Fix Sonar

Author: ComputerDaddyGuy

src/example/java/io/github/computerdaddyguy/jfiletreeprettyprinter/example/Emojis.java

@@ -6,7 +6,7 @@ public class Emojis {
 
 	public static void main(String[] args) {
 		var prettyPrinter = FileTreePrettyPrinter.builder()
-			.customizeOptions(options -> options.withDefaultEmojis())
+			.customizeOptions(options -> options.withDefaultEmojis()) // or withEmojis(EmojiMapping) for custom mapping
 			.build();
 		var tree = prettyPrinter.prettyPrint("src/example/resources/emojis");
 		System.out.println(tree);

src/main/java/io/github/computerdaddyguy/jfiletreeprettyprinter/renderer/emoji/MappingUtils.java

@@ -0,0 +1,25 @@
+package io.github.computerdaddyguy.jfiletreeprettyprinter.renderer.emoji;
+
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+final class MappingUtils {
+
+	private MappingUtils() {
+		// Helper class
+	}
+
+	public static Map<String, String> toLowerCaseKeys(Map<String, String> mapping) {
+		Objects.requireNonNull(mapping, "mapping is null");
+		return mapping.entrySet().stream()
+			.collect(
+				Collectors.toMap(
+					entry -> entry.getKey().toLowerCase(),
+					Entry::getValue
+				)
+			);
+	}
+
+}

src/main/java/io/github/computerdaddyguy/jfiletreeprettyprinter/renderer/emoji/PathExtensionEmojiFunction.java

@@ -4,9 +4,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.Objects;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.Nullable;
 
@@ -16,7 +14,7 @@ class PathExtensionEmojiFunction implements Function<Path, String> {
 	private final Map<String, String> mapping;
 
 	public PathExtensionEmojiFunction(Map<String, String> mapping) {
-		this.mapping = toLowerCaseKeys(mapping);
+		this.mapping = MappingUtils.toLowerCaseKeys(mapping);
 	}
 
 	@Override
@@ -36,17 +34,6 @@ public String apply(Path path) {
 		return null;
 	}
 
-	private static Map<String, String> toLowerCaseKeys(Map<String, String> mapping) {
-		Objects.requireNonNull(mapping, "mapping is null");
-		return mapping.entrySet().stream()
-			.collect(
-				Collectors.toMap(
-					entry -> entry.getKey().toLowerCase(),
-					entry -> entry.getValue()
-				)
-			);
-	}
-
 	/**
 	 * Build the list of all extensions of given path, from most specific to less specific.
 	 * For "myFile.txt", return list ["txt"]

src/main/java/io/github/computerdaddyguy/jfiletreeprettyprinter/renderer/emoji/PathNameEmojiFunction.java

@@ -2,9 +2,7 @@
 
 import java.nio.file.Path;
 import java.util.Map;
-import java.util.Objects;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.Nullable;
 
@@ -14,18 +12,7 @@ class PathNameEmojiFunction implements Function<Path, String> {
 	private final Map<String, String> mapping;
 
 	public PathNameEmojiFunction(Map<String, String> mapping) {
-		this.mapping = toLowerCaseKeys(mapping);
-	}
-
-	private static Map<String, String> toLowerCaseKeys(Map<String, String> mapping) {
-		Objects.requireNonNull(mapping, "mapping is null");
-		return mapping.entrySet().stream()
-			.collect(
-				Collectors.toMap(
-					entry -> entry.getKey().toLowerCase(),
-					entry -> entry.getValue()
-				)
-			);
+		this.mapping = MappingUtils.toLowerCaseKeys(mapping);
 	}
 
 	@Override