Groovy闭包中的这个、所有者、委托

Groovy闭包中的这个、所有者、委托,groovy,closures,Groovy,Closures,这是我的密码: class SpecialMeanings{ String prop1 = "prop1" def closure = { String prop1 = "inner_prop1" println this.class.name //Prints the class name println this.prop1 println owner.prop1 println delegate.prop1 } } def clos

这是我的密码:

class SpecialMeanings{
  String prop1 = "prop1"
  def closure = {
    String prop1 = "inner_prop1"  
    println this.class.name //Prints the class name
    println this.prop1
    println owner.prop1
    println delegate.prop1
  }
}

def closure = new SpecialMeanings().closure
closure()
输出为

prop1
prop1
prop1

我希望第一行是prop1,因为它引用了定义闭包的对象。但是,所有者(并且是默认的委托人)应该引用实际的闭包。所以接下来的两行应该是内部的。为什么没有呢?

这就是它的工作原理。您必须了解
所有者
代表
的实际参考:


脚本的最后3行显示了如何更改默认委托并将其设置为闭包的示例。最后一次调用
closure
将打印脚本中的
prop1
值,该值是
println
#3

处脚本的
prop1
属性,答案是
默认情况下
所有者等于
,默认情况下
委托等于
所有者
。因此,默认情况下,
委托
等于
。当然,除非您更改
委托
的设置,否则您将获得与

class SpecialMeanings{
  String prop1 = "prop1"
  def closure = {
    String prop1 = "inner_prop1"  
    println this.class.name //Prints the class name

    //Refers to SpecialMeanings instance
    println this.prop1 // 1

    // owner indicates Owner of the surrounding closure which is SpecialMeaning
    println owner.prop1 // 2

    // delegate indicates the object on which the closure is invoked 
    // here Delegate of closure is SpecialMeaning
    println delegate.prop1 // 3

    // This is where prop1 from the closure itself in referred
    println prop1 // 4
  }
}

def closure = new SpecialMeanings().closure
closure()

//Example of modifying the delegate to the script itself
prop1 = "PROPERTY FROM SCRIPT"
closure.delegate = this
closure()