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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Contibutors: Alex Blewitt 
//              Markus Oestreicher 
//              Frank Hoering 
//              Nelson Minar 
//              Jim Cakalic 
//              Avy Sharell 
//              Ciaran Treanor 
//              Jeff Turner 
//              Michael Horwitz 
//              Calvin Chan 
//              Aaron Greenhouse 
//              Beat Meier 
//              Colin Sampaleanu 

package org.apache.log4j;

import org.apache.log4j.spi.AppenderAttachable;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.spi.LoggerRepository;
import org.apache.log4j.spi.HierarchyEventListener;
import org.apache.log4j.helpers.NullEnumeration;
import org.apache.log4j.helpers.AppenderAttachableImpl;

import java.util.Enumeration;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Vector;

/**
 * This class has been deprecated and replaced by the
 * {@link Logger} subclass. It will be kept around to
 * preserve backward compatibility until mid 2003.
 * 
 * 

* Logger is a subclass of Category, i.e. it extends Category. In * other words, a logger is a category. Thus, all operations that can * be performed on a category can be performed on a logger. Internally, whenever * log4j is asked to produce a Category object, it will instead produce a Logger * object. Log4j 1.2 will never produce Category objects but only * Logger instances. In order to preserve backward compatibility, * methods that previously accepted category objects still continue to accept * category objects. * *

* For example, the following are all legal and will work as expected. * *

     // Deprecated form:
     Category cat = Category.getInstance("foo.bar")
 
     // Preferred form for retrieving loggers:
     Logger logger = Logger.getLogger("foo.bar")
 * 
* *

* The first form is deprecated and should be avoided. * *

* There is absolutely no need for new client code to use or refer to the * Category class. Whenever possible, please avoid referring to * it or using it. * *

* See the short manual for an * introduction on this class. *

* See the document entitled * preparing for log4j * 1.3 for a more detailed discussion. * * @author Ceki Gülcü * @author Anders Kristensen */ public class Category implements AppenderAttachable { /** * The hierarchy where categories are attached to by default. */ // static // public // final Hierarchy defaultHierarchy = new Hierarchy(new // RootCategory(Level.DEBUG)); /** * The name of this category. */ protected String name; /** * The assigned level of this category. The level variable need not * be assigned a value in which case it is inherited form the hierarchy. */ volatile protected Level level; /** * The parent of this category. All categories have at least one ancestor which * is the root category. */ volatile protected Category parent; /** * The fully qualified name of the Category class. See also the getFQCN method. */ private static final String FQCN = Category.class.getName(); protected ResourceBundle resourceBundle; // Categories need to know what Hierarchy they are in protected LoggerRepository repository; AppenderAttachableImpl aai; /** * Additivity is set to true by default, that is children inherit the appenders * of their ancestors by default. If this variable is set to false * then the appenders found in the ancestors of this category are not used. * However, the children of this category will inherit its appenders, unless the * children have their additivity flag set to false too. See the * user manual for more details. */ protected boolean additive = true; /** * This constructor created a new Category instance and sets its * name. * *

* It is intended to be used by sub-classes only. You should not create * categories directly. * * @param name The name of the category. */ protected Category(String name) { this.name = name; } /** * Add newAppender to the list of appenders of this Category * instance. * *

* If newAppender is already in the list of appenders, then it * won't be added again. */ synchronized public void addAppender(Appender newAppender) { if (aai == null) { aai = new AppenderAttachableImpl(); } aai.addAppender(newAppender); repository.fireAddAppenderEvent(this, newAppender); } /** * If assertion parameter is false, then logs * msg as an {@link #error(Object) error} statement. * *

* The assert method has been renamed to assertLog * because assert is a language reserved word in JDK 1.4. * * @param assertion * @param msg The message to print if assertion is false. * * @since 1.2 */ public void assertLog(boolean assertion, String msg) { if (!assertion) this.error(msg); } /** * Call the appenders in the hierrachy starting at this. If no * appenders could be found, emit a warning. * *

