package com.java8tutorial;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Stream;
public class TestStreaming {
public static void main(String[] args) {
// Print the stream
Stream<String> stream = Stream.of(“a”, “b”, “c”, “d”);
stream.forEach(System.out::println);
//Output
/*a
b
c
d*/
//Print from source
Collection<String> collection = Arrays.asList(“John”, “Doe”, “Mark”, “Johnson”);
Stream<String> stream1 = collection.stream();
stream1.forEach(System.out::println);
/*
* John
Doe
Mark
Johnson */
//Print from list
List<String> list = Arrays.asList(“John”, “Doe”, “Mark”, “Johnson”);
Stream<String> stream2 = collection.stream();
stream2.forEach(System.out::println);
//Print from source
Set<String> set = new HashSet<>(list);
Stream<String> stream3 = collection.stream();
stream3.forEach(System.out::println);
String[] strArray = {“a”, “b”, “c”, “d”};
Stream<String> stream4 = Arrays.stream(strArray);
stream4.forEach(System.out::println);
String[] strrArray = {“John”, “Doe”, “Mark”, “Johnson”};
Stream<String> stream5 = Arrays.stream(strrArray);
stream5.forEach(System.out::println);
}
}
//Output
a
b
c
d
John
Doe
Mark
Johnson
John
Doe
Mark
Johnson
John
Doe
Mark
Johnson
a
b
c
d
John
Doe
Mark
Johnson
Stream Api
package com.java8tutorial;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
public class StreamingExample {
public static void main(String[] args) {
//Java 7 method
List<Product> list = new ArrayList<Product>();
for(Product product : getProducts()) {
if(product.getPrice()>0) {
list.add(product);
}
}
for(Product product : list) {
System.out.println(product);
}
/*
* Output:
Product [id=1, name=Zinc, price=200.0]
Product [id=2, name=Bed, price=120.0]
Product [id=3, name=Robber, price=65.0]
Product [id=4, name=Table, price=95.0]
Product [id=5, name=Television, price=400.0]*/
//Java 8
List<Product> list1 =list.stream().filter((product)->product.getPrice()
>0).collect(Collectors.toList());
list1.forEach(System.out::println);
/*
* Output:
Product [id=1, name=Zinc, price=200.0]
Product [id=2, name=Bed, price=120.0]
Product [id=3, name=Robber, price=65.0]
Product [id=4, name=Table, price=95.0]
Product [id=5, name=Television, price=400.0]*/
getProducts()
.stream().filter((product)->product.getPrice()>0)
.forEach(System.out::println);
/*
* Output:
Product [id=1, name=Zinc, price=200.0]
Product [id=2, name=Bed, price=120.0]
Product [id=3, name=Robber, price=65.0]
Product [id=4, name=Table, price=95.0]
Product [id=5, name=Television, price=400.0]*/
}
private static List<Product> getProducts(){
List<Product> list = new ArrayList<Product>();
list.add(new Product(1, “Zinc”, 200));
list.add(new Product(2, “Bed”, 120));
list.add(new Product(3, “Robber”, 65));
list.add(new Product(4, “Table”, 95));
list.add(new Product(5, “Television”, 400));
return list;
}
}
package com.java8tutorial;
public class Product {
private int id;
private String name;
private float price;
public Product(int id, String name, float price) {
super();
this.id = id;
this.name = name;
this.price = price;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
@Override
public String toString() {
return “Product [id=” + id + “, name=” + name + “, price=” + price + “]”;
}
}
package com.sorting.stream;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
public class SortTutorial {
public static void main(String[] args) {
List<String> list = new ArrayList<String>();
list.add(“Mango”);
list.add(“Gova”);
list.add(“Pinapple”);
list.add(“Pear”);
List<String> sortedList=list.stream().sorted(Comparator.naturalOrder()).collect(Collectors.toList());
System.out.println(sortedList);
//Lambad expression
List<String> sortedList0=list.stream().sorted((o1,o2)->o1.compareTo(o2)).collect(Collectors.toList());
System.out.println(sortedList0);
//output: [Gova, Mango, Pear, Pinapple]
