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 * 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package java.util.logging;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.ResourceBundle;

/**

 * 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 String defaultBundle = "sun.util.logging.resources.logging";

    /**

     * @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 String localizedLevelName;

    /**

     * 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);

    /**

     * 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.

     * <p>

     * @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) {

        if (name == null) {

            throw new NullPointerException();

        }

        this.name = name;

        this.value = value;

        this.resourceBundleName = resourceBundleName;

        this.localizedLevelName = resourceBundleName == null ? name : null;

        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;

    }

    final synchronized String getLocalizedLevelName() {

        if (localizedLevelName != null) {

            return localizedLevelName;

        }

        try {

            ResourceBundle rb = ResourceBundle.getBundle(resourceBundleName);

            localizedLevelName = rb.getString(name);

        } catch (Exception ex) {

            localizedLevelName = name;

        }

        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();

        }

        KnownLevel level;

        // Look for a known Level with the given non-localized name.

        level = KnownLevel.findByName(name);

        if (level != null) {

            return level.mirroredLevel;

        }

        // 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);

            if (level == null) {

                // add new Level

                Level levelObject = new Level(name, x);

                level = KnownLevel.findByValue(x);

            }

            return level.mirroredLevel;

        } catch (NumberFormatException ex) {

            // Not an integer.

            // Drop through.

        }

        level = KnownLevel.findByLocalizedLevelName(name);

        if (level != null) {

            return level.mirroredLevel;

        }

        return null;

    }

    /**

     * Returns a string representation of this Level.

     *

     * @return the non-localized name of the Level, for example "INFO".

     */

    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() {

        KnownLevel o = KnownLevel.matches(this);

        if (o != null) {

            return o.levelObject;

        }

        // Woops.  Whoever sent us this object knows

        // about a new log level.  Add it to our list.

        Level level = new Level(this.name, this.value, this.resourceBundleName);

        return level;

    }

    /**

     * 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();

        KnownLevel level;

        // Look for a known Level with the given non-localized name.

        level = KnownLevel.findByName(name);

        if (level != null) {

            return level.levelObject;

        }

        // 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);

            if (level == null) {

                // add new Level

                Level levelObject = new Level(name, x);

                level = KnownLevel.findByValue(x);

            }

            return level.levelObject;

        } 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.findByLocalizedName(name);

        if (level != null) {

            return level.levelObject;

        }

        // 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.

     */

    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

     */

    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 {

        private static Map<String, List<KnownLevel>> nameToLevels = new HashMap<>();

        private static Map<Integer, List<KnownLevel>> intToLevels = new HashMap<>();

        final Level levelObject;     // instance of Level class or Level subclass

        final Level mirroredLevel;   // instance of Level class

        KnownLevel(Level l) {

            this.levelObject = l;

            if (l.getClass() == Level.class) {

                this.mirroredLevel = l;

            } else {

                this.mirroredLevel = new Level(l.name, l.value, l.resourceBundleName);

            }

        }

        static synchronized void add(Level l) {

            // 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);

        }

        // Returns a KnownLevel with the given non-localized name.

        static synchronized KnownLevel findByName(String name) {

            List<KnownLevel> list = nameToLevels.get(name);

            if (list != null) {

                return list.get(0);

            }

            return null;

        }

        // Returns a KnownLevel with the given value.

        static synchronized KnownLevel findByValue(int value) {

            List<KnownLevel> list = intToLevels.get(value);

            if (list != null) {

                return list.get(0);

            }

            return null;

        }

        // 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).