* This method calls all the appenders inherited from the hierarchy * circumventing any evaluation of whether to log or not to log the particular * log request. * * @param event the event to log. */ public void callAppenders(LoggingEvent event) { int writes = 0; for (Category c = this; c != null; c = c.parent) { // Protected against simultaneous call to addAppender, removeAppender,... synchronized (c) { if (c.aai != null) { writes += c.aai.appendLoopOnAppenders(event); } if (!c.additive) { break; } } } if (writes == 0) { repository.emitNoAppenderWarning(this); } } /** * Close all attached appenders implementing the AppenderAttachable interface. * * @since 1.0 */ synchronized void closeNestedAppenders() { Enumeration enumeration = this.getAllAppenders(); if (enumeration != null) { while (enumeration.hasMoreElements()) { Appender a = (Appender) enumeration.nextElement(); if (a instanceof AppenderAttachable) { a.close(); } } } } /** * Log a message object with the {@link Level#DEBUG DEBUG} level. * *

* This method first checks if this category is DEBUG enabled by * comparing the level of this category with the {@link Level#DEBUG DEBUG} * level. If this category is DEBUG enabled, then it converts the * message object (passed as parameter) to a string by invoking the appropriate * {@link org.apache.log4j.or.ObjectRenderer}. It then proceeds to call all the * registered appenders in this category and also higher in the hierarchy * depending on the value of the additivity flag. * *

* WARNING Note that passing a {@link Throwable} to this method will * print the name of the Throwable but no stack trace. To print a * stack trace use the {@link #debug(Object, Throwable)} form instead. * * @param message the message object to log. */ public void debug(Object message) { if (repository.isDisabled(Level.DEBUG_INT)) return; if (Level.DEBUG.isGreaterOrEqual(this.getEffectiveLevel())) { forcedLog(FQCN, Level.DEBUG, message, null); } } /** * Log a message object with the DEBUG level including the stack * trace of the {@link Throwable} t passed as parameter. * *

* See {@link #debug(Object)} form for more detailed information. * * @param message the message object to log. * @param t the exception to log, including its stack trace. */ public void debug(Object message, Throwable t) { if (repository.isDisabled(Level.DEBUG_INT)) return; if (Level.DEBUG.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.DEBUG, message, t); } /** * Log a message object with the {@link Level#ERROR ERROR} Level. * *

* This method first checks if this category is ERROR enabled by * comparing the level of this category with {@link Level#ERROR ERROR} Level. If * this category is ERROR enabled, then it converts the message * object passed as parameter to a string by invoking the appropriate * {@link org.apache.log4j.or.ObjectRenderer}. It proceeds to call all the * registered appenders in this category and also higher in the hierarchy * depending on the value of the additivity flag. * *

* WARNING Note that passing a {@link Throwable} to this method will * print the name of the Throwable but no stack trace. To print a * stack trace use the {@link #error(Object, Throwable)} form instead. * * @param message the message object to log */ public void error(Object message) { if (repository.isDisabled(Level.ERROR_INT)) return; if (Level.ERROR.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.ERROR, message, null); } /** * Log a message object with the ERROR level including the stack * trace of the {@link Throwable} t passed as parameter. * *

* See {@link #error(Object)} form for more detailed information. * * @param message the message object to log. * @param t the exception to log, including its stack trace. */ public void error(Object message, Throwable t) { if (repository.isDisabled(Level.ERROR_INT)) return; if (Level.ERROR.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.ERROR, message, t); } /** * If the named category exists (in the default hierarchy) then it returns a * reference to the category, otherwise it returns null. * * @deprecated Please use {@link LogManager#exists} instead. * * @since 0.8.5 */ public static Logger exists(String name) { return LogManager.exists(name); } /** * Log a message object with the {@link Level#FATAL FATAL} Level. * *

