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/*
* Copyright (c) 2015, 2021, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*
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package jdk.internal.logger;
import jdk.internal.misc.VM;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;
import java.util.Objects;
import java.lang.System.LoggerFinder;
import java.lang.System.Logger;
import java.lang.ref.ReferenceQueue;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Collection;
import java.util.ResourceBundle;
/**
* Internal Service Provider Interface (SPI) that makes it possible to use
* {@code java.util.logging} as backend when the {@link
* sun.util.logging.internal.LoggingProviderImpl
* sun.util.logging.internal.LoggingProviderImpl} is present.
*
* The JDK default implementation of the {@link LoggerFinder} will
* attempt to locate and load an {@linkplain
* java.util.ServiceLoader#loadInstalled(java.lang.Class) installed}
* implementation of the {@code DefaultLoggerFinder}. If {@code java.util.logging}
* is present, this will usually resolve to an instance of {@link
* sun.util.logging.internal.LoggingProviderImpl sun.util.logging.internal.LoggingProviderImpl}.
* Otherwise, if no concrete service provider is declared for
* {@code DefaultLoggerFinder}, the default implementation provided by this class
* will be used.
*
* When the {@link sun.util.logging.internal.LoggingProviderImpl
* sun.util.logging.internal.LoggingProviderImpl} is not present then the
* default implementation provided by this class is to use a simple logger
* that will log messages whose level is INFO and above to the console.
* These simple loggers are not configurable.
*
* When configuration is needed, an application should either link with
* {@code java.util.logging} - and use the {@code java.util.logging} for
* configuration, or link with {@link LoggerFinder another implementation}
* of the {@link LoggerFinder}
* that provides the necessary configuration.
*
* @apiNote Programmers are not expected to call this class directly.
* Instead they should rely on the static methods defined by {@link
* java.lang.System java.lang.System} or {@link sun.util.logging.PlatformLogger
* sun.util.logging.PlatformLogger}.
*
* @see java.lang.System.LoggerFinder
* @see jdk.internal.logger
* @see sun.util.logging.internal
*
*/
public class DefaultLoggerFinder extends LoggerFinder {
static final RuntimePermission LOGGERFINDER_PERMISSION =
new RuntimePermission("loggerFinder");
/**
* Creates a new instance of DefaultLoggerFinder.
* @throws SecurityException if the calling code does not have the
* {@code RuntimePermission("loggerFinder")}
*/
protected DefaultLoggerFinder() {
this(checkPermission());
}
private DefaultLoggerFinder(Void unused) {
// nothing to do.
}
private static Void checkPermission() {
@SuppressWarnings("removal")
final SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(LOGGERFINDER_PERMISSION);
}
return null;
}
// SharedLoggers is a default cache of loggers used when JUL is not
// present - in that case we use instances of SimpleConsoleLogger which
// cannot be directly configure through public APIs.
//
// We can therefore afford to simply maintain two domains - one for the
// system, and one for the application.
//
static final class SharedLoggers {
private final Map> loggers =
new HashMap<>();
private final ReferenceQueue queue = new ReferenceQueue<>();
synchronized Logger get(Function loggerSupplier, final String name) {
Reference ref = loggers.get(name);
Logger w = ref == null ? null : ref.get();
if (w == null) {
w = loggerSupplier.apply(name);
loggers.put(name, new WeakReference<>(w, queue));
}
// Remove stale mapping...
Collection> values = null;
while ((ref = queue.poll()) != null) {
if (values == null) values = loggers.values();
values.remove(ref);
}
return w;
}
static final SharedLoggers system = new SharedLoggers();
static final SharedLoggers application = new SharedLoggers();
}
@SuppressWarnings("removal")
public static boolean isSystem(Module m) {
return AccessController.doPrivileged(new PrivilegedAction<>() {
@Override
public Boolean run() {
// returns true if moduleCL is the platform class loader
// or one of its ancestors.
return VM.isSystemDomainLoader(m.getClassLoader());
}
});
}
@Override
public final Logger getLogger(String name, Module module) {
Objects.requireNonNull(name, "name");
Objects.requireNonNull(module, "module");
checkPermission();
return demandLoggerFor(name, module);
}
@Override
public final Logger getLocalizedLogger(String name, ResourceBundle bundle,
Module module) {
return super.getLocalizedLogger(name, bundle, module);
}
/**
* Returns a {@link Logger logger} suitable for use within the
* given {@code module}.
*
* @implSpec The default implementation for this method is to return a
* simple logger that will print all messages of INFO level and above
* to the console. That simple logger is not configurable.
*
* @param name The name of the logger.
* @param module The module on behalf of which the logger is created.
* @return A {@link Logger logger} suitable for the application usage.
* @throws SecurityException if the calling code does not have the
* {@code RuntimePermission("loggerFinder")}.
*/
protected Logger demandLoggerFor(String name, Module module) {
checkPermission();
if (isSystem(module)) {
return SharedLoggers.system.get(SimpleConsoleLogger::makeSimpleLogger, name);
} else {
return SharedLoggers.application.get(SimpleConsoleLogger::makeSimpleLogger, name);
}
}
}