Tuesday, April 14, 2009

OpenJPA Enhancement Eclipse Builder

As I wrote about in a previous blog post, enhancement is HIGHLY recommended when developing an application that uses OpenJPA. The OpenJPA community has been vigilant about trying to cover every enhancement scenario, but after my last posting a reader brought up new somewhat uncovered situation. I say somewhat, because I'm sure the user could have enhanced using one of the existing methods, but it would not have been pretty. My understanding is that they are using Eclipse WTP to write and deploy their application, and orm.xml to map their Entities. We have the first two variants covered with an Eclipse plugin, but the third is something that we have not addressed. I did some research and found that creating a custom Ant builder may be the perfect fit. This builder will be executed by Eclipse after compilation has completed. Below I've documented the steps required to create an Ant builder that will enhance your Entities after each compile.

Please contact me with any questions/comments.


For steps documented below, I have the following directory structure. Note, these steps must be followed for each project that has Entities that need to be enhanced.
enhance.xml <- the OpenJPA builder.... download here.
/bin <- Compile directory
/src <- Source directory
/jpa_lib <- OpenJPA binary and all jars from the lib dir of the binary download
/lib <- other libs

  1. After you add the enhance.xml file to your file system, make sure to refresh your Eclipse workspace so it knows about the newly added file. Make sure that the enhance.xml file is listed in the Navigator view.
  2. Right click on the Eclipse project that you want to enhance and click on properties.
  3. Click on the builders filter, and create a new Ant builder.
  4. Name your builder, then click on "Browse Workspace" in the buildfile box. If you downloaded the enhance.xml file and refreshed your workspace, it should be listed there. If not, go back to step 1 and make sure that Eclipse detects your enhance.xml file.
  5. In the "Base Directory" box, click on the variables button and select build_project. This should refer to the root of your project. In the directory structure above, it refers to "builder_project".
  6. In the "Arguments" box you need to add the following properties -Dopenjpa.libs and -Dbuild.dir. -Dopenjpa.libs is the path to the OpenJPA libs, relative to the root of the project. -Dbuild.dir is the path to the build directory, relative to the root of the project. In the directory structure above, openjpa.libs should be set to jpa_lib and build.dir should be set to bin.
  7. Click on the "Targets" tab along the top.
  8. You need to set the enhance target to run as a part of "Manual Build" and "Auto Build".


[1]http://filebin.ca/zbfbg/enhance.xml -- enhance.xml
[2]http://filebin.ca/aayeg/navigator.png -- Navigator pane
[3]http://filebin.ca/cznvmv/main.png -- Edit builder configuration - main
[4]http://filebin.ca/fqnadv/targets.png -- Edit builder configuration - targets


shikida said...

the screenshots are broken :-(

shikida said...

try imageshack :-)

Rick Curtis said...

I'll try to see if I can find those screenshots and reupload them somewhere else. Sorry about that.

Patrick Co Eban said...

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