//output: [Gova, Mango, Pear, Pinapple]
List<String> sortedList1=list.stream().sorted().collect(Collectors.toList());
System.out.println(sortedList1);
//output: [Gova, Mango, Pear, Pinapple]
//Descending order
List<String> sortedList2=list.stream().sorted(Comparator.reverseOrder()).collect(Collectors.toList());
System.out.println(sortedList2);
//Lambad expression
List<String> sortedList3=list.stream().sorted((o1,o2)->o2.compareTo(o1)).collect(Collectors.toList());
System.out.println(sortedList3);
//Output:
//[Pinapple, Pear, Mango, Gova]
//[Pinapple, Pear, Mango, Gova]
}
}
public class Product {
private int id;
private String name;
private float price;
public Product(int id, String name, float price) {
super();
this.id = id;
this.name = name;
this.price = price;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
@Override
public String toString() {
return “Product [id=” + id + “, name=” + name + “, price=” + price + “]”;
}
}
package com.java8tutorial;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
public class StreamingExample {
public static void main(String[] args) {
//Java 7 method
List<Product> list = new ArrayList<Product>();
for(Product product : getProducts()) {
if(product.getPrice()>0) {
list.add(product);
}
}
for(Product product : list) {
System.out.println(product);
}
/*
* Output:
Product [id=1, name=Zinc, price=200.0]
Product [id=2, name=Bed, price=120.0]
Product [id=3, name=Robber, price=65.0]
Product [id=4, name=Table, price=95.0]
Product [id=5, name=Television, price=400.0]*/
//Java 8
List<Product> list1 =list.stream().filter((product)->product.getPrice()
>0).collect(Collectors.toList());
list1.forEach(System.out::println);
/*
* Output:
Product [id=1, name=Zinc, price=200.0]
Product [id=2, name=Bed, price=120.0]
Product [id=3, name=Robber, price=65.0]
Product [id=4, name=Table, price=95.0]
Product [id=5, name=Television, price=400.0]*/
getProducts()
.stream().filter((product)->product.getPrice()>0)
.forEach(System.out::println);
/*
* Output:
Product [id=1, name=Zinc, price=200.0]
Product [id=2, name=Bed, price=120.0]
Product [id=3, name=Robber, price=65.0]
Product [id=4, name=Table, price=95.0]
Product [id=5, name=Television, price=400.0]*/
}
private static List<Product> getProducts(){
List<Product> list = new ArrayList<Product>();
list.add(new Product(1, “Zinc”, 200));
list.add(new Product(2, “Bed”, 120));
list.add(new Product(3, “Robber”, 65));
list.add(new Product(4, “Table”, 95));
list.add(new Product(5, “Television”, 400));
return list;
}
}
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
public class SortTutorial {
public static void main(String[] args) {
List<String> list = new ArrayList<String>();
list.add(“Mango”);
list.add(“Gova”);
list.add(“Pinapple”);
list.add(“Pear”);
List<String> sortedList=list.stream().sorted(Comparator.naturalOrder()).collect(Collectors.toList());
System.out.println(sortedList);
//Lambad expression
List<String> sortedList0=list.stream().sorted((o1,o2)->o1.compareTo(o2)).collect(Collectors.toList());
System.out.println(sortedList0);
List<String> sortedList1=list.stream().sorted().collect(Collectors.toList());
System.out.println(sortedList1);
//Descending order
List<String> sortedList2=list.stream().sorted(Comparator.reverseOrder()).collect(Collectors.toList());
System.out.println(sortedList2);
//Lambad expression
List<String> sortedList3=list.stream().sorted((o1,o2)->o2.compareTo(o1)).collect(Collectors.toList());
System.out.println(sortedList3);
}
}
//output: [Gova, Mango, Pear, Pinapple]
//output: [Gova, Mango, Pear, Pinapple]
package adding;
//Program to find the missing number
import java.util.HashSet;
public class MissingNumber {
public int solution(int[] A) {
HashSet<Integer> x = new HashSet<Integer>();
for(int i=1; i<=A.length+1; i++) {
x.add(i);
}
