src/main/java/org/apache/log4j/Hierarchy.java - logging-log4j1 - Git at Google

 /*
  * 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.
  */

 // WARNING This class MUST not have references to the Category or
 // WARNING RootCategory classes in its static initiliazation neither
 // WARNING directly nor indirectly.

 // Contributors:
 //                Luke Blanshard <luke@quiq.com>
 //                Mario Schomburg - IBM Global Services/Germany
 //                Anders Kristensen
 //                Igor Poteryaev

 package org.apache.log4j;


 import java.util.Hashtable;
 import java.util.Enumeration;
 import java.util.Vector;

 import org.apache.log4j.spi.LoggerFactory;
 import org.apache.log4j.spi.HierarchyEventListener;
 import org.apache.log4j.spi.LoggerRepository;
 import org.apache.log4j.spi.RendererSupport;
 import org.apache.log4j.or.RendererMap;
 import org.apache.log4j.or.ObjectRenderer;
 import org.apache.log4j.helpers.LogLog;
 import org.apache.log4j.spi.ThrowableRendererSupport;
 import org.apache.log4j.spi.ThrowableRenderer;

 /**
    This class is specialized in retrieving loggers by name and also
    maintaining the logger hierarchy.

    <p><em>The casual user does not have to deal with this class
    directly.</em>

    <p>The structure of the logger hierarchy is maintained by the
    {@link #getLogger} method. The hierarchy is such that children link
    to their parent but parents do not have any pointers to their
    children. Moreover, loggers can be instantiated in any order, in
    particular descendant before ancestor.

    <p>In case a descendant is created before a particular ancestor,
    then it creates a provision node for the ancestor and adds itself
    to the provision node. Other descendants of the same ancestor add
    themselves to the previously created provision node.

    @author Ceki G&uuml;lc&uuml;

 */
 public class Hierarchy implements LoggerRepository, RendererSupport, ThrowableRendererSupport {

   private LoggerFactory defaultFactory;
   private Vector listeners;

   Hashtable ht;
   Logger root;
   RendererMap rendererMap;

   int thresholdInt;
   Level threshold;

   boolean emittedNoAppenderWarning = false;
   boolean emittedNoResourceBundleWarning = false;

   private ThrowableRenderer throwableRenderer = null;

   /**
      Create a new logger hierarchy.

      @param root The root of the new hierarchy.

    */
   public
   Hierarchy(Logger root) {
     ht = new Hashtable();
     listeners = new Vector(1);
     this.root = root;
     // Enable all level levels by default.
     setThreshold(Level.ALL);
     this.root.setHierarchy(this);
     rendererMap = new RendererMap();
     defaultFactory = new DefaultCategoryFactory();
   }

   /**
      Add an object renderer for a specific class.
    */
   public
   void addRenderer(Class classToRender, ObjectRenderer or) {
     rendererMap.put(classToRender, or);
   }

   public
   void addHierarchyEventListener(HierarchyEventListener listener) {
     if(listeners.contains(listener)) {
       LogLog.warn("Ignoring attempt to add an existent listener.");
     } else {
       listeners.addElement(listener);
     }
   }

   /**
      This call will clear all logger definitions from the internal
      hashtable. Invoking this method will irrevocably mess up the
      logger hierarchy.

      <p>You should <em>really</em> know what you are doing before
      invoking this method.

      @since 0.9.0 */
   public
   void clear() {
     //System.out.println("\n\nAbout to clear internal hash table.");
     ht.clear();
   }

   public
   void emitNoAppenderWarning(Category cat) {
     // No appenders in hierarchy, warn user only once.
     if(!this.emittedNoAppenderWarning) {
       LogLog.warn("No appenders could be found for logger (" +
 		   cat.getName() + ").");
       LogLog.warn("Please initialize the log4j system properly.");
       LogLog.warn("See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.");
       this.emittedNoAppenderWarning = true;
     }
   }

   /**
      Check if the named logger exists in the hierarchy. If so return
      its reference, otherwise returns <code>null</code>.

      @param name The name of the logger to search for.

