Lesson 57 (stream collect collector)

src/com/walking/lesson57_stream_collect_collector/Main.java

@@ -1,5 +1,7 @@
 package com.walking.lesson57_stream_collect_collector;
 
+import java.util.stream.Stream;
+
 /**
  * Необходимо реализовать набор функций для HRM-системы компании,
  * каждая из которых сводится к формированию определенной статистики на базе информации

src/com/walking/lesson57_stream_collect_collector/model/Department.java

@@ -6,4 +6,28 @@ public class Department {
     private String name;
     private int vacancyAmount;
     private List<Employee> employees;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getVacancyAmount() {
+        return vacancyAmount;
+    }
+
+    public void setVacancyAmount(int vacancyAmount) {
+        this.vacancyAmount = vacancyAmount;
+    }
+
+    public List<Employee> getEmployees() {
+        return employees;
+    }
+
+    public void setEmployees(List<Employee> employees) {
+        this.employees = employees;
+    }
 }

src/com/walking/lesson57_stream_collect_collector/model/Employee.java

@@ -1,8 +1,64 @@
 package com.walking.lesson57_stream_collect_collector.model;
 
+import java.util.Objects;
+
 public class Employee {
     private String name;
     private boolean isMale;
     private String position;
     private int age;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public boolean isMale() {
+        return isMale;
+    }
+
+    public void setMale(boolean male) {
+        isMale = male;
+    }
+
+    public String getPosition() {
+        return position;
+    }
+
+    public void setPosition(String position) {
+        this.position = position;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        Employee employee = (Employee) o;
+        return isMale == employee.isMale && age == employee.age && Objects.equals(name,
+                employee.name);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Objects.hashCode(name);
+        result = 31 * result + Boolean.hashCode(isMale);
+        result = 31 * result + age;
+        return result;
+    }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task1.java

@@ -4,13 +4,18 @@
 import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте список всех сотрудников компании.
  */
 public class Task1 implements StatisticTask<List<Employee>> {
     @Override
     public List<Employee> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .distinct()
+                          .collect(Collectors.toList());
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task10.java

@@ -5,13 +5,18 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте список сотрудников по каждому имени.
  */
 public class Task10 implements StatisticTask<Map<String, List<Employee>>> {
     @Override
     public Map<String, List<Employee>> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .distinct()
+                          .collect(Collectors.groupingBy(Employee::getName));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task11.java

@@ -5,6 +5,9 @@
 
 import java.util.List;
 import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте список сотрудников по каждому имени.
@@ -13,6 +16,10 @@
 public class Task11 implements StatisticTask<SortedMap<String, List<Employee>>> {
     @Override
     public SortedMap<String, List<Employee>> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .distinct()
+                          .collect(Collectors.groupingBy(Employee::getName, TreeMap::new, Collectors.toList()));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task12.java

@@ -1,16 +1,22 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте количество сотрудников старше 50 по каждому департаменту.
  */
 public class Task12 implements StatisticTask<Map<String, Long>> {
     @Override
     public Map<String, Long> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .collect(Collectors.groupingBy(Department::getName, Collectors.flatMapping(
+                                  d -> d.getEmployees()
+                                        .stream()
+                                        .filter(e -> e.getAge() > 50), Collectors.counting())));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task13.java

@@ -1,15 +1,22 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте информацию о среднем возрасте сотрудников компании.
  */
 public class Task13 implements StatisticTask<Double> {
     @Override
     public Double calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .distinct()
+                          .collect(Collectors.averagingDouble(Employee::getAge));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task14.java

@@ -1,16 +1,21 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте информацию о среднем возрасте сотрудников по каждому департаменту.
  */
 public class Task14 implements StatisticTask<Map<String, Double>> {
     @Override
     public Map<String, Double> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .collect(Collectors.groupingBy(Department::getName, Collectors.flatMapping(
+                                  d -> d.getEmployees()
+                                        .stream(), Collectors.averagingDouble(Employee::getAge))));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task15.java

@@ -1,16 +1,26 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте соотношение женщин и мужчин по каждому департаменту.
  */
 public class Task15 implements StatisticTask<Map<String, Double>> {
     @Override
     public Map<String, Double> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .collect(Collectors.groupingBy(Department::getName, Collectors.teeing(Collectors.flatMapping(
+                                          d -> d.getEmployees()
+                                                .stream()
+                                                .filter(e -> !e.isMale()), Collectors.counting()), Collectors.flatMapping(
+                                          d -> d.getEmployees()
+                                                .stream()
+                                                .filter(Employee::isMale), Collectors.counting()),
+                                  (womenCount, manCount) -> (double) womenCount / manCount)));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task16.java

@@ -1,9 +1,11 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * По каждой должности (position) предоставьте список сотрудников,
@@ -12,6 +14,11 @@
 public class Task16 implements StatisticTask<Map<String, List<String>>> {
     @Override
     public Map<String, List<String>> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .distinct()
+                          .collect(Collectors.groupingBy(Employee::getPosition,
+                                  Collectors.mapping(Employee::getName, Collectors.toList())));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task17.java

@@ -1,16 +1,26 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте информацию по максимальному возрасту сотрудников в каждом из департаментов.
  */
 public class Task17 implements StatisticTask<Map<String, Integer>> {
     @Override
     public Map<String, Integer> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .collect(Collectors.toMap(Department::getName, d -> d.getEmployees()
+                                                                               .stream()
+                                                                               .mapToInt(Employee::getAge)
+                                                                               .max()
+                                                                               .orElse(0)));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task18.java

@@ -5,13 +5,18 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте список сотрудников женского пола и сотрудников мужского пола в компании.
  */
 public class Task18 implements StatisticTask<Map<Boolean, List<Employee>>> {
     @Override
     public Map<Boolean, List<Employee>> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .distinct()
+                          .collect(Collectors.partitioningBy(Employee::isMale));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task19.java

@@ -5,13 +5,17 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте список сотрудников женского пола и сотрудников мужского пола по каждому департаменту.
  */
 public class Task19 implements StatisticTask<Map<String, Map<Boolean, List<Employee>>>> {
     @Override
     public Map<String, Map<Boolean, List<Employee>>> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .collect(Collectors.groupingBy(Department::getName, Collectors.flatMapping(
+                                  d -> d.getEmployees()
+                                        .stream(), Collectors.partitioningBy(Employee::isMale))));
     }
 }

src/com/walking/lesson57_stream_collect_collector/task/Task2.java

@@ -1,16 +1,22 @@
 package com.walking.lesson57_stream_collect_collector.task;
 
 import com.walking.lesson57_stream_collect_collector.model.Department;
+import com.walking.lesson57_stream_collect_collector.model.Employee;
 
 import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 /**
  * Предоставьте полный перечень оригинальных имен сотрудников компании.
  */
 public class Task2 implements StatisticTask<Set<String>> {
     @Override
     public Set<String> calculate(List<Department> departments) {
-        return null;
+        return departments.stream()
+                          .flatMap(d -> d.getEmployees()
+                                         .stream())
+                          .map(Employee::getName)
+                          .collect(Collectors.toSet());
     }
 }