Tripwire.java revision e86a81ca1ae9ddbdd1c3239d31fb2e49b4a5cf33 
1/*
2 * Copyright (c) 2012, 2013, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 * questions.
24 */
25package java.util;
26
27import sun.util.logging.PlatformLogger;
28
29import java.security.AccessController;
30import java.security.PrivilegedAction;
31
32/**
33 * Utility class for detecting inadvertent uses of boxing in
34 * {@code java.util} classes.  The detection is turned on or off based on
35 * whether the system property {@code org.openjdk.java.util.stream.tripwire} is
36 * considered {@code true} according to {@link Boolean#getBoolean(String)}.
37 * This should normally be turned off for production use.
38 *
39 * @apiNote
40 * Typical usage would be for boxing code to do:
41 * <pre>{@code
42 *     if (Tripwire.ENABLED)
43 *         Tripwire.trip(getClass(), "{0} calling PrimitiveIterator.OfInt.nextInt()");
44 * }</pre>
45 *
46 * @since 1.8
47 */
48final class Tripwire {
49    private static final String TRIPWIRE_PROPERTY = "org.openjdk.java.util.stream.tripwire";
50
51    /** Should debugging checks be enabled? */
52    static final boolean ENABLED = AccessController.doPrivileged(
53            (PrivilegedAction<Boolean>) () -> Boolean.getBoolean(TRIPWIRE_PROPERTY));
54
55    private Tripwire() { }
56
57    /**
58     * Produces a log warning, using {@code PlatformLogger.getLogger(className)},
59     * using the supplied message.  The class name of {@code trippingClass} will
60     * be used as the first parameter to the message.
61     *
62     * @param trippingClass Name of the class generating the message
63     * @param msg A message format string of the type expected by
64     * {@link PlatformLogger}
65     */
66    static void trip(Class<?> trippingClass, String msg) {
67        PlatformLogger.getLogger(trippingClass.getName()).warning(msg, trippingClass.getName());
68    }
69}
70