   */
   public
   Logger exists(String name) {
     Object o = ht.get(new CategoryKey(name));
     if(o instanceof Logger) {
       return (Logger) o;
     } else {
       return null;
     }
   }

   /**
      The string form of {@link #setThreshold(Level)}.
   */
   public
   void setThreshold(String levelStr) {
     Level l = (Level) Level.toLevel(levelStr, null);
     if(l != null) {
       setThreshold(l);
     } else {
       LogLog.warn("Could not convert ["+levelStr+"] to Level.");
     }
   }


   /**
      Enable logging for logging requests with level <code>l</code> or
      higher. By default all levels are enabled.

      @param l The minimum level for which logging requests are sent to
      their appenders.  */
   public
   void setThreshold(Level l) {
     if(l != null) {
       thresholdInt = l.level;
       threshold = l;
     }
   }

   public
   void fireAddAppenderEvent(Category logger, Appender appender) {
     if(listeners != null) {
       int size = listeners.size();
       HierarchyEventListener listener;
       for(int i = 0; i < size; i++) {
 	listener = (HierarchyEventListener) listeners.elementAt(i);
 	listener.addAppenderEvent(logger, appender);
       }
     }
   }

   void fireRemoveAppenderEvent(Category logger, Appender appender) {
     if(listeners != null) {
       int size = listeners.size();
       HierarchyEventListener listener;
       for(int i = 0; i < size; i++) {
 	listener = (HierarchyEventListener) listeners.elementAt(i);
 	listener.removeAppenderEvent(logger, appender);
       }
     }
   }

   /**
      Returns a {@link Level} representation of the <code>enable</code>
      state.

      @since 1.2 */
   public
   Level getThreshold() {
     return threshold;
   }

   /**
      Returns an integer representation of the this repository's
      threshold.

      @since 1.2 */
   //public
   //int getThresholdInt() {
   //  return thresholdInt;
   //}


   /**
      Return a new logger instance named as the first parameter using
      the default factory.

      <p>If a logger of that name already exists, then it will be
      returned.  Otherwise, a new logger will be instantiated and
      then linked with its existing ancestors as well as children.

      @param name The name of the logger to retrieve.

  */
   public
   Logger getLogger(String name) {
     return getLogger(name, defaultFactory);
   }

  /**
      Return a new logger instance named as the first parameter using
      <code>factory</code>.

      <p>If a logger of that name already exists, then it will be
      returned.  Otherwise, a new logger will be instantiated by the
      <code>factory</code> parameter and linked with its existing
      ancestors as well as children.

      @param name The name of the logger to retrieve.
      @param factory The factory that will make the new logger instance.

  */
   public
   Logger getLogger(String name, LoggerFactory factory) {
     //System.out.println("getInstance("+name+") called.");
     CategoryKey key = new CategoryKey(name);
     // Synchronize to prevent write conflicts. Read conflicts (in
     // getChainedLevel method) are possible only if variable
     // assignments are non-atomic.
     Logger logger;

     synchronized(ht) {
       Object o = ht.get(key);
       if(o == null) {
 	logger = factory.makeNewLoggerInstance(name);
 	logger.setHierarchy(this);
 	ht.put(key, logger);
 	updateParents(logger);
 	return logger;
       } else if(o instanceof Logger) {
 	return (Logger) o;
       } else if (o instanceof ProvisionNode) {
 	//System.out.println("("+name+") ht.get(this) returned ProvisionNode");
 	logger = factory.makeNewLoggerInstance(name);
 	logger.setHierarchy(this);
 	ht.put(key, logger);
 	updateChildren((ProvisionNode) o, logger);
 	updateParents(logger);
 	return logger;
       }
       else {
 	// It should be impossible to arrive here
 	return null;  // but let's keep the compiler happy.
       }
     }
   }

   /**
      Returns all the currently defined categories in this hierarchy as
      an {@link java.util.Enumeration Enumeration}.

      <p>The root logger is <em>not</em> included in the returned
      {@link Enumeration}.  */
   public
   Enumeration getCurrentLoggers() {
     // The accumlation in v is necessary because not all elements in
     // ht are Logger objects as there might be some ProvisionNodes
     // as well.
     Vector v = new Vector(ht.size());

     Enumeration elems = ht.elements();
     while(elems.hasMoreElements()) {
       Object o = elems.nextElement();
       if(o instanceof Logger) {
 	v.addElement(o);
       }
     }
     return v.elements();
   }

   /**
      @deprecated Please use {@link #getCurrentLoggers} instead.
    */
   public
   Enumeration getCurrentCategories() {
     return getCurrentLoggers();
   }


   /**
      Get the renderer map for this hierarchy.
   */
   public
   RendererMap getRendererMap() {
     return rendererMap;
   }


   /**
      Get the root of this hierarchy.

