| /* |
| * Copyright (c) 2005, 2018, 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 6267846 6275009 |
| * @summary Test Collections.nCopies |
| * @author Martin Buchholz |
| */ |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.AbstractList; |
| import java.util.List; |
| import java.util.Objects; |
| |
| public class NCopies { |
| static volatile int passed = 0, failed = 0; |
| |
| static void fail(String msg) { |
| failed++; |
| new AssertionError(msg).printStackTrace(); |
| } |
| |
| static void pass() { |
| passed++; |
| } |
| |
| static void unexpected(Throwable t) { |
| failed++; |
| t.printStackTrace(); |
| } |
| |
| static void check(boolean condition, String msg) { |
| if (condition) |
| passed++; |
| else |
| fail(msg); |
| } |
| |
| static void check(boolean condition) { |
| check(condition, "Assertion failure"); |
| } |
| |
| private static void checkEmpty(List<String> x) { |
| check(x.isEmpty()); |
| check(x.size() == 0); |
| check(x.indexOf("foo") == -1); |
| check(x.lastIndexOf("foo") == -1); |
| check(x.toArray().length == 0); |
| check(x.toArray().getClass() == Object[].class); |
| } |
| |
| private static void checkFoos(List<String> x) { |
| check(! x.isEmpty()); |
| check(x.indexOf(new String("foo")) == 0); |
| check(x.lastIndexOf(new String("foo")) == x.size()-1); |
| check(x.toArray().length == x.size()); |
| check(x.toArray().getClass() == Object[].class); |
| String[] sa = x.toArray(new String[x.size()]); |
| check(sa.getClass() == String[].class); |
| check(sa[0].equals("foo")); |
| check(sa[sa.length-1].equals("foo")); |
| check(x.get(x.size()/2).equals("foo")); |
| checkEmpty(x.subList(x.size()/2, x.size()/2)); |
| } |
| |
| private static <T> List<T> referenceNCopies(int n, T o) { |
| // A simplest correct implementation of nCopies to compare with the actual optimized implementation |
| return new AbstractList<>() { |
| public int size() { return n; } |
| |
| public T get(int index) { |
| Objects.checkIndex(index, n); |
| return o; |
| } |
| }; |
| } |
| |
| private static void checkHashCode() { |
| int[] sizes = {0, 1, 2, 3, 5, 10, 31, 32, 100, 1000}; |
| String[] elements = {null, "non-null"}; |
| for (int size : sizes) { |
| for (String element : elements) { |
| int expectedHashCode = referenceNCopies(size, element).hashCode(); |
| int actualHashCode = Collections.nCopies(size, element).hashCode(); |
| check(expectedHashCode == actualHashCode, |
| "Collections.nCopies(" + size + ", " + element + ").hashCode()"); |
| } |
| } |
| } |
| |
| private static void checkEquals() { |
| int[][] sizePairs = {{0, 0}, {0, 1}, {1, 0}, {1, 1}, {1, 2}, {2, 1}}; |
| String[] elements = {null, "non-null"}; |
| for (int[] pair : sizePairs) { |
| for (String element : elements) { |
| boolean equal = pair[0] == pair[1]; |
| String msg = "[" + pair[0] + ", " + element + "] <=> [" + pair[1] + ", " + element + "]"; |
| check(equal == Collections.nCopies(pair[0], element).equals(Collections.nCopies(pair[1], element)), msg); |
| check(equal == Collections.nCopies(pair[0], element).equals(referenceNCopies(pair[1], element)), msg); |
| check(equal == referenceNCopies(pair[0], element).equals(Collections.nCopies(pair[1], element)), msg); |
| } |
| } |
| List<String> nulls = Collections.nCopies(10, null); |
| List<String> nonNulls = Collections.nCopies(10, "non-null"); |
| List<String> nullsButOne = new ArrayList<>(nulls); |
| nullsButOne.set(9, "non-null"); |
| List<String> nonNullsButOne = new ArrayList<>(nonNulls); |
| nonNullsButOne.set(9, null); |
| check(!nulls.equals(nonNulls)); |
| check(!nulls.equals(nullsButOne)); |
| check(!nulls.equals(nonNullsButOne)); |
| check(!nonNulls.equals(nonNullsButOne)); |
| check(Collections.nCopies(0, null).equals(Collections.nCopies(0, "non-null"))); |
| } |
| |
| public static void main(String[] args) { |
| try { |
| List<String> empty = Collections.nCopies(0, "foo"); |
| checkEmpty(empty); |
| checkEmpty(empty.subList(0,0)); |
| |
| List<String> foos = Collections.nCopies(42, "foo"); |
| check(foos.size() == 42); |
| checkFoos(foos.subList(foos.size()/2, foos.size()-1)); |
| |
| checkHashCode(); |
| |
| checkEquals(); |
| |
| } catch (Throwable t) { unexpected(t); } |
| |
| System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); |
| if (failed > 0) throw new Error("Some tests failed"); |
| } |
| } |