Difference between revisions of "EclipseLink/Examples/Foundation/Logging"

Latest revision as of 20:56, 9 November 2011

How do I integrate with a third party logging framework

EclipseLink's default logging is based on Java (1.4 an higher) java.util.logging but is also extensible to allow other logging frameworks to be used.

This how-to example will illustrate how other logging solutions such as Log4J and Apache common logging can be easily used with EclipseLink.

References

How to configure a custom logger in JPA

Logging Extension Basics

Customizing EclipseLink to use another logging framework or integrate with an existing logging infrastructure involves:

1. Implementing your own SessionLog
2. Configuring the use of your SessionLog

Using Log4J

Two bug reports exist for that point :

1. : apache commons logging & log4J integration
2. : documentation

The first deals about apache commons Logging 1.1 & Log4J integration with eclipseLink 1.x and the second about Log4J integration only.

Both propose custom implementations for the abstract SessionLog class.

How to use Log4J :

- add apache commons logging 1.1 & log4J libraries in your classpath

- add the sample log4.xml in your classpath : log4j.xml template

- add the following classes in the org.eclipse.persistence.logging package of your own project : CommonsLoggingSessionLog class : FastLogFormatter class

- add the property eclipselink.logging.logger to your persistence.xml :

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" 
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
      xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
      http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

    <persistence-unit name="myPersistenceUnit" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <properties>            
            <!-- custom SessionLog implementation to use apache commons logging 1.1 API (so log4J) -->
            <property name="eclipselink.logging.logger" value="org.eclipse.persistence.logging.CommonsLoggingSessionLog"/>
        </properties>
...
...
    </persistence-unit>
</persistence>


<property name="eclipselink.logging.logger" value="org.eclipse.persistence.logging.CommonsLoggingSessionLog"/>

- Compile & deploy your code : that's done.

About log4J levels & eclipselink log levels :

Altough the log4j.xml defines a log4J level for the 'org.eclipse.persistence' logger, the CommonsLoggingSessionLog overrides that level at runtime to be compatible with the chosen eclipselink.logging.level :

For example, in log4j.xml :

  <logger name="org.eclipse.persistence">
    <level value="info"/>
  </logger>

- add the property eclipselink.logging.level to your persistence.xml :

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" 
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
      xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
      http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

    <persistence-unit name="myPersistenceUnit" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <properties>            
            <!--
            # -----------------------------------------------------------------------------
            # Logging level :
            #        OFF \u2013 disables logging
            #        SEVERE \u2013 logs exceptions indicating EclipseLink cannot continue, as well as any exceptions generated during login. This includes a stack trace.
            #        WARNING \u2013 logs exceptions that do not force EclipseLink to stop, including all exceptions not logged with severe level. This does not include a stack trace.
            #        INFO \u2013 logs the login/logout per sever session, including the user name. After acquiring the session, detailed information is logged.
            #        CONFIG \u2013 logs only login, JDBC connection, and database information.
            #        FINE \u2013 logs SQL.
            #        FINER \u2013 similar to warning. Includes stack trace.
            #        FINEST \u2013 includes additional low level information. 
            #
            # -----------------------------------------------------------------------------
            -->
            <property name="eclipselink.logging.level" value="severe" />
            <!-- custom SessionLog implementation to use apache commons logging 1.1 API (so log4J) -->
            <property name="eclipselink.logging.logger" value="org.eclipse.persistence.logging.CommonsLoggingSessionLog"/>
        </properties>
...
...
    </persistence-unit>
</persistence>

However, you should check that your root logger and appenders are well defined to produce log outputs (console, files or whatever appender ...)

Change Log levels at runtime : As you may not know, log4J levels can be changed at runtime for debug purposes : see the CommonsLoggingSessionLog#setLevel() method :

    /**
     * PUBLIC:  Set the log level to a logger with name space extracted from the given category.
     *
     * @param level value according to the java.util.logging.Levels
     * @param category category
     */
    @Override
    public final void setLevel(final int level, final String category)

Using Apache Commons Logging

An eclipselink bug report exists : : apache commons Logging 1.1 & Log4J integration

It deals about apache commons Logging 1.1 & Log4J integration with eclipseLink 1.x.

To use Apache Commons Logging without Apache Log4J, you can get inspired by this class : : CommonsLoggingSessionLog class

Just remove any reference to org.apache.log4j classes ...

Please contribute to eclipselink then.

References

• http://wiki.eclipse.org/EclipseLink/Examples/JPA/CustomLogger
• http://bugs.eclipse.org/247852