Convert between Date and YearMonth

AnghelLeonard · AnghelLeonard · commit 469355afd84a · 2020-12-31T16:42:55.000+02:00
diff --git a/Chapter03/BONUS_1_ConvertYearMonthToDate/README.md b/Chapter03/BONUS_1_ConvertYearMonthToDate/README.md
@@ -0,0 +1,2 @@
+# Converting `Iterable` to `List`
+Write a program that converts an `Iterable` to `List`. 
diff --git a/Chapter03/BONUS_1_ConvertYearMonthToDate/pom.xml b/Chapter03/BONUS_1_ConvertYearMonthToDate/pom.xml
@@ -0,0 +1,14 @@
+<?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>com.app</groupId>
+    <artifactId>BONUS_1_ConvertYearMonthToDate</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>13</maven.compiler.source>
+        <maven.compiler.target>13</maven.compiler.target>
+    </properties>
+    <name>BONUS_1_ConvertYearMonthToDate</name>
+</project>
diff --git a/Chapter03/BONUS_1_ConvertYearMonthToDate/src/main/java/modern/challenge/Converters.java b/Chapter03/BONUS_1_ConvertYearMonthToDate/src/main/java/modern/challenge/Converters.java
@@ -0,0 +1,33 @@
+package modern.challenge;
+
+import java.time.YearMonth;
+import java.time.ZoneId;
+import java.util.Date;
+
+public class Converters {
+
+    private Converters() {
+        throw new AssertionError("Cannot be instantiatied");
+    }
+
+    public static YearMonth toYearMonth(Date date) {
+
+        if (date == null) {
+            throw new IllegalArgumentException("The given date cannot be null");
+        }
+
+        return YearMonth.from(date.toInstant()
+                .atZone(ZoneId.systemDefault())
+                .toLocalDate());
+    }
+
+    public static Date toDate(YearMonth ym) {
+
+        if (ym == null) {
+            throw new IllegalArgumentException("The given year-month cannot be null");
+        }
+
+        return Date.from(ym.atDay(1)
+                .atStartOfDay(ZoneId.systemDefault()).toInstant());
+    }
+}
diff --git a/Chapter03/BONUS_1_ConvertYearMonthToDate/src/main/java/modern/challenge/MainApplication.java b/Chapter03/BONUS_1_ConvertYearMonthToDate/src/main/java/modern/challenge/MainApplication.java
@@ -0,0 +1,13 @@
+package modern.challenge;
+
+import java.time.YearMonth;
+import java.util.Date;
+
+public class MainApplication {
+
+    public static void main(String[] args) {       
+        
+        System.out.println("Date to YearMonth: " + Converters.toYearMonth(new Date()));
+        System.out.println("YearMonth to Date: " + Converters.toDate(YearMonth.now()));        
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+# Converting `Iterable` to `List`
	`2`	+Write a program that converts an `Iterable` to `List`.