Creating the Implementation Class

There is very little that needs to be done by application developers to create a basic business entity. In addition to the setup of the CI_MD_* tables describing the entity and its constraints, only an implementation class (or Impl) needs to be added. In this case, a developer added Person_Impl. The following is a simple example of an Impl class for the Person entity. 


			/**
			 * @BusinessEntity
			 *   (tableName = CI_PER,
			 *    oneToManyCollections  = { @Child( collectionName = names,
			 *                                 childTableName = CI_PER_NAME,
			 *                                 orderByColumnNames = { SEQ_NUM } )
			 *                            }
			 *   )
			 */
			public class Person_Impl
			    extends Person_Gen {
			    /**
			     * @return the UI Display "info" for this person
			     */
			    public String getInfo() {
			        return "PrimaryName: " + getPrimaryName().getInfo();
			    }
			}

Important parts of the implementation class are described below:

  • The implementation class name must end with the suffix _Impl. For example, if the entity has a person name, then the implementation class name would be some.package.Person_Impl. This also means that the generated business interface will be named as some.package.Person.
  • A Class Annotation which declares:
    • What table this entity represents.
    • What the owned-child tables are and what they should be called.
    • Other information. Please see the BusinessEntityAnnotation class for more details.
  • The class extends an abstract superclass having the suffix of _Gen. Continuing the example of an entity with a person name, the implementation class would extend a not-yet-created abstract superclass named some.package.Person_Gen. This superclass is created by the artifact generator based on metadata about the table and contains:
    • Getter methods for properties, including parent objects and collections.
    • The getDTO() and setDTO(...) methods that allow for properties to be changed.
    • Access to standard framework methods like createQuery(...).
  • Business methods. Any hand-coded public methods are automatically exported onto the generated business interface (for example, some.package.Person). Client code can then access the added business method as follows:

			 Person aPerson = some logic retrieving a person instance
			 String thePersonsInfo = aPerson.getInfo();
  • Constants. Any hand-coded public static final variables are automatically exported onto the generated business interface. This will be useful for constants related to the entity.
  • Having created a new entity, it is likely that validation rules and other behaviors should be added to it. See Adding Change Handlers for more information.