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I was wondering new features in Java 8 and wanted to play around with Lambda expressions. So I’ve eventually ended up preparing some collection examples. Hope you’ll easily summarize and understand it
The Code
package com.oracle.lambda;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;
public class CollectionExample {
public static void main(String[] args) {
List<Developers> developers = new ArrayList<>(Arrays.asList(
new Developers("Bjarne", "C++", "M", 6000),
new Developers("Tugrul", "Java", "M", 4500),
new Developers("James", "Java", "M", 9000),
new Developers("Ada", "Ada", "F", 6000),
new Developers("Diane", "C++", "F", 4000),
new Developers("Bill", ".NOT", "M", 2000),
new Developers("Rebecca", "C++", "F", 8500),
new Developers("Laura", "Java", "F", 7500),
new Developers("Adam", "Java", "M", 9800),
new Developers("Jane", "C++", "F", 7500),
new Developers("Mark", "Java", "M", 7500)
)
);
System.out.println("\n\nList of Developers");
System.out.println("Name\tLanguage\tGender\tSalary");
developers.forEach(dev -> System.out.println(dev.getName() + '\t' + dev.getLanguage() + '\t' + '\t' + dev.getGender() + '\t' + dev.getSalary()));
//Filter developers by salary
Predicate<Developers> salaryFilter = dev -> (dev.getSalary() >= 4500);
//Filter developers by gender
Predicate<Developers> genderFilter = dev -> (dev.getGender().equals("M"));
//Filter developers by language
Predicate<Developers> languageFilter = dev -> (dev.getLanguage().equals("Java"));
System.out.println("\n\nList of Developers - Sort by Male Java Developers earn 4500 and more");
System.out.println("Name\tLanguage\tGender\tSalary");
//Apply filter
developers.stream()
.filter(salaryFilter)
.filter(genderFilter)
.filter(languageFilter)
.forEach(dev -> System.out.println(dev.getName() + '\t' + dev.getLanguage() + '\t' + '\t' + dev.getGender() + '\t' + dev.getSalary()));
System.out.println("\n\nList of Developers - Limited to 3 of them");
System.out.println("Name\tLanguage\tGender\tSalary");
//Apply filter
developers.stream()
.limit(3)
.forEach(dev -> System.out.println(dev.getName() + '\t' + dev.getLanguage() + '\t' + '\t' + dev.getGender() + '\t' + dev.getSalary()));
System.out.println("\n\nList of Developers - Sorted by Name Ascending");
System.out.println("Name\tLanguage\tGender\tSalary");
//Apply filter
developers.stream()
.sorted((dev1, dev2) -> (dev1.getName().compareTo(dev2.getName())))
.forEach(dev -> System.out.println(dev.getName() + '\t' + dev.getLanguage() + '\t' + '\t' + dev.getGender() + '\t' + dev.getSalary()));
System.out.println("\n\nList of Developers - Sorted by Salary Ascending");
System.out.println("Name\tLanguage\tGender\tSalary");
//Apply filter
developers.stream()
.sorted((dev1, dev2) -> (dev1.getSalary() - dev2.getSalary()))
.forEach(dev -> System.out.println(dev.getName() + '\t' + dev.getLanguage() + '\t' + '\t' + dev.getGender() + '\t' + dev.getSalary()));
System.out.println("\n\nThe Developer earning the lowest salary");
System.out.println("Name\tLanguage\tGender\tSalary");
//Apply filter
Developers developerMin = developers.stream()
.min((dev1, dev2) -> (dev1.getSalary() - dev2.getSalary()))
.get();
System.out.println(developerMin.getName() + '\t' + developerMin.getLanguage() + '\t' + '\t' + developerMin.getGender() + '\t' + developerMin.getSalary());
System.out.println("\n\nThe Developer earning the highest salary");
System.out.println("Name\tLanguage\tGender\tSalary");
//Apply filter
Developers developerMax = developers.stream()
.max((dev1, dev2) -> (dev1.getSalary() - dev2.getSalary()))
.get();
System.out.println(developerMax.getName() + '\t' + developerMax.getLanguage() + '\t' + '\t' + developerMax.getGender() + '\t' + developerMax.getSalary());
}
}
class Developers {
private String name;
private String language;
private String gender;
private int salary;
public Developers(String name, String language, String gender, int salary) {
this.name = name;
this.language = language;
this.gender = gender;
this.salary = salary;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLanguage() {
return language;
}
public void setLanguage(String language) {
this.language = language;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
}
The output
List of Developers Name Language Gender Salary Bjarne C++ M 6000 Tugrul Java M 4500 James Java M 9000 Ada Ada F 6000 Diane C++ F 4000 Bill .NOT M 2000 Rebecca C++ F 8500 Laura Java F 7500 Adam Java M 9800 Jane C++ F 7500 Mark Java M 7500 List of Developers - Sort by Male Java Developers earn 4500 and more Name Language Gender Salary Tugrul Java M 4500 James Java M 9000 Adam Java M 9800 Mark Java M 7500 List of Developers - Limited to 3 of them Name Language Gender Salary Bjarne C++ M 6000 Tugrul Java M 4500 James Java M 9000 List of Developers - Sorted by Name Ascending Name Language Gender Salary Ada Ada F 6000 Adam Java M 9800 Bill .NOT M 2000 Bjarne C++ M 6000 Diane C++ F 4000 James Java M 9000 Jane C++ F 7500 Laura Java F 7500 Mark Java M 7500 Rebecca C++ F 8500 Tugrul Java M 4500 List of Developers - Sorted by Salary Ascending Name Language Gender Salary Bill .NOT M 2000 Diane C++ F 4000 Tugrul Java M 4500 Bjarne C++ M 6000 Ada Ada F 6000 Laura Java F 7500 Jane C++ F 7500 Mark Java M 7500 Rebecca C++ F 8500 James Java M 9000 Adam Java M 9800 The Developer earning the lowest salary Name Language Gender Salary Bill .NOT M 2000 The Developer earning the highest salary Name Language Gender Salary Adam Java M 9800