Introduction The command pattern is abehavioraldesign pattern. This pattern encapsulates a request as an object that contains all the information about the request, including requests for queues or logs, allowing for much more complex architectures. It even allows operations like undo and redo. In t...
The Command pattern allows requests to be encapsulated as objects, thereby allowing clients to be parametrized with different requests. The "check" at a diner is an example of a Command pattern. The waiter or waitress takes an order or command from a customer and encapsulates that order by wri...
Command design pattern example in C# In the next section we’ll explore how we can implement the command design pattern. In our example, we will implement a simple calculator using the following classes: Command (Command abstract base class) SimpleCalculator (Receiver class) AddCommand (concrete ...
/// Command Design Pattern /// </summary> public class Program { public static void Main() { // Create user and let her compute var user = new User(); // Issue several compute commands user.Compute('+', 100); user.Compute('-', 50); user.Compute('*', 10); user.Compute('/'...
You can assemble commands into a composite command. An example is the MacroCommand class described earlier. 你可以将命令组合成一个复合命令.例如前面的MacroCommand类描述的那样. It's easy to add new Commands, because you don't have to change existing classes. ...
In the Command Pattern an object encapsulates everything needed to execute a method in another object. In this example, aBookStarsOnCommandobject is instantiated with an instance of theBookComandeeclass. TheBookStarsOnCommandobject will call thatBookComandeeobject'sbookStarsOn()function when it'sex...
Command Design Pattern Now we need to create implementations for all the different types of action performed by the receiver. Since we have three actions we will create three Command implementations. Each Command implementation will forward the request to the appropriate method of receiver....
Command pattern -- Structural example using System; // "Command" abstract class Command { // Fields protected Receiver receiver; // Constructors public Command( Receiver receiver ) { this.receiver = receiver; } // Methods abstract public void Execute(); ...
Programmatic Example 这个例子中有法师、妖精、咒语三个类,法师管理咒语的发放、撤销、并能保存施咒记录,妖精则为被咒语作用的对象。 /*** Base class for spell target 抽象命令作用目标*/classTargetTarget;publicabstractclassTarget{privateSizesize;privateVisibilityvisibility;publicSize(*getSize)(Target*self);pub...
GoF的书的定义为:“Command pattern encapsulate request as an object, thereby letting you parameterize clients with different request, queue or log request, and support undoable operations” 换言之,讲命令封装成一个对象,既有状态也能执行动作,发出命令者不需要知道命令最终是谁执行的,如何执行,它只依赖抽...