Smalltalk中new和initialize之间的区别？

Question

一个新手问题,new和initialize有什么区别？

奥斯卡

Answer 1

究竟.当您发送消息#new时,它不仅会创建对象,还会发送#initialize信息.这使您可以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是创建对象的原语.通常,你使用#new,如果你不想要任何特殊的东西,你就不会实现#initialize,因此会执行#ProtoObject的空实现.否则,您可以直接发送#basicNew,但您可能不应该这样做.

干杯

Answer 2

使用new,您可以创建一个新Object,而初始化方法在创建新Object时执行,并初始化Object.