Question

我了解到，默认情况下，委派首先与所有者合作，否则需要特定的委派。我不明白嵌套闭包委托的工作方式。我的例子：

class App1 {
String bar = "App1"
}

class App2 {
Closure c1 = {
    String bar = "App2"
    println("Closure 1 - $bar")
    Closure c2 = {
        println("Closure2 - $bar")
    }
    c2.delegate = new App1()
    c2.resolveStrategy = Closure.DELEGATE_ONLY
    c2()
  }
}

App2 app2 = new App2() 
App1 app1 = new App1()

app2.c1.delegate = app1
app2.c1() 
println("***************")

app2.c1.resolveStrategy = Closure.DELEGATE_ONLY // Delegation strictly to 
app2.c1()

喜欢是结果

Closure 1 - App2
Closure2 - App2
***************
Closure 1 - App2
Closure2 - App2

对我来说没有意义的是最后一行。即使在使用DELEGATE_ONLY将Closure c2委派给App1之后，为什么还要考虑bar =“ App2”？！

Answer 1

它选择bar作为局部变量bar，它根本不需要看委托来解决它，所以一切都是App2

如果将其移至app2中的闭包之外：

class App2 {
    String bar = "App2"
    Closure c1 = {
        println("Closure 1 - $bar")
        Closure c2 = {
            println("Closure2 - $bar")
        }
        c2.delegate = new App1()
        c2.resolveStrategy = Closure.DELEGATE_ONLY
        c2()
    }
}

您得到了输出

Closure 1 - App2
Closure2 - App1
***************
Closure 1 - App1
Closure2 - App1

Groovy-嵌套闭包委托的问题

1 个答案: