Getting error in binding a set in command object

Question

I am trying to bind request to a command object. I have to map a set in command object,but i am getting error "type mismatch,rejected value null". i am stuck here, how can i resolve this.

my command object is

@Validateable
public class CreateFundingCommand extends BaseCommand {
    Set<Causes> 
}

my domain class is

class CrowdFunding extends BaseEntity{

Set<Causes> 

}

my controller is

 def saveCreateFunding(CreateFundingCommand createFundingCommand){
        log.debug"hello"+params
        createFundingCommand.validate()
        if(createFundingCommand.hasErrors()){
            log.debugg"errors"+createFundingCommand.errors
        }else{
            crowdFundingService.saveCreateFunding(createFundingCommand.getCrowdFunding())
        }
    }

Causes class is

class Causes extends BaseEntity {
    String name
    String description
    String icon
}

My params are :

causes:{"name":"prabh","description":"ggg","icon":"deec"}

errrors are :

rejected value [{"name":"prabh","description":"ggg","icon":"deec"}]; codes [com.volcare.command.crowdFunding.CreateFundingCommand.causes.typeMismatch.error,com.volcare.command.crowdFunding.CreateFundingCommand.causes.typeMismatch,createFundingCommand.causes.typeMismatch.error,createFundingCommand.causes.typeMismatch,typeMismatch.com.volcare.command.crowdFunding.CreateFundingCommand.causes,typeMismatch.causes,typeMismatch.java.util.Set,typeMismatch]; arguments [causes]; default message [Could not find matching constructor for: com.volcare.domain.setting.Causes(java.lang.String)]

Answer 1

The problem is probably the following:

causes:{"name":"prabh","description":"ggg","icon":"deec"}

You probably want that to be something like this:

causes:[{"name":"prabh","description":"ggg","icon":"deec"}]

Notice that the value of causes should be a list of Map, not a Map.

See https://github.com/jeffbrown/fundbinding. That project includes the following:

src/groovy/demo/CreateFundingCommand.groovy

package demo

@grails.validation.Validateable
class CreateFundingCommand extends BaseCommand {
    Set<Cause> causes
}

grails-app/controllers/demo/DemoController.groovy

package demo

class DemoController {

    def saveCreateFunding(CreateFundingCommand createFundingCommand){
        if(createFundingCommand.hasErrors()){
            render 'Errors were found'
        }else{
            render 'No errors were found'
        }
    }
}

test/unit/demo/DemoControllerSpec.groovy

package demo

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

@TestFor(DemoController)
class DemoControllerSpec extends Specification {

    void "test valid command object"() {
        when:
        request.json = '{"causes":[{"name":"prabh","description":"ggg","icon":"deec"}]}'
        controller.saveCreateFunding()

        then:
        response.text == 'No errors were found'
    }

    void "test invalid command object"() {
        when:
        request.json = '{"causes":{"name":"prabh","description":"ggg","icon":"deec"}}'
        controller.saveCreateFunding()

        then:
        response.text == 'Errors were found'
    }
}

Also note that in your code you are calling createFundingCommand.validate() inside of you controller action which is not necessary. The instance will already have been validated before your code executes.

I hope that helps.