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Texo/EntityManagerObjectStore
Contents
Introduction
The Texo ObjectStore concept integrates the model layer with JPA. It provides the following functionality:
- It makes it possible to query using an EClass
- Supports cross reference queries
- Supports (de-)serialization with (de-)resolving of references in the XML/XMI against the ObjectStore (the database)
Jar files/Plugins
The Texo Object Store is defined in the org.eclipse.emf.texo.server plugin which is part of the Texo runtime feature (see Download & Install).
Creating an Object Store
An Object Store instance can be created directly if you have an EntityManager available:
EntityManagerObjectStore objectStore = new EntityManagerObjectStore(); objectStore.setEntityManager(entityManager); // the URI is used for de-resolving references when serializing to XML, see below objectStore.setUri("http://jpa.test");
Cross Reference Queries
The ObjectStore allows you to retrieve all the objects which reference a certain target object:
In a later version the cross-reference api will be extended to only query for non-contained references.
(De-)Serializing XML with correct id's
When (de-)serializing XML most of the time the references to other objects should be serialized as external references (the referenced object is not present in the XML). When de-serializing the XML these references should be correctly resolved to objects again. This resolving needs to be able to read the objects from the database again.
This (de-)resolving of references while reading from the database is done using the ObjectStore.