EclipseLink/Examples/OSGi/Equinox Byte Code Weaving
In EclipseLink 1.1.2 (Galileo) and above, EclipseLink JPA byte code weaving is supported in Equinox OSGi. Configuration is straight forward and the requirements on your JPA persistence unit bundle are minimal.
Byte code weaving support is implemented through two fragments: org.eclipse.persistence.jpa.equinox.weaving and org.eclipse.persistence.jpa.equinox. o.e.p.j.equinox.weaving is a fragment for the system bundle org.eclipse.osgi. Extending the system bundle is a special case in OSGi and such a fragment is called a framework extension. This extension make use of the Equinox AdaptorHook framework to hook into the byte code loading process and perform weaving when necessary. Configuring a framework extension is done using the standard OSGi osgi.framework.extensions property. This property needs to be declared either in your config.ini or on the commandline as:
o.e.p.j.equinox is a fragment for the org.eclipse.persistence.jpa bundle that registers byte code weavers for persistence units that require it. All that is necessary to enable this is to deploy it with your other bundles.
NOTE: This example does not address how to develop an EclipseLink OSGi application in Eclipse PDE. It covers how to configure a runtime environment that supports byte code weaving for EclipseLink JPA. See Developing EclipseLink OSGi in PDE to learn how to develop EclipseLink OSGi applications in Eclipse
- Create a root folder for the example, we'll refer to it as HOME.
- Download Equinox 3.5 to obtain the following bundles and place them in HOME\plugins.
- From the Equinox download page, download the launcher appropriate for your operating system. The launcher comes in two parts: a bundle and a native platform library. Copy both the launcher jar and native library folder to HOME\plugins.
- From an Eclipse 3.5 install's plugins folder copy the following bundle to HOME\plugins:
- Download the Apache Derby database bundle org.apache.derby from the Eclipse Orbit download page and place it in HOME\plugins. The Orbit bundle does not contain the client driver so we'll use an embedded database in this example.
- Download EclipseLink 1.1.2 (or above) and place the bundles into HOME\plugins
- Create the file config.ini in HOME\configuration with the contents:
osgi.bundles.defaultStartLevel=6 eclipse.ignoreApp=true osgi.noShutdown=true osgi.framework.extensions=org.eclipse.persistence.jpa.equinox.weaving osgi.bundles= \ org.eclipse.equinox.common@2:start, \ org.eclipse.update.configurator@3:start, \ javax.persistence@4:start, \ org.eclipse.persistence.jpa@5:start, \ org.eclipse.persistence.antlr, \ org.eclipse.persistence.asm, \ org.eclipse.persistence.core, \ org.eclipse.persistence.jpa.equinox, \ org.eclipse.persistence.example.equinox.weaving@start, \ org.apache.derby