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	/*
	* Copyright (c) 2000, 2016, 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.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.util.logging;

	import java.lang.ref.Reference;
	import java.lang.ref.ReferenceQueue;
	import java.lang.ref.WeakReference;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Locale;
	import java.util.Map;
	import java.util.Optional;
	import java.util.ResourceBundle;
	import java.util.function.Function;
	import jdk.internal.loader.ClassLoaderValue;
	import jdk.internal.misc.JavaUtilResourceBundleAccess;
	import jdk.internal.misc.SharedSecrets;

	/**
	* The Level class defines a set of standard logging levels that
	* can be used to control logging output. The logging Level objects
	* are ordered and are specified by ordered integers. Enabling logging
	* at a given level also enables logging at all higher levels.
	* <p>
	* Clients should normally use the predefined Level constants such
	* as Level.SEVERE.
	* <p>
	* The levels in descending order are:
	* <ul>
	* <li>SEVERE (highest value)
	* <li>WARNING
	* <li>INFO
	* <li>CONFIG
	* <li>FINE
	* <li>FINER
	* <li>FINEST (lowest value)
	* </ul>
	* In addition there is a level OFF that can be used to turn
	* off logging, and a level ALL that can be used to enable
	* logging of all messages.
	* <p>
	* It is possible for third parties to define additional logging
	* levels by subclassing Level. In such cases subclasses should
	* take care to chose unique integer level values and to ensure that
	* they maintain the Object uniqueness property across serialization
	* by defining a suitable readResolve method.
	*
	* @since 1.4
	*/

	public class Level implements java.io.Serializable {
	private static final String defaultBundle =
	"sun.util.logging.resources.logging";

	// Calling SharedSecrets.getJavaUtilResourceBundleAccess()
	// forces the initialization of ResourceBundle.class, which
	// can be too early if the VM has not finished booting yet.
	private static final class RbAccess {
	static final JavaUtilResourceBundleAccess RB_ACCESS =
	SharedSecrets.getJavaUtilResourceBundleAccess();
	}

	/**
	* @serial The non-localized name of the level.
	*/
	private final String name;

	/**
	* @serial The integer value of the level.
	*/
	private final int value;

	/**
	* @serial The resource bundle name to be used in localizing the level name.
	*/
	private final String resourceBundleName;

	// localized level name
	private transient String localizedLevelName;
	private transient Locale cachedLocale;

	/**
	* OFF is a special level that can be used to turn off logging.
	* This level is initialized to <CODE>Integer.MAX_VALUE</CODE>.
	*/
	public static final Level OFF = new Level("OFF",Integer.MAX_VALUE, defaultBundle);

	/**
	* SEVERE is a message level indicating a serious failure.
	* <p>
	* In general SEVERE messages should describe events that are
	* of considerable importance and which will prevent normal
	* program execution. They should be reasonably intelligible
	* to end users and to system administrators.
	* This level is initialized to <CODE>1000</CODE>.
	*/
	public static final Level SEVERE = new Level("SEVERE",1000, defaultBundle);

	/**
	* WARNING is a message level indicating a potential problem.
	* <p>
	* In general WARNING messages should describe events that will
	* be of interest to end users or system managers, or which
	* indicate potential problems.
	* This level is initialized to <CODE>900</CODE>.
	*/
	public static final Level WARNING = new Level("WARNING", 900, defaultBundle);

	/**
	* INFO is a message level for informational messages.
	* <p>
	* Typically INFO messages will be written to the console
	* or its equivalent. So the INFO level should only be
	* used for reasonably significant messages that will
	* make sense to end users and system administrators.
	* This level is initialized to <CODE>800</CODE>.
	*/
	public static final Level INFO = new Level("INFO", 800, defaultBundle);

	/**
	* CONFIG is a message level for static configuration messages.
	* <p>
	* CONFIG messages are intended to provide a variety of static
	* configuration information, to assist in debugging problems
	* that may be associated with particular configurations.
	* For example, CONFIG message might include the CPU type,
	* the graphics depth, the GUI look-and-feel, etc.
	* This level is initialized to <CODE>700</CODE>.
	*/
	public static final Level CONFIG = new Level("CONFIG", 700, defaultBundle);

