Grails on Groovy > Bind Metamethod of Hibernate Criteria Builder > Create Custom Function / Custom Method Under HibernateCriteriaBuilder > HibernateCriteriaBuilder Meta Method

To bind custom method with hibernate criteria builder you first need to create a groovy file named HibernateCriteriaListener like below:

package com.pkm import grails.util.Holders import org.codehaus.groovy.grails.commons.GrailsApplication import org.grails.datastore.mapping.core.Datastore import org.grails.datastore.mapping.engine.event.* import org.springframework.context.ApplicationEvent import grails.orm.HibernateCriteriaBuilder class HibernateCriteriaListener extends AbstractPersistenceEventListener { protected HibernateCriteriaListener(Datastore datastore) { super(datastore) HibernateCriteriaBuilder.metaClass.myMethod = { info, value = null -> println("NAME=${info} VALUE=${value}") } } @Override protected void onPersistenceEvent(AbstractPersistenceEvent event) { } @Override boolean supportsEventType(Class<? extends ApplicationEvent> aClass) { return false } static void initialize(GrailsApplication application) { application.mainContext.eventTriggeringInterceptor.datastores.each { k, datastore -> Holders.applicationContext.addApplicationListener(new HibernateCriteriaListener(datastore)) } } }

Now we need to register the above functionality from BootStrap, so you need to do following:

import com.pkm.HibernateCriteriaListener import org.codehaus.groovy.grails.commons.GrailsApplication import org.codehaus.groovy.grails.web.servlet.GrailsApplicationAttributes import org.hibernate.dialect.function.SQLFunctionTemplate import org.springframework.context.ApplicationContext class BootStrap { def init = { servletContext -> ApplicationContext applicationContext = servletContext.getAttribute(GrailsApplicationAttributes.APPLICATION_CONTEXT) GrailsApplication application = (GrailsApplication) applicationContext.getBean("grailsApplication") /* REGISTER HIBERNATE EVENT LISTENER */ HibernateCriteriaListener.initialize(application) } def destroy = { } }

And finally you can use custom criteria method using below sample:

Table1.createCriteria().list { delegate.myMethod("name", "value") }