关于Java 设计模式 访问者模式 Visitor

1、IComputerPart.java

package com.ssm.cts.pattern.visitor;

public interface IComputerPart {
  public void accept(IComputerPartVisitor computerPartVisitor);
}

2、Keyboard.java

package com.ssm.cts.pattern.visitor;

public class Keyboard implements IComputerPart {
  @Override
  public void accept(IComputerPartVisitor computerPartVisitor) {
    computerPartVisitor.visit(this);
  }
}

3、Monitor.java

package com.ssm.cts.pattern.visitor;

public class Monitor implements IComputerPart {
  @Override
  public void accept(IComputerPartVisitor computerPartVisitor) {
    computerPartVisitor.visit(this);
  }
}

4、Mouse.java

package com.ssm.cts.pattern.visitor;

public class Mouse implements IComputerPart {
  @Override
  public void accept(IComputerPartVisitor computerPartVisitor) {
    computerPartVisitor.visit(this);
  }
}

5、Computer.java

package com.ssm.cts.pattern.visitor;

public class Computer implements IComputerPart {
  IComputerPart[] parts;

  public Computer() {
    parts = new IComputerPart[] { new Mouse(), new Keyboard(), new Monitor() };
  }

  @Override
  public void accept(IComputerPartVisitor computerPartVisitor) {
    for (int i = 0; i < parts.length; i++) {
      parts[i].accept(computerPartVisitor);
    }
    computerPartVisitor.visit(this);
  }
}

6、IComputerPartVisitor.java

package com.ssm.cts.pattern.visitor;

public interface IComputerPartVisitor {
  public void visit(Computer computer);

  public void visit(Mouse mouse);

  public void visit(Keyboard keyboard);

  public void visit(Monitor monitor);
}

7、ComputerPartDisplayVisitor.java

package com.ssm.cts.pattern.visitor;

public class ComputerPartDisplayVisitor implements IComputerPartVisitor {
  @Override
  public void visit(Computer computer) {
    System.out.println("计算机");
  }

  @Override
  public void visit(Mouse mouse) {
    System.out.println("鼠标");
  }

  @Override
  public void visit(Keyboard keyboard) {
    System.out.println("键盘");
  }

  @Override
  public void visit(Monitor monitor) {
    System.out.println("显示器");
  }
}

8、Demo.java

package com.ssm.cts.pattern.visitor;

public class Demo {
  // 测试
  public static void main(String[] args) {

    IComputerPart computer = new Computer();
    computer.accept(new ComputerPartDisplayVisitor());
  }
}