4.9. OSGi配置

在 OSGi 关联的上下文比如大量的应用服务器（e.g. Glassfish ）和基于 Eclipse 的系统中，Neo4j能被明确地建立起来而不是通过Java服务加载机制来发现。

4.9.1. Simple OSGi Activator 脚本

如同在下面的范例中看到的一样，为了代替依赖Neo4j内核的类加载，Neo4j Bundle被作为库 bundles，而像 IndexProviders 和 CacheProviders 这样的服务被明确地实例化，配置和注册了秩序。只需要确保必要的jars，所以所有必须的类都被导出并且包括这Activator。

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public class Neo4jActivator implements BundleActivator {

    private static GraphDatabaseService db;
    private ServiceRegistration serviceRegistration;
    private ServiceRegistration indexServiceRegistration;

    @Override
    public void start( BundleContext context ) throws Exception
    {
        //the cache providers
        ArrayList<CacheProvider> cacheList = new ArrayList<CacheProvider>();
        cacheList.add( new SoftCacheProvider() );

        //the index providers
        IndexProvider lucene = new LuceneIndexProvider();
        ArrayList<IndexProvider> provs = new ArrayList<IndexProvider>();
        provs.add( lucene );
        ListIndexIterable providers = new ListIndexIterable();
        providers.setIndexProviders( provs );

        //the database setup
        GraphDatabaseFactory gdbf = new GraphDatabaseFactory();
        gdbf.setIndexProviders( providers );
        gdbf.setCacheProviders( cacheList );
        db = gdbf.newEmbeddedDatabase( "target/db" );

        //the OSGi registration
        serviceRegistration = context.registerService(
                GraphDatabaseService.class.getName(), db, new Hashtable<String,String>() );
        System.out.println( "registered " + serviceRegistration.getReference() );
        indexServiceRegistration = context.registerService(
                Index.class.getName(), db.index().forNodes( "nodes" ),
                new Hashtable<String,String>() );
        Transaction tx = db.beginTx();
        try
        {
            Node firstNode = db.createNode();
            Node secondNode = db.createNode();
            Relationship relationship = firstNode.createRelationshipTo(
                    secondNode, DynamicRelationshipType.withName( "KNOWS" ) );

            firstNode.setProperty( "message", "Hello, " );
            secondNode.setProperty( "message", "world!" );
            relationship.setProperty( "message", "brave Neo4j " );
            db.index().forNodes( "nodes" ).add( firstNode, "message", "Hello" );
            tx.success();
        }
        catch ( Exception e )
        {
            e.printStackTrace();
            throw new RuntimeException( e );
        }
        finally
        {
            tx.finish();
        }

    }

    @Override
    public void stop( BundleContext context ) throws Exception
    {
        serviceRegistration.unregister();
        indexServiceRegistration.unregister();
        db.shutdown();

    }

}