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<document>
  <properties>
    <title>Upgrading from JCS 2.x to 3.0</title>
    <author email="tv@apache.org">Thomas Vandahl</author>
  </properties>

  <body>
    <section name="Upgrading from JCS 2.x to 3.0">
      <p>
        This document lists a number of things that changed in Commons JCS 
        3.0. 
      </p>
      <subsection name="Package Names and Maven Coordinates">
        <p>
          The Apache Commons project requires a change of the package names 
          and Maven coordinates on a major release.
          So in all your code replace
        <source><![CDATA[
import org.apache.commons.jcs.*;
]]></source>
          with
        <source><![CDATA[
import org.apache.commons.jcs3.*;
]]></source>
          The Maven coordinates change from
        <source><![CDATA[
<dependency>
    <groupId>org.apache.jcs</groupId>
    <artifactId>jcs</artifactId>
    <version>1.3</version>
</dependency>
]]></source>
          to
        <source><![CDATA[
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-jcs3-core</artifactId>
    <version>3.0</version>
</dependency>
]]></source>
        </p>
      </subsection>
      <subsection name="Adjusting the Configuration">
        <p>
          Here again, change all package names in configuration entries
          from e.g.
        <source><![CDATA[
jcs.default.cacheattributes=org.apache.commons.jcs.engine.CompositeCacheAttributes
]]></source>
          to
        <source><![CDATA[
jcs.default.cacheattributes=org.apache.commons.jcs3.engine.CompositeCacheAttributes
]]></source>
        </p>
      </subsection>
      <subsection name="Logging Abstraction">
        <p>
          JCS 3.0 uses its own log abstraction layer. As newer and better
          log systems become available, JCS is no longer limited to 
          commons-logging. As a result, JCS now uses java.util.logging as
          default and does not depend on commons-logging anymore.
         </p>
         <p>
           Optionally, JCS can use Log4j2 as a log system. You can activate 
           it by providing log4j.core as a dependency, a log configuration
           such as log4j2.xml and a system property
          <source><![CDATA[
-Djcs.logSystem=log4j2
]]></source>
           As log initialization occurs very early in the startup process,
           be sure to add this property before accessing any of JCS' classes.
        </p>
        <p>
           JCS uses the Java SPI mechanism to find its log systems. If you want
           to roll your own, you will need to implement a 
           <code>org.apache.commons.jcs.log.Log</code> object and a 
           <code>org.apache.commons.jcs.log.LogFactory</code>
           and provide the implementation class in a text file 
           <code>META-INF/services/org.apache.commons.jcs.log.LogFactory</code>
           in your code. Choose a name for your log system and activate it via 
           the system property as described above.
        </p>
      </subsection>
    </section>
  </body>
</document>