java 8 stream

Author: basahota

demo/ForEachDemo.java

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+package com.javatechie.stream.demo;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+
+public class ForEachDemo {
+
+	// filter----> conditional check
+
+	public static void main(String[] args) {
+
+		List<String> list = new ArrayList<>();
+		list.add("Murrit");
+		list.add("john");
+		list.add("piter");
+		list.add("marek");
+		list.add("mac");
+
+		for (String s : list) {
+			if (s.startsWith("m")) {
+				System.out.println(s);
+			}
+		}
+
+		list.stream().filter(t -> t.startsWith("m")).forEach(t -> System.out.println(t));
+
+		Map<Integer, String> map = new HashMap<>();
+
+		map.put(1, "a");
+		map.put(2, "b");
+		map.put(3, "c");
+		map.put(4, "d");
+
+		/*
+		 * map.forEach((key,value)->System.out.println(key+": "+value));*/
+		
+		  map.entrySet().stream().filter(k->k.getKey()%2==0).forEach(obj->System.out.println(obj));
+		 
+
+		/*
+		 * Consumer<String> consumer=(t)->System.out.println(t); for(String s1:list) {
+		 * consumer.accept(s1); }
+		 */
+
+	}
+}

example/DataBase.java

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+package com.javatechie.stream.api.example;
+
+import java.util.ArrayList;
+import java.util.List;
+//DAO layer
+public class DataBase {
+
+	public static List<Employee> getEmployees() {
+		List<Employee> list = new ArrayList<>();
+		list.add(new Employee(176, "Roshan", "IT", 600000));
+		list.add(new Employee(388, "Bikash", "CIVIL", 900000));
+		list.add(new Employee(470, "Bimal", "DEFENCE", 500000));
+		list.add(new Employee(624, "Sourav", "CORE", 400000));
+		list.add(new Employee(176, "Prakash", "SOCIAL", 1200000));
+		return list;
+	}
+
+}

example/Employee.java

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+package com.javatechie.stream.api.example;
+
+public class Employee {
+
+	private int id;
+	private String name;
+	private String dept;
+	private long salary;
+
+	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 String getDept() {
+		return dept;
+	}
+
+	public void setDept(String dept) {
+		this.dept = dept;
+	}
+
+	public long getSalary() {
+		return salary;
+	}
+
+	public void setSalary(long salary) {
+		this.salary = salary;
+	}
+
+	public Employee(int id, String name, String dept, long salary) {
+		super();
+		this.id = id;
+		this.name = name;
+		this.dept = dept;
+		this.salary = salary;
+	}
+
+	public Employee() {
+		super();
+		// TODO Auto-generated constructor stub
+	}
+
+	@Override
+	public String toString() {
+		return "Employee [id=" + id + ", name=" + name + ", dept=" + dept + ", salary=" + salary + "]";
+	}
+
+}

example/TaxService.java

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+package com.javatechie.stream.api.example;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class TaxService {
+
+	public static List<Employee> evaluateTaxUsers(String input) {
+		return (input.equalsIgnoreCase("tax"))
+				? DataBase.getEmployees().stream().filter(emp -> emp.getSalary() > 500000).collect(Collectors.toList())
+				: DataBase.getEmployees().stream().filter(emp -> emp.getSalary() <= 500000)
+						.collect(Collectors.toList());
+
+	}
+
+	public static void main(String[] args) {
+		System.out.println(evaluateTaxUsers("tax"));
+	}
+}