1 /* 2 * Copyright (c) 2015, 2016, 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.lang.reflect.Module; 37 import java.security.AccessController; 38 import java.security.PrivilegedAction; 39 import java.util.Collection; 40 import java.util.ResourceBundle; 41 42 /** 43 * Internal Service Provider Interface (SPI) that makes it possible to use 44 * {@code java.util.logging} as backend when the {@link 45 * sun.util.logging.internal.LoggingProviderImpl 46 * sun.util.logging.internal.LoggingProviderImpl} is present. 47 * <p> 48 * The JDK default implementation of the {@link LoggerFinder} will 49 * attempt to locate and load an {@linkplain 50 * java.util.ServiceLoader#loadInstalled(java.lang.Class) installed} 51 * implementation of the {@code DefaultLoggerFinder}. If {@code java.util.logging} 52 * is present, this will usually resolve to an instance of {@link 53 * sun.util.logging.internal.LoggingProviderImpl sun.util.logging.internal.LoggingProviderImpl}. 54 * Otherwise, if no concrete service provider is declared for 55 * {@code DefaultLoggerFinder}, the default implementation provided by this class 56 * will be used. 57 * <p> 58 * When the {@link sun.util.logging.internal.LoggingProviderImpl 59 * sun.util.logging.internal.LoggingProviderImpl} is not present then the 60 * default implementation provided by this class is to use a simple logger 61 * that will log messages whose level is INFO and above to the console. 62 * These simple loggers are not configurable. 63 * <p> 64 * When configuration is needed, an application should either link with 65 * {@code java.util.logging} - and use the {@code java.util.logging} for 66 * configuration, or link with {@link LoggerFinder another implementation} 67 * of the {@link LoggerFinder} 68 * that provides the necessary configuration. 69 * 70 * @apiNote Programmers are not expected to call this class directly. 71 * Instead they should rely on the static methods defined by {@link 72 * java.lang.System java.lang.System} or {@link sun.util.logging.PlatformLogger 73 * sun.util.logging.PlatformLogger}. 74 * 75 * @see java.lang.System.LoggerFinder 76 * @see jdk.internal.logger 77 * @see sun.util.logging.internal 78 * 79 */ 80 public class DefaultLoggerFinder extends LoggerFinder { 81 82 static final RuntimePermission LOGGERFINDER_PERMISSION = 83 new RuntimePermission("loggerFinder"); 84 85 /** 86 * Creates a new instance of DefaultLoggerFinder. 87 * @throws SecurityException if the calling code does not have the 88 * {@code RuntimePermission("loggerFinder")} 89 */ 90 protected DefaultLoggerFinder() { 91 this(checkPermission()); 92 } 93 94 private DefaultLoggerFinder(Void unused) { 95 // nothing to do. 96 } 97 98 private static Void checkPermission() { 99 final SecurityManager sm = System.getSecurityManager(); 100 if (sm != null) { 101 sm.checkPermission(LOGGERFINDER_PERMISSION); 102 } 103 return null; 104 } 105 106 // SharedLoggers is a default cache of loggers used when JUL is not 107 // present - in that case we use instances of SimpleConsoleLogger which 108 // cannot be directly configure through public APIs. 109 // 110 // We can therefore afford to simply maintain two domains - one for the 111 // system, and one for the application. 112 // 113 static final class SharedLoggers { 114 private final Map<String, Reference<Logger>> loggers = 115 new HashMap<>(); 116 private final ReferenceQueue<Logger> queue = new ReferenceQueue<>(); 117 118 synchronized Logger get(Function<String, Logger> loggerSupplier, final String name) { 119 Reference<? extends Logger> ref = loggers.get(name); 120 Logger w = ref == null ? null : ref.get(); 121 if (w == null) { 122 w = loggerSupplier.apply(name); 123 loggers.put(name, new WeakReference<>(w, queue)); 124 } 125 126 // Remove stale mapping... 127 Collection<Reference<Logger>> values = null; 128 while ((ref = queue.poll()) != null) { 129 if (values == null) values = loggers.values(); 130 values.remove(ref); 131 } 132 return w; 133 } 134 135 final static SharedLoggers system = new SharedLoggers(); 136 final static SharedLoggers application = new SharedLoggers(); 137 } 138 139 public static boolean isSystem(Module m) { 140 return AccessController.doPrivileged(new PrivilegedAction<>() { 141 @Override 142 public Boolean run() { 143 final ClassLoader moduleCL = m.getClassLoader(); 144 if (moduleCL == null) return true; 145 ClassLoader cl = ClassLoader.getPlatformClassLoader(); 146 while (cl != null && moduleCL != cl) { 147 cl = cl.getParent(); 148 } 149 // returns true if moduleCL is the platform class loader 150 // or one of its ancestors. 151 return moduleCL == cl; 152 } 153 }); 154 } 155 156 @Override 157 public final Logger getLogger(String name, Module module) { 158 checkPermission(); 159 return demandLoggerFor(name, module); 160 } 161 162 @Override 163 public final Logger getLocalizedLogger(String name, ResourceBundle bundle, 164 Module module) { 165 return super.getLocalizedLogger(name, bundle, module); 166 } 167 168 /** 169 * Returns a {@link Logger logger} suitable for use within the 170 * given {@code module}. 171 * 172 * @implSpec The default implementation for this method is to return a 173 * simple logger that will print all messages of INFO level and above 174 * to the console. That simple logger is not configurable. 175 * 176 * @param name The name of the logger. 177 * @param module The module on behalf of which the logger is created. 178 * @return A {@link Logger logger} suitable for the application usage. 179 * @throws SecurityException if the calling code does not have the 180 * {@code RuntimePermission("loggerFinder")}. 181 */ 182 protected Logger demandLoggerFor(String name, Module module) { 183 checkPermission(); 184 if (isSystem(module)) { 185 return SharedLoggers.system.get(SimpleConsoleLogger::makeSimpleLogger, name); 186 } else { 187 return SharedLoggers.application.get(SimpleConsoleLogger::makeSimpleLogger, name); 188 } 189 } 190 191 }