架构师训练营第三周作业

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发布于: 2020 年 06 月 24 日

单例模式      单例模式保证产生单一实例，一个类只产生一个实例。为什么需要单例模式，从性能上来说，可以减少实例频繁的创建和销毁带来的资源消耗；从功能上来说，当多个用户使用这个实例的时候，便于统一控制。下面是手写的饿汉式与懒汉式的单例模式。
单例模式-饿汉式
单例模式-懒汉式
组合模式      组合模式可以解决树形结构这种场景的问题，如窗口结构如图2所示，需要打印出图1的窗口
WindowComponent
public interface WindowComponent {
    public void draw();
}
ContainerComponent
public class ContainerComponent implements WindowComponent {
    private String name;
    public ContainerComponent(String name) {
        this.name = name;
    }
    private List<WindowComponent> windowComponentList = new ArrayList<WindowComponent>();
    public void draw() {
        System.out.println(this.name);
        for (WindowComponent windowComponent: windowComponentList) {
            windowComponent.draw();
        }
    }
    public void addComponent(WindowComponent windowComponent) {
        windowComponentList.add(windowComponent);
    }
}
LeafComponent
public class LeafComponent implements WindowComponent {
    private String name;
    public LeafComponent(String name) {
        this.name = name;
    }
    public void draw() {
        System.out.println(this.name);
    }
}
Client
public class Client {
    public static void main(String[] args) {
        ContainerComponent windowsComponent = new ContainerComponent("print WinForm(WINDOWS窗口)");
        LeafComponent pictureComponent = new LeafComponent("print Picture(LOGO图片)");
        LeafComponent loginButtonComponent = new LeafComponent("print Button(登录)");
        LeafComponent registerButtonComponent = new LeafComponent("print Button(注册)");
        ContainerComponent frameComponent = new ContainerComponent("print Frame(FRAME1)");
        windowsComponent.addComponent(pictureComponent);
        windowsComponent.addComponent(loginButtonComponent);
        windowsComponent.addComponent(registerButtonComponent);
        windowsComponent.addComponent(frameComponent);
        LeafComponent usernameLabelComponent = new LeafComponent("print Label(用户名)");
        LeafComponent usernameTextBoxComponent = new LeafComponent("print TextBox(文本框)");
        LeafComponent passwordLabelComponent = new LeafComponent("print Label(密码)");
        LeafComponent passwordTextBoxComponent = new LeafComponent("print PasswordBox(密码框)");
        LeafComponent checkBoxComponent = new LeafComponent("print CheckBox(复选框)");
        LeafComponent textBoxComponent = new LeafComponent("print TextBox(记住用户名)");
        LeafComponent linkLabelComponent = new LeafComponent("print LinkLabel(忘记密码)");
        frameComponent.addComponent(usernameLabelComponent);
        frameComponent.addComponent(usernameTextBoxComponent);
        frameComponent.addComponent(passwordLabelComponent);
        frameComponent.addComponent(passwordTextBoxComponent);
        frameComponent.addComponent(checkBoxComponent);
        frameComponent.addComponent(textBoxComponent);
        frameComponent.addComponent(linkLabelComponent);
        windowsComponent.draw();
    }
}
结果输出
print WinForm(WINDOWS窗口)
print Picture(LOGO图片)
print Button(登录)
print Button(注册)
print Frame(FRAME1)
print Label(用户名)
print TextBox(文本框)
print Label(密码)
print PasswordBox(密码框)
print CheckBox(复选框)
print TextBox(记住用户名)
print LinkLabel(忘记密码)
﻿