sort map using lambda

Author: basahota

sort/SortMapDemo.java

@@ -0,0 +1,50 @@
+package com.javatechie.stream.sort;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.TreeMap;
+
+import com.javatechie.stream.api.example.Employee;
+
+public class SortMapDemo {
+
+	public static void main(String[] args) {
+
+		Map<String, Integer> map = new HashMap<>();
+		map.put("eight", 8);
+		map.put("four", 4);
+		map.put("ten", 10);
+		map.put("two", 2);
+
+		Map<Employee, Integer> employeeMap = new TreeMap<>((o1, o2) -> (int) (o2.getSalary() - o1.getSalary()));
+		employeeMap.put(new Employee(176, "Roshan", "IT", 600000), 60);
+		employeeMap.put(new Employee(388, "Bikash", "CIVIL", 900000), 90);
+		employeeMap.put(new Employee(470, "Bimal", "DEFENCE", 500000), 50);
+		employeeMap.put(new Employee(624, "Sourav", "CORE", 400000), 40);
+		employeeMap.put(new Employee(284, "Prakash", "SOCIAL", 1200000), 120);
+
+		System.out.println(employeeMap);
+
+		List<Entry<String, Integer>> entries = new ArrayList<>(map.entrySet());
+		Collections.sort(entries, (o1, o2) -> o1.getKey().compareTo(o2.getKey()));
+
+		/*
+		 * for (Entry<String, Integer> entry : entries) {
+		 * System.out.println(entry.getKey() + "   " + entry.getValue()); }
+		 */
+
+		// map.entrySet().stream().sorted(Map.Entry.comparingByKey()).forEach(System.out::println);
+		System.out.println("****************************");
+		// map.entrySet().stream().sorted(Map.Entry.comparingByValue()).forEach(System.out::println);
+
+		employeeMap.entrySet().stream()
+				.sorted(Map.Entry.comparingByKey(Comparator.comparing(Employee::getDept).reversed()))
+				.forEach(System.out::println);
+
+	}
+}