How to use Object Type Converter
- by arun.x.sridharan(at)oracle.com
UseCase Description
A person form where in user will enter String which has to
be converted to Number while persisting.
From the User Interface we might be getting a String value which has to be
persisted in the database as a number in that scenario we can use converters to
map the java object which is of type String to its database value which is a
Number.
For example , there is a 'Person' table in database which is used to store
the user details passed from the User Interface. It has a 'Status' column which
is of the value Number. But from the User Interface String values
(Active/InActive) are passed . For persisting the user details we can use Object
type converter and provide the mappings for status column corresponding to the
String values.
Object type converter can be used if you wanted to have a mapping for a field
for example when departmentName on the entity was of String value and mapped to
dept_name field on the database table which is of the value NUMBER.
Implementation steps
Sample EJB API for setting the value of status on Person Entity as a
String
public void createPerson(String status,String firstName,String lastName)
{ Person person = new Person(); //
status will be set as a String value received from the User
Interface person.setStatus(status);
person.setFirstname(firstName);
person.setLastname(lastName); persistPerson(person);
}
In the sample code shown above status is passed as a String, this has to be
converted to Number. The String value obtained will be set on Person object and
persistPerson API will be called for creating a new person from the values
passed from the User Interface.
Steps to configure Object type converter: 1. Navigate to Person
Entity from persistence.xml and navigate to status field2. Click on
Conversion tab and select Converted check box3. Select Object Type Converter
radio button and set the Data Type Class to java.math.BigDecimal and Object Type
Class to java.lang.String4. Specify the conversion values for all the values
that can be passed from the user interface as shown below5. Set the Default
Object value
