How to get the DiscriminatorValue at run time

Question

We have the following classes

@Entity @Inheritance(strategy = InheritanceType.SINGLE_TABLE) // optional annotation as this is default @DiscriminatorColumn(name = "apType", discriminatorType = DiscriminatorType.STRING, length = 255) @DiscriminatorValue("AP") public class ApplicationProcess { } 

And this

@Entity @DiscriminatorValue("APS") public class ApplicationProcessScheme extends ApplicationProcess { } 

Now I need to know at runtime if the ApplicationProcess is of DiscriminatorValue AP or APS. Since this is automatically handled by jpa, I have no way of getting this value.

We are calling a method that takes an ApplicationProcess as parameter, and I want to avoid using instanceof to check what type it is. Would be cooler if I could do something like

applicationProcess.getApType().equals("AP"); 

Answer 1

You can map your discriminator as a read-only property:

public class ApplicationProcess {       ...      @Column(name = "apType", insertable = false, updatable = false)     private String apType;  } 

Answer 2

I can imagine few cases where it might be helpful, but despite the reason why you need this, you could create on your abstract class method like

@Transient public String getDiscriminatorValue(){     DiscriminatorValue val = this.getClass().getAnnotation( DiscriminatorValue.class );      return val == null ? null : val.value(); }