54 new sun.tools.java.MethodSet() 55 .lookupName(sun.tools.java.Identifier.lookup("")); 56 testEmptyIterator(x); 57 } 58 59 <T> void testEmptyEnumeration(final Enumeration<T> e) { 60 check(e == emptyEnumeration()); 61 check(! e.hasMoreElements()); 62 THROWS(NoSuchElementException.class, 63 new F(){void f(){ e.nextElement(); }}); 64 } 65 66 <T> void testEmptyIterator(final Iterator<T> it) { 67 check(it == emptyIterator()); 68 check(! it.hasNext()); 69 THROWS(NoSuchElementException.class, 70 new F(){void f(){ it.next(); }}); 71 THROWS(IllegalStateException.class, 72 new F(){void f(){ it.remove(); }}); 73 } 74 75 void testEmptyMap(Map<Object, Object> m) { 76 check(m == emptyMap()); 77 check(m.entrySet().iterator() == 78 Collections.<Map.Entry<Object,Object>>emptyIterator()); 79 check(m.values().iterator() == emptyIterator()); 80 check(m.keySet().iterator() == emptyIterator()); 81 equal(m, unmodifiableMap(m)); 82 83 testEmptyCollection(m.keySet()); 84 testEmptyCollection(m.entrySet()); 85 testEmptyCollection(m.values()); 86 } 87 88 <E> void testToArray(final Collection<E> c) { 89 Object[] a = c.toArray(); 90 equal(a.length, 0); 91 equal(a.getClass().getComponentType(), Object.class); 92 THROWS(NullPointerException.class, 93 new F(){void f(){ c.toArray((Object[])null); }}); 94 95 { 96 String[] t = new String[0]; 97 check(c.toArray(t) == t); 98 } 99 100 { 101 String[] t = nCopies(10, "").toArray(new String[0]); 102 check(c.toArray(t) == t); 103 check(t[0] == null); 104 for (int i=1; i<t.length; i++) 105 check(t[i] == ""); 106 } 107 } 108 109 <E> void testEmptyCollection(final Collection<E> c) { 110 testEmptyIterator(c.iterator()); 111 112 check(c.iterator() == emptyIterator()); 113 if (c instanceof List) 114 check(((List<?>)c).listIterator() == emptyListIterator()); 115 116 testToArray(c); 117 } 118 119 //--------------------- Infrastructure --------------------------- 120 volatile int passed = 0, failed = 0; 121 void pass() {passed++;} 122 void fail() {failed++; Thread.dumpStack();} 123 void fail(String msg) {System.err.println(msg); fail();} 124 void unexpected(Throwable t) {failed++; t.printStackTrace();} 125 void check(boolean cond) {if (cond) pass(); else fail();} 126 void equal(Object x, Object y) { 127 if (x == null ? y == null : x.equals(y)) pass(); 128 else fail(x + " not equal to " + y);} 129 public static void main(String[] args) throws Throwable { 130 new EmptyIterator().instanceMain(args);} 131 void instanceMain(String[] args) throws Throwable { 132 try {test(args);} catch (Throwable t) {unexpected(t);} 133 System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); 134 if (failed > 0) throw new AssertionError("Some tests failed");} 135 abstract class F {abstract void f() throws Throwable;} 136 void THROWS(Class<? extends Throwable> k, F... fs) { 137 for (F f : fs) 138 try {f.f(); fail("Expected " + k.getName() + " not thrown");} 139 catch (Throwable t) { 140 if (k.isAssignableFrom(t.getClass())) pass(); 141 else unexpected(t);}} 142 }