Grails- Criteria builders - createCriteria - grails

Question

The Scenario is like this:
Every Process has multiple ProcessingSteps
The code that I have written is able to fetch all the processes without correspondence to ProcessingSteps.
I know that I am missing a where clause, I want to ask how do we do that in Grails.
I only want to fetch for each Process the corresponding ProcessingStepUpdate
I have two domain classes ProcessingStep and ProcessingStepUpdate
package a.b.c
public class ProcessingStep {
Process process
}
public class ProcessingStepUpdate{
static belongsTo = [processingStep: ProcessingStep]
ProcessingStep processingStep
}
Here is the script that I was writing
Process.list(max:1).each {
//List<ProcessingStep> test2= ProcessingStep.findAllByProcess(it)
//println it
def test3 = ProcessingStep.createCriteria().list() {
eq("process",it)
}
println it
it.list().each {
//not telling it where to get the list from
ProcessingStep.list().each { pstep ->
def test4 = ProcessingStepUpdate.createCriteria().list() {
eq("processingStep",pstep)
// Projections are aggregating, reporting, and
// filtering functions that can be applied after
// the query has finished.
// A common use for projections is to summarize data
// in a query
/* projections{
groupProperty("processingStep")
}*/
}
println pstep
//List<ProcessingStepUpdate> test = ProcessingStepUpdate.findAllByProcessingStep(it)
//List<ProcessingStepUpdate> test = ProcessingStepUpdate.findWhere()
//println "it"
}
}
}
I have been stuck on this problem in one day.. new to OOPS world!

Answer 1

I'll try to guesss that the task is only to iterate children of children. Then it is like this:
public class Process {
static hasMany = [processingSteps: ProcessingStep]
}
public class ProcessingStep {
static belongsTo = [process: Process]
static hasMany = [updates: ProcessingStepUpdate]
}
public class ProcessingStepUpdate {
static belongsTo = [processingStep: ProcessingStep]
}
Process.list().each{ process ->
process.processingSteps.each { step ->
step.updates.each {
println "Process: $process, Update: $it"
}
}
}
Or even
def updates = Process.list()*.processingSteps.flatten()*.updates.flatten()
println updates.join('\n')
Take a look a Groovy Collections, especially at "star-dot '*.' operator" section.