1 /*
2 * Copyright (c) 2015, 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
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.logger;
27
28 import java.lang.ref.Reference;
29 import java.lang.ref.WeakReference;
30 import java.util.HashMap;
31 import java.util.Map;
32 import java.util.function.Function;
33 import java.lang.System.LoggerFinder;
34 import java.lang.System.Logger;
35 import java.lang.ref.ReferenceQueue;
36 import java.util.Collection;
37 import java.util.ResourceBundle;
38
39 /**
40 * Internal Service Provider Interface (SPI) that makes it possible to use
41 * {@code java.util.logging} as backend when the {@link
42 * sun.util.logging.internal.LoggingProviderImpl
43 * sun.util.logging.internal.LoggingProviderImpl} is present.
44 * <p>
45 * The JDK default implementation of the {@link LoggerFinder} will
46 * attempt to locate and load an {@linkplain
47 * java.util.ServiceLoader#loadInstalled(java.lang.Class) installed}
48 * implementation of the {@code DefaultLoggerFinder}. If {@code java.util.logging}
49 * is present, this will usually resolve to an instance of {@link
50 * sun.util.logging.internal.LoggingProviderImpl sun.util.logging.internal.LoggingProviderImpl}.
51 * Otherwise, if no concrete service provider is declared for
52 * {@code DefaultLoggerFinder}, the default implementation provided by this class
53 * will be used.
54 * <p>
55 * When the {@link sun.util.logging.internal.LoggingProviderImpl
56 * sun.util.logging.internal.LoggingProviderImpl} is not present then the
57 * default implementation provided by this class is to use a simple logger
58 * that will log messages whose level is INFO and above to the console.
59 * These simple loggers are not configurable.
60 * <p>
61 * When configuration is needed, an application should either link with
62 * {@code java.util.logging} - and use the {@code java.util.logging} for
63 * configuration, or link with {@link LoggerFinder another implementation}
64 * of the {@link LoggerFinder}
65 * that provides the necessary configuration.
66 *
67 * @apiNote Programmers are not expected to call this class directly.
68 * Instead they should rely on the static methods defined by {@link
69 * java.lang.System java.lang.System} or {@link sun.util.logging.PlatformLogger
70 * sun.util.logging.PlatformLogger}.
71 *
72 * @see java.lang.System.LoggerFinder
73 * @see jdk.internal.logger
74 * @see sun.util.logging.internal
75 *
76 */
77 public class DefaultLoggerFinder extends LoggerFinder {
78
79 static final RuntimePermission LOGGERFINDER_PERMISSION =
80 new RuntimePermission("loggerFinder");
81
82 /**
83 * Creates a new instance of DefaultLoggerFinder.
84 * @throws SecurityException if the calling code does not have the
85 * {@code RuntimePermission("loggerFinder")}
86 */
87 protected DefaultLoggerFinder() {
88 this(checkPermission());
89 }
90
91 private DefaultLoggerFinder(Void unused) {
92 // nothing to do.
93 }
94
95 private static Void checkPermission() {
96 final SecurityManager sm = System.getSecurityManager();
97 if (sm != null) {
98 sm.checkPermission(LOGGERFINDER_PERMISSION);
99 }
100 return null;
101 }
102
103 // SharedLoggers is a default cache of loggers used when JUL is not
104 // present - in that case we use instances of SimpleConsoleLogger which
105 // cannot be directly configure through public APIs.
106 //
107 // We can therefore afford to simply maintain two domains - one for the
108 // system, and one for the application.
109 //
110 static final class SharedLoggers {
111 private final Map<String, Reference<Logger>> loggers =
112 new HashMap<>();
113 private final ReferenceQueue<Logger> queue = new ReferenceQueue<>();
114
115 synchronized Logger get(Function<String, Logger> loggerSupplier, final String name) {
116 Reference<? extends Logger> ref = loggers.get(name);
117 Logger w = ref == null ? null : ref.get();
118 if (w == null) {
119 w = loggerSupplier.apply(name);
120 loggers.put(name, new WeakReference<>(w, queue));
121 }
122
123 // Remove stale mapping...
124 Collection<Reference<Logger>> values = null;
125 while ((ref = queue.poll()) != null) {
126 if (values == null) values = loggers.values();
127 values.remove(ref);
128 }
129 return w;
130 }
131
132
133 final static SharedLoggers system = new SharedLoggers();
134 final static SharedLoggers application = new SharedLoggers();
135 }
136
137 @Override
138 public final Logger getLogger(String name, /* Module */ Class<?> caller) {
139 checkPermission();
140 return demandLoggerFor(name, caller);
141 }
142
143 @Override
144 public final Logger getLocalizedLogger(String name, ResourceBundle bundle,
145 /* Module */ Class<?> caller) {
146 return super.getLocalizedLogger(name, bundle, caller);
147 }
148
149
150
151 /**
152 * Returns a {@link Logger logger} suitable for the caller usage.
153 *
154 * @implSpec The default implementation for this method is to return a
155 * simple logger that will print all messages of INFO level and above
156 * to the console. That simple logger is not configurable.
157 *
158 * @param name The name of the logger.
159 * @param caller The class on behalf of which the logger is created.
160 * @return A {@link Logger logger} suitable for the application usage.
161 * @throws SecurityException if the calling code does not have the
162 * {@code RuntimePermission("loggerFinder")}.
163 */
164 protected Logger demandLoggerFor(String name, /* Module */ Class<?> caller) {
165 checkPermission();
166 if (caller.getClassLoader() == null) {
167 return SharedLoggers.system.get(SimpleConsoleLogger::makeSimpleLogger, name);
168 } else {
169 return SharedLoggers.application.get(SimpleConsoleLogger::makeSimpleLogger, name);
170 }
171 }
172
173 }