Package org.ujoframework.orm

The ORM support.

See:
Description

Interface Summary

OrmUjo

The OrmUjo is a basic interface of the persistent object in this ORM-UJO module.

Class Summary

AbstractMetaModel	Abstract Metamodel
CriterionDecoder	SQL Criterion Decoder.
JdbcStatement	JdbcStatement
OrmHandler	The basic class for an ORM support.
Query<UJO extends OrmUjo>	ORM query.
Session	The ORM session.
SqlDialect	SQL dialect abstract class.
TypeBook	A book of popular Java types.
UjoSequencer	The default sequence provider.
UniqueKey	A Unique key of a table

Enum Summary

DbType

Supported DbTypes

Package org.ujoframework.orm Description

The ORM support.

ORM module of the UJO Framework

a new implementation of the object-relation mapping

Why a new ORM mapping?

• framework has a type safe query language which allows the java compiler find a syntax error similar like a 4GL language
• never more a LazyInitialization exception though a lazy initialization is supported
• no confusing proxy business objects
• no list properties are supported but a special object called UjoIterator is designed for a collection. The UjoIterator provides a toList() method however
• easy to configure the ORM model by java source code, optionaly by annotations or a XML file
• very small framework without more library dependencies, the current size of the JAR file is around 160 kB
• great performance mainly for the SQL SELECT statement

Some other features:

• all persistent objects are based on the OrmUjo interface, namely on the OrmTable implementation
• resources for ORM mapping can be a database table, view, or your own SQL SELECT
• default ORM mapping is described by UjoProperties however there is possible overwrite the mapping by annotations and the annotations can be overwrited by a XML files
• JDBC query parameters are passed by a question notation to the PreparedStatement for a high security
• internal object cache is based on the WeakHashMap class so that large transactions does not cause any OutOfMemoryException
• the API was inspired by a Cayenne and Hibernate ORM frameworks

Note: the current release is an early BETA release with the support of CREATE TABLE, INSERT, SELECT, UPDATE, DELETE statements.

A sample of use

See how to create database and to how to INSERT an order with two items into database:

  OrmHandler.getInstance().loadDatabase(Database.class);

  Order order = new Order();
  order.setDate(new Date());
  order.setDescr("John's order");

  Item item1 = new Item();
  item1.setOrder(order);
  item1.setDescr("Yellow table");

  Item item2 = new Item();
  item2.setOrder(order);
  item2.setDescr("Green window");

  Session session = OrmHandler.getInstance().getSession();
  session.save(order);
  session.save(item1);
  session.save(item2);

  session.commit();

The next source code calls a SELECT by the UJO Criteria:

  Criterion<Order> criter1 = Criterion.newInstance(Order.DESCR, "John's order");
  Criterion<Order> criter2 = Criterion.newInstance(Order.DATE, Operator.LE, new Date());
  Criterion<Order> criterion = criter1.and(criter2);

  Session session = OrmHandler.getInstance().getSession();
  UjoIterator<Order> orders = session.createQuery(criterion).iterate();
  System.out.println("ORDER COUNT: " + orders.count()); // method calls SQL SELECT COUNT(*) in case the iterator can provide first item!

  for (Order order : orders) {
      String descr = order.getDescr();
      System.out.println("ORDER ROW: " + order + " // descr: " + descr);
  }

The next source code calls a SELECT by an UJO object relation:

  Session session = OrmHandler.getInstance().getSession();
  Database db = session.getDatabase();
  UjoIterator<Order> orders = db.get(Database.ORDERS);

  for (Order order : orders) {
      String descr = order.getDescr();
      System.out.println("Order: " + order + " // descr: " + descr);

      for (Item item : order.getItems()) {
          Long itemId = item.getId();
          String itemDescr = item.getDescr();
          System.out.println(" Item id: " + itemId + " descr: " + itemDescr);
      }
  }

More sources:

• Order - Java source of the Order business object
• Item - Java source of the Item business object
• Database - Java source of a database description of a metamodel
• View - Use of a native SQL query
• Sample - short preview of the ORM using, the code is ready for immediate launch inside the project.
• ORM project sources
• XML configuration file - sample
• JavaDoc stable version
• UJO quick start (a slide show)

License:

• UJO Framework has a license Apache License, Version 2.0
• no more dependences