覆盖addTo和removeFrom以侦听Grails中属性的更改

Question

我是Grails的新手，我需要在“has-many”属性发生变化时进行一些计算，我认为最好的地方是在属性的setter中，因为我的属性是列表中最好的位置应该在addTo和removeFrom方法中，我试图覆盖它们但没有奏效。

这是最好的方法吗？ 我的代码出了什么问题？

这是代码：

Cicle.groovy

class Cicle {

String machine
int cicleValue

static hasMany = [measurements:Measurement]

static constraints = {
    machine blank:false 
    cicleValue nullable:false 
}

public void addToMeasurements(Measurement measurement){
    super.addToMeasurements(measurement)
    updateCalculations()
}

public void updateCalculations(){

    int sumCicles = 0

    measurements.each{ measurement ->
        sumCicles += measurement.cicleValue
    }

    cicleValue = sumCicles / measurements.size()
    this.save(failOnError: true) 
}
}

这是我得到的例外：

No signature of method: com.rpc.mock.app.Cicle.addToMeasurements() is applicable for argument types: (com.rpc.mock.app.Measurement) values: [com.rpc.mock.app.Measurement : (unsaved)]
Possible solutions: addToMeasurements(com.rpc.mock.app.Measurement), addToMeasurements(java.lang.Object), getMeasurements(). Stacktrace follows:
Message: No signature of method: com.rpc.mock.app.Cicle.addToMeasurements() is applicable for argument types: (com.rpc.mock.app.Measurement) values: [com.rpc.mock.app.Measurement : (unsaved)]
Possible solutions: addToMeasurements(com.rpc.mock.app.Measurement), addToMeasurements(java.lang.Object), getMeasurements()
    Line | Method
->>   16 | addToMeasurements in com.rpc.mock.app.Cicle
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|     43 | $tt__save         in com.rpc.mock.app.MeasurementController
|    200 | doFilter . . . .  in grails.plugin.cache.web.filter.PageFragmentCachingFilter
|     63 | doFilter          in grails.plugin.cache.web.filter.AbstractFilter
|   1145 | runWorker . . . . in java.util.concurrent.ThreadPoolExecutor
|    615 | run               in java.util.concurrent.ThreadPoolExecutor$Worker
^    744 | run . . . . . . . in java.lang.Thread

谢谢

Answer 1

当您处理域对象时，GORM支持将事件注册为在发生某些事件（例如删除，插入和更新）时被触发的方法：

beforeInsert - Executed before an object is initially persisted to the database
beforeUpdate - Executed before an object is updated
beforeDelete - Executed before an object is deleted
beforeValidate - Executed before an object is validated
afterInsert - Executed after an object is persisted to the database
afterUpdate - Executed after an object has been updated
afterDelete - Executed after an object has been deleted
onLoad - Executed when an object is loaded from the database

然后，您可以在域对象中添加updateCalculations() ，如下所示：

static constraints = {
    machine blank:false 
    cicleValue nullable:false 
}

def beforeUpdate() { updateCalculations()  }

作为一般的良好设计实践，最好将逻辑实现保留在域对象之外，Grails允许将服务注入域（POGO）。