	/**
	* FINE is a message level providing tracing information.
	* <p>
	* All of FINE, FINER, and FINEST are intended for relatively
	* detailed tracing. The exact meaning of the three levels will
	* vary between subsystems, but in general, FINEST should be used
	* for the most voluminous detailed output, FINER for somewhat
	* less detailed output, and FINE for the lowest volume (and
	* most important) messages.
	* <p>
	* In general the FINE level should be used for information
	* that will be broadly interesting to developers who do not have
	* a specialized interest in the specific subsystem.
	* <p>
	* FINE messages might include things like minor (recoverable)
	* failures. Issues indicating potential performance problems
	* are also worth logging as FINE.
	* This level is initialized to <CODE>500</CODE>.
	*/
	public static final Level FINE = new Level("FINE", 500, defaultBundle);

	/**
	* FINER indicates a fairly detailed tracing message.
	* By default logging calls for entering, returning, or throwing
	* an exception are traced at this level.
	* This level is initialized to <CODE>400</CODE>.
	*/
	public static final Level FINER = new Level("FINER", 400, defaultBundle);

	/**
	* FINEST indicates a highly detailed tracing message.
	* This level is initialized to <CODE>300</CODE>.
	*/
	public static final Level FINEST = new Level("FINEST", 300, defaultBundle);

	/**
	* ALL indicates that all messages should be logged.
	* This level is initialized to <CODE>Integer.MIN_VALUE</CODE>.
	*/
	public static final Level ALL = new Level("ALL", Integer.MIN_VALUE, defaultBundle);

	private static final Level[] standardLevels = {
	OFF, SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST, ALL
	};

	/**
	* Create a named Level with a given integer value.
	* <p>
	* Note that this constructor is "protected" to allow subclassing.
	* In general clients of logging should use one of the constant Level
	* objects such as SEVERE or FINEST. However, if clients need to
	* add new logging levels, they may subclass Level and define new
	* constants.
	* @param name the name of the Level, for example "SEVERE".
	* @param value an integer value for the level.
	* @throws NullPointerException if the name is null
	*/
	protected Level(String name, int value) {
	this(name, value, null);
	}

	/**
	* Create a named Level with a given integer value and a
	* given localization resource name.
	*
	* @param name the name of the Level, for example "SEVERE".
	* @param value an integer value for the level.
	* @param resourceBundleName name of a resource bundle to use in
	* localizing the given name. If the resourceBundleName is null
	* or an empty string, it is ignored.
	* @throws NullPointerException if the name is null
	*/
	protected Level(String name, int value, String resourceBundleName) {
	this(name, value, resourceBundleName, true);
	}

	// private constructor to specify whether this instance should be added
	// to the KnownLevel list from which Level.parse method does its look up
	private Level(String name, int value, String resourceBundleName, boolean visible) {
	if (name == null) {
	throw new NullPointerException();
	}
	this.name = name;
	this.value = value;
	this.resourceBundleName = resourceBundleName;
	this.localizedLevelName = resourceBundleName == null ? name : null;
	this.cachedLocale = null;
	if (visible) {
	KnownLevel.add(this);
	}
	}

	/**
	* Return the level's localization resource bundle name, or
	* null if no localization bundle is defined.
	*
	* @return localization resource bundle name
	*/
	public String getResourceBundleName() {
	return resourceBundleName;
	}

	/**
	* Return the non-localized string name of the Level.
	*
	* @return non-localized name
	*/
	public String getName() {
	return name;
	}

	/**
	* Return the localized string name of the Level, for
	* the current default locale.
	* <p>
	* If no localization information is available, the
	* non-localized name is returned.
	*
	* @return localized name
	*/
	public String getLocalizedName() {
	return getLocalizedLevelName();
	}

	// package-private getLevelName() is used by the implementation
	// instead of getName() to avoid calling the subclass's version
	final String getLevelName() {
	return this.name;
	}

	private String computeLocalizedLevelName(Locale newLocale) {
	// Resource bundle should be loaded from the defining module
	// or its defining class loader, if it's unnamed module,
	// of this Level instance that can be a custom Level subclass;
	Module module = this.getClass().getModule();
	ResourceBundle rb = RbAccess.RB_ACCESS.getBundle(resourceBundleName,
	newLocale, module);

	final String localizedName = rb.getString(name);
	final boolean isDefaultBundle = defaultBundle.equals(resourceBundleName);
	if (!isDefaultBundle) return localizedName;

