Objects, Immutability, Pattern Matching, and Switch Expressions

Author: AnghelLeonard

Chapter02/P38_AsciiVsUnicode/src/main/java/modern/challenge/Charsets.java

@@ -16,7 +16,7 @@ public static String strToBinary(String str) {
 
         String binary = str.chars()
                 .mapToObj(Integer::toBinaryString)
-                .map(t -> "0" + (String) t)
+                .map(t -> "0" + t)
                 .collect(Collectors.joining(" "));
 
         return binary;

Chapter02/P38_Emoji/README.md

@@ -0,0 +1,2 @@
+# Explain and exemplify UTF-8, UTF-16, and UTF-32: 
+Provide a detailed explanation of what are UTF-8, UTF-16, and UTF-32. Also, include several snippets of code to show how these work in Java.

Chapter02/P38_Emoji/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>java.modern.challenge</groupId>
+    <artifactId>P38_Emoji</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+    </properties>
+    <name>P38_Emoji</name>
+</project>

Chapter02/P38_Emoji/src/main/java/modern/challenge/Charsets.java

@@ -0,0 +1,41 @@
+package modern.challenge;
+
+import java.util.List;
+import java.util.regex.Pattern;
+import static java.util.stream.Collectors.toList;
+import java.util.stream.IntStream;
+
+public class Charsets {
+
+    private Charsets() {
+        throw new AssertionError("Cannot be instantiated");
+    }
+
+    public static boolean containsEmojiV1(String str) {
+
+        if (str == null) {
+            throw new IllegalArgumentException("The given string cannot be null");
+        }
+
+        return str.codePoints().anyMatch(Character::isEmoji);
+    }
+
+    public static boolean containsEmojiV2(String str) {
+
+        if (str == null) {
+            throw new IllegalArgumentException("The given string cannot be null");
+        }
+
+        // using snake-regex you can write {IsEmoji_Modifier_Base}, {IsEmoji_Presentation}, and so on
+        return Pattern.compile("\\p{IsEmoji}").matcher(str).find();
+    }
+
+    public static List<String> getAllEmoji() {
+
+        return IntStream.range(0, Integer.MAX_VALUE)
+                .filter(Character::isEmoji)
+                .mapToObj(Character::toChars)
+                .map(String::valueOf)
+                .collect(toList());
+    }
+}

Chapter02/P38_Emoji/src/main/java/modern/challenge/Main.java

@@ -0,0 +1,22 @@
+package modern.challenge;
+
+import java.util.List;
+
+public class Main {
+
+    public static final String STR_NO_EMOJI = "?I love you so much!";
+    public static final String STR_WITH_EMOJI = "😍 I love 💕 you Ӝ so much 💕 😍 🎼🎼🎼!";
+
+    public static void main(String[] args) {
+
+        System.out.println(Charsets.containsEmojiV1(STR_NO_EMOJI));
+        System.out.println(Charsets.containsEmojiV1(STR_WITH_EMOJI));
+        
+        System.out.println(Charsets.containsEmojiV2(STR_NO_EMOJI));
+        System.out.println(Charsets.containsEmojiV2(STR_WITH_EMOJI));
+        
+        List<String> allEmoji = Charsets.getAllEmoji();
+        System.out.println("There are " + allEmoji.size() + " emoji \n");
+        System.out.println(allEmoji);
+    }
+}

Chapter02/P60_RewritingEqualsTypePatternInstanceof/src/main/java/modern/challenge/MyPointGenericNew.java

@@ -2,7 +2,7 @@
 
 import java.util.Objects;
 
-public class MyPointGenericNew<E> {
+public final class MyPointGenericNew<E> {
 
     private final E x;
     private final E y;

Chapter02/P60_RewritingEqualsTypePatternInstanceof/src/main/java/modern/challenge/MyPointGenericOld.java

@@ -2,7 +2,7 @@
 
 import java.util.Objects;
 
-public class MyPointGenericOld<E> {
+public final class MyPointGenericOld<E> {
 
     private final E x;
     private final E y;

Chapter02/P60_RewritingEqualsTypePatternInstanceof/src/main/java/modern/challenge/MyPointNew.java

@@ -1,6 +1,6 @@
 package modern.challenge;
 
-public class MyPointNew {
+public final class MyPointNew {
 
     private final int x;
     private final int y;

Chapter02/P60_RewritingEqualsTypePatternInstanceof/src/main/java/modern/challenge/MyPointOld.java

@@ -1,6 +1,6 @@
 package modern.challenge;
 
-public class MyPointOld {
+public final class MyPointOld {
 
     private final int x;
     private final int y;