      @since 0.9.0
    */
   public
   Logger getRootLogger() {
     return root;
   }

   /**
      This method will return <code>true</code> if this repository is
      disabled for <code>level</code> object passed as parameter and
      <code>false</code> otherwise. See also the {@link
      #setThreshold(Level) threshold} emthod.  */
   public
   boolean isDisabled(int level) {
     return thresholdInt > level;
   }

   /**
      @deprecated Deprecated with no replacement.
   */
   public
   void overrideAsNeeded(String override) {
     LogLog.warn("The Hiearchy.overrideAsNeeded method has been deprecated.");
   }

   /**
      Reset all values contained in this hierarchy instance to their
      default.  This removes all appenders from all categories, sets
      the level of all non-root categories to <code>null</code>,
      sets their additivity flag to <code>true</code> and sets the level
      of the root logger to {@link Level#DEBUG DEBUG}.  Moreover,
      message disabling is set its default "off" value.

      <p>Existing categories are not removed. They are just reset.

      <p>This method should be used sparingly and with care as it will
      block all logging until it is completed.</p>

      @since 0.8.5 */
   public
   void resetConfiguration() {

     getRootLogger().setLevel((Level) Level.DEBUG);
     root.setResourceBundle(null);
     setThreshold(Level.ALL);

     // the synchronization is needed to prevent JDK 1.2.x hashtable
     // surprises
     synchronized(ht) {
       shutdown(); // nested locks are OK

       Enumeration cats = getCurrentLoggers();
       while(cats.hasMoreElements()) {
 	Logger c = (Logger) cats.nextElement();
 	c.setLevel(null);
 	c.setAdditivity(true);
 	c.setResourceBundle(null);
       }
     }
     rendererMap.clear();
     throwableRenderer = null;
   }

   /**
      Does nothing.

      @deprecated Deprecated with no replacement.
    */
   public
   void setDisableOverride(String override) {
     LogLog.warn("The Hiearchy.setDisableOverride method has been deprecated.");
   }


   /**
      Used by subclasses to add a renderer to the hierarchy passed as parameter.
    */
   public
   void setRenderer(Class renderedClass, ObjectRenderer renderer) {
     rendererMap.put(renderedClass, renderer);
   }

     /**
      * {@inheritDoc}
      */
   public void setThrowableRenderer(final ThrowableRenderer renderer) {
       throwableRenderer = renderer;
   }

     /**
      * {@inheritDoc}
      */
   public ThrowableRenderer getThrowableRenderer() {
       return throwableRenderer;
   }


   /**
      Shutting down a hierarchy will <em>safely</em> close and remove
      all appenders in all categories including the root logger.

      <p>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.

      <p>The <code>shutdown</code> method is careful to close nested
      appenders before closing regular appenders. This is allows
      configurations where a regular appender is attached to a logger
      and again to a nested appender.


      @since 1.0 */
   public
   void shutdown() {
     Logger root = getRootLogger();

     // begin by closing nested appenders
     root.closeNestedAppenders();

     synchronized(ht) {
       Enumeration cats = this.getCurrentLoggers();
       while(cats.hasMoreElements()) {
 	Logger c = (Logger) cats.nextElement();
 	c.closeNestedAppenders();
       }

       // then, remove all appenders
       root.removeAllAppenders();
       cats = this.getCurrentLoggers();
       while(cats.hasMoreElements()) {
 	Logger c = (Logger) cats.nextElement();
 	c.removeAllAppenders();
       }
     }
   }


   /**
      This method loops through all the *potential* parents of
      'cat'. There 3 possible cases:

      1) No entry for the potential parent of 'cat' exists

         We create a ProvisionNode for this potential parent and insert
         'cat' in that provision node.

      2) There entry is of type Logger for the potential parent.

         The entry is 'cat's nearest existing parent. We update cat's
         parent field with this entry. We also break from the loop
         because updating our parent's parent is our parent's
         responsibility.

      3) There entry is of type ProvisionNode for this potential parent.

