04 optional

.gitignore

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+.idea
+*.iml
+.classpath
+.project
+.settings
+/target/
+/bin/

pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>devinstitut</groupId>
+    <artifactId>java-java17</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <project.build.sourceEncoding>utf-8</project.build.sourceEncoding>
+    </properties>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <configuration>
+                        <source>1.17</source>
+                        <target>1.17</target>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-library</artifactId>
+            <version>1.3</version>
+        </dependency>
+    </dependencies>
+
+</project>

src/test/java/java17/data/Account.java

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+package java17.data;
+
+public class Account {
+
+    private Person owner;
+    private Integer balance;
+
+    public Person getOwner() {
+        return owner;
+    }
+
+    public void setOwner(Person owner) {
+        this.owner = owner;
+    }
+
+    public Integer getBalance() {
+        return balance;
+    }
+
+    public void setBalance(Integer balance) {
+        this.balance = balance;
+    }
+}

src/test/java/java17/data/Data.java

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+package java17.data;
+
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class Data {
+
+    public static List<Person> buildPersonList(int nb) {
+        return IntStream.rangeClosed(1,nb)
+                .mapToObj(i -> new Person("first_" + i, "last_" + i, i, i % 9 == 0 ? "test": "password"+i))
+                .collect(Collectors.toList());
+    }
+}

src/test/java/java17/data/Person.java

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+package java17.data;
+
+public class Person {
+
+    private String firstname;
+    private String lastname;
+    private Integer age;
+    private String password;
+
+    public Person() {
+    }
+
+    public Person(String firstname, String lastname, Integer age, String password) {
+        this.firstname = firstname;
+        this.lastname = lastname;
+        this.age = age;
+        this.password = password;
+    }
+
+    public String getFirstname() {
+        return firstname;
+    }
+
+    public void setFirstname(String firstname) {
+        this.firstname = firstname;
+    }
+
+    public String getLastname() {
+        return lastname;
+    }
+
+    public void setLastname(String lastname) {
+        this.lastname = lastname;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+}

src/test/java/java17/ex01/Optional_01_Test.java

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+package java17.ex01;
+
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+
+import org.junit.Test;
+
+import java17.data.Data;
+import java17.data.Person;
+
+/**
+ * Exercice 02 - Filter, Map
+ */
+public class Optional_01_Test {
+
+	class NotPresentException extends RuntimeException {
+
+	}
+
+    @Test
+    public void test_optional_ifPresent() throws Exception {
+
+    	List<Person> persons = Data.buildPersonList(10);
+
+        // TODO rechercher dans la liste ci-dessus la 1ère personne ayant 18 ans
+        // TODO utiliser la méthode "findFirst"
+        Optional<Person> optPerson = persons.stream().findFirst();
+        assertThat(optPerson.isPresent(), is(true));
+
+        // TODO afficher la personne en question si l'optional contient une personne
+        System.out.println(optPerson.get().getFirstname());
+    }
+
+    @Test(expected=NotPresentException.class)
+    public void test_optional_notPresent() throws Exception {
+    	List<Person> persons = Data.buildPersonList(50);
+
+        // TODO rechercher dans la liste ci-dessus la 1ère personne ayant 75 ans
+        // TODO utiliser la méthode "findFirst"
+        Optional<Person> optPerson = persons.stream().filter(person->person.getAge()==75).findFirst();
+        assertThat(optPerson.isPresent(), is(false));
+
+        Person person = optPerson.orElseThrow(NotPresentException::new);
+        // TODO si la personne n'existe pas, jeter une exception NotPresentException
+        // TODO utiliser la méthode "orElseThrow"
+
+    }
+}