关于java:桥接模式的示例

依据不同的告警规定，触发不同类型的告警。告警反对多种告诉渠道，包含：邮件、短信、微信、主动语音电话。告诉的紧急水平有多种类型，包含：SEVERE（重大）、URGENCY（紧急）、NORMAL（一般）、TRIVIAL（无关紧要）。不同的紧急水平对应不同的告诉渠道。比方，SERVE（重大）级别的音讯会通过“主动语音电话”告知相干人员。

import java.util.List;public enum NotificationEmergencyLevel {    SEVERE, URGENCY, NORMAL, TRIVIAL}class Notification{    private List emailAddresses;    private List telephones;    private List wechatIds;    public Notification() {}    public void setEmailAddress(List emailAddress) {        this.emailAddresses = emailAddress;    }    public void setTelephones(List telephones) {        this.telephones = telephones;    }    public void setWechatIds(List wechatIds) {        this.wechatIds = wechatIds;    }    public void notify(NotificationEmergencyLevel level,String message){        if (level.equals(NotificationEmergencyLevel.SEVERE)){            //电话告诉        }else if (level.equals(NotificationEmergencyLevel.URGENCY)){            //微信        }else  if (level.equals(NotificationEmergencyLevel.NORMAL)){            //邮件        }else if (level.equals(NotificationEmergencyLevel.TRIVIAL)){            //邮件        }    }}//客户端如何应用class ErrorAlertHandler extends AlertHandler {    public ErrorAlertHandler(AlertRule rule, Notification notification){        super(rule, notification);    }    @Override    public void check(ApiStatInfo apiStatInfo){        if (apiStatInfo.getErrorCount() > rule.getMatchedRule(apiStatInfo.getApi()).getMaxErrorCount()){            notification.notify(NotificationEmergencyLevel.SEVERE, "...");        }    }}/*Notification类有一处显著的问题就是应用的if太多了，另外if里的是发送报警逻辑会很简单，咱们将不同渠道的发送逻辑剥离进去，造成独立的音讯发送类（MsgSender 相干类）。其中，Notification 类相当于形象，MsgSender 类相当于实现，两者能够独立开发，通过组合关系（也就是桥梁）任意组合在一起*/---------------改良版本-------------interface MsgSender{    void send(String message);}class TelephoneMsgSender implements MsgSender{    private List telephones;    public TelephoneMsgSender(List telephones) {        this.telephones = telephones;    }    @Override    public void send(String message) {        //...    }}class EmailMsgSender implements MsgSender {    // 与TelephoneMsgSender代码构造相似，所以省略...}class WechatMsgSender implements MsgSender {    // 与TelephoneMsgSender代码构造相似，所以省略...}abstract class Notification {    protected MsgSender msgSender;    public Notification(MsgSender msgSender) {        this.msgSender = msgSender;    }    public abstract void notify(String message);}class SevereNotification extends Notification {    public SevereNotification(MsgSender msgSender){        super(msgSender);    }    @Override    public void notify(String message) {        msgSender.send(message);    }}class UrgencyNotification extends Notification {// 与SevereNotification代码构造相似，所以省略...}    class NormalNotification extends Notification { // 与SevereNotification代码构造相似，所以省略...}class TrivialNotification extends Notification { // 与SevereNotification代码构造相似，所以省略...}