Message domain class

The very first thing you need to do is create a domain class to represent messages so that they can be saved to the database. You saw how to create domain classes in Chapter 2. Go to the grails-app/domain/app directory and create a file called Message.groovy and then add the following code to this file:

package app
class Message {
String title
String detail
Date dateCreated
Date lastUpdated
static constraints = {
title( blank: false, size: 1..50 )
detail( blank: false )
dateCreated( nullable: true )
lastUpdated( nullable: true )
}
}

There is nothing in the above code that is unfamiliar. But let's have a recap anyway. You have created a Groovy class called Message with the following properties:

You have also specified that the title cannot be blank and must be between 1 and 50 characters in length; notice the use of a Groovy range here. The detail of the message cannot be blank and the dateCreated and lastUpdated properties can be null.