/*
* 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.geode;
import java.util.logging.Handler;
import org.apache.geode.distributed.DistributedSystem;
import org.apache.geode.i18n.LogWriterI18n;
/**
* Defines methods available to clients that want to write a log message to their GemFire
* distributed system log file.
* <p>
* Instances of this interface can be obtained by calling {@link DistributedSystem#getLogWriter}.
* <p>
* For any logged message the log file will contain:
* <ul>
* <li>The message's level.
* <li>The time the message was logged.
* <li>The id of the thread that logged the message.
* <li>The message itself which can be a string and/or an exception including the exception's stack
* trace.
* </ul>
* <p>
* A message always has a level. Logging levels are ordered. Enabling logging at a given level also
* enables logging at higher levels. The higher the level the more important and urgent the message.
* <p>
* The levels, in descending order, are:
* <ul>
* <li><code>severe</code> (highest value) is a message level indicating a serious failure. In
* general <code>severe</code> messages should describe events that are of considerable importance
* and which will prevent normal program execution. They should be reasonably intelligible to end
* users and to information managers.
* <li><code>error</code> In general <code>error</code> messages should describe events that are of
* considerable importance but will not prevent normal program execution. They should be reasonably
* intelligible to end users and to information managers. They are weaker than <code>severe</code>
* and stronger than <code>warning</code>.
* <li><code>warning</code> is a message level indicating a potential problem. In general
* <code>warning</code> messages should describe events that will be of interest to end users or
* information managers, or which indicate potential problems.
* <li><code>info</code> is a message level for informational messages. Typically <code>info</code>
* messages should be reasonably significant and should make sense to end users and system
* administrators.
* <li><code>config</code> is a message level for static configuration messages. <code>config</code>
* messages are intended to provide a variety of static configuration information, to assist in
* debugging problems that may be associated with particular configurations.
* <li><code>fine</code> is a message level providing tracing information. In general the
* <code>fine</code> level should be used for information that will be broadly interesting to
* developers. This level is for the lowest volume, and most important, tracing messages.
* <li><code>finer</code> indicates a fairly detailed tracing message. Logging calls for entering,
* returning, or throwing an exception are traced at the <code>finer</code> level.
* <li><code>finest</code> (lowest value) indicates a highly detailed tracing message. In general
* the <code>finest</code> level should be used for the most voluminous detailed tracing messages.
* </ul>
* <p>
* For each level methods exist that will request a message, at that level, to be logged. These
* methods are all named after their level.
* <p>
* For each level a method exists that returns a boolean indicating if messages at that level will
* currently be logged. The names of these methods are of the form:
* <em>level</em><code>Enabled</code>.
*
*/
public interface LogWriter {
/**
* Returns true if "severe" log messages are enabled. Returns false if "severe" log messages are
* disabled.
*/
public boolean severeEnabled();
/**
* Writes both a message and exception to this writer. The message level is "severe".
*/
public void severe(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "severe".
*/
public void severe(String msg);
/**
* Writes an exception to this writer. The exception level is "severe".
*/
public void severe(Throwable ex);
/**
* Returns true if "error" log messages are enabled. Returns false if "error" log messages are
* disabled.
*/
public boolean errorEnabled();
/**
* Writes both a message and exception to this writer. The message level is "error".
*/
public void error(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "error".
*/
public void error(String msg);
/**
* Writes an exception to this writer. The exception level is "error".
*/
public void error(Throwable ex);
/**
* Returns true if "warning" log messages are enabled. Returns false if "warning" log messages are
* disabled.
*/
public boolean warningEnabled();
/**
* Writes both a message and exception to this writer. The message level is "warning".
*/
public void warning(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "warning".
*/
public void warning(String msg);
/**
* Writes an exception to this writer. The exception level is "warning".
*/
public void warning(Throwable ex);
/**
* Returns true if "info" log messages are enabled. Returns false if "info" log messages are
* disabled.
*/
public boolean infoEnabled();
/**
* Writes both a message and exception to this writer. The message level is "information".
*/
public void info(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "information".
*/
public void info(String msg);
/**
* Writes an exception to this writer. The exception level is "information".
*/
public void info(Throwable ex);
/**
* Returns true if "config" log messages are enabled. Returns false if "config" log messages are
* disabled.
*/
public boolean configEnabled();
/**
* Writes both a message and exception to this writer. The message level is "config".
*/
public void config(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "config".
*/
public void config(String msg);
/**
* Writes an exception to this writer. The exception level is "config".
*/
public void config(Throwable ex);
/**
* Returns true if "fine" log messages are enabled. Returns false if "fine" log messages are
* disabled.
*/
public boolean fineEnabled();
/**
* Writes both a message and exception to this writer. The message level is "fine".
*/
public void fine(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "fine".
*/
public void fine(String msg);
/**
* Writes an exception to this writer. The exception level is "fine".
*/
public void fine(Throwable ex);
/**
* Returns true if "finer" log messages are enabled. Returns false if "finer" log messages are
* disabled.
*/
public boolean finerEnabled();
/**
* Writes both a message and exception to this writer. The message level is "finer".
*/
public void finer(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "finer".
*/
public void finer(String msg);
/**
* Writes an exception to this writer. The exception level is "finer".
*/
public void finer(Throwable ex);
/**
* Log a method entry.
* <p>
* The logging is done using the <code>finer</code> level. The string message will start with
* <code>"ENTRY"</code> and include the class and method names.
*
* @param sourceClass Name of class that issued the logging request.
* @param sourceMethod Name of the method that issued the logging request.
*/
public void entering(String sourceClass, String sourceMethod);
/**
* Log a method return.
* <p>
* The logging is done using the <code>finer</code> level. The string message will start with
* <code>"RETURN"</code> and include the class and method names.
*
* @param sourceClass Name of class that issued the logging request.
* @param sourceMethod Name of the method that issued the logging request.
*/
public void exiting(String sourceClass, String sourceMethod);
/**
* Log throwing an exception.
* <p>
* Use to log that a method is terminating by throwing an exception. The logging is done using the
* <code>finer</code> level.
* <p>
* This is a convenience method that could be done instead by calling
* {@link #finer(String, Throwable)}. The string message will start with <code>"THROW"</code> and
* include the class and method names.
*
* @param sourceClass Name of class that issued the logging request.
* @param sourceMethod Name of the method that issued the logging request.
* @param thrown The Throwable that is being thrown.
*/
public void throwing(String sourceClass, String sourceMethod, Throwable thrown);
/**
* Returns true if "finest" log messages are enabled. Returns false if "finest" log messages are
* disabled.
*/
public boolean finestEnabled();
/**
* Writes both a message and exception to this writer. The message level is "finest".
*/
public void finest(String msg, Throwable ex);
/**
* Writes a message to this writer. The message level is "finest".
*/
public void finest(String msg);
/**
* Writes an exception to this writer. The exception level is "finest".
*/
public void finest(Throwable ex);
/**
* Returns a 1.4 logging handler that can be used to direct application output to this GemFire
* logger using the standard JDK logger APIs. Each time this method is called it creates a new
* instance of a Handler so care should be taken to not call this method too often.
*/
public Handler getHandler();
/**
* A mechanism for accessing the abstraction layer used for internationalization.
*
* @return LogWriterI18n
*/
public LogWriterI18n convertToLogWriterI18n();
}