w4-张思渊-202401070104

project/src/project/analysis/MovieAnalyzer.java

@@ -0,0 +1,42 @@
+package project.analysis;
+
+import project.bean.Movie;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class MovieAnalyzer {
+    public static Map<Double, Long> getRatingDistribution(List<Movie> movies) {
+        return movies.stream()
+                .collect(Collectors.groupingBy(Movie::getRating, Collectors.counting()));
+    }
+
+    public static Map<Integer, Double> getYearRatingCorrelation(List<Movie> movies) {
+        return movies.stream()
+                .collect(Collectors.groupingBy(Movie::getYear,
+                        Collectors.averagingDouble(Movie::getRating)));
+    }
+
+    public static Map<String, Long> getDirectorMovieCount(List<Movie> movies) {
+        return movies.stream()
+                .collect(Collectors.groupingBy(Movie::getDirector, Collectors.counting()))
+                .entrySet().stream()
+                .filter(entry -> entry.getValue() > 1)
+                .sorted(Map.Entry.<String, Long>comparingByValue().reversed())
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
+    }
+
+    public static double getAverageRating(List<Movie> movies) {
+        return movies.stream()
+                .mapToDouble(Movie::getRating)
+                .average()
+                .orElse(0.0);
+    }
+
+    public static List<Movie> getTopRatedMovies(List<Movie> movies, int count) {
+        return movies.stream()
+                .sorted(Comparator.comparingDouble(Movie::getRating).reversed())
+                .limit(count)
+                .collect(Collectors.toList());
+    }
+}