optional examples (#2537)
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lor6
Eugen
parent
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>com.stackify</groupId>
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<artifactId>core-java-9</artifactId>
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<version>0.0.1-SNAPSHOT</version>
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<dependencies>
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<dependency>
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<groupId>junit</groupId>
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<artifactId>junit</artifactId>
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<version>4.12</version>
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</dependency>
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</dependencies>
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<build>
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<plugins>
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<plugin>
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<artifactId>maven-compiler-plugin</artifactId>
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<version>3.6.2</version>
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<configuration>
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<source>1.9</source>
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<target>1.9</target>
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</configuration>
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</plugin>
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</plugins>
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</build>
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</project>
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package com.stackify.optional;
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public class User {
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private String email;
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private String password;
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public User(String email, String password) {
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super();
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this.email = email;
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this.password = password;
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}
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public String getEmail() {
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return email;
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}
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public void setEmail(String email) {
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this.email = email;
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}
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public String getPassword() {
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return password;
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}
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public void setPassword(String password) {
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this.password = password;
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}
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}
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package com.stackify.optional;
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import org.junit.Test;
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import java.util.Optional;
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import java.util.List;
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import static org.junit.Assert.*;
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import java.util.stream.Collectors;
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public class OptionalTest {
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private User user;
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@Test
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public void whenEmptyOptional_thenGetValueFromOr() {
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User result = Optional.ofNullable(user)
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.or( () -> Optional.of(new User("default","1234"))).get();
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assertEquals(result.getEmail(), "default");
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}
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@Test
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public void whenIfPresentOrElse_thenOk() {
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Optional.ofNullable(user)
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.ifPresentOrElse( u -> System.out.println("User is:" + u.getEmail()), () -> System.out.println("User not found"));
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}
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@Test
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public void whenGetStream_thenOk() {
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User user = new User("john@gmail.com", "1234");
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List<String> emails = Optional.ofNullable(user)
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.stream()
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.filter(u -> u.getEmail() != null && u.getEmail().contains("@"))
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.map( u -> u.getEmail())
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.collect(Collectors.toList());
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assertTrue(emails.size() == 1);
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assertEquals(emails.get(0), user.getEmail());
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}
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}
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>com.stackify</groupId>
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<artifactId>core-java</artifactId>
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<version>0.0.1-SNAPSHOT</version>
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<dependencies>
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<dependency>
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<groupId>junit</groupId>
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<artifactId>junit</artifactId>
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<version>4.12</version>
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</dependency>
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<dependency>
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<groupId>org.apache.logging.log4j</groupId>
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<artifactId>log4j-core</artifactId>
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<version>${log4j2.version}</version>
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</dependency>
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</dependencies>
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<build>
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<plugins>
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<plugin>
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<artifactId>maven-compiler-plugin</artifactId>
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<version>3.5</version>
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<configuration>
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<source>1.8</source>
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<target>1.8</target>
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</configuration>
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</plugin>
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</plugins>
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</build>
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<properties>
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<log4j2.version>2.8.2</log4j2.version>
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</properties>
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</project>
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package com.stackify.optional;
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public class Address {
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private String addressLine;
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private String city;
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private Country country;
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public Address(String addressLine, String city, Country country) {
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super();
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this.addressLine = addressLine;
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this.city = city;
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this.country = country;
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}
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public String getAddressLine() {
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return addressLine;
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}
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public void setAddressLine(String addressLine) {
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this.addressLine = addressLine;
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}
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public String getCity() {
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return city;
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}
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public void setCity(String city) {
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this.city = city;
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}
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public Country getCountry() {
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return country;
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}
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public void setCountry(Country country) {
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this.country = country;
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}
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}
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package com.stackify.optional;
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public class Country {
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private String name;
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private String isocode;
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public Country(String name, String isocode) {
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super();
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this.name = name;
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this.isocode = isocode;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public String getIsocode() {