         We add 'cat' to the list of children for this potential parent.
    */
   final
   private
   void updateParents(Logger cat) {
     String name = cat.name;
     int length = name.length();
     boolean parentFound = false;

     //System.out.println("UpdateParents called for " + name);

     // if name = "w.x.y.z", loop thourgh "w.x.y", "w.x" and "w", but not "w.x.y.z"
     for(int i = name.lastIndexOf('.', length-1); i >= 0;
 	                                 i = name.lastIndexOf('.', i-1))  {
       String substr = name.substring(0, i);

       //System.out.println("Updating parent : " + substr);
       CategoryKey key = new CategoryKey(substr); // simple constructor
       Object o = ht.get(key);
       // Create a provision node for a future parent.
       if(o == null) {
 	//System.out.println("No parent "+substr+" found. Creating ProvisionNode.");
 	ProvisionNode pn = new ProvisionNode(cat);
 	ht.put(key, pn);
       } else if(o instanceof Category) {
 	parentFound = true;
 	cat.parent = (Category) o;
 	//System.out.println("Linking " + cat.name + " -> " + ((Category) o).name);
 	break; // no need to update the ancestors of the closest ancestor
       } else if(o instanceof ProvisionNode) {
 	((ProvisionNode) o).addElement(cat);
       } else {
 	Exception e = new IllegalStateException("unexpected object type " +
 					o.getClass() + " in ht.");
 	e.printStackTrace();
       }
     }
     // If we could not find any existing parents, then link with root.
     if(!parentFound)
       cat.parent = root;
   }

   /**
       We update the links for all the children that placed themselves
       in the provision node 'pn'. The second argument 'cat' is a
       reference for the newly created Logger, parent of all the
       children in 'pn'

       We loop on all the children 'c' in 'pn':

          If the child 'c' has been already linked to a child of
          'cat' then there is no need to update 'c'.

 	 Otherwise, we set cat's parent field to c's parent and set
 	 c's parent field to cat.

   */
   final
   private
   void updateChildren(ProvisionNode pn, Logger logger) {
     //System.out.println("updateChildren called for " + logger.name);
     final int last = pn.size();

     for(int i = 0; i < last; i++) {
       Logger l = (Logger) pn.elementAt(i);
       //System.out.println("Updating child " +p.name);

       // Unless this child already points to a correct (lower) parent,
       // make cat.parent point to l.parent and l.parent to cat.
       if(!l.parent.name.startsWith(logger.name)) {
 	logger.parent = l.parent;
 	l.parent = logger;
       }
     }
   }

 }
	/*
	* 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.
	*/

	// WARNING This class MUST not have references to the Category or
	// WARNING RootCategory classes in its static initiliazation neither
	// WARNING directly nor indirectly.

	// Contributors:
	// Luke Blanshard <luke@quiq.com>
	// Mario Schomburg - IBM Global Services/Germany
	// Anders Kristensen
	// Igor Poteryaev

	package org.apache.log4j;


	import java.util.Hashtable;
	import java.util.Enumeration;
	import java.util.Vector;

	import org.apache.log4j.spi.LoggerFactory;
	import org.apache.log4j.spi.HierarchyEventListener;
	import org.apache.log4j.spi.LoggerRepository;
	import org.apache.log4j.spi.RendererSupport;
	import org.apache.log4j.or.RendererMap;
	import org.apache.log4j.or.ObjectRenderer;
	import org.apache.log4j.helpers.LogLog;
	import org.apache.log4j.spi.ThrowableRendererSupport;
	import org.apache.log4j.spi.ThrowableRenderer;

	/**
	This class is specialized in retrieving loggers by name and also
	maintaining the logger hierarchy.

	<p><em>The casual user does not have to deal with this class
	directly.</em>

	<p>The structure of the logger hierarchy is maintained by the
	{@link #getLogger} method. The hierarchy is such that children link
	to their parent but parents do not have any pointers to their
	children. Moreover, loggers can be instantiated in any order, in
	particular descendant before ancestor.

	<p>In case a descendant is created before a particular ancestor,
	then it creates a provision node for the ancestor and adds itself
	to the provision node. Other descendants of the same ancestor add
	themselves to the previously created provision node.

	@author Ceki Gülcü

	*/
	public class Hierarchy implements LoggerRepository, RendererSupport, ThrowableRendererSupport {

	private LoggerFactory defaultFactory;
	private Vector listeners;

	Hashtable ht;
	Logger root;
	RendererMap rendererMap;

	int thresholdInt;
	Level threshold;

	boolean emittedNoAppenderWarning = false;
	boolean emittedNoResourceBundleWarning = false;

	private ThrowableRenderer throwableRenderer = null;

	/**
	Create a new logger hierarchy.

