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/*
* 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.*;
import java.util.concurrent.*;
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<T>() {
public int size() { return n; }
public T get(int index) {
check(0 <= index && index < n, "Index is incorrect");
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");
}
}
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