/*
    * 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.
   */
  package org.apache.logging.log4j;
  
  import org.apache.logging.log4j.message.Message;
  import org.apache.logging.log4j.message.MessageFactory;
  import org.apache.logging.log4j.util.MessageSupplier;
  import org.apache.logging.log4j.util.Supplier;
  
  /**
   * This is the central interface in the log4j package. Most logging operations, except configuration, are done through
   * this interface.
   *
   * <p>
   * The canonical way to obtain a Logger for a class is through {@link LogManager#getLogger()}. Typically, each class
   * gets its own Logger named after its fully qualified class name (the default Logger name when obtained through the
   * {@link LogManager#getLogger()} method). Thus, the simplest way to use this would be like so:
   * </p>
   * <pre>
   *     public class MyClass {
   *         private static final Logger LOGGER = LogManager.getLogger();
   *         // ...
   *     }
   * </pre>
   * <p>
   * For ease of filtering, searching, sorting, etc., it is generally a good idea to create Loggers for each class rather
   * than sharing Loggers. Instead, {@link Marker Markers} should be used for shared, filterable identification.
   * </p>
   * <p>
   * For service provider implementations, it is recommended to extend the
   * {@link org.apache.logging.log4j.spi.AbstractLogger} class rather than implementing this interface directly.
   * </p>
   *
   * Since 2.4, methods have been added to the {@code Logger} interface to support lambda expressions.
   * The new methods allow client code to lazily log messages without explicitly checking if the requested log level is
   * enabled. For example, previously one would write:
   * 
   * <pre>
   * // pre-Java 8 style optimization: explicitly check the log level
   * // to make sure the expensiveOperation() method is only called if necessary
   * if (logger.isTraceEnabled()) {
   *     logger.trace(&quot;Some long-running operation returned {}&quot;, expensiveOperation());
   * }</pre>
   * <p>
   * With Java 8, the same effect can be achieved with a lambda expression:
   * 
   * <pre>
   * // Java-8 style optimization: no need to explicitly check the log level:
   * // the lambda expression is not evaluated if the TRACE level is not enabled
   * logger.trace(&quot;Some long-running operation returned {}&quot;, () -&gt; expensiveOperation());
   * </pre>
   */
  public interface Logger {
  
      /**
       * Logs an exception or error that has been caught to a specific logging level.
       *
       * @param level The logging Level.
       * @param t The Throwable.
       */
      void catching(Level level, Throwable t);
  
      /**
       * Logs an exception or error that has been caught. Normally, one may wish to provide additional information with
       * an exception while logging it; in these cases, one would not use this method. In other cases where simply
       * logging the fact that an exception was swallowed somewhere (e.g., at the top of the stack trace in a
       * {@code main()} method), this method is ideal for it.
       *
       * @param t The Throwable.
       */
      void catching(Throwable t);
  
      /**
       * Logs a message with the specific Marker at the {@link Level#DEBUG DEBUG} level.
       *
       * @param marker the marker data specific to this log statement
       * @param msg the message string to be logged
       */
      void debug(Marker marker, Message msg);
  
      /**
       * Logs a message with the specific Marker at the {@link Level#DEBUG DEBUG} level.
       *
       * @param marker the marker data specific to this log statement
       * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void debug(Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level with
      * the specified Marker. The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the
      * {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void debug(Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter. The
      * {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void debug(Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#DEBUG DEBUG} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void debug(Marker marker, Object message);
 
     /**
      * Logs a message at the {@link Level#DEBUG DEBUG} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void debug(Marker marker, Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#DEBUG DEBUG} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void debug(Marker marker, String message);
 
     /**
      * Logs a message with parameters at the {@link Level#DEBUG DEBUG} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      */
     void debug(Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#DEBUG
      * DEBUG} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void debug(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#DEBUG DEBUG} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void debug(Marker marker, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level with
      * the specified Marker.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void debug(Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void debug(Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#DEBUG DEBUG} level.
      *
      * @param msg the message string to be logged
      */
     void debug(Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#DEBUG DEBUG} level.
      *
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void debug(Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level. The
      * {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void debug(MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter. The {@code MessageSupplier} may or may
      * not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void debug(MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#DEBUG DEBUG} level.
      *
      * @param message the message object to log.
      */
     void debug(Object message);
 
     /**
      * Logs a message at the {@link Level#DEBUG DEBUG} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void debug(Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#DEBUG DEBUG} level.
      *
      * @param message the message string to log.
      */
     void debug(String message);
 
     /**
      * Logs a message with parameters at the {@link Level#DEBUG DEBUG} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      */
     void debug(String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#DEBUG
      * DEBUG} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void debug(String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#DEBUG DEBUG} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void debug(String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void debug(Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#DEBUG DEBUG} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void debug(Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs entry to a method. Used when the method in question has no parameters or when the parameters should not be
      * logged.
      */
     void entry();
 
     /**
      * Logs entry to a method along with its parameters. For example,
      * <pre>
      *     public void doSomething(String foo, int bar) {
      *         LOGGER.entry(foo, bar);
      *         // do something
      *     }
      * </pre>
      * <p>The use of methods such as this are more effective when combined with aspect-oriented programming or other
      * bytecode manipulation tools. It can be rather tedious (and messy) to use this type of method manually.</p>
      *
      * @param params The parameters to the method.
      * TODO Use of varargs results in array creation which can be a substantial portion of no-op case. LogMF/LogSF
      *        provides several overrides to avoid vararg except in edge cases. (RG) LogMF and LogSF implement these in
      *        LogXF which calls logger.callAppenders. callAppenders is part of the implementation and cannot be used by
      *        the API. Adding more methods here and in AbstractLogger is sufficient.
      */
     void entry(Object... params);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#ERROR ERROR} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      */
     void error(Marker marker, Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#ERROR ERROR} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void error(Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level with
      * the specified Marker. 
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void error(Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void error(Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#ERROR ERROR} level.
      *
      * @param marker the marker data specific to this log statement.
      * @param message the message object to log.
      */
     void error(Marker marker, Object message);
 
     /**
      * Logs a message at the {@link Level#ERROR ERROR} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement.
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void error(Marker marker, Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#ERROR ERROR} level.
      *
      * @param marker the marker data specific to this log statement.
      * @param message the message object to log.
      */
     void error(Marker marker, String message);
 
     /**
      * Logs a message with parameters at the {@link Level#ERROR ERROR} level.
      *
      * @param marker the marker data specific to this log statement.
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call. (RG) I assume you meant error, not info. It isn't possible to be
      *        misinterpreted as the previous method is for that signature. Methods should be added to avoid varargs for
      *        1, 2 or 3 parameters.
      */
     void error(Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#ERROR
      * ERROR} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void error(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#ERROR ERROR} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement.
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void error(Marker marker, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level with
      * the specified Marker.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void error(Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void error(Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#ERROR ERROR} level.
      *
      * @param msg the message string to be logged
      */
     void error(Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#ERROR ERROR} level.
      *
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void error(Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void error(MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void error(MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#ERROR ERROR} level.
      *
      * @param message the message object to log.
      */
     void error(Object message);
 
     /**
      * Logs a message at the {@link Level#ERROR ERROR} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void error(Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#ERROR ERROR} level.
      *
      * @param message the message string to log.
      */
     void error(String message);
 
     /**
      * Logs a message with parameters at the {@link Level#ERROR ERROR} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call. (RG) I assume you meant error, not info. It isn't possible to be
      *        misinterpreted as the previous method is for that signature. Methods should be added to avoid varargs for
      *        1, 2 or 3 parameters.
      */
     void error(String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#ERROR
      * ERROR} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void error(String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#ERROR ERROR} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void error(String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#ERROR ERROR} level.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void error(Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#ERROR ERROR} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void error(Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs exit from a method. Used for methods that do not return anything.
      */
     void exit();
 
     /**
      * Logs exiting from a method with the result. This may be coded as:
      * <pre>
      *     return LOGGER.exit(myResult);
      * </pre>
      *
      * @param <R> The type of the parameter and object being returned.
      * @param result The result being returned from the method call.
      * @return the result.
      */
     <R> R exit(R result);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#FATAL FATAL} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      */
     void fatal(Marker marker, Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#FATAL FATAL} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void fatal(Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level with
      * the specified Marker. 
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void fatal(Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void fatal(Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#FATAL FATAL} level.
      *
      * @param marker The marker data specific to this log statement.
      * @param message the message object to log.
      */
     void fatal(Marker marker, Object message);
 
