Metaclass deligate不是实例 [英] Metaclass deligate not being instance

问题描述

我有这段代码添加动态属性。我使用MongoDB并且想要动态添加属性。这是我在单元测试时试图做的。

I have this stub of code to add dynamic attributes. I work with mongodb and i want to add the properties dynamically. This is what i tried to do when unit testing.

User.metaClass.dynamicAttributes = [:]

User.metaClass.propertyMissing = { String name ->
    delegate.dynamicAttributes[name]
}

User.metaClass.propertyMissing = { String name, value ->
    delegate.dynamicAttributes[name] = value
}

我超过了我的耐心限制！

But this fails and i am stepping over my patience limit!

User u = new User()
u.ppt = 0

User u2 = new User()
u2.ppt = 1

assert u2.ppt == 1
assert u.ppt == 0 // fails here, println shows that u.ppt is also 1! 

推荐答案

更改此项

User.metaClass.dynamicAttributes = [:]

User.metaClass.propertyMissing = { String name ->
    delegate.dynamicAttributes[name]
}

User.metaClass.propertyMissing = { String name, value ->
    delegate.dynamicAttributes[name] = value
}

p>

to this

User.metaClass.propertyMissing = { String name ->
    if (!delegate.metaClass.hasProperty('dynamicAttributes') delegate.metaClass.dynamicAttributes = [:]
    delegate.dynamicAttributes[name]
}

User.metaClass.propertyMissing = { String name, value ->
    if (!delegate.metaClass.hasProperty('dynamicAttributes') delegate.metaClass.dynamicAttributes = [:]
    delegate.dynamicAttributes[name] = value
}

解决了它！我不确定，但它看起来像groovy共享通过metaClass提供的属性！

Solved it! I am not sure, but it seems like groovy shares the attribute put through metaClass!

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