for(int a : A) {
x.remove(a);
}
return x.iterator().next();
}
public static void main(String[] args) {
MissingNumber mn = new MissingNumber();
System.out.println(mn.solution(new int[] {-1, -3}));
}}
Output: 1
package learningPractise;
//Printing strings
public class Duplicates {
static void findDuplicates(String str) {
String[] x = str.split(” “);
for(String temp : x) {
System.out.println(temp);
}
}
public static void main(String[] args) {
findDuplicates(“The Lord is is is my my shephard”);
}
}
/*Output: The
Lord
is
is
is
my
my
shephard*/
//Finding words
package learningPractise;
import java.util.HashMap;
public class Duplicates {
static void findDuplicates(String str) {
HashMap<String, Integer> h = new HashMap<>();
String[] x = str.split(” “);
for(String temp : x) {
h.put(temp, 1);
}
System.out.println(h);
}
public static void main(String[] args) {
findDuplicates(“The Lord is is is my my shephard”);
}
}
/*Output: {The=1, Lord=1, shephard=1, is=1, my=1}*/
//Find number of Occurance of a word
package learningPractise;
import java.util.HashMap;
public class Duplicates {
static void findDuplicates(String str) {
HashMap<String, Integer> h = new HashMap<>();
String[] x = str.split(” “);
for(String temp : x) {
if(h.get(temp)!=null) {
h.put(temp, h.get(temp) + 1);
}
else {
h.put(temp, 1);
}
}
System.out.println(h);
}
public static void main(String[] args) {
findDuplicates(“The Lord is is is my my shephard”);
}
}
/*Output: {The=1, Lord=1, shephard=1, is=3, my=2}
*/
//Find duplicate words
import java.util.HashMap;
import java.util.Iterator;
public class Duplicates {
static void findDuplicates(String str) {
HashMap<String, Integer> h = new HashMap<>();
String[] x = str.split(” “);
for(String temp : x) {
if(h.get(temp)!=null) {
h.put(temp, h.get(temp) + 1);
}
else {
h.put(temp, 1);
}
}
Iterator<String> temp = h.keySet().iterator();
while(temp.hasNext()) {
String n = temp.next();
if(h.get(n)> 1) {
System.out.println(“Words : ” + n + ” appeared ” + h.get(n) + ” times”);
}
}
}
public static void main(String[] args) {
findDuplicates(“The Lord is is is my my shephard”);
}
}
/*Output: Words : is appeared 3 times
Words : my appeared 2 times
*/
import java.util.HashMap;
import java.util.Iterator;
public class Duplicates {
static void findDuplicates(String str) {
HashMap<String, Integer> h = new HashMap<>();
String[] x = str.split(” “);
for(String temp : x) {
if(h.get(temp)!=null) {
h.put(temp, h.get(temp) + 1);
}
else {
h.put(temp, 1);
}
}
Iterator<String> temp = h.keySet().iterator();
while(temp.hasNext()) {
String n = temp.next();
if(h.get(n)> 1) {
System.out.println(“Words : ” + n + ” appeared ” + h.get(n) + ” times”);
}
}
}
static void findDuplicateCharacters(String str) {
HashMap<Character, Integer> c = new HashMap<>();
for(int i=0;i<str.length();i++) {
char a = str.charAt(i);
if(c.get(a)!=null) {
c.put(a, c.get(a)+1);
}
c.put(a, 1);
}
System.out.println(c);
}
public static void main(String[] args) {
findDuplicates(“The Lord is is is my my shephard”);
findDuplicateCharacters(“abacdeceffghddij”);
}
}
/*Words : is appeared 3 times
Words : my appeared 2 times
{a=1, b=1, c=1, d=1, e=1, f=1, g=1, h=1, i=1, j=1}
import java.util.HashMap;
import java.util.Iterator;
public class Duplicates {
static void findDuplicates(String str) {
HashMap<String, Integer> h = new HashMap<>();
String[] x = str.split(” “);
for(String temp : x) {
if(h.get(temp)!=null) {
h.put(temp, h.get(temp) + 1);
}
else {
h.put(temp, 1);
}
}
Iterator<String> temp = h.keySet().iterator();
while(temp.hasNext()) {
String n = temp.next();
if(h.get(n)> 1) {
System.out.println(“Words : ” + n + ” appeared ” + h.get(n) + ” times”);
}
}
}
static void findDuplicateCharacters(String str) {
HashMap<Character, Integer> c = new HashMap<>();
for(int i=0;i<str.length();i++) {
char a = str.charAt(i);
