Java 中装饰者模式与策略模式在埋点系统中的应用

前言

在软件开发中，装饰者模式和策略模式是两种常用的设计模式，它们在特定的业务场景下能够发挥巨大的作用。本文将通过一个实际的埋点系统案例，探讨如何在 Java 中运用装饰者模式和策略模式，以及如何结合工厂方法模式来优化代码结构。

业务场景分析

随着互联网的发展，用户行为分析变得越来越重要，而埋点技术是实现用户行为分析的关键手段之一。埋点系统需要记录用户在应用中的各种操作行为，如点击、浏览、提交等，以便后续进行数据分析和业务决策。

假设我们正在开发一个在线教育平台，需要实现以下埋点功能：

点击埋点：记录用户点击的位置。
课程埋点：记录用户点击的课程信息。
任务埋点：记录用户点击的任务信息。

这些埋点功能需要根据不同的业务场景进行动态组合，例如在课程页面的点击操作需要记录点击位置和课程信息，而在任务页面的点击操作需要记录点击位置和任务信息。

装饰者模式的应用

装饰者模式允许我们在不修改原有代码的基础上，动态地给对象添加职责。它由以下几部分组成：

Component：定义对象的接口。
Concrete Component：实现 Component 接口的具体对象。
Decorator：维护一个对 Component 对象的引用，并定义与 Component 接口相同的接口。
Concrete Decorator：实现 Decorator 接口，负责给 Component 对象添加特定的职责。

实现埋点功能

// Component 接口
public interface SaveMessage {void saveMessage(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest);
}// Concrete Component：基础点击埋点
public class CommonClickPoint implements SaveMessage {@Overridepublic void saveMessage(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {pointSaveBean.setClickLocation(pointSaveRequest.getClickLocation());}
}// Decorator 抽象类
public abstract class AddPointMessageService implements SaveMessage {protected SaveMessage saveMessage;public AddPointMessageService(SaveMessage saveMessage) {this.saveMessage = saveMessage;}@Overridepublic void saveMessage(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {saveMessage.saveMessage(pointSaveBean, pointSaveRequest);}
}// Concrete Decorator：课程埋点
public class CourseClickPoint extends AddPointMessageService {public CourseClickPoint(SaveMessage saveMessage) {super(saveMessage);}@Overridepublic void saveMessage(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {super.saveMessage(pointSaveBean, pointSaveRequest);pointSaveBean.setCourseId(pointSaveRequest.getCourseId());}
}// Concrete Decorator：任务埋点
public class TaskClickPoint extends AddPointMessageService {public TaskClickPoint(SaveMessage saveMessage) {super(saveMessage);}@Overridepublic void saveMessage(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {super.saveMessage(pointSaveBean, pointSaveRequest);pointSaveBean.setTaskId(pointSaveRequest.getTaskId());}
}

客户端代码

public class CommonMain {public static void main(String[] args) {// 初始化埋点类型列表List<PointSaveType> types = Arrays.asList(PointSaveType.TASK, PointSaveType.COURSE);// 初始化埋点保存对象PointSaveBean pointSaveBean = new PointSaveBean();// 初始化埋点请求对象PointSaveRequest pointSaveRequest = PointSaveRequest.builder().pointSaveTypeList(types).clickLocation("右上角落").courseId("英语").taskId("任务1").build();// 初始化基础保存逻辑SaveMessage saveMessage = new CommonClickPoint();saveMessage.saveMessage(pointSaveBean, pointSaveRequest);System.out.println("基础埋点保存数据: " + pointSaveBean);// 根据埋点类型动态添加保存逻辑for (PointSaveType type : types) {if (type == PointSaveType.COURSE) {saveMessage = new CourseClickPoint(saveMessage);} else if (type == PointSaveType.TASK) {saveMessage = new TaskClickPoint(saveMessage);}saveMessage.saveMessage(pointSaveBean, pointSaveRequest);}// 打印最终埋点数据System.out.println("最终埋点保存数据: " + pointSaveBean);}
}

策略模式的应用

策略模式定义了一系列算法，并将每个算法封装到具有共同接口的独立类中，使它们可以互相替换。当埋点逻辑之间存在复杂的组合关系时，结合策略模式可以更好地管理这些组合逻辑。

