在Smalltalk中新建和初始化的区别？

Question

一个新手问题，new和initialize有什么区别？

奥斯卡

Answer 1

没错。当您发送消息#new时，它不仅创建对象，而且还发送消息#initialize。这可让您自定义对象的初始化。看：

Behavior >> new 
"Answer a new initialized instance of the receiver (which is a class) with no indexable variables. Fail if the class is indexable." 

^ self basicNew initialize 

然后：

ProtoObject >> initialize 
"Subclasses should redefine this method to perform initializations on instance creation" 

和：

Behaviour >> basicNew 
"Primitive. Answer an instance of the receiver (which is a class) with no 
indexable variables. Fail if the class is indexable. Essential. See Object 
documentation whatIsAPrimitive." 

<primitive: 70> 
self isVariable ifTrue: [^self basicNew: 0 ]. 
"space must be low" 
OutOfMemory signal. 
^ self basicNew "retry if user proceeds" 

所以...＃basicNew是原始的创建对象。通常情况下，你使用#new，如果你不想特殊的东西，你不会实现#initialize，因此#ProtoObject的空实现将被执行。否则，你可以直接发送#basicNew，但你可能不应该这样做。

干杯

Answer 2

有了新创建一个新的对象，而在创建新对象时，执行初始化方法，以及初始化对象。

Answer 3

Bavarious是正确的。

Behavior >> new 
     "Answer a new instance of the receiver. If the instance can have indexable variables, it will have 0 indexable variables." 

     "Primitive fails if the class is indexable." 
     <primitive: 70> 
     self isVariable ifTrue: [^self new: 0]. 
     self primitiveFailed 

Object >> initialize 
    "Initialize the object to its default state. This is typically used in a convention that the class implements the #new method to call #initialize automatically. This is not done for all objects in VisualWorks, but the initialize method is provided here so that subclasses can call 'super initialize' and not get an exception." 

    ^self.