* This method first checks if this category is FATAL enabled by * comparing the level of this category with {@link Level#FATAL FATAL} Level. If * the category is FATAL enabled, then it converts the message * object passed as parameter to a string by invoking the appropriate * {@link org.apache.log4j.or.ObjectRenderer}. It proceeds to call all the * registered appenders in this category and also higher in the hierarchy * depending on the value of the additivity flag. * *

* WARNING Note that passing a {@link Throwable} to this method will * print the name of the Throwable but no stack trace. To print a stack trace * use the {@link #fatal(Object, Throwable)} form instead. * * @param message the message object to log */ public void fatal(Object message) { if (repository.isDisabled(Level.FATAL_INT)) return; if (Level.FATAL.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.FATAL, message, null); } /** * Log a message object with the FATAL level including the stack * trace of the {@link Throwable} t passed as parameter. * *

* See {@link #fatal(Object)} for more detailed information. * * @param message the message object to log. * @param t the exception to log, including its stack trace. */ public void fatal(Object message, Throwable t) { if (repository.isDisabled(Level.FATAL_INT)) return; if (Level.FATAL.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.FATAL, message, t); } /** * This method creates a new logging event and logs the event without further * checks. */ protected void forcedLog(String fqcn, Priority level, Object message, Throwable t) { callAppenders(new LoggingEvent(fqcn, this, level, message, t)); } /** * Get the additivity flag for this Category instance. */ public boolean getAdditivity() { return additive; } /** * Get the appenders contained in this category as an {@link Enumeration}. If no * appenders can be found, then a {@link NullEnumeration} is returned. * * @return Enumeration An enumeration of the appenders in this category. */ synchronized public Enumeration getAllAppenders() { if (aai == null) return NullEnumeration.getInstance(); else return aai.getAllAppenders(); } /** * Look for the appender named as name. * *

* Return the appender with that name if in the list. Return null * otherwise. */ synchronized public Appender getAppender(String name) { if (aai == null || name == null) return null; return aai.getAppender(name); } /** * Starting from this category, search the category hierarchy for a non-null * level and return it. Otherwise, return the level of the root category. * *

* The Category class is designed so that this method executes as quickly as * possible. */ public Level getEffectiveLevel() { for (Category c = this; c != null; c = c.parent) { if (c.level != null) return c.level; } return null; // If reached will cause an NullPointerException. } /** * * @deprecated Please use the the {@link #getEffectiveLevel} method instead. */ public Priority getChainedPriority() { for (Category c = this; c != null; c = c.parent) { if (c.level != null) return c.level; } return null; // If reached will cause an NullPointerException. } /** * Returns all the currently defined categories in the default hierarchy as an * {@link java.util.Enumeration Enumeration}. * *

* The root category is not included in the returned * {@link Enumeration}. * * @deprecated Please use {@link LogManager#getCurrentLoggers()} instead. */ public static Enumeration getCurrentCategories() { return LogManager.getCurrentLoggers(); } /** * Return the default Hierarchy instance. * * @deprecated Please use {@link LogManager#getLoggerRepository()} instead. * * @since 1.0 */ public static LoggerRepository getDefaultHierarchy() { return LogManager.getLoggerRepository(); } /** * Return the the {@link Hierarchy} where this Category instance is * attached. * * @deprecated Please use {@link #getLoggerRepository} instead. * * @since 1.1 */ public LoggerRepository getHierarchy() { return repository; } /** * Return the the {@link LoggerRepository} where this Category is * attached. * * @since 1.2 */ public LoggerRepository getLoggerRepository() { return repository; } /** * @deprecated Make sure to use {@link Logger#getLogger(String)} instead. */ public static Category getInstance(String name) { return LogManager.getLogger(name); } /** * @deprecated Please make sure to use {@link Logger#getLogger(Class)} instead. */ public static Category getInstance(Class clazz) { return LogManager.getLogger(clazz); } /** * Return the category name. */ public final String getName() { return name; } /** * Returns the parent of this category. Note that the parent of a given category * may change during the lifetime of the category. * *