	@param root The root of the new hierarchy.

	*/
	public
	Hierarchy(Logger root) {
	ht = new Hashtable();
	listeners = new Vector(1);
	this.root = root;
	// Enable all level levels by default.
	setThreshold(Level.ALL);
	this.root.setHierarchy(this);
	rendererMap = new RendererMap();
	defaultFactory = new DefaultCategoryFactory();
	}

	/**
	Add an object renderer for a specific class.
	*/
	public
	void addRenderer(Class classToRender, ObjectRenderer or) {
	rendererMap.put(classToRender, or);
	}

	public
	void addHierarchyEventListener(HierarchyEventListener listener) {
	if(listeners.contains(listener)) {
	LogLog.warn("Ignoring attempt to add an existent listener.");
	} else {
	listeners.addElement(listener);
	}
	}

	/**
	This call will clear all logger definitions from the internal
	hashtable. Invoking this method will irrevocably mess up the
	logger hierarchy.

	<p>You should <em>really</em> know what you are doing before
	invoking this method.

	@since 0.9.0 */
	public
	void clear() {
	//System.out.println("\n\nAbout to clear internal hash table.");
	ht.clear();
	}

	public
	void emitNoAppenderWarning(Category cat) {
	// No appenders in hierarchy, warn user only once.
	if(!this.emittedNoAppenderWarning) {
	LogLog.warn("No appenders could be found for logger (" +
	cat.getName() + ").");
	LogLog.warn("Please initialize the log4j system properly.");
	LogLog.warn("See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.");
	this.emittedNoAppenderWarning = true;
	}
	}

	/**
	Check if the named logger exists in the hierarchy. If so return
	its reference, otherwise returns <code>null</code>.

	@param name The name of the logger to search for.

	*/
	public
	Logger exists(String name) {
	Object o = ht.get(new CategoryKey(name));
	if(o instanceof Logger) {
	return (Logger) o;
	} else {
	return null;
	}
	}

	/**
	The string form of {@link #setThreshold(Level)}.
	*/
	public
	void setThreshold(String levelStr) {
	Level l = (Level) Level.toLevel(levelStr, null);
	if(l != null) {
	setThreshold(l);
	} else {
	LogLog.warn("Could not convert ["+levelStr+"] to Level.");
	}
	}


	/**
	Enable logging for logging requests with level <code>l</code> or
	higher. By default all levels are enabled.

	@param l The minimum level for which logging requests are sent to
	their appenders. */
	public
	void setThreshold(Level l) {
	if(l != null) {
	thresholdInt = l.level;
	threshold = l;
	}
	}

	public
	void fireAddAppenderEvent(Category logger, Appender appender) {
	if(listeners != null) {
	int size = listeners.size();
	HierarchyEventListener listener;
	for(int i = 0; i < size; i++) {
	listener = (HierarchyEventListener) listeners.elementAt(i);
	listener.addAppenderEvent(logger, appender);
	}
	}
	}

	void fireRemoveAppenderEvent(Category logger, Appender appender) {
	if(listeners != null) {
	int size = listeners.size();
	HierarchyEventListener listener;
	for(int i = 0; i < size; i++) {
	listener = (HierarchyEventListener) listeners.elementAt(i);
	listener.removeAppenderEvent(logger, appender);
	}
	}
	}

	/**
	Returns a {@link Level} representation of the <code>enable</code>
	state.

	@since 1.2 */
	public
	Level getThreshold() {
	return threshold;
	}

	/**
	Returns an integer representation of the this repository's
	threshold.

	@since 1.2 */
	//public
	//int getThresholdInt() {
	// return thresholdInt;
	//}


	/**
	Return a new logger instance named as the first parameter using
	the default factory.

	<p>If a logger of that name already exists, then it will be
	returned. Otherwise, a new logger will be instantiated and
	then linked with its existing ancestors as well as children.

	@param name The name of the logger to retrieve.

	*/
	public
	Logger getLogger(String name) {
	return getLogger(name, defaultFactory);
	}

	/**
	Return a new logger instance named as the first parameter using
	<code>factory</code>.

	<p>If a logger of that name already exists, then it will be
	returned. Otherwise, a new logger will be instantiated by the
	<code>factory</code> parameter and linked with its existing
	ancestors as well as children.

