protected FastIDSet getAllOtherItems(long[] theNeighborhood, long theUserID, boolean includeKnownItems) throws Exception { DataModel dataModel = getDataModel(); FastIDSet possibleItemIDs = new FastIDSet(); for (long userID : theNeighborhood) { possibleItemIDs.addAll(dataModel.getItemIDsFromUser(userID)); } if (!includeKnownItems) { possibleItemIDs.removeAll(dataModel.getItemIDsFromUser(theUserID)); } return possibleItemIDs; } private final class Estimator implements TopItems.Estimator<Long> { private final long theUserID; private final long[] theNeighborhood; Estimator(long theUserID, long[] theNeighborhood) { this.theUserID = theUserID; this.theNeighborhood = theNeighborhood; } @Override public double estimate(Long itemID) throws Exception { return GenericUserBasedRecommender.this.doEstimatePreference(theUserID, theNeighborhood, itemID); } } 解释代码
时间: 2023-12-06 13:40:34 浏览: 34
这段代码是一个基于用户的推荐算法中的一个方法,其中包含了一个内部类 Estimator。该方法的作用是获取用户邻居中所有的物品,并返回一个 FastIDSet 类型的对象。其中的 theNeighborhood 参数是一个 long 类型数组,表示用户邻居的 ID;theUserID 参数表示当前用户的 ID;includeKnownItems 参数表示是否包含当前用户已经评分过的物品。
Estimator 类是一个实现了 TopItems.Estimator 接口的内部类,它的作用是计算一个物品的预测得分。该类包含了两个成员变量 theUserID 和 theNeighborhood,分别表示当前用户的 ID 和用户邻居的 ID 数组。该类实现了 TopItems.Estimator 接口中的 estimate 方法,该方法接受一个 Long 类型的 itemID 参数,表示要计算预测得分的物品的 ID。该方法调用了 GenericUserBasedRecommender 类的 doEstimatePreference 方法来计算物品的预测得分,并返回该得分。
相关问题
protected FastIDSet getAllOtherItems(long[] theNeighborhood, long theUserID, boolean includeKnownItems) throws Exception { DataModel dataModel = getDataModel(); FastIDSet possibleItemIDs = new FastIDSet(); for (long userID : theNeighborhood) { possibleItemIDs.addAll(dataModel.getItemIDsFromUser(userID)); } if (!includeKnownItems) { possibleItemIDs.removeAll(dataModel.getItemIDsFromUser(theUserID)); } return possibleItemIDs; } 解释代码
这段代码实现了一个获取邻居用户(theNeighborhood参数)所评价过的所有物品集合(possibleItemIDs)的方法。如果includeKnownItems为false,则排除当前用户(theUserID参数)已评价过的物品。
具体实现思路为,在循环遍历邻居用户ID时,使用DataModel对象获取该用户评价过的所有物品ID,并将这些物品ID添加到可能的物品集合中。如果includeKnownItems为false,则使用DataModel对象再获取当前用户已评价过的所有物品ID,并在可能的物品集合中去除这些物品ID。最终返回可能的物品集合。
@Slf4j public class LoopCallInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { //调用接口 // 头部获取当前请求所经过且没结束请求的path列表 // 判定path列表中是否包含当前path //无则正常访问 并记录到列表中 //有则告警循环调用,并终止调用,返回异常 return true; //return HandlerInterceptor.super.preHandle(request, response, handler); } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { //HandlerInterceptor.super.postHandle(request, response, handler, modelAndView); //正常结束接口 //获取头部path列表 //从path列表中删除当前path } }
This is a Java class named `LoopCallInterceptor` that implements the `HandlerInterceptor` interface. The `HandlerInterceptor` interface is part of the Spring MVC framework and provides a way to intercept and handle requests and responses for Spring MVC applications.
The purpose of the `LoopCallInterceptor` class is to prevent circular or recursive calls to a Spring MVC controller method, which can cause infinite loops and consume excessive resources.
The `preHandle` method is called before a request is handled by a controller method. It takes in the `HttpServletRequest` and `HttpServletResponse` objects, as well as the `Object` representing the handler method that will handle the request.
The `preHandle` method first checks if the current request path is already present in the request header path list. If it is not present, it adds the current request path to the path list and returns `true` to indicate that the request can proceed normally. If it is already present, it logs a warning message for the circular or recursive call and returns `false` to indicate that the request should be stopped.
The `postHandle` method is called after a request has been handled by a controller method. It takes in the `HttpServletRequest`, `HttpServletResponse`, `Object` representing the handler method, and the `ModelAndView` object that contains the view and model data returned by the handler method.
The `postHandle` method removes the current request path from the request header path list.
Note that the `HandlerInterceptor` interface has three methods, but the `LoopCallInterceptor` class only implements the `preHandle` and `postHandle` methods. The `afterCompletion` method is called after the response has been rendered, but before the response has been committed.
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