理解Groovy闭包委托

发表于 2018-03-08 更新于 2023-09-22 评论：阅读次数：

[TODO]

thisObject, owner, delegate

Closure有三个属性，分别是 thisObject, owner, delegate。通常delegate被设置为owner。来源

Idea的Groovy Console中运行代码：

def testClosure(closure) {
    closure()
}
testClosure() {
    println "this is " + thisObject + ", super:" + this.getClass().superclass.name
    println "owner is " + owner + ", super:" + owner.getClass().superclass.name
    println "delegate is " + delegate + ", super:" + delegate.getClass().superclass.name

    testClosure() {
        println "this is " + thisObject + ", super:" + this.getClass().superclass.name
        println "owner is " + owner + ", super:" + owner.getClass().superclass.name
        println "delegate is " + delegate + ", super:" + delegate.getClass().superclass.name
    }
}

输出如下：

this is ideaGroovyConsole@710636b0, super:groovy.lang.Script
owner is ideaGroovyConsole@710636b0, super:groovy.lang.Script
delegate is ideaGroovyConsole@710636b0, super:groovy.lang.Script
this is ideaGroovyConsole@710636b0, super:groovy.lang.Script
owner is ideaGroovyConsole$_run_closure1@4e5ed836, super:groovy.lang.Closure
delegate is ideaGroovyConsole$_run_closure1@4e5ed836, super:groovy.lang.Closure

resolveStrategy

demo

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