     /**
      * Logs a message at the {@link Level#FATAL FATAL} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker The marker data specific to this log statement.
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void fatal(Marker marker, Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#FATAL FATAL} level.
      *
      * @param marker The marker data specific to this log statement.
      * @param message the message object to log.
      */
     void fatal(Marker marker, String message);
 
     /**
      * Logs a message with parameters at the {@link Level#FATAL FATAL} level.
      *
      * @param marker The marker data specific to this log statement.
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call.(RG) I assume you meant fatal, not info. It isn't possible to be
      *        misinterpreted as the previous method is for that signature. Methods should be added to avoid varargs for
      *        1, 2 or 3 parameters.
      */
     void fatal(Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#FATAL
      * FATAL} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void fatal(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#FATAL FATAL} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker The marker data specific to this log statement.
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void fatal(Marker marker, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level with
      * the specified Marker.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void fatal(Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void fatal(Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#FATAL FATAL} level.
      *
      * @param msg the message string to be logged
      */
     void fatal(Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#FATAL FATAL} level.
      *
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void fatal(Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void fatal(MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void fatal(MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#FATAL FATAL} level.
      *
      * @param message the message object to log.
      */
     void fatal(Object message);
 
     /**
      * Logs a message at the {@link Level#FATAL FATAL} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void fatal(Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#FATAL FATAL} level.
      *
      * @param message the message string to log.
      */
     void fatal(String message);
 
     /**
      * Logs a message with parameters at the {@link Level#FATAL FATAL} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call.(RG) I assume you meant fatal, not info. It isn't possible to be
      *        misinterpreted as the previous method is for that signature. Methods should be added to avoid varargs for
      *        1, 2 or 3 parameters.
      */
     void fatal(String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#FATAL
      * FATAL} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void fatal(String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#FATAL FATAL} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void fatal(String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#FATAL FATAL} level.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void fatal(Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#FATAL FATAL} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void fatal(Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Gets the Level associated with the Logger.
      *
      * @return the Level associate with the Logger.
      */
     Level getLevel();
 
     /**
      * Gets the message factory used to convert message Objects and Strings into actual log Messages.
      *
      * @return the message factory.
      */
     MessageFactory getMessageFactory();
 
     /**
      * Gets the logger name.
      *
      * @return the logger name.
      */
     String getName();
 
     /**
      * Logs a message with the specific Marker at the {@link Level#INFO INFO} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      */
     void info(Marker marker, Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#INFO INFO} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void info(Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level with
      * the specified Marker. 
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void info(Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void info(Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#INFO INFO} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void info(Marker marker, Object message);
 
     /**
      * Logs a message at the {@link Level#INFO INFO} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void info(Marker marker, Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#INFO INFO} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void info(Marker marker, String message);
 
     /**
      * Logs a message with parameters at the {@link Level#INFO INFO} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call. (RG) It isn't possible to be misinterpreted as the previous method
      *        is for that signature. Methods should be added to avoid varargs for 1, 2 or 3 parameters.
      */
     void info(Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#INFO
      * INFO} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void info(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#INFO INFO} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void info(Marker marker, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level with the
      * specified Marker.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void info(Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void info(Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#INFO INFO} level.
      *
      * @param msg the message string to be logged
      */
     void info(Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#INFO INFO} level.
      *
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void info(Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void info(MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void info(MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#INFO INFO} level.
      *
      * @param message the message object to log.
      */
     void info(Object message);
 
     /**
      * Logs a message at the {@link Level#INFO INFO} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void info(Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#INFO INFO} level.
      *
      * @param message the message string to log.
      */
     void info(String message);
 
     /**
      * Logs a message with parameters at the {@link Level#INFO INFO} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call. (RG) It isn't possible to be misinterpreted as the previous method
      *        is for that signature. Methods should be added to avoid varargs for 1, 2 or 3 parameters.
      */
     void info(String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#INFO
      * INFO} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void info(String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#INFO INFO} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void info(String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#INFO INFO} level.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void info(Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#INFO INFO} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void info(Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#DEBUG DEBUG} Level.
      *
      * @return boolean - {@code true} if this Logger is enabled for level DEBUG, {@code false} otherwise.
      */
     boolean isDebugEnabled();
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#DEBUG DEBUG} Level.
      *
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level DEBUG, {@code false} otherwise.
      */
     boolean isDebugEnabled(Marker marker);
 
     /**
      * Checks whether this Logger is enabled for the the given Level.
      * <p>
      * Note that passing in {@link Level#OFF OFF} always returns {@code true}.
      * </p>
      *
      * @param level the level to check
      * @return boolean - {@code true} if this Logger is enabled for level, {@code false} otherwise.
      */
     boolean isEnabled(Level level);
 
     /**
      * Checks whether this logger is enabled at the specified level and an optional Marker.
      *
      * @param level The Level to check.
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#WARN WARN}, {@code false}
      *         otherwise.
      */
     boolean isEnabled(Level level, Marker marker);
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#ERROR ERROR} Level.
      *
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#ERROR ERROR}, {@code false}
      *         otherwise.
      */
     boolean isErrorEnabled();
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#ERROR ERROR} Level.
      *
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#ERROR ERROR}, {@code false}
      *         otherwise.
      */
     boolean isErrorEnabled(Marker marker);
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#FATAL FATAL} Level.
      *
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#FATAL FATAL}, {@code false}
      *         otherwise.
      */
     boolean isFatalEnabled();
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#FATAL FATAL} Level.
      *
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#FATAL FATAL}, {@code false}
      *         otherwise.
      */
     boolean isFatalEnabled(Marker marker);
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#INFO INFO} Level.
      *
      * @return boolean - {@code true} if this Logger is enabled for level INFO, {@code false} otherwise.
      */
     boolean isInfoEnabled();
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#INFO INFO} Level.
      *
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level INFO, {@code false} otherwise.
      */
     boolean isInfoEnabled(Marker marker);
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#TRACE TRACE} level.
      *
      * @return boolean - {@code true} if this Logger is enabled for level TRACE, {@code false} otherwise.
      */
     boolean isTraceEnabled();
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#TRACE TRACE} level.
      *
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level TRACE, {@code false} otherwise.
      */
     boolean isTraceEnabled(Marker marker);
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#WARN WARN} Level.
      *
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#WARN WARN}, {@code false}
      *         otherwise.
      */
     boolean isWarnEnabled();
 
     /**
      * Checks whether this Logger is enabled for the {@link Level#WARN WARN} Level.
      *
      * @param marker The marker data specific to this log statement.
      * @return boolean - {@code true} if this Logger is enabled for level {@link Level#WARN WARN}, {@code false}
      *         otherwise.
      */
     boolean isWarnEnabled(Marker marker);
 
     /**
      * Logs a message with the specific Marker at the given level.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      */
     void log(Level level, Marker marker, Message msg);
 
     /**
      * Logs a message with the specific Marker at the given level.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void log(Level level, Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the specified level with
      * the specified Marker. 
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void log(Level level, Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the specified level) with the
      * specified Marker and including the stack log of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void log(Level level, Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the given level.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void log(Level level, Marker marker, Object message);
 
     /**
      * Logs a message at the given level including the stack trace of the {@link Throwable} <code>t</code> passed as
      * parameter.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void log(Level level, Marker marker, Object message, Throwable t);
 
 
     /**
      * Logs a message object with the given level.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void log(Level level, Marker marker, String message);
 
     /**
      * Logs a message with parameters at the given level.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      */
     void log(Level level, Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the specified level.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void log(Level level, Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the given level including the stack trace of the {@link Throwable} <code>t</code> passed as
      * parameter.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void log(Level level, Marker marker, String message, Throwable t);
 
     /**
      * Logs a message (only to be constructed if the logging level is the specified level) with the specified Marker.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void log(Level level, Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the specified level) with the specified Marker and
      * including the stack log of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param level the logging level
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void log(Level level, Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the given level.
      *
      * @param level the logging level
      * @param msg the message string to be logged
      */
     void log(Level level, Message msg);
 