* The root category will return null. * * @since 1.2 */ final public Category getParent() { return this.parent; } /** * Returns the assigned {@link Level}, if any, for this Category. * * @return Level - the assigned Level, can be null. */ final public Level getLevel() { return this.level; } /** * @deprecated Please use {@link #getLevel} instead. */ final public Level getPriority() { return this.level; } /** * @deprecated Please use {@link Logger#getRootLogger()} instead. */ final public static Category getRoot() { return LogManager.getRootLogger(); } /** * Return the inherited {@link ResourceBundle} for this category. * *

* This method walks the hierarchy to find the appropriate resource bundle. It * will return the resource bundle attached to the closest ancestor of this * category, much like the way priorities are searched. In case there is no * bundle in the hierarchy then null is returned. * * @since 0.9.0 */ public ResourceBundle getResourceBundle() { for (Category c = this; c != null; c = c.parent) { if (c.resourceBundle != null) return c.resourceBundle; } // It might be the case that there is no resource bundle return null; } /** * Returns the string resource coresponding to key in this * category's inherited resource bundle. See also {@link #getResourceBundle}. * *

* If the resource cannot be found, then an {@link #error error} message will be * logged complaining about the missing resource. */ protected String getResourceBundleString(String key) { ResourceBundle rb = getResourceBundle(); // This is one of the rare cases where we can use logging in order // to report errors from within log4j. if (rb == null) { // if(!hierarchy.emittedNoResourceBundleWarning) { // error("No resource bundle has been set for category "+name); // hierarchy.emittedNoResourceBundleWarning = true; // } return null; } else { try { return rb.getString(key); } catch (MissingResourceException mre) { error("No resource is associated with key \"" + key + "\"."); return null; } } } /** * Log a message object with the {@link Level#INFO INFO} Level. * *

* This method first checks if this category is INFO enabled by * comparing the level of this category with {@link Level#INFO INFO} Level. If * the category is INFO enabled, then it converts the message * object passed as parameter to a string by invoking the appropriate * {@link org.apache.log4j.or.ObjectRenderer}. It proceeds to call all the * registered appenders in this category and also higher in the hierarchy * depending on the value of the additivity flag. * *

* WARNING Note that passing a {@link Throwable} to this method will * print the name of the Throwable but no stack trace. To print a stack trace * use the {@link #info(Object, Throwable)} form instead. * * @param message the message object to log */ public void info(Object message) { if (repository.isDisabled(Level.INFO_INT)) return; if (Level.INFO.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.INFO, message, null); } /** * Log a message object with the INFO level including the stack * trace of the {@link Throwable} t passed as parameter. * *

* See {@link #info(Object)} for more detailed information. * * @param message the message object to log. * @param t the exception to log, including its stack trace. */ public void info(Object message, Throwable t) { if (repository.isDisabled(Level.INFO_INT)) return; if (Level.INFO.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.INFO, message, t); } /** * Is the appender passed as parameter attached to this category? */ public boolean isAttached(Appender appender) { if (appender == null || aai == null) return false; else { return aai.isAttached(appender); } } /** * Check whether this category is enabled for the DEBUG Level. * *

* This function is intended to lessen the computational cost of disabled log * debug statements. * *

* For some cat Category object, when you write, * *

     * cat.debug("This is entry number: " + i);
     * 
* *

* You incur the cost constructing the message, concatenatiion in this case, * regardless of whether the message is logged or not. * *

* If you are worried about speed, then you should write * *

     * if (cat.isDebugEnabled()) {
     *     cat.debug("This is entry number: " + i);
     * }
     * 
* *

