buildtime bytecode instrumentation for lazy loading

madchen · **Joined:** Tue Jul 20, 2010 6:20 pm **Posts:** 1

Hi, I'm trying to implement lazy property loading, but according to the documentation, I need to buildtime bytecode instrumentation.

I've tried multiple tutorials on it from around the internet and can't seem to get it to work. I've tried using Ant Tasks and Maven Pom, but I couldn't get either. I'm guessing that I'm missing something simple, but if someone could help me out, that would be great. Thanks!

hallmit · **Posted:** Wed Jul 21, 2010 4:45 am

buildtime bytecode instrumentation is only required if you want use lazy loading for basic properties (String, byte[], etc).

for lazy loading associations just use fetch plan in your mapping e.g: @OneToOne(fetch = FetchType.LAZY)

for lazy loading basic properties: @Basic(fetch = FetchType.LAZY) and enhance your entities with Ant task like:

Code:

<project name="enhance" basedir="." default="instrument">
   <property name="root_dir" value="/libraries" />

   <path id="compilation.classpath.id">
      <fileset dir="${root_dir}/hibernate">
         <include name="*.jar" />
      </fileset>
      <fileset dir="${root_dir}/javassist">
         <include name="*.jar" />
      </fileset>
      <fileset dir="${root_dir}/slf4j">
         <include name="*.jar" />
      </fileset>
      <fileset dir="${root_dir}/log4j">
         <include name="*.jar" />
      </fileset>
   </path>

   <target name="instrument">
      <taskdef name="hibernateinstrument" classname="org.hibernate.tool.instrument.javassist.InstrumentTask">
         <classpath>
            <path refid="compilation.classpath.id" />
            <pathelement path="bin" />
         </classpath>
      </taskdef>
      <hibernateinstrument verbose="true">
         <fileset dir="bin">
            <include name="**/*.class" />
         </fileset>
      </hibernateinstrument>
   </target>
</project>