Merge pull request #5237 from MherBaghinyan/BAEL-2180

Bael 2180

core-java-collections/src/main/java/com/baeldung/performance/Employee.java

@@ -44,4 +44,12 @@ public class Employee {
         result = 31 * result + name.hashCode();
         return result;
     }
+
+    @Override
+    public String toString() {
+        return "Employee{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                '}';
+    }
 }

core-java-collections/src/main/java/com/baeldung/sort/Employee.java

@@ -0,0 +1,60 @@
+package com.baeldung.sort;
+
+public class Employee implements Comparable<Employee> {
+
+    private Long id;
+    private String name;
+
+    public Employee(Long id, String name) {
+        this.name = name;
+        this.id = id;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Employee employee = (Employee) o;
+
+        if (!id.equals(employee.id)) return false;
+        return name.equals(employee.name);
+
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id.hashCode();
+        result = 31 * result + name.hashCode();
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "Employee{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                '}';
+    }
+
+    @Override
+    public int compareTo(Employee employee) {
+        return (int)(this.id - employee.getId());
+    }
+}

core-java-collections/src/main/java/com/baeldung/sort/SortHashMap.java

@@ -0,0 +1,104 @@
+package com.baeldung.sort;
+
+import com.google.common.base.Functions;
+import com.google.common.collect.ImmutableSortedMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Ordering;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class SortHashMap {
+
+    private static Map<String, Employee> map = new HashMap<>();
+
+    public static void main(String[] args) {
+
+        initialize();
+
+        treeMapSortByKey();
+
+        arrayListSortByValue();
+        arrayListSortByKey();
+
+        sortStream();
+
+        sortGuava();
+
+        addDuplicates();
+
+        treeSetByKey();
+        treeSetByValue();
+
+    }
+
+    private static void sortGuava() {
+        final Ordering naturalOrdering =
+        Ordering.natural().onResultOf(Functions.forMap(map, null));
+
+        System.out.println(ImmutableSortedMap.copyOf(map, naturalOrdering));
+    }
+
+    private static void sortStream() {
+        map.entrySet().stream()
+                .sorted(Map.Entry.<String, Employee>comparingByKey().reversed())
+                .forEach(System.out::println);
+
+        Map<String, Employee> result = map.entrySet().stream()
+                .sorted(Map.Entry.comparingByValue())
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
+                (oldValue, newValue) -> oldValue, LinkedHashMap::new));
+
+        result.entrySet().forEach(System.out::println);
+    }
+
+    private static void treeSetByValue() {
+        SortedSet<Employee> values = new TreeSet<>(map.values());
+        System.out.println(values);
+    }
+
+    private static void treeSetByKey() {
+        SortedSet<String> keysSet = new TreeSet<>(map.keySet());
+        System.out.println(keysSet);
+    }
+
+    private static void treeMapSortByKey() {
+        TreeMap<String, Employee> sorted = new TreeMap<>(map);
+        sorted.putAll(map);
+
+        sorted.entrySet().forEach(System.out::println);
+
+    }
+
+    private static void arrayListSortByValue() {
+        List<Employee> employeeById = new ArrayList<>(map.values());
+
+        Collections.sort(employeeById);
+
+        System.out.println(employeeById);
+    }
+
+    private static void arrayListSortByKey() {
+        List<String> employeeByKey = new ArrayList<>(map.keySet());
+        Collections.sort(employeeByKey);
+        System.out.println(employeeByKey);
+    }
+
+    private static void initialize() {
+        Employee employee1 = new Employee(1L, "Mher");
+        map.put(employee1.getName(), employee1);
+        Employee employee2 = new Employee(22L, "Annie");
+        map.put(employee2.getName(), employee2);
+        Employee employee3 = new Employee(8L, "John");
+        map.put(employee3.getName(), employee3);
+        Employee employee4 = new Employee(2L, "George");
+        map.put(employee4.getName(), employee4);
+    }
+
+    private static void addDuplicates() {
+        Employee employee5 = new Employee(1L, "Mher");
+        map.put(employee5.getName(), employee5);
+        Employee employee6 = new Employee(22L, "Annie");
+        map.put(employee6.getName(), employee6);
+    }
+}