Example of using the Grails dataBind method to change values of a command object after it has already been created

TestController.groovy

package testcommandobjects

class TestController {

    static final int VALID = 5
    static final int INVALID = 50

    def resetToValid = { TestCommand cmd ->
        rebindAgeAndRenderResponse(cmd, true)
    }

    def resetToInvalid = { TestCommand cmd ->
        rebindAgeAndRenderResponse(cmd, false)
    }

    def gatherCommandData(cmd){
        [value: cmd as String,
         validates: cmd.validate()]
    }
    
    def rebindAgeAndRenderResponse(cmd, boolean changeToValid) {
        def value = changeToValid ? VALID : INVALID
        def before = gatherCommandData(cmd)
        bindData(cmd, [age: value])
        def after = gatherCommandData(cmd)
        render buildOutput(before, after)
    }

    def buildOutput(before, after) {
        def writer = new StringWriter()
        def builder = new groovy.xml.MarkupBuilder(writer)
        builder.html {
            head {
                title 'dataBind demo'
            }
            body {
                h1 'dataBind demo'
                h3 'valid data for age: 5..10'
                p "$before"
                p "$after"
            }
        }
        writer.toString()
    }

}

class TestCommand {

    static constraints = {
        age(range: 5..10)
    }

    int age

    String toString() {
        "age:[$age]"
    }
}

I think you mean "bindData" not "dataBind" :)