Grails Data Binding and Transients

Question

Consider the following class:

Class Timesheet {
    BigDecimal hoursWorked
    Boolean reviewedByCustomer
    Boolean approvedByCustomer
    ...
}

The timesheet can have three states in terms of customer review:

1. TO_BE_CHECKED (reviewedByCustomer == false && approvedByCustomer == null)
2. APPROVED (reviewedByCustomer == true && approvedByCustomer == true)
3. DENIED (reviewedByCustomer == false && approvedByCustomer == false)

I want to use an enum type ReviewStatus to represent these states that can be retrieved from a timesheet or used to update the timesheet. The two boolean values shall not be used anymore. With the following parameter map: [reviewStatus:'APPROVED'], data binding should work as follows .

def timesheet = new Timesheet(params)

or

bindData(timesheet, params)

The Status should be checked as follows:

if(timesheet.reviewStatus == ReviewStatus.TO_BE_REVIEWED){
    //do Logic
}

To achieve this behaviour, I use a transient property and getter and setter methods:

...

//reviewStatus does only exist as getter and setter methods, not as fields
static transients = ['reviewStatus']

ReviewStatus getReviewStatus(){
    if(reviewedByCustomer == false && approvedByCustomer == null){
        ReviewStatus.TO_BE_REVIEWED
    } else if(reviewedByCustomer == true && approvedByCustomer == true){
        ReviewStatus.APPROVED 
    } else if(reviewedByCustomer == true && approvedByCustomer == false){
        ReviewStatus.DENIED
    }
}

void setReviewStatus(ReviewStatus reviewStatus){
    if(reviewStatus == ReviewStatus.TO_BE_REVIEWED){
        reviewedByCustomer = false
        approvedByCustomer = null
    } else if(reviewStatus == ReviewStatus.APPROVED){
        reviewedByCustomer = true
        approvedByCustomer = true
    } else if(reviewStatus == ReviewStatus.DENIED){
        reviewedByCustomer = true
        approvedByCustomer = false
    }
}
...

However, it does not work. Not even with bindable:true. I found this as an answer for similar questions, but they seem to have been using an earlier version of Grails. The only way I could get it to work was by using bindData(object, params, [exclude:[]]). I assume that the empty map prevents the transient properties from being added to the exclusion list automatically.

I would prefer to use the bindable constraint instead, because this would be a cleaner solution than passing an empty map every time I bind data to a timesheet

Using Grails 2.4.2.

EDIT 1: Using Grails 2.4.2 data binder, not spring data binder.

Answer 1

The project at https://github.com/jeffbrown/enumprop demonstrates one way to do this.

Domain Class:

// grails-app/domain/demo/Timesheet.groovy
package demo

class Timesheet {
    Boolean reviewedByCustomer
    Boolean approvedByCustomer

    static transients = ['reviewStatus']

    ReviewStatus getReviewStatus(){
        if(reviewedByCustomer == false && approvedByCustomer == null){
            ReviewStatus.TO_BE_REVIEWED
        } else if(reviewedByCustomer == true && approvedByCustomer == true){
            ReviewStatus.APPROVED
        } else if(reviewedByCustomer == true && approvedByCustomer == false){
            ReviewStatus.DENIED
        }
    }

    void setReviewStatus(ReviewStatus reviewStatus){
        if(reviewStatus == ReviewStatus.TO_BE_REVIEWED){
            reviewedByCustomer = false
            approvedByCustomer = null
        } else if(reviewStatus == ReviewStatus.APPROVED){
            reviewedByCustomer = true
            approvedByCustomer = true
        } else if(reviewStatus == ReviewStatus.DENIED){
            reviewedByCustomer = true
            approvedByCustomer = false
        }
    }
}

Unit test:

// test/unit/demo/TimesheetSpec.groovy
package demo

import grails.test.mixin.TestFor
import spock.lang.Specification
import spock.lang.Unroll

@TestFor(Timesheet)
class TimesheetSpec extends Specification {

    @Unroll('When reviewStatus is #reviewStatus reviewedByCustomer should be #reviewedByCustomer and approvedByCustomer should be #approvedByCustomer')
    void "test enum property binding"() {
        given:
        def timesheet = new Timesheet(reviewStatus: reviewStatus)

        expect:
        timesheet.reviewedByCustomer == reviewedByCustomer
        timesheet.approvedByCustomer == approvedByCustomer

        where:
        reviewStatus     | reviewedByCustomer | approvedByCustomer
        'APPROVED'       | true               | true
        'DENIED'         | true               | false
        'TO_BE_REVIEWED' | false              | null
    }

    @Unroll('When reviewedByCustomer is #reviewedByCustomer and approvedByCustomer is #approvedByCustomer then reviewStatus should be #reviewStatus')
    void "test retrieving the value of the enum property"() {
        given:
        def timesheet = new Timesheet(reviewedByCustomer: reviewedByCustomer,
                                      approvedByCustomer: approvedByCustomer)

        expect:
        timesheet.reviewStatus == reviewStatus

        where:
        reviewStatus                | reviewedByCustomer | approvedByCustomer
        ReviewStatus.APPROVED       | true               | true
        ReviewStatus.DENIED         | true               | false
        ReviewStatus.TO_BE_REVIEWED | false              | null
    }
}