1_3_HW0_optional2.patch

Index: src/main/java/ru/javawebinar/topjava/util/MealsUtil.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/main/java/ru/javawebinar/topjava/util/MealsUtil.java	(date 1509555460000)
+++ src/main/java/ru/javawebinar/topjava/util/MealsUtil.java	(revision )
@@ -8,7 +8,12 @@
 import java.time.LocalTime;
 import java.time.Month;
 import java.util.*;
+import java.util.stream.Collector;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toList;
 
 public class MealsUtil {
     public static void main(String[] args) {
@@ -24,6 +29,8 @@
         mealsWithExceeded.forEach(System.out::println);
 
         System.out.println(getFilteredWithExceededByCycle(meals, LocalTime.of(7, 0), LocalTime.of(12, 0), 2000));
+        System.out.println(getFilteredWithExceededInOnePass(meals, LocalTime.of(7, 0), LocalTime.of(12, 0), 2000));
+        System.out.println(getFilteredWithExceededInOnePass2(meals, LocalTime.of(7, 0), LocalTime.of(12, 0), 2000));
     }
 
     public static List<MealWithExceed> getFilteredWithExceeded(List<Meal> meals, LocalTime startTime, LocalTime endTime, int caloriesPerDay) {
@@ -36,7 +43,7 @@
         return meals.stream()
                 .filter(meal -> TimeUtil.isBetween(meal.getTime(), startTime, endTime))
                 .map(meal -> createWithExceed(meal, caloriesSumByDate.get(meal.getDate()) > caloriesPerDay))
-                .collect(Collectors.toList());
+                .collect(toList());
     }
 
     public static List<MealWithExceed> getFilteredWithExceededByCycle(List<Meal> meals, LocalTime startTime, LocalTime endTime, int caloriesPerDay) {
@@ -53,6 +60,51 @@
         return mealsWithExceeded;
     }
 
+    public static List<MealWithExceed> getFilteredWithExceededInOnePass(List<Meal> meals, LocalTime startTime, LocalTime endTime, int caloriesPerDay) {
+        Collection<List<Meal>> list = meals.stream()
+                .collect(Collectors.groupingBy(Meal::getDate)).values();
+
+        return list.stream().flatMap(dayMeals -> {
+            boolean exceed = dayMeals.stream().mapToInt(Meal::getCalories).sum() > caloriesPerDay;
+            return dayMeals.stream().filter(meal ->
+                    TimeUtil.isBetween(meal.getTime(), startTime, endTime))
+                    .map(meal -> createWithExceed(meal, exceed));
+        }).collect(toList());
+    }
+
+    public static List<MealWithExceed> getFilteredWithExceededInOnePass2(List<Meal> meals, LocalTime startTime, LocalTime endTime, int caloriesPerDay) {
+        final class Aggregate {
+            private final List<Meal> dailyMeals = new ArrayList<>();
+            private int dailySumOfCalories;
+
+            private void accumulate(Meal meal) {
+                dailySumOfCalories += meal.getCalories();
+                if (TimeUtil.isBetween(meal.getDateTime().toLocalTime(), startTime, endTime)) {
+                    dailyMeals.add(meal);
+                }
+            }
+
+            // never invoked if the upstream is sequential
+            private Aggregate combine(Aggregate that) {
+                this.dailySumOfCalories += that.dailySumOfCalories;
+                this.dailyMeals.addAll(that.dailyMeals);
+                return this;
+            }
+
+            private Stream<MealWithExceed> finisher() {
+                final boolean exceed = dailySumOfCalories > caloriesPerDay;
+                return dailyMeals.stream().map(meal -> createWithExceed(meal, exceed));
+            }
+        }
+
+        Collection<Stream<MealWithExceed>> values = meals.stream()
+                .collect(Collectors.groupingBy(Meal::getDate,
+                        Collector.of(Aggregate::new, Aggregate::accumulate, Aggregate::combine, Aggregate::finisher))
+                ).values();
+
+        return values.stream().flatMap(identity()).collect(toList());
+    }
+
     public static MealWithExceed createWithExceed(Meal meal, boolean exceeded) {
         return new MealWithExceed(meal.getDateTime(), meal.getDescription(), meal.getCalories(), exceeded);
     }