* This way you will not incur the cost of parameter construction if debugging * is disabled for cat. On the other hand, if the cat * is debug enabled, you will incur the cost of evaluating whether the category * is debug enabled twice. Once in isDebugEnabled and once in the * debug. This is an insignificant overhead since evaluating a * category takes about 1%% of the time it takes to actually log. * * @return boolean - true if this category is debug enabled, * false otherwise. */ public boolean isDebugEnabled() { if (repository.isDisabled(Level.DEBUG_INT)) return false; return Level.DEBUG.isGreaterOrEqual(this.getEffectiveLevel()); } /** * Check whether this category is enabled for a given {@link Level} passed as * parameter. * * See also {@link #isDebugEnabled}. * * @return boolean True if this category is enabled for level. */ public boolean isEnabledFor(Priority level) { if (repository.isDisabled(level.level)) return false; return level.isGreaterOrEqual(this.getEffectiveLevel()); } /** * Check whether this category is enabled for the info Level. See also * {@link #isDebugEnabled}. * * @return boolean - true if this category is enabled for level * info, false otherwise. */ public boolean isInfoEnabled() { if (repository.isDisabled(Level.INFO_INT)) return false; return Level.INFO.isGreaterOrEqual(this.getEffectiveLevel()); } /** * Log a localized message. The user supplied parameter key is * replaced by its localized version from the resource bundle. * * @see #setResourceBundle * * @since 0.8.4 */ public void l7dlog(Priority priority, String key, Throwable t) { if (repository.isDisabled(priority.level)) { return; } if (priority.isGreaterOrEqual(this.getEffectiveLevel())) { String msg = getResourceBundleString(key); // if message corresponding to 'key' could not be found in the // resource bundle, then default to 'key'. if (msg == null) { msg = key; } forcedLog(FQCN, priority, msg, t); } } /** * Log a localized and parameterized message. First, the user supplied * key is searched in the resource bundle. Next, the resulting * pattern is formatted using * {@link java.text.MessageFormat#format(String,Object[])} method with the user * supplied object array params. * * @since 0.8.4 */ public void l7dlog(Priority priority, String key, Object[] params, Throwable t) { if (repository.isDisabled(priority.level)) { return; } if (priority.isGreaterOrEqual(this.getEffectiveLevel())) { String pattern = getResourceBundleString(key); String msg; if (pattern == null) msg = key; else msg = java.text.MessageFormat.format(pattern, params); forcedLog(FQCN, priority, msg, t); } } /** * This generic form is intended to be used by wrappers. */ public void log(Priority priority, Object message, Throwable t) { if (repository.isDisabled(priority.level)) { return; } if (priority.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, priority, message, t); } /** * This generic form is intended to be used by wrappers. */ public void log(Priority priority, Object message) { if (repository.isDisabled(priority.level)) { return; } if (priority.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, priority, message, null); } /** * * This is the most generic printing method. It is intended to be invoked by * wrapper classes. * * @param callerFQCN The wrapper class' fully qualified class name. * @param level The level of the logging request. * @param message The message of the logging request. * @param t The throwable of the logging request, may be null. */ public void log(String callerFQCN, Priority level, Object message, Throwable t) { if (repository.isDisabled(level.level)) { return; } if (level.isGreaterOrEqual(this.getEffectiveLevel())) { forcedLog(callerFQCN, level, message, t); } } /** * LoggerRepository forgot the fireRemoveAppenderEvent method, if using the * stock Hierarchy implementation, then call its fireRemove. Custom repositories * can implement HierarchyEventListener if they want remove notifications. * * @param appender appender, may be null. */ private void fireRemoveAppenderEvent(final Appender appender) { if (appender != null) { if (repository instanceof Hierarchy) { ((Hierarchy) repository).fireRemoveAppenderEvent(this, appender); } else if (repository instanceof HierarchyEventListener) { ((HierarchyEventListener) repository).removeAppenderEvent(this, appender); } } } /** * Remove all previously added appenders from this Category instance. * *

