设计模式 - 行为型模式 - 中介者模式

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//抽象中介者
abstract class Mediator {
    public abstract void componentChanged(Component c);
}

//具体中介者
class ConcreteMediator extends Mediator {
    //维持对各个同事对象的引用
    public Button addButton;
    public List list;
    public TextBox userNameTextBox;
    public ComboBox cb;

    //封装同事对象之间的交互
    public void componentChanged(Component c) {
        //单击按钮
        if (c == addButton) {
            System.out.println("--单击增加按钮--");
            list.update();
            cb.update();
            userNameTextBox.update();
        }
        //从列表框选择客户
        else if (c == list) {
            System.out.println("--从列表框选择客户--");
            cb.select();
            userNameTextBox.setText();
        }
        //从组合框选择客户
        else if (c == cb) {
            System.out.println("--从组合框选择客户--");
            cb.select();
            userNameTextBox.setText();
        }
    }
}

//抽象组件类：抽象同事类
abstract class Component {
    protected Mediator mediator;

    public void setMediator(Mediator mediator) {
        this.mediator = mediator;
    }

    //转发调用
    public void changed() {
        mediator.componentChanged(this);
    }

    public abstract void update();
}

//按钮类：具体同事类
class Button extends Component {
    public void update() {
        //按钮不产生交互
    }
}

//列表框类：具体同事类
class List extends Component {
    public void update() {
        System.out.println("列表框增加一项：张无忌。");
    }

    public void select() {
        System.out.println("列表框选中项：小龙女。");
    }
}

//组合框类：具体同事类
class ComboBox extends Component {
    public void update() {
        System.out.println("组合框增加一项：张无忌。");
    }

    public void select() {
        System.out.println("组合框选中项：小龙女。");
    }
}

//文本框类：具体同事类
class TextBox extends Component {
    public void update() {
        System.out.println("客户信息增加成功后文本框清空。");
    }

    public void setText() {
        System.out.println("文本框显示：小龙女。");
    }
}

class Client {
    public static void main(String args[]) {
        //定义中介者对象
        ConcreteMediator mediator;
        mediator = new ConcreteMediator();
        //定义同事对象
        Button addBT = new Button();
        List list = new List();
        ComboBox cb = new ComboBox();
        TextBox userNameTB = new TextBox();
        addBT.setMediator(mediator);
        list.setMediator(mediator);
        cb.setMediator(mediator);
        userNameTB.setMediator(mediator);
        mediator.addButton = addBT;
        mediator.list = list;
        mediator.cb = cb;
        mediator.userNameTextBox = userNameTB;
        addBT.changed();
        System.out.println("-----------------------------");
        list.changed();
    }
}