Eclipse provides a powerful development environment for Java systems. DataNucleus provides
its own plugin for use within Eclipse, giving access to many features of DataNucleus from the
convenience of your development environment.
The DataNucleus plugin requires Eclipse 3.1 or above. To obtain and install the
DataNucleus Eclipse plugin select
Help -> Software Updates -> Find and Install
On the panel that pops up select
Search for new features to install
Select
New Remote Site
, and in that new window set the URL as
http://www.datanucleus.org/downloads/eclipse-update/
and the name as DataNucleus.
Now select the site it has added "DataNucleus", and click "Finish".
This will then find the releases of the DataNucleus plugin.
Select the latest version of the DataNucleus Eclipse plugin
.
Eclipse then downloads and installs the plugin. Easy!
The DataNucleus Eclipse plugin allows saving of preferences so that you get nice defaults
for all subsequent usage. You can set the preferences at two levels :-
-
Globally for the Plugin
: Go to
Window -> Preferences -> DataNucleus Eclipse Plugin
and see the options below that
-
For a Project
: Go to
{your project} -> Properties -> DataNucleus Eclipse Plugin
and select "Enable project-specific properties"
Firstly open the main plugin preferences page and configure the libraries needed by
DataNucleus. These are in addition to whatever you already have in your projects
CLASSPATH, but to run the DataNucleus Enhancer you will require ASM/BCEL (depending
which you are using), JDO (but you'll likely have this in your project CLASSPATH),
DataNucleus Core/Enhancer/RDBMS jars, as well as LOG4J, and your JDBC driver
(if using RDBMS). Below this you can set the location of a configuration file for
Log4j to use.
This is useful when you want to debug the Enhancer/SchemaTool operations.
Open the "Enhancer" page. You have the following settings
-
Input file extensions
: the enhancer accepts input defining the classes to
be enhanced. This is typically performed by passing in the JDO MetaData files.
When you use annotations you need to pass in
class
files. So you select
the suffices you need
-
Verbose
: selecting this means you get much more output from the enhancer
-
Persistence API
: DataNucleus supports JDO and JPA
-
ClassEnhancer
: DataNucleus provides an enhancer using ASM.
Open the "SchemaTool" page. You have the following settings
-
Input file extensions
: SchemaTool accepts input defining the classes to
have their schema generated. This is typically performed by passing in the JDO
MetaData files. When you use annotations you need to pass in
class
files.
So you select the suffices you need
-
Verbose
: selecting this means you get much more output from SchemaTool
-
Persistence API
: DataNucleus supports JDO and JPA
-
Datastore details
: You can either specify the location of a properties
file defining the location of your datastore, or you supply the driver name, URL,
username and password.
First thing to note is that the DataNucleus plugin is for Eclipse "Java project"s only.
After having configured the plugin you can now add DataNucleus support on your projects.
Simply right-click on your project and select
DataNucleus->"Add DataNucleus Support"
from the context menu.
It is standard practice to define the MetaData for your persistable classes in the same
package as these classes. You now define your MetaData, by right-click on a package in
your project and select "Create JDO 2.0 Metadata File" from DataNucleus context menu.
The dialog prompts for the file name to be used and creates a basic Metadata file for all
classes in this package, which can now be adapted to your needs. You can also perform same
steps as above on a *.java file, which will create the metadata for the selected file
only. Please note that the wizard will overwrite existing files without further notice.
You can also use the DataNucleus plugin to generate a "persistence.xml" file adding all
classes into a single
persistence-unit
. You do this by right-clicking on
your project, and selecting the option. The "persistence.xml" is generated under
META-INF for the source folder.
Please note that the wizard will overwrite existing files without further notice.
The DataNucleus Eclipse plugin allows you to easily byte-code enhance your classes using
the DataNucleus enhancer. Right-click on your project and select "Enable Auto-Enhancement"
from the DataNucleus context menu. Now that you have the enhancer set up you can enable
enhancement of your classes. The DataNucleus Eclipse plugin currently works by
enabling/disabling automatic enhancement as a follow on process for the Eclipse build
step. This means that when you enable it, every time Eclipse builds your classes it will
then enhance the classes defined by the available "jdo" MetaData files. Thereafter every
time that you build your classes the JDO enabled ones will be enhanced. Easy! Messages
from the enhancement process will be written to the Eclipse Console.
Make sure that you have your Java files in a source folder, and that the binary class
files are written elsewhere
If everything is set-up right, you should see the output below.
Once your classes have been enhanced you are in a position to create the database schema
(assuming you will be using a new schema - omit this step if you already have your schema).
Click on the project under "Package Explorer" and under "DataNucleus" there is an option
"Run Schema Tool". This brings up a panel to define your database location (URL, login,
password etc). You enter these details and the schema will be generated.
Messages from the SchemaTool process will be written to the Eclipse Console.