* This is useful when re-reading configuration information. */ synchronized public void removeAllAppenders() { if (aai != null) { Vector appenders = new Vector(); for (Enumeration iter = aai.getAllAppenders(); iter != null && iter.hasMoreElements();) { appenders.add(iter.nextElement()); } aai.removeAllAppenders(); for (Enumeration iter = appenders.elements(); iter.hasMoreElements();) { fireRemoveAppenderEvent((Appender) iter.nextElement()); } aai = null; } } /** * Remove the appender passed as parameter form the list of appenders. * * @since 0.8.2 */ synchronized public void removeAppender(Appender appender) { if (appender == null || aai == null) return; boolean wasAttached = aai.isAttached(appender); aai.removeAppender(appender); if (wasAttached) { fireRemoveAppenderEvent(appender); } } /** * Remove the appender with the name passed as parameter form the list of * appenders. * * @since 0.8.2 */ synchronized public void removeAppender(String name) { if (name == null || aai == null) return; Appender appender = aai.getAppender(name); aai.removeAppender(name); if (appender != null) { fireRemoveAppenderEvent(appender); } } /** * Set the additivity flag for this Category instance. * * @since 0.8.1 */ public void setAdditivity(boolean additive) { this.additive = additive; } /** * Only the Hiearchy class can set the hiearchy of a category. Default package * access is MANDATORY here. */ final void setHierarchy(LoggerRepository repository) { this.repository = repository; } /** * Set the level of this Category. If you are passing any of * Level.DEBUG, Level.INFO, Level.WARN, * Level.ERROR, Level.FATAL as a parameter, you need * to case them as Level. * *

* As in * *

     * logger.setLevel((Level) Level.DEBUG);
     * 
* * *

* Null values are admitted. */ public void setLevel(Level level) { this.level = level; } /** * Set the level of this Category. * *

* Null values are admitted. * * @deprecated Please use {@link #setLevel} instead. */ public void setPriority(Priority priority) { this.level = (Level) priority; } /** * Set the resource bundle to be used with localized logging methods * {@link #l7dlog(Priority,String,Throwable)} and * {@link #l7dlog(Priority,String,Object[],Throwable)}. * * @since 0.8.4 */ public void setResourceBundle(ResourceBundle bundle) { resourceBundle = bundle; } /** * Calling this method will safely close and remove all appenders in * all the categories including root contained in the default hierachy. * *

* Some appenders such as {@link org.apache.log4j.net.SocketAppender} and * {@link AsyncAppender} need to be closed before the application exists. * Otherwise, pending logging events might be lost. * *

* The shutdown method is careful to close nested appenders before * closing regular appenders. This is allows configurations where a regular * appender is attached to a category and again to a nested appender. * * @deprecated Please use {@link LogManager#shutdown()} instead. * * @since 1.0 */ public static void shutdown() { LogManager.shutdown(); } /** * Log a message object with the {@link Level#WARN WARN} Level. * *

* This method first checks if this category is WARN enabled by * comparing the level of this category with {@link Level#WARN WARN} Level. If * the category is WARN enabled, then it converts the message * object passed as parameter to a string by invoking the appropriate * {@link org.apache.log4j.or.ObjectRenderer}. It proceeds to call all the * registered appenders in this category and also higher in the hieararchy * depending on the value of the additivity flag. * *

* WARNING Note that passing a {@link Throwable} to this method will * print the name of the Throwable but no stack trace. To print a stack trace * use the {@link #warn(Object, Throwable)} form instead. *

* * @param message the message object to log. */ public void warn(Object message) { if (repository.isDisabled(Level.WARN_INT)) return; if (Level.WARN.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.WARN, message, null); } /** * Log a message with the WARN level including the stack trace of * the {@link Throwable} t passed as parameter. * *

* See {@link #warn(Object)} for more detailed information. * * @param message the message object to log. * @param t the exception to log, including its stack trace. */ public void warn(Object message, Throwable t) { if (repository.isDisabled(Level.WARN_INT)) return; if (Level.WARN.isGreaterOrEqual(this.getEffectiveLevel())) forcedLog(FQCN, Level.WARN, message, t); } }





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