     /**
      * Logs a message with the specific Marker at the given level.
      *
      * @param level the logging level
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void log(Level level, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the specified level.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param level the logging level
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void log(Level level, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the specified level) including the
      * stack log of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param level the logging level
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack log.
      * @since 2.4
      */
     void log(Level level, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the given level.
      *
      * @param level the logging level
      * @param message the message object to log.
      */
     void log(Level level, Object message);
 
     /**
      * Logs a message at the given level including the stack trace of the {@link Throwable} <code>t</code> passed as
      * parameter.
      *
      * @param level the logging level
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void log(Level level, Object message, Throwable t);
 
     /**
      * Logs a message object with the given level.
      *
      * @param level the logging level
      * @param message the message string to log.
      */
     void log(Level level, String message);
 
     /**
      * Logs a message with parameters at the given level.
      *
      * @param level the logging level
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      */
     void log(Level level, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the specified level.
      *
      * @param level the logging level
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void log(Level level, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the given level including the stack trace of the {@link Throwable} <code>t</code> passed as
      * parameter.
      *
      * @param level the logging level
      * @param message the message to log.
      * @param t the exception to log, including its stack trace.
      */
     void log(Level level, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the specified level.
      *
      * @param level the logging level
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void log(Level level, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the specified level) including the stack log of
      * the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param level the logging level
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack log.
      * @since 2.4
      */
     void log(Level level, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a formatted message using the specified format string and arguments.
      *
      * @param level The logging Level.
      * @param marker the marker data specific to this log statement.
      * @param format The format String.
      * @param params Arguments specified by the format.
      */
     void printf(Level level, Marker marker, String format, Object... params);
 
     /**
      * Logs a formatted message using the specified format string and arguments.
      *
      * @param level The logging Level.
      * @param format The format String.
      * @param params Arguments specified by the format.
      */
     void printf(Level level, String format, Object... params);
 
     /**
      * Logs an exception or error to be thrown. This may be coded as:
      * <pre>
      *     throw logger.throwing(Level.DEBUG, myException);
      * </pre>
      *
      * @param <T> the Throwable type.
      * @param level The logging Level.
      * @param t The Throwable.
      * @return the Throwable.
      */
     <T extends Throwable> T throwing(Level level, T t);
 
     /**
      * Logs an exception or error to be thrown. This may be coded as:
      * <pre>
      *     throw logger.throwing(myException);
      * </pre>
      *
      * @param <T> the Throwable type.
      * @param t The Throwable.
      * @return the Throwable.
      */
     <T extends Throwable> T throwing(T t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#TRACE TRACE} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      */
     void trace(Marker marker, Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#TRACE TRACE} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void trace(Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level with
      * the specified Marker. 
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void trace(Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void trace(Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#TRACE TRACE} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void trace(Marker marker, Object message);
 
     /**
      * Logs a message at the {@link Level#TRACE TRACE} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      * @see #debug(String)
      */
     void trace(Marker marker, Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#TRACE TRACE} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message string to log.
      */
     void trace(Marker marker, String message);
 
     /**
      * Logs a message with parameters at the {@link Level#TRACE TRACE} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      */
     void trace(Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#TRACE
      * TRACE} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void trace(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#TRACE TRACE} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      * @see #debug(String)
      */
     void trace(Marker marker, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level with
      * the specified Marker.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void trace(Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) with the
      * specified Marker and including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void trace(Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#TRACE TRACE} level.
      *
      * @param msg the message string to be logged
      */
     void trace(Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#TRACE TRACE} level.
      *
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void trace(Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void trace(MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void trace(MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#TRACE TRACE} level.
      *
      * @param message the message object to log.
      */
     void trace(Object message);
 
     /**
      * Logs a message at the {@link Level#TRACE TRACE} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      * @see #debug(String)
      */
     void trace(Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#TRACE TRACE} level.
      *
      * @param message the message string to log.
      */
     void trace(String message);
 
     /**
      * Logs a message with parameters at the {@link Level#TRACE TRACE} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      */
     void trace(String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#TRACE
      * TRACE} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void trace(String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#TRACE TRACE} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      * @see #debug(String)
      */
     void trace(String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#TRACE TRACE} level.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void trace(Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#TRACE TRACE} level) including the
      * stack trace of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack trace.
      * @since 2.4
      */
     void trace(Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#WARN WARN} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      */
     void warn(Marker marker, Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#WARN WARN} level.
      *
      * @param marker the marker data specific to this log statement
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void warn(Marker marker, Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level with
      * the specified Marker. 
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void warn(Marker marker, MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) with the
      * specified Marker and including the stack warn of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void warn(Marker marker, MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#WARN WARN} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void warn(Marker marker, Object message);
 