	// This is a trick to determine whether the name has been translated
	// or not. If it has not been translated, we need to use Locale.ROOT
	// when calling toUpperCase().
	final Locale rbLocale = rb.getLocale();
	final Locale locale =
	Locale.ROOT.equals(rbLocale)
	\|\| name.equals(localizedName.toUpperCase(Locale.ROOT))
	? Locale.ROOT : rbLocale;

	// ALL CAPS in a resource bundle's message indicates no translation
	// needed per Oracle translation guideline. To workaround this
	// in Oracle JDK implementation, convert the localized level name
	// to uppercase for compatibility reason.
	return Locale.ROOT.equals(locale) ? name : localizedName.toUpperCase(locale);
	}

	// Avoid looking up the localizedLevelName twice if we already
	// have it.
	final String getCachedLocalizedLevelName() {

	if (localizedLevelName != null) {
	if (cachedLocale != null) {
	if (cachedLocale.equals(Locale.getDefault())) {
	// OK: our cached value was looked up with the same
	// locale. We can use it.
	return localizedLevelName;
	}
	}
	}

	if (resourceBundleName == null) {
	// No resource bundle: just use the name.
	return name;
	}

	// We need to compute the localized name.
	// Either because it's the first time, or because our cached
	// value is for a different locale. Just return null.
	return null;
	}

	final synchronized String getLocalizedLevelName() {

	// See if we have a cached localized name
	final String cachedLocalizedName = getCachedLocalizedLevelName();
	if (cachedLocalizedName != null) {
	return cachedLocalizedName;
	}

	// No cached localized name or cache invalid.
	// Need to compute the localized name.
	final Locale newLocale = Locale.getDefault();
	try {
	localizedLevelName = computeLocalizedLevelName(newLocale);
	} catch (Exception ex) {
	localizedLevelName = name;
	}
	cachedLocale = newLocale;
	return localizedLevelName;
	}

	// Returns a mirrored Level object that matches the given name as
	// specified in the Level.parse method. Returns null if not found.
	//
	// It returns the same Level object as the one returned by Level.parse
	// method if the given name is a non-localized name or integer.
	//
	// If the name is a localized name, findLevel and parse method may
	// return a different level value if there is a custom Level subclass
	// that overrides Level.getLocalizedName() to return a different string
	// than what's returned by the default implementation.
	//
	static Level findLevel(String name) {
	if (name == null) {
	throw new NullPointerException();
	}

	Optional<Level> level;

	// Look for a known Level with the given non-localized name.
	level = KnownLevel.findByName(name, KnownLevel::mirrored);
	if (level.isPresent()) {
	return level.get();
	}

	// Now, check if the given name is an integer. If so,
	// first look for a Level with the given value and then
	// if necessary create one.
	try {
	int x = Integer.parseInt(name);
	level = KnownLevel.findByValue(x, KnownLevel::mirrored);
	if (level.isPresent()) {
	return level.get();
	}
	// add new Level
	Level levelObject = new Level(name, x);
	// There's no need to use a reachability fence here because
	// KnownLevel keeps a strong reference on the level when
	// level.getClass() == Level.class.
	return KnownLevel.findByValue(x, KnownLevel::mirrored).get();
	} catch (NumberFormatException ex) {
	// Not an integer.
	// Drop through.
	}

	level = KnownLevel.findByLocalizedLevelName(name,
	KnownLevel::mirrored);
	if (level.isPresent()) {
	return level.get();
	}

	return null;
	}

	/**
	* Returns a string representation of this Level.
	*
	* @return the non-localized name of the Level, for example "INFO".
	*/
	@Override
	public final String toString() {
	return name;
	}

	/**
	* Get the integer value for this level. This integer value
	* can be used for efficient ordering comparisons between
	* Level objects.
	* @return the integer value for this level.
	*/
	public final int intValue() {
	return value;
	}

	private static final long serialVersionUID = -8176160795706313070L;

	// Serialization magic to prevent "doppelgangers".
	// This is a performance optimization.
	private Object readResolve() {
	Optional<Level> level = KnownLevel.matches(this);
	if (level.isPresent()) {
	return level.get();
	}
	// Woops. Whoever sent us this object knows
	// about a new log level. Add it to our list.
	return new Level(this.name, this.value, this.resourceBundleName);
	}

