使用对象访问属性。“$ {property}” [英] Accessing a property with object."${property}"

问题描述

  class可筛选{
 def statusId 
 def secondaryFilterable 
 
 ... 
 def filter = new Filter（validIds：[1]，fieldName：'statusId'）
 ... 
 class Filter {
 
 def validIds = [] as Set 
 def fieldName 
 private boolean containsFieldValue（input）{
 def fieldValue = input。$ {fieldName} 
 return fieldValue in validIds 
} 
} 
  

罚款一个财产。然而，现在我需要通过二次过滤来过滤 - 就像

  def filter = new Filter（validIds：[1]， fieldName：'secondaryFilterable.statusId'）
  

抛出 groovy.lang。 MissingPropertyException 。任何建议？

解决方案

引用的属性假定一个点是属性名称的一部分。 $ b

一个简单的解决方案是：

  ... 
 def fieldValue = fieldName.split（/ \ ./）。inject（input）{parent，property  - > parent？。$ property} 
 ... 
  

这将递归查找字段值，使用点符号表示子元素。

I在Groovy Web控制台上提供一个工作示例。

I'm working on some dynamic filtering, and have this:

class Filterable {
    def statusId
    def secondaryFilterable
}
...
def filter = new Filter(validIds: [1], fieldName: 'statusId')
...
class Filter {

    def validIds = [] as Set
    def fieldName
    private boolean containsFieldValue(input) {
        def fieldValue = input."${fieldName}"
        return fieldValue in validIds
    }
}

Which works just fine for one property. However, now I need to filter by the secondary filterable - something like

def filter = new Filter(validIds: [1], fieldName: 'secondaryFilterable.statusId')

Which throws a groovy.lang.MissingPropertyException. Any advice?

解决方案

Quoted properties assume a dot is part of the property name.

A simple solution would be:

...
def fieldValue = fieldName.split(/\./).inject(input){ parent, property -> parent?."$property" }
...

This will recursively look up the field value using dot notation for child properties.

I put up a working example here on the Groovy web console.

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