     /**
      * Logs a message at the {@link Level#WARN WARN} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void warn(Marker marker, Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#WARN WARN} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      */
     void warn(Marker marker, String message);
 
     /**
      * Logs a message with parameters at the {@link Level#WARN WARN} level.
      *
      * @param marker the marker data specific to this log statement.
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call. (RG) I assume you meant warn, not info. It isn't possible to be
      *        misinterpreted as the previous method is for that signature.Methods should be added to avoid varargs for
      *        1, 2 or 3 parameters.
      */
     void warn(Marker marker, String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#WARN
      * WARN} level.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void warn(Marker marker, String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#WARN WARN} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void warn(Marker marker, String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level with the
      * specified Marker.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void warn(Marker marker, Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) with the
      * specified Marker and including the stack warn of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param marker the marker data specific to this log statement
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t A Throwable or null.
      * @since 2.4
      */
     void warn(Marker marker, Supplier<?> msgSupplier, Throwable t);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#WARN WARN} level.
      *
      * @param msg the message string to be logged
      */
     void warn(Message msg);
 
     /**
      * Logs a message with the specific Marker at the {@link Level#WARN WARN} level.
      *
      * @param msg the message string to be logged
      * @param t A Throwable or null.
      */
     void warn(Message msg, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @since 2.4
      */
     void warn(MessageSupplier msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) including the
      * stack warn of the {@link Throwable} <code>t</code> passed as parameter.
      * The {@code MessageSupplier} may or may not use the {@link MessageFactory} to construct the {@code Message}.
      *
      * @param msgSupplier A function, which when called, produces the desired log message.
      * @param t the exception to log, including its stack warn.
      * @since 2.4
      */
     void warn(MessageSupplier msgSupplier, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#WARN WARN} level.
      *
      * @param message the message object to log.
      */
     void warn(Object message);
 
     /**
      * Logs a message at the {@link Level#WARN WARN} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void warn(Object message, Throwable t);
 
     /**
      * Logs a message object with the {@link Level#WARN WARN} level.
      *
      * @param message the message string to log.
      */
     void warn(String message);
 
     /**
      * Logs a message with parameters at the {@link Level#WARN WARN} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param params parameters to the message.
      * @see #getMessageFactory()
      *
      * TODO Likely to misinterpret existing log4j client code that intended to call info(Object,Throwable). Incurs
      *        array creation expense on every call. (RG) I assume you meant warn, not info. It isn't possible to be
      *        misinterpreted as the previous method is for that signature.Methods should be added to avoid varargs for
      *        1, 2 or 3 parameters.
      */
     void warn(String message, Object... params);
 
     /**
      * Logs a message with parameters which are only to be constructed if the logging level is the {@link Level#WARN
      * WARN} level.
      *
      * @param message the message to log; the format depends on the message factory.
      * @param paramSuppliers An array of functions, which when called, produce the desired log message parameters.
      * @since 2.4
      */
     void warn(String message, Supplier<?>... paramSuppliers);
 
     /**
      * Logs a message at the {@link Level#WARN WARN} level including the stack trace of the {@link Throwable}
      * <code>t</code> passed as parameter.
      *
      * @param message the message object to log.
      * @param t the exception to log, including its stack trace.
      */
     void warn(String message, Throwable t);
 
     /**
      * Logs a message which is only to be constructed if the logging level is the {@link Level#WARN WARN} level.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @since 2.4
      */
     void warn(Supplier<?> msgSupplier);
 
     /**
      * Logs a message (only to be constructed if the logging level is the {@link Level#WARN WARN} level) including the
      * stack warn of the {@link Throwable} <code>t</code> passed as parameter.
      *
      * @param msgSupplier A function, which when called, produces the desired log message; the format depends on the
      *            message factory.
      * @param t the exception to log, including its stack warn.
      * @since 2.4
      */
     void warn(Supplier<?> msgSupplier, Throwable t);
 
 }