1 /*
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3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
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8  * particular file as subject to the "Classpath" exception as provided
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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).
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17  * You should have received a copy of the GNU General Public License version
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24  */
25 package java.util.stream;
26 
27 import java.security.AccessController;
28 import java.security.PrivilegedAction;
29 
30 import sun.util.logging.PlatformLogger;
31 
32 /**
33  * Utility class for detecting inadvertent uses of boxing in
34  * {@code java.util.stream} 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 Sink.OfInt.accept(Integer)");
44  * }</pre>
45  *
46  * @since 1.8
47  */
48 final 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 
Tripwire()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      */
trip(Class<?> trippingClass, String msg)66     static void trip(Class<?> trippingClass, String msg) {
67         PlatformLogger.getLogger(trippingClass.getName()).warning(msg, trippingClass.getName());
68     }
69 }
70