JDK8/Java8源码在线阅读
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*
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* accompanied this code).
*
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package java.util.logging;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
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 final 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 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);
/**
* 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) {
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) {
ResourceBundle rb = ResourceBundle.getBundle(resourceBundleName, newLocale);
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();
}
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".
*/
@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() {
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.findByLocalizedLevelName(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.
*/
@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 {
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; // mirror of the custom Level
KnownLevel(Level l) {
this.levelObject = l;
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);
}
}
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);
}
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