	@param name The name of the logger to retrieve.
	@param factory The factory that will make the new logger instance.

	*/
	public
	Logger getLogger(String name, LoggerFactory factory) {
	//System.out.println("getInstance("+name+") called.");
	CategoryKey key = new CategoryKey(name);
	// Synchronize to prevent write conflicts. Read conflicts (in
	// getChainedLevel method) are possible only if variable
	// assignments are non-atomic.
	Logger logger;

	synchronized(ht) {
	Object o = ht.get(key);
	if(o == null) {
	logger = factory.makeNewLoggerInstance(name);
	logger.setHierarchy(this);
	ht.put(key, logger);
	updateParents(logger);
	return logger;
	} else if(o instanceof Logger) {
	return (Logger) o;
	} else if (o instanceof ProvisionNode) {
	//System.out.println("("+name+") ht.get(this) returned ProvisionNode");
	logger = factory.makeNewLoggerInstance(name);
	logger.setHierarchy(this);
	ht.put(key, logger);
	updateChildren((ProvisionNode) o, logger);
	updateParents(logger);
	return logger;
	}
	else {
	// It should be impossible to arrive here
	return null; // but let's keep the compiler happy.
	}
	}
	}

	/**
	Returns all the currently defined categories in this hierarchy as
	an {@link java.util.Enumeration Enumeration}.

	<p>The root logger is <em>not</em> included in the returned
	{@link Enumeration}. */
	public
	Enumeration getCurrentLoggers() {
	// The accumlation in v is necessary because not all elements in
	// ht are Logger objects as there might be some ProvisionNodes
	// as well.
	Vector v = new Vector(ht.size());

	Enumeration elems = ht.elements();
	while(elems.hasMoreElements()) {
	Object o = elems.nextElement();
	if(o instanceof Logger) {
	v.addElement(o);
	}
	}
	return v.elements();
	}

	/**
	@deprecated Please use {@link #getCurrentLoggers} instead.
	*/
	public
	Enumeration getCurrentCategories() {
	return getCurrentLoggers();
	}


	/**
	Get the renderer map for this hierarchy.
	*/
	public
	RendererMap getRendererMap() {
	return rendererMap;
	}


	/**
	Get the root of this hierarchy.

	@since 0.9.0
	*/
	public
	Logger getRootLogger() {
	return root;
	}

	/**
	This method will return <code>true</code> if this repository is
	disabled for <code>level</code> object passed as parameter and
	<code>false</code> otherwise. See also the {@link
	#setThreshold(Level) threshold} emthod. */
	public
	boolean isDisabled(int level) {
	return thresholdInt > level;
	}

	/**
	@deprecated Deprecated with no replacement.
	*/
	public
	void overrideAsNeeded(String override) {
	LogLog.warn("The Hiearchy.overrideAsNeeded method has been deprecated.");
	}

	/**
	Reset all values contained in this hierarchy instance to their
	default. This removes all appenders from all categories, sets
	the level of all non-root categories to <code>null</code>,
	sets their additivity flag to <code>true</code> and sets the level
	of the root logger to {@link Level#DEBUG DEBUG}. Moreover,
	message disabling is set its default "off" value.

	<p>Existing categories are not removed. They are just reset.

	<p>This method should be used sparingly and with care as it will
	block all logging until it is completed.</p>

	@since 0.8.5 */
	public
	void resetConfiguration() {

	getRootLogger().setLevel((Level) Level.DEBUG);
	root.setResourceBundle(null);
	setThreshold(Level.ALL);

	// the synchronization is needed to prevent JDK 1.2.x hashtable
	// surprises
	synchronized(ht) {
	shutdown(); // nested locks are OK

	Enumeration cats = getCurrentLoggers();
	while(cats.hasMoreElements()) {
	Logger c = (Logger) cats.nextElement();
	c.setLevel(null);
	c.setAdditivity(true);
	c.setResourceBundle(null);
	}
	}
	rendererMap.clear();
	throwableRenderer = null;
	}

	/**
	Does nothing.

