Making a domain non-persistent

In grails app, there might come scenarios where one need to create a non-persistent domain rather than creating a command obejct or POJO / POGO.

GORM comes with a handy static property mapWith which has default value GORM (which associates any domain with gorm persistence layer).
To make a domain non persistent set mapWith=”none”. For example, see Ticket domain below

public class Ticket {
    String id
    List<Long> productInstanceId
    static hasMany = [productInstanceId:Long]
    static mapWith = "none"
}

Advantages:-

1. Still behaves like a GORM Domain in most of the cases like Ticket domain above is still accessible by GrailsDomainClass
2. When using multiple database , still respects the convention over configuration policy.
3. supports scaffolding while same can’t be done for command objects.

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Also, at some point of time to check on a particular domain that what type of mapping it has, fetch the static property with domain class. For the domain above, it would be

Ticket.mapWith 

or

Ticket.class.mapWith

If doing a dynamic check then can find it with the help of DefaultGrailsDomainClass.

GrailsDomainClass domainClass = new DefaultGrailsDomainClass(Ticket.class)
domainClass.mappingStrategy