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Difference between revisions of "Texo/EntityManagerObjectStore"
Line 24: | Line 24: | ||
The ObjectStore allows you to retrieve all the objects which reference a certain target object: | The ObjectStore allows you to retrieve all the objects which reference a certain target object: | ||
− | <source lang="java"> | + | <source lang="java">// get maximum 3 referers and include containment referers |
− | + | List<Object> referers = objectStore.getReferingObjects(target, 3, true); | |
</source> | </source> | ||
− | + | See the ObjectStore getReferingObjects api and the isReferenced method. | |
== (De-)Serializing XML with correct id's == | == (De-)Serializing XML with correct id's == | ||
Line 34: | Line 34: | ||
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. | 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. | + | This (de-)resolving of references while reading from the database is done using the ObjectStore. It is quite simple: |
+ | <source lang="java">// serialize a set of objects to xml, use XMI (specified by the second parameter | ||
+ | String xml = objectStore.toXML(objects, true); | ||
+ | // and get it back | ||
+ | List<Object> objects = objectStore.fromXML(xml, true); | ||
+ | </source> |
Revision as of 17:17, 24 August 2011
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:
// get maximum 3 referers and include containment referers List<Object> referers = objectStore.getReferingObjects(target, 3, true);
See the ObjectStore getReferingObjects api and the isReferenced method.
(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. It is quite simple:
// serialize a set of objects to xml, use XMI (specified by the second parameter String xml = objectStore.toXML(objects, true); // and get it back List<Object> objects = objectStore.fromXML(xml, true);