1. The behavior of objects in the real world is more complex than simply being in one state at a time. the conditions of an Object being in more than one state at a time is called "concurrency" or concurrent states. CSE-307-Software-Engineering…
15.1 User-defined typesWe have used many of Python’s built-in types; now we are going to define a new type. As an example, we will create a type called Point that represents a point in two-dimensional space.In mathematical notation, points are often…
[MVVM的定义] MVVM的目的是什么? 简单总结起来一句话:分离UI逻辑和业务逻辑.这一点和被大家熟知的MVP和MVC是一致的. 下面详细来说明下这个问题,下面一段英文来自Msdn: The Model-View-ViewModel (MVVM) pattern helps you to cleanly separate the business and presentation logic of your application from its user inte…
The NSOperationQueue class regulates the execution of a set of NSOperation objects. After being added to a queue, an operation remains in that queue until it is explicitly canceled or finishes executing its task. Operations within the queue (but not…
先给出NSOpetation的官方指导https://developer.apple.com/library/ios/documentation/Cocoa/Reference/NSOperation_class/ NSOperation The NSOperation class is an abstract class you use to encapsulate the code and data associated with a single task. Because it is a…
原文 "If builders built buildings the way programmers wrote programs, then the first woodpecker that came along would destroy civilization." - Gerald Weinberg You should architect and design software solutions with maintainability in mind. The pri…
概要 Association, Aggregation and Composition are terms that represent relationships among objects. They are very basic stuff of Object Oriented Programming. 关联 Association is a relationship among the objects. Association is "*a*" relationship amo…
