设计模式-结构型-装饰器模式-decorator

发票基本类

public class Invoice {
    public void printInvoice() {
        System.out.println("打印发票正文");
    }
}

发票正文类

public class Decorator extends Invoice {
    protected Invoice ticket;

    public Decorator(Invoice ticket) {
        this.ticket = ticket;
    }

    @Override
    public void printInvoice() {
        if (ticket != null) {
            ticket.printInvoice();
        }
    }
}

发票头部类

public class HeadDecorator extends Decorator {
    public HeadDecorator(Invoice ticket) {
        super(ticket);
    }

    @Override
    public void printInvoice() {
        System.out.println("打印发票头");
        super.printInvoice();
    }
}

发票尾部类

public class FootDecorator extends Decorator {
    public FootDecorator(Invoice ticket) {
        super(ticket);
    }

    @Override
    public void printInvoice() {
        super.printInvoice();
        System.out.println("打印发票尾");
    }
}

演示类

public class Demo {
    public static void main(String[] args) {
        Invoice t= new Invoice();
        Decorator ticket;
        ticket=new FootDecorator(new HeadDecorator(t));

        ticket.printInvoice();
    }
}

演示结果