Programmatically handling the Entity Objects in Oracle ADF

Entity Object is n object oriented representation of data base objects like table. It represents a table or view. It encapsulates the properties of a Row like the validation rules, security and presenting values. It is used to perform all the DML operations.

Files related to Entity Object

1. Entity definition XML file- Defines the structure of  the entity object. It acts as a template for the creation of entity objects.
2. Entity Object class - It represents an entity instance. It wraps the business logic for a row like having default values at the time of row creation, lock() method to lock the row and doDML() method to perform DML operations.
3. Entity Collection Class- Caches the rows particular to a DB transaction.

Use the below code to create the entity rows. You can have it in the Application module implementation classes.

Creating a new entity row

public void createEntityObject(){

EntityDefImpl sampleEODef=sampleEOImpl.getDefinitionObject();//Here get the definition object using the EOImpl like EntityImpl

SampleEOImpl newEOInstance=sampleEODef.createInstance2(this.getDBTransaction(), null);

//The entity status is STATUS_NEW now and qualifies to participate in a transaction.

//Use the newEOInstance object to set the attribute values.

}

Finding an entity row and updating it

public void updateEntity(String primaryKey){

//Key creation by passing the primary key

Key key= SampleEOImpl.createPrimaryKey(primaryKey);

//get the definition object

//The row status here is STATUS_UNMODIFIED now

EntityEOImpl rowTobeUpdated =

(DepartmentEOImpl)SampleEOImpl.

getDefinitionObject().

findByPrimaryKey(getDBTransaction(), key);

rowTobeUpdated .setAttributes()

//The row status here is STATUS_MODIFIED and qualifies for row the transaction.

}

Removing an entity row

The below method takes a key attribute value in a row as input and performs find and delete operations.

public void removeEntity(Integer key){

            //Key creation by passing the key

            Key key= SampleEOImpl.createPrimaryKey(key);

            EntityEOImpl rowTobeDelted =

             (SampleEOImpl)SampleEOImpl.

             getDefinitionObject().

            findByPrimaryKey(getDBTransaction(), key);

           //Row status is STATUS_UNMODIFIED

           rowTobeDelted.remove();

          //Row status is STATUS_DELETED

 }

Committing a transaction

     public void commitTransaction(){

       getDBTransaction().commit();

      }