	@deprecated Deprecated with no replacement.
	*/
	public
	void setDisableOverride(String override) {
	LogLog.warn("The Hiearchy.setDisableOverride method has been deprecated.");
	}



	/**
	Used by subclasses to add a renderer to the hierarchy passed as parameter.
	*/
	public
	void setRenderer(Class renderedClass, ObjectRenderer renderer) {
	rendererMap.put(renderedClass, renderer);
	}

	/**
	* {@inheritDoc}
	*/
	public void setThrowableRenderer(final ThrowableRenderer renderer) {
	throwableRenderer = renderer;
	}

	/**
	* {@inheritDoc}
	*/
	public ThrowableRenderer getThrowableRenderer() {
	return throwableRenderer;
	}


	/**
	Shutting down a hierarchy will <em>safely</em> close and remove
	all appenders in all categories including the root logger.

	<p>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.

	<p>The <code>shutdown</code> method is careful to close nested
	appenders before closing regular appenders. This is allows
	configurations where a regular appender is attached to a logger
	and again to a nested appender.


	@since 1.0 */
	public
	void shutdown() {
	Logger root = getRootLogger();

	// begin by closing nested appenders
	root.closeNestedAppenders();

	synchronized(ht) {
	Enumeration cats = this.getCurrentLoggers();
	while(cats.hasMoreElements()) {
	Logger c = (Logger) cats.nextElement();
	c.closeNestedAppenders();
	}

	// then, remove all appenders
	root.removeAllAppenders();
	cats = this.getCurrentLoggers();
	while(cats.hasMoreElements()) {
	Logger c = (Logger) cats.nextElement();
	c.removeAllAppenders();
	}
	}
	}


	/**
	This method loops through all the potential parents of
	'cat'. There 3 possible cases:

	1) No entry for the potential parent of 'cat' exists

	We create a ProvisionNode for this potential parent and insert
	'cat' in that provision node.

	2) There entry is of type Logger for the potential parent.

	The entry is 'cat's nearest existing parent. We update cat's
	parent field with this entry. We also break from the loop
	because updating our parent's parent is our parent's
	responsibility.

	3) There entry is of type ProvisionNode for this potential parent.

	We add 'cat' to the list of children for this potential parent.
	*/
	final
	private
	void updateParents(Logger cat) {
	String name = cat.name;
	int length = name.length();
	boolean parentFound = false;

	//System.out.println("UpdateParents called for " + name);

	// if name = "w.x.y.z", loop thourgh "w.x.y", "w.x" and "w", but not "w.x.y.z"
	for(int i = name.lastIndexOf('.', length-1); i >= 0;
	i = name.lastIndexOf('.', i-1)) {
	String substr = name.substring(0, i);

	//System.out.println("Updating parent : " + substr);
	CategoryKey key = new CategoryKey(substr); // simple constructor
	Object o = ht.get(key);
	// Create a provision node for a future parent.
	if(o == null) {
	//System.out.println("No parent "+substr+" found. Creating ProvisionNode.");
	ProvisionNode pn = new ProvisionNode(cat);
	ht.put(key, pn);
	} else if(o instanceof Category) {
	parentFound = true;
	cat.parent = (Category) o;
	//System.out.println("Linking " + cat.name + " -> " + ((Category) o).name);
	break; // no need to update the ancestors of the closest ancestor
	} else if(o instanceof ProvisionNode) {
	((ProvisionNode) o).addElement(cat);
	} else {
	Exception e = new IllegalStateException("unexpected object type " +
	o.getClass() + " in ht.");
	e.printStackTrace();
	}
	}
	// If we could not find any existing parents, then link with root.
	if(!parentFound)
	cat.parent = root;
	}

	/**
	We update the links for all the children that placed themselves
	in the provision node 'pn'. The second argument 'cat' is a
	reference for the newly created Logger, parent of all the
	children in 'pn'

	We loop on all the children 'c' in 'pn':

	If the child 'c' has been already linked to a child of
	'cat' then there is no need to update 'c'.

	Otherwise, we set cat's parent field to c's parent and set
	c's parent field to cat.

	*/
	final
	private
	void updateChildren(ProvisionNode pn, Logger logger) {
	//System.out.println("updateChildren called for " + logger.name);
	final int last = pn.size();

	for(int i = 0; i < last; i++) {
	Logger l = (Logger) pn.elementAt(i);
	//System.out.println("Updating child " +p.name);

	// Unless this child already points to a correct (lower) parent,
	// make cat.parent point to l.parent and l.parent to cat.
	if(!l.parent.name.startsWith(logger.name)) {
	logger.parent = l.parent;
	l.parent = logger;
	}
	}
	}

	}