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return isocode;
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}
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public void setIsocode(String isocode) {
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this.isocode = isocode;
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}
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}
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package com.stackify.optional;
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import java.util.Optional;
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public class User {
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private String email;
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private String password;
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private Address address;
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private String position;
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public User(String email, String password) {
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super();
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this.email = email;
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this.password = password;
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}
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public String getEmail() {
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return email;
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}
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public void setEmail(String email) {
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this.email = email;
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}
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public String getPassword() {
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return password;
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}
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public void setPassword(String password) {
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this.password = password;
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}
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public Address getAddress() {
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return address;
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}
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public void setAddress(Address address) {
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this.address = address;
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}
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public Optional<String> getPosition() {
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return Optional.ofNullable(position);
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}
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public void setPosition(String position) {
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this.position = position;
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}
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}
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package com.stackify.optional.chaining;
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import java.util.Optional;
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public class Address {
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private String addressLine;
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private String city;
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private Country country;
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public Address(String addressLine, String city) {
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this.addressLine = addressLine;
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this.city = city;
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}
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public String getAddressLine() {
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return addressLine;
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}
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public void setAddressLine(String addressLine) {
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this.addressLine = addressLine;
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}
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public String getCity() {
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return city;
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}
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public void setCity(String city) {
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this.city = city;
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}
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public Optional<Country> getCountry() {
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return Optional.ofNullable(country);
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}
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public void setCountry(Country country) {
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this.country = country;
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}
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}
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package com.stackify.optional.chaining;
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public class Country {
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private String name;
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private String isocode;
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public Country(String name) {
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this.name = name;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public String getIsocode() {
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return isocode;
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}
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public void setIsocode(String isocode) {
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this.isocode = isocode;
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}
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}
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package com.stackify.optional.chaining;
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import java.util.Optional;
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public class User {
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private String email;
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private String password;
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private Address address;
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private String position;
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public User(String email, String password) {
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this.email = email;
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this.password = password;
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}
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public String getEmail() {
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return email;
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}
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public void setEmail(String email) {
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this.email = email;
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}
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public String getPassword() {
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return password;
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}
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public void setPassword(String password) {
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this.password = password;
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}
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public Optional<Address> getAddress() {
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return Optional.ofNullable(address);
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}
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public void setAddress(Address address) {
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this.address = address;
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}
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public Optional<String> getPosition() {
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return Optional.ofNullable(position);
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}
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public void setPosition(String position) {
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this.position = position;
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}
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}
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<?xml version="1.0" encoding="UTF-8"?>
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<Configuration status="WARN">
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<Appenders>
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<Console name="Console" target="SYSTEM_OUT">
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<PatternLayout pattern="%msg%n" />
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</Console>
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</Appenders>
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<Loggers>
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<Root level="info">
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<AppenderRef ref="Console" />
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</Root>
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</Loggers>
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</Configuration>
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package com.stackify.optional;
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import static org.junit.Assert.*;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.NoSuchElementException;
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import java.util.Optional;
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import org.apache.logging.log4j.LogManager;
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import org.apache.logging.log4j.Logger;
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import org.junit.Test;
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public class OptionalTest {
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private User user;
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private Logger logger = LogManager.getLogger(OptionalTest.class);
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@Test(expected = NullPointerException.class)
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public void testNull() {
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String isocode = user.getAddress().getCountry().getIsocode().toUpperCase();
