On branch master

Author: AssouaAlbert

.idea/.gitignore

@@ -0,0 +1,3 @@
+{
+    "java.debug.settings.onBuildFailureProceed": true
+}

.idea/misc.xml

@@ -1,10 +1,13 @@
 package com.javatechie;
 
+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.stream.Collectors;
+import java.util.Map.Entry;
 
 public class NthHighestSalaryDemo {
 
@@ -14,12 +17,12 @@ public static void main(String[] args) {
         map1.put("anil", 1000);
         map1.put("bhavna", 1300);
         map1.put("micael", 1500);
-        map1.put("tom", 1600);//output
+        map1.put("tom", 1600);// output
         map1.put("ankit", 1200);
         map1.put("daniel", 1700);
         map1.put("james", 1400);
 
-        Map.Entry<String, Integer> results = getNthHighestSalary(4, map1);
+        Map.Entry<String, Integer> results = getNthHighestSalaryCustomComparator(3, map1);
         System.out.println(results);
 
         Map<String, Integer> map2 = new HashMap<>();
@@ -31,8 +34,7 @@ public static void main(String[] args) {
         map2.put("tom", 1300);
         map2.put("daniel", 1300);
 
-        //System.out.println(getNthHighestSalary(2, map2));
-
+        // System.out.println(getNthHighestSalary(2, map2));
 
         System.out.println(getDynamicNthHighestSalary(3, map1));
 
@@ -42,15 +44,44 @@ public static Map.Entry<String, Integer> getNthHighestSalary(int num, Map<String
         return map.entrySet().stream()
                 .sorted(Collections.reverseOrder(Map.Entry.comparingByValue()))
                 .collect(Collectors.toList())
-                .get(num - 1);
+                .get(num);
+    }
+
+    /**
+     * 
+     * @param n   : Entry at position to retrieve from sorted map.
+     * @param map : Map to sort in reverse oder.
+     * @return : Return the sorted map.
+     */
+
+    public static Map.Entry<String, Integer> getNthHighestSalaryCustomComparator(int n,
+            Map<String, Integer> map) {
+        Comparator<Entry<String, Integer>> customComparator = new Comparator<Entry<String, Integer>>() {
+            /**
+             * 
+             * @param entry1 : First entry to compare.
+             * @param entry2 : Second entry to compare.
+             * @return : Return 0 if they are equal, 1 if value1 is greater than value2, or
+             *         -1 id value1 is less than value2
+             */
+            @Override
+            public int compare(Entry<String, Integer> entry1, Entry<String, Integer> entry2) {
+                int Value1 = entry1.getValue();
+                int Value2 = entry1.getValue();
+                return Integer.compare(Value2, Value1);
+            }
+        };
+        return map.entrySet().stream()
+                .sorted(Collections.sort(customComparator))
+                .collect(Collectors.toList())
+                .get(n - 1);
     }
 
     public static Map.Entry<Integer, List<String>> getDynamicNthHighestSalary(int num, Map<String, Integer> map) {
         return map.entrySet()
                 .stream()
                 .collect(Collectors.groupingBy(Map.Entry::getValue,
-                        Collectors.mapping(Map.Entry::getKey, Collectors.toList())
-                ))
+                        Collectors.mapping(Map.Entry::getKey, Collectors.toList())))
                 .entrySet()
                 .stream()
                 .sorted(Collections.reverseOrder(Map.Entry.comparingByKey()))

.idea/modules.xml

@@ -1,4 +1,4 @@
-package com.javatechie;
+package com.javatechie.mapVsflatMap;
 
 import java.util.List;
 import java.util.Optional;

.idea/vcs.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" packagePrefix="com.javatechie.lambda.demo" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.vscode/settings.json

@@ -1,4 +1,4 @@
-package com.javatechie;
+package com.javatechie.mapVsflatMap;
 
 import java.util.Arrays;
 import java.util.List;

NthHighestSalaryDemo.java

@@ -1,4 +1,4 @@
-package com.javatechie;
+package com.javatechie.mapVsflatMap;
 
 import java.util.List;
 import java.util.stream.Collectors;

Optional/Customer.java

@@ -0,0 +1,3 @@
+{
+    "java.debug.settings.onBuildFailureProceed": true
+}

java8-map-vs-flatMap.iml

@@ -0,0 +1,14 @@
+# java8
+Java 8 features
+
+Differences between Java 8 Map() Vs flatMap() :
+
+map() | flatMap() | 
+--- | --- |  
+It processes stream of values. | It processes stream of stream of values. 
+It does only mapping. | It performs mapping as well as flattening.
+It’s mapper function produces single value for each input value. | It’s mapper function produces multiple values for each input value. 
+It is a One-To-One mapping. | It is a One-To-Many mapping. 
+Data Transformation : From Stream<T> to Stream<R> | Data Transformation : From Stream<Stream<T> to Stream<R> 
+Use this method when the mapper function is producing a single value for each input value. | Use this method when the mapper function is producing multiple values for each input value. 
+

mapVsflatMap/EkartDataBase.java

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" packagePrefix="com.javatechie.lambda.demo" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

mapVsflatMap/MapVsFlatMap.java

@@ -0,0 +1,11 @@
+Differences between Java 8 Map() Vs flatMap() :
+
+map() | flatMap() | 
+--- | --- |  
+It processes stream of values. | It processes stream of stream of values. 
+It does only mapping. | It performs mapping as well as flattening.
+It’s mapper function produces single value for each input value. | It’s mapper function produces multiple values for each input value. 
+It is a One-To-One mapping. | It is a One-To-Many mapping. 
+Data Transformation : From Stream<T> to Stream<R> | Data Transformation : From Stream<Stream<T> to Stream<R> 
+Use this method when the mapper function is producing a single value for each input value. | Use this method when the mapper function is producing multiple values for each input value. 
+