if(c.get(a)!=null) {
c.put(a, c.get(a)+1);
}
else {
c.put(a, 1);
}
}
System.out.println(c);
}
public static void main(String[] args) {
findDuplicates(“The Lord is is is my my shephard”);
findDuplicateCharacters(“abacdeceffghddij”);
}
}
/*Words : is appeared 3 times
Words : my appeared 2 times
{a=2, b=1, c=2, d=3, e=2, f=2, g=1, h=1, i=1, j=1}
*/
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collectors;
public class EmployeeProgram {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<Employee> list = new ArrayList<>();
list.add(new Employee(1, "John Doe", 111, "inactive", 25000));
list.add(new Employee(2, "Mark Bruce", 221, "active", 55000));
list.add(new Employee(3, "Gary King", 221, "active", 85000));
list.add(new Employee(4, "Jerry Khan", 111, "active", 80000));
list.add(new Employee(5, "Congo Box", 111, "active", 66000));
//List all employees by department
list.stream().collect(Collectors.groupingBy(Employee::getDeptId, Collectors.toList()));
Map<Integer, List<Employee>>listBasedOnDept=list.stream().collect(Collectors.groupingBy(Employee::getDeptId, Collectors.toList()));
listBasedOnDept.entrySet().forEach(x -> {
System.out.println(x.getKey() + "--" + x.getValue()
);
});
/*System.out.println("List all employees by department ....");
221--[Employee [empid=2, empName=Mark Bruce, deptId=221, status=active, salary=55000], Employee [empid=3, empName=Gary King, deptId=221, status=active, salary=85000]]
111--[Employee [empid=1, empName=John Doe, deptId=111, status=inactive, salary=25000], Employee [empid=4, empName=Jerry Khan, deptId=111, status=active, salary=80000], Employee [empid=5, empName=Congo Box, deptId=111, status=active, salary=66000]]*/
//Counting no. of departments and employees in each department
Map<Integer, Long> empCountDept = list.stream().collect(Collectors.groupingBy(Employee::getDeptId, Collectors.counting()));
empCountDept.entrySet().forEach(x-> {
System.out.println(x.getKey() + "--" + x.getValue());
});
/*System.out.println("//Counting no. of departments and employees in each department ....");
221--2
111--3*/
//Count active and inactive employees
Long activeEmpCount = list.stream().filter(x -> "active".equals(x.getStatus())).count();
Long inactiveEmpCount = list.stream().filter(x -> "inactive".equals(x.getStatus())).count();
System.out.println("active emp count -- " + activeEmpCount);
System.out.println("inactive emp count -- " + inactiveEmpCount);
/*System.out.println("Count active and inactive employees ....");
active emp count -- 4
inactive emp count -- 1*/
System.out.println("Print maximum and minimum salaries ....");
//Print maximum and minimum salaries
Optional<Employee> emp1 =list.stream().max(Comparator.comparing(Employee::getSalary));
Optional<Employee> emp2 =list.stream().min(Comparator.comparing(Employee::getSalary));
System.out.println(emp1);
System.out.println(emp2);
/* Print maximum and minimum salaries ....
Optional[Employee [empid=3, empName=Gary King, deptId=221, status=active, salary=85000]]
Optional[Employee [empid=1, empName=John Doe, deptId=111, status=inactive, salary=25000]]*/
System.out.println("List department and top salary earners ....");
//List department and top salary earners
Map<Integer, Optional<Employee>> topSalaryEmpDept = list.stream().collect(Collectors.groupingBy(Employee::getDeptId,
Collectors.reducing(BinaryOperator.maxBy(Comparator.comparing(Employee::getSalary)))));
topSalaryEmpDept.entrySet().forEach(x-> {
System.out.println("Dept " + x.getKey() + " topEmp " + x.getValue());
});
/* List department and top salary earners ....
Dept 221 topEmp Optional[Employee [empid=3, empName=Gary King, deptId=221, status=active, salary=85000]]
Dept 111 topEmp Optional[Employee [empid=4, empName=Jerry Khan, deptId=111, status=active, salary=80000]]*/
}}