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Groovy 似乎有一些与“Groovy Beans”和闭包相关的非常不愉快的行为，这些行为可能导致它在某些情况下屏蔽局部变量。

这是已知的行为吗？是否有一些文档详细说明了这些内容？我浪费了很多时间试图弄清楚什么不起作用......

考虑以下代码：

class TestClass {

    def doIt(Closure closure) {
        closure.setDelegate(this)
        closure.call()
    }

    def getRevision() {
        return "testclass revision"
    }
}

def testIt() {
    def revision = "testit revision"

    println "1: " + revision + " (expect: testit)"

    TestClass tester = new TestClass()
    tester.doIt {
        println "2: " + getRevision()  + " (expect: testclass)"
    }

    println "3: " + revision + " (expect: testit)"

    tester.doIt {
        println "4: " + revision + " (expect: testit)"
        revision = getRevision()
        println "5: " + revision + " (expect: testclass)"
        println "6: ${getRevision()} (expect: testclass)"
        println "7: " + getRevision() + " (expect: testclass)"
    }

    // expect to have been set to testclass value in previous closure
    println "8: " + revision + " (expect: testclass)"

    tester.doIt {
        println "9: ${getRevision()} (expect: testclass)"
        println "10: " + getRevision() + " (expect: testclass)"
    }

    println "11: " + revision + " (expect: testclass)"
}

testIt()

运行此代码会产生以下输出：

1: testit revision (expect: testit)
2: testclass revision (expect: testclass)
3: testit revision (expect: testit)
4: testit revision (expect: testit)
5: testit revision (expect: testclass)
6: testit revision (expect: testclass)
7: testit revision (expect: testclass)
8: testit revision (expect: testclass)
9: testclass revision (expect: testclass)
10: testclass revision (expect: testclass)
11: testit revision (expect: testclass)

我的主要问题是 5/6/7。似乎只是revision在闭包中使用局部变量“隐藏”getRevision()了委托中的方法，并将其替换为自动生成的 bean 样式getRevision()以匹配revision“属性”。如果我不使用该revision变量，则调用getRevision()不会调用此 bean 行为。

任何见解或文档链接将不胜感激！

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1 回答 1

1

Groovy 闭包具有resolveStrategy可用于控制解析顺序的属性。默认策略是从“拥有”对象中查找属性，并且只有在无法找到该属性时才能使用委托。我相信将其设置为DELEGATE_FIRST将获得您所期望的行为。

于 2012-04-26T18:16:26.700 回答