	/**
	* Parse a level name string into a Level.
	* <p>
	* The argument string may consist of either a level name
	* or an integer value.
	* <p>
	* For example:
	* <ul>
	* <li> "SEVERE"
	* <li> "1000"
	* </ul>
	*
	* @param name string to be parsed
	* @throws NullPointerException if the name is null
	* @throws IllegalArgumentException if the value is not valid.
	* Valid values are integers between <CODE>Integer.MIN_VALUE</CODE>
	* and <CODE>Integer.MAX_VALUE</CODE>, and all known level names.
	* Known names are the levels defined by this class (e.g., <CODE>FINE</CODE>,
	* <CODE>FINER</CODE>, <CODE>FINEST</CODE>), or created by this class with
	* appropriate package access, or new levels defined or created
	* by subclasses.
	*
	* @return The parsed value. Passing an integer that corresponds to a known name
	* (e.g., 700) will return the associated name (e.g., <CODE>CONFIG</CODE>).
	* Passing an integer that does not (e.g., 1) will return a new level name
	* initialized to that value.
	*/
	public static synchronized Level parse(String name) throws IllegalArgumentException {
	// Check that name is not null.
	name.length();

	Optional<Level> level;

	// Look for a known Level with the given non-localized name.
	level = KnownLevel.findByName(name, KnownLevel::referent);
	if (level.isPresent()) {
	return level.get();
	}

	// Now, check if the given name is an integer. If so,
	// first look for a Level with the given value and then
	// if necessary create one.
	try {
	int x = Integer.parseInt(name);
	level = KnownLevel.findByValue(x, KnownLevel::referent);
	if (level.isPresent()) {
	return level.get();
	}
	// add new Level.
	Level levelObject = new Level(name, x);
	// There's no need to use a reachability fence here because
	// KnownLevel keeps a strong reference on the level when
	// level.getClass() == Level.class.
	return KnownLevel.findByValue(x, KnownLevel::referent).get();
	} catch (NumberFormatException ex) {
	// Not an integer.
	// Drop through.
	}

	// Finally, look for a known level with the given localized name,
	// in the current default locale.
	// This is relatively expensive, but not excessively so.
	level = KnownLevel.findByLocalizedLevelName(name, KnownLevel::referent);
	if (level .isPresent()) {
	return level.get();
	}

	// OK, we've tried everything and failed
	throw new IllegalArgumentException("Bad level \"" + name + "\"");
	}

	/**
	* Compare two objects for value equality.
	* @return true if and only if the two objects have the same level value.
	*/
	@Override
	public boolean equals(Object ox) {
	try {
	Level lx = (Level)ox;
	return (lx.value == this.value);
	} catch (Exception ex) {
	return false;
	}
	}

	/**
	* Generate a hashcode.
	* @return a hashcode based on the level value
	*/
	@Override
	public int hashCode() {
	return this.value;
	}

	// KnownLevel class maintains the global list of all known levels.
	// The API allows multiple custom Level instances of the same name/value
	// be created. This class provides convenient methods to find a level
	// by a given name, by a given value, or by a given localized name.
	//
	// KnownLevel wraps the following Level objects:
	// 1. levelObject: standard Level object or custom Level object
	// 2. mirroredLevel: Level object representing the level specified in the
	// logging configuration.
	//
	// Level.getName, Level.getLocalizedName, Level.getResourceBundleName methods
	// are non-final but the name and resource bundle name are parameters to
	// the Level constructor. Use the mirroredLevel object instead of the
	// levelObject to prevent the logging framework to execute foreign code
	// implemented by untrusted Level subclass.
	//
	// Implementation Notes:
	// If Level.getName, Level.getLocalizedName, Level.getResourceBundleName methods
	// were final, the following KnownLevel implementation can be removed.
	// Future API change should take this into consideration.
	static final class KnownLevel extends WeakReference<Level> {
	private static Map<String, List<KnownLevel>> nameToLevels = new HashMap<>();
	private static Map<Integer, List<KnownLevel>> intToLevels = new HashMap<>();
	private static final ReferenceQueue<Level> QUEUE = new ReferenceQueue<>();

	// CUSTOM_LEVEL_CLV is used to register custom level instances with
	// their defining class loader, so that they are garbage collected
	// if and only if their class loader is no longer strongly
	// referenced.
	private static final ClassLoaderValue<List<Level>> CUSTOM_LEVEL_CLV =
	new ClassLoaderValue<>();

	final Level mirroredLevel; // mirror of the custom Level
	KnownLevel(Level l) {
	super(l, QUEUE);
	if (l.getClass() == Level.class) {
	this.mirroredLevel = l;
	} else {
	// this mirrored level object is hidden
	this.mirroredLevel = new Level(l.name, l.value,
	l.resourceBundleName, false);
	}
	}

	Optional<Level> mirrored() {
	return Optional.of(mirroredLevel);
	}

	Optional<Level> referent() {
	return Optional.ofNullable(get());
	}

	private void remove() {
	Optional.ofNullable(nameToLevels.get(mirroredLevel.name))
	.ifPresent((x) -> x.remove(this));
	Optional.ofNullable(intToLevels.get(mirroredLevel.value))
	.ifPresent((x) -> x.remove(this));
	}

	// Remove all stale KnownLevel instances
	static synchronized void purge() {
	Reference<? extends Level> ref;
	while ((ref = QUEUE.poll()) != null) {
	if (ref instanceof KnownLevel) {
	((KnownLevel)ref).remove();
	}
	}
	}

	private static void registerWithClassLoader(Level customLevel) {
	PrivilegedAction<ClassLoader> pa =
	() -> customLevel.getClass().getClassLoader();
	PrivilegedAction<String> pn = customLevel.getClass()::getName;
	final String name = AccessController.doPrivileged(pn);
	final ClassLoader cl = AccessController.doPrivileged(pa);
	CUSTOM_LEVEL_CLV.computeIfAbsent(cl, (c, v) -> new ArrayList<>())
	.add(customLevel);
	}

	static synchronized void add(Level l) {
	purge();
	// the mirroredLevel object is always added to the list
	// before the custom Level instance
	KnownLevel o = new KnownLevel(l);
	List<KnownLevel> list = nameToLevels.get(l.name);
	if (list == null) {
	list = new ArrayList<>();
	nameToLevels.put(l.name, list);
	}
	list.add(o);

	list = intToLevels.get(l.value);
	if (list == null) {
	list = new ArrayList<>();
	intToLevels.put(l.value, list);
	}
	list.add(o);

	// keep the custom level reachable from its class loader
	// This will ensure that custom level values are not GC'ed
	// until there class loader is GC'ed.
	if (o.mirroredLevel != l) {
	registerWithClassLoader(l);
	}

	}

	// Returns a KnownLevel with the given non-localized name.
	static synchronized Optional<Level> findByName(String name,
	Function<KnownLevel, Optional<Level>> selector) {
	purge();
	return nameToLevels.getOrDefault(name, Collections.emptyList())
	.stream()
	.map(selector)
	.flatMap(Optional::stream)
	.findFirst();
	}

	// Returns a KnownLevel with the given value.
	static synchronized Optional<Level> findByValue(int value,
	Function<KnownLevel, Optional<Level>> selector) {
	purge();
	return intToLevels.getOrDefault(value, Collections.emptyList())
	.stream()
	.map(selector)
	.flatMap(Optional::stream)
	.findFirst();
	}

	// Returns a KnownLevel with the given localized name matching
	// by calling the Level.getLocalizedLevelName() method (i.e. found
	// from the resourceBundle associated with the Level object).
	// This method does not call Level.getLocalizedName() that may
	// be overridden in a subclass implementation
	static synchronized Optional<Level> findByLocalizedLevelName(String name,
	Function<KnownLevel, Optional<Level>> selector) {
	purge();
	return nameToLevels.values().stream()
	.flatMap(List::stream)
	.map(selector)
	.flatMap(Optional::stream)
	.filter(l -> name.equals(l.getLocalizedLevelName()))
	.findFirst();
	}

	static synchronized Optional<Level> matches(Level l) {
	purge();
	List<KnownLevel> list = nameToLevels.get(l.name);
	if (list != null) {
	for (KnownLevel ref : list) {
	Level levelObject = ref.get();
	if (levelObject == null) continue;
	Level other = ref.mirroredLevel;
	Class<? extends Level> type = levelObject.getClass();
	if (l.value == other.value &&
	(l.resourceBundleName == other.resourceBundleName \|\|
	(l.resourceBundleName != null &&
	l.resourceBundleName.equals(other.resourceBundleName)))) {
	if (type == l.getClass()) {
	return Optional.of(levelObject);
	}
	}
	}
	}
	return Optional.empty();
	}
	}

	}

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