实现埋点功能

// 策略接口
public interface PointSaveStrategy {void save(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest);
}// 具体策略：点击埋点
public class ClickPointSaveStrategy implements PointSaveStrategy {@Overridepublic void save(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {pointSaveBean.setClickLocation(pointSaveRequest.getClickLocation());}
}// 具体策略：课程埋点
public class CoursePointSaveStrategy implements PointSaveStrategy {@Overridepublic void save(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {pointSaveBean.setCourseId(pointSaveRequest.getCourseId());}
}// 具体策略：任务埋点
public class TaskPointSaveStrategy implements PointSaveStrategy {@Overridepublic void save(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {pointSaveBean.setTaskId(pointSaveRequest.getTaskId());}
}// 策略上下文
public class PointSaveStrategyContext {private List<PointSaveStrategy> strategies = new ArrayList<>();public void addStrategy(PointSaveStrategy strategy) {strategies.add(strategy);}public void execute(PointSaveBean pointSaveBean, PointSaveRequest pointSaveRequest) {for (PointSaveStrategy strategy : strategies) {strategy.save(pointSaveBean, pointSaveRequest);}}
}// 策略配置
public class PointSaveStrategyConfig {private static final Map<PointSaveType, PointSaveStrategy> STRATEGY_MAP = new HashMap<>();static {STRATEGY_MAP.put(PointSaveType.CLICK, new ClickPointSaveStrategy());STRATEGY_MAP.put(PointSaveType.COURSE, new CoursePointSaveStrategy());STRATEGY_MAP.put(PointSaveType.TASK, new TaskPointSaveStrategy());}public static PointSaveStrategy getStrategy(PointSaveType type) {return STRATEGY_MAP.getOrDefault(type, null);}
}

客户端代码

public class CommonMain {public static void main(String[] args) {// 初始化埋点类型列表List<PointSaveType> types = Arrays.asList(PointSaveType.TASK, PointSaveType.COURSE);// 初始化埋点保存对象PointSaveBean pointSaveBean = new PointSaveBean();// 初始化埋点请求对象PointSaveRequest pointSaveRequest = PointSaveRequest.builder().pointSaveTypeList(types).clickLocation("右上角落").courseId("英语").taskId("任务1").build();// 创建策略上下文PointSaveStrategyContext context = new PointSaveStrategyContext();// 添加基础策略context.addStrategy(new ClickPointSaveStrategy());// 根据埋点类型动态添加策略for (PointSaveType type : types) {PointSaveStrategy strategy = PointSaveStrategyConfig.getStrategy(type);if (strategy != null) {context.addStrategy(strategy);}}// 执行所有策略context.execute(pointSaveBean, pointSaveRequest);// 打印最终埋点数据System.out.println("最终埋点保存数据: " + pointSaveBean);}
}

工厂方法模式的结合

为了进一步简化客户端代码，我们可以引入工厂方法模式来创建装饰者对象。

// 工厂类
public class PointSaveDecoratorFactory {public static SaveMessage getDecorator(PointSaveType type, SaveMessage saveMessage) {switch (type) {case COURSE:return new CourseClickPoint(saveMessage);case TASK:return new TaskClickPoint(saveMessage);default:System.out.println("未知的埋点类型: " + type);return saveMessage;}}
}

客户端代码优化

public class CommonMain {public static void main(String[] args) {// 初始化埋点类型列表List<PointSaveType> types = Arrays.asList(PointSaveType.TASK, PointSaveType.COURSE);// 初始化埋点保存对象PointSaveBean pointSaveBean = new PointSaveBean();// 初始化埋点请求对象PointSaveRequest pointSaveRequest = PointSaveRequest.builder().pointSaveTypeList(types).clickLocation("右上角落").courseId("英语").taskId("任务1").build();// 初始化基础保存逻辑SaveMessage saveMessage = new CommonClickPoint();saveMessage.saveMessage(pointSaveBean, pointSaveRequest);System.out.println("基础埋点保存数据: " + pointSaveBean);// 根据埋点类型动态添加保存逻辑for (PointSaveType type : types) {saveMessage = PointSaveDecoratorFactory.getDecorator(type, saveMessage);saveMessage.saveMessage(pointSaveBean, pointSaveRequest);}// 打印最终埋点数据System.out.println("最终埋点保存数据: " + pointSaveBean);}
}