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}
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@Test
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public void test() {
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if (user != null) {
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Address address = user.getAddress();
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if (address != null) {
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Country country = address.getCountry();
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if (country != null) {
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String isocode = country.getIsocode();
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if (isocode != null) {
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isocode = isocode.toUpperCase();
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}
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}
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}
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}
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}
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@Test(expected = NoSuchElementException.class)
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public void whenCreateEmptyOptional_thenNull() {
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Optional<User> emptyOpt = Optional.empty();
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emptyOpt.get();
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}
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@Test(expected = NullPointerException.class)
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public void whenCreateOfEmptyOptional_thenNullPointerException() {
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Optional<User> opt = Optional.of(user);
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}
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@Test
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public void whenCreateOfNullableOptional_thenOk() {
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String name = "John";
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Optional<String> opt = Optional.ofNullable(name);
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assertEquals("John", opt.get());
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}
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@Test
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public void whenCheckIsPresent_thenOk() {
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user = new User("john@gmail.com", "1234");
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Optional<User> opt = Optional.ofNullable(user);
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assertTrue(opt.isPresent());
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assertEquals(user.getEmail(), opt.get().getEmail());
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}
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@Test
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public void whenCheckIfPresent_thenOk() {
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user = new User("john@gmail.com", "1234");
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Optional<User> opt = Optional.ofNullable(user);
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assertTrue(opt.isPresent());
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opt.ifPresent(u -> assertEquals(user.getEmail(), u.getEmail()));
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}
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@Test
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public void whenEmptyValue_thenReturnDefault() {
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User user = null;
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User user2 = new User("anna@gmail.com", "1234");
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User result = Optional.ofNullable(user).orElse(user2);
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assertEquals("anna@gmail.com", result.getEmail());
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}
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@Test
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public void whenValueNotNull_thenIgnoreDefault() {
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User user = new User("john@gmail.com", "1234");
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User user2 = new User("anna@gmail.com", "1234");
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User result = Optional.ofNullable(user).orElse(user2);
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assertEquals("john@gmail.com", result.getEmail());
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}
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@Test
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public void whenSetDefaultOrElseGet_thenOk() {
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User user = null;
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User user2 = new User("anna@gmail.com", "1234");
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User result = Optional.ofNullable(user).orElseGet(() -> user2);
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assertEquals("anna@gmail.com", result.getEmail());
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}
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@Test
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public void givenPresentValue_whenCompare_thenOk() {
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User user = new User("john@gmail.com", "1234");
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logger.info("Using orElse");
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User result = Optional.ofNullable(user).orElse(createNewUser());
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logger.info("Using orElseGet");
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User result2 = Optional.ofNullable(user).orElseGet(() -> createNewUser());
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}
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private User createNewUser() {
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logger.info("Creating New User");
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return new User("extra@gmail.com", "1234");
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}
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@Test
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public void givenEmptyValue_whenCompare_thenOk() {
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User user = null;
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logger.info("Using orElse");
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User result = Optional.ofNullable(user).orElse(createNewUser());
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logger.info("Using orElseGet");
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User result2 = Optional.ofNullable(user).orElseGet(() -> createNewUser());
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}
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@Test(expected = IllegalArgumentException.class)
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public void whenThrowException_thenOk() {
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User result = Optional.ofNullable(user).orElseThrow(() -> new IllegalArgumentException());
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}
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@Test
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public void whenMap_thenOk() {
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user = new User("anna@gmail.com", "1234");
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String email = Optional.ofNullable(user).map(u -> u.getEmail()).orElse("default@gmail.com");
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assertEquals(email, user.getEmail());
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}
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@Test
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public void whenFlatMap_thenOk() {
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user = new User("anna@gmail.com", "1234");
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user.setPosition("Developer");
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String position = Optional.ofNullable(user).flatMap(u -> u.getPosition()).orElse("default");
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assertEquals(position, user.getPosition().get());
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}
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@Test
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public void whenFilter_thenOk() {
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user = new User("anna@gmail.com", "1234");
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Optional<User> result = Optional.ofNullable(user).filter(u -> u.getEmail() != null && u.getEmail().contains("@"));
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assertTrue(result.isPresent());
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}
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@Test
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public void whenStream_thenOk() {
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List<User> users = new ArrayList<>();
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User user = users.stream().findFirst().orElse(new User("default", "1234"));
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assertEquals(user.getEmail(), "default");
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}
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}
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@ -0,0 +1,36 @@
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package com.stackify.optional.chaining;
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import static org.junit.Assert.*;
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import java.util.Optional;
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|
||||
import org.junit.Test;
|
||||
|
||||
public class OptionalChainingTest {
|
||||
|
||||
@Test
|
||||
public void whenChaining_thenOk() {
|
||||
User user = new User("anna@gmail.com", "1234");
|
||||
|
||||
String result = Optional.ofNullable(user)
|
||||
.flatMap(u -> u.getAddress())
|
||||
.flatMap(a -> a.getCountry())
|
||||
.map(c -> c.getIsocode())
|
||||
.orElse("default");
|
||||
|
||||
assertEquals(result, "default");
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenChainingWithMethodReferences_thenOk() {
|
||||
User user = new User("anna@gmail.com", "1234");
|
||||
|
||||
String result = Optional.ofNullable(user)
|
||||
.flatMap(User::getAddress)
|
||||
.flatMap(Address::getCountry)
|
||||
.map(Country::getIsocode)
|
||||
.orElse("default");
|
||||
|
||||
assertEquals(result, "default");
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue