Grails Constraints with Java Classes and Hibernate Mappings - grails

Question

I have the following Java class defined in src/java
package org.davisworld.trip;
public class AirportHbm {
private long id;
private String name;
private String iata;
private String state;
private String lat;
private String lng;
// getters/setters defined
}
I have the hbm.cfg.xml file defined as follows in conf/hibernate:
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<mapping resource="AirportHbm.hbm.xml"/>
</session-factory>
</hibernate-configuration>
I have the AirportHbm.hbm.xml file configured as follows in conf/hibernate:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="org.davisworld.trip.AirportHbm" table="usgs_airports">
<id name="id" column="airport_id">
<generator class="native"/>
</id>
<property name="name" type="java.lang.String">
<column name="airport_name" not-null="true" />
</property>
<property name="iata" type="java.lang.String">
<column name="locid" not-null="true" />
</property>
<property name="state" />
<property name="lat" column="latitude" />
<property name="lng" column="longitude" />
</class>
</hibernate-mapping>
And lastly, I have an AirportHbmConstraints.groovy file in the src/java folder:
package org.davisworld.trip
class AirportHbmConstraints {
static constraints = {
name()
iata(maxSize:3)
state(maxSize:2)
lat()
lng()
}
}
When I try to run the app, I get this error when Spring is initializing the web app context:
Caused by: java.lang.ClassCastException: org.davisworld.trip.AirportHbmConstraints cannot be cast to groovy.lang.Script
The tutorial I was following originally said that the AirportHbmConstraints.groovy file shouldn't have a class; it should just be a script:
package org.davisworld.trip
static constraints = {
name()
iata(maxSize:3)
state(maxSize:2)
lat()
lng()
}
But when I do that, STS gives me a compiler error:
Groovy:Modifier 'static' not allowed here.
Anyone know what I'm doing wrong? What is the correct way to apply constraints in Groovy to a Java domain class?
Many thanks,
Vito

Answer 1

When using constraints scripts with a Hibernate domain you do not use a class declaration or the static modifier as explained in section 15.3 Adding Constraints of the Grails documentation.
The correct constraint script would be:
constraints = {
iata maxSize: 3
state maxSize: 2
}
Note that fields without a constraint and the parentheses on the field declaration are optional.