| Modules | General purpose | OSGi integration |
|---|---|---|
| Model | Implements the data model | Fragment Host: org.neo4j.ogm-core |
| API | Contract definition | |
| Impl | Contract implementation (incl. DB session init) | Provide a service |
| Client | Fetch existing data from store at startup | Consume the service |
| Command | CLI based CRUD operations | Consume the service |
| Feature | Generate deployment description (DD) | Launch the project within the OSGi-ecosystem Apache Karaf |
| ITest | Validate integrity of deployment description | Launch the application in different OSGi-Runtime implementations Equinox / Apache Felix |
The binding of the application model and Neo4j-OGM in an OSGi environment gets negotiated using the fragment host declaration.
Fragment Host: org.neo4j.ogm-osgi
The attribute fragment-host has to get defined in the model`s bundle configuration. A respective entry gets generates in the bundles MANIFEST.MF file in the build phase.
The class DomainInfo, part of Neo4j-OGM's core module, is responsible for scanning domain objects. The configuration requires one or more package names in which domain objects get defined.
In this demo only one package hosts domain objects; its org.neo4j.ogm.demo.osgi.model.
Status - (Fully working)
Status - (Fully working)
Note: Apache Felix works out of the box. Despite a minor issue with fragment-bundles, more precise fragment-hosts will not get refreshed when you start Apache Karaf for a second time, and bundles are in the cache, see the build instruction for Apache Felix.
Requirements: Apache Karaf, Neo4j-Desktop
Follow the installation and setup instructions provided on the Apache Karaf's website.
Apache Karaf's default OSGi runtime setting is Apache Felix. To switch Apache Felix in favor for Equinox change the configuration as follows.
-
Go to the /etc folder, located relative to your Apache Karaf installation
-
Modify file config.properties file and set the value of property karaf.framework set to equinox
karaf.framework=equinox
Follow the installation and setup instructions provided on the Neo4j's website.
-
Start the Neo4j desktop application
-
Add a new local graph store
Add Database => Create a local Graph => Set password neo4jPWD
- Start the database created store
mvn -s settings.xml clean install
mvn -s settings.xml clean install -P felix
To get all project artifacts necessary, two options are available.
- Configure Apache Karaf to use remote maven repositories which host the build artifacts
1.1 Install Apache Karaf's maven feature
feature:install maven
1.2 Add relevant maven repositories to Apache Karaf's settings
Neo4j-Java-Driver - (OSGi compatible runtime dependencies)
maven:repository-add -idx 0 -id neo4j-java-driver.repository --snapshots https://gitlab.com/api/v4/projects/18622687/packages/maven
Neo4j-OGM - (OSGi compatible runtime dependencies)
maven:repository-add -idx 1 -id neo4j-ogm.repository --snapshots https://gitlab.com/api/v4/projects/18591736/packages/maven
Fragment Bundle Refresh - (OSGi runtime dependency, optional - Relevant only for Apache Felix relevant)
maven:repository-add -idx 2 -id osgi-helper.repository --snapshots https://gitlab.com/api/v4/projects/18953434/packages/maven
Neo4j-OGM-Demo
maven:repository-add -idx 3 -id neo4j-ogm.demo.repository --snapshots https://gitlab.com/api/v4/projects/18785831/packages/maven
- Add the projects feature repository
repo-add mvn:org.neo4j/neo4j-ogm-demo-osgi-feature/1.0.0/xml/features
- Install the feature
feature:install neo4j-ogm-demo-osgi-feature
-
Follow the build instructions
-
Add the projects feature repository
repo-add file:${placeholder-replace-with-absolute-path-to-project}/neo4j-ogm-demo-osgi/demo-feature/target/feature/feature.xml
- Install the feature
feature:install neo4j-ogm-demo-osgi-feature
Session configuration gets handled in an OSGi agnostic manner, meaning the OSGi configuration methodology gets used to serve configuration to the application.
To adjust the configuration, edit the session.config file located in the resource folder of module demo-feature. Making the adjustments effective requires a rebuild of the application, see build instructions.
The application uses the operation variant "bolt"; only the respective configuration options are described.
username="neo4j"
password="neo4jPWD"
uri="bolt://localhost:7687"
domain.packages=[ \
"org.neo4j.ogm.demo.osgi.model", \
"org.neo4j.ogm.demo.osgi.model.second", \
]
The Neo4j-OGM provides much more configuration options than those mentioned here. Only the options mentioned in the example above for driver and domain object model are supported, yet.
As mentioned in the configuration, the OSGi configuration methodology gets used to delegate configuration to the Neo4j OGM SessionFactory. The delegation approach followed introduces repetitive variable declarations for configuration options see module neo4j-ogm-osgi OGMSessionConfig
More information about supported configuration methods and the respective options can be found in the configuration wiki entry.
After installing the feature neo4j-ogm-demo-osgi-feature, the application starts; the client prints existing objects in the data store persisted from a previous session.
The demo application provides several CLI commands to execute CRUD operations against the data-store.
More information about available commands and the respective options can be found in the commands wiki entry.