jdk-24/test/jdk/java/lang/ref/ReferenceRefersTo.java
Kim Barrett 6023f6b1bf 8188055: (ref) Add Reference::refersTo predicate
Reviewed-by: mchung, pliden, rriggs, dholmes, ihse, smarks, alanb
2020-11-04 09:18:23 +00:00

81 lines
2.8 KiB
Java

/*
* Copyright (c) 2020, 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 8188055
* @summary Basic functional test of Reference.refersTo.
*/
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.PhantomReference;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
public class ReferenceRefersTo {
private static final void fail(String msg) throws Exception {
throw new RuntimeException(msg);
}
private static final <T extends Reference> void test(T ref,
Object expectedValue,
Object unexpectedValue,
String kind) throws Exception {
if ((expectedValue != null) && ref.refersTo(null)) {
fail(kind + "refers to null");
}
if (!ref.refersTo(expectedValue)) {
fail(kind + " doesn't refer to expected value");
}
if (ref.refersTo(unexpectedValue)) {
fail(kind + " refers to unexpected value");
}
}
public static void main(String[] args) throws Exception {
var queue = new ReferenceQueue<Object>();
var obj0 = new Object();
var obj1 = new Object();
var obj2 = new Object();
var obj3 = new Object();
var pref = new PhantomReference(obj0, queue);
var wref = new WeakReference(obj1);
var sref = new SoftReference(obj2);
test(pref, obj0, obj3, "phantom");
test(wref, obj1, obj3, "weak");
test(sref, obj2, obj3, "soft");
pref.clear();
wref.clear();
sref.clear();
test(pref, null, obj3, "phantom");
test(wref, null, obj3, "weak");
test(sref, null, obj3, "soft");
}
}