Restore command names case as in v3

This commit restores the kebab-case used for command names
as in v3. Utils.unCamelify copied verbatim from v3.

Resolves #1281

Author: fmbenhassine

spring-shell-core/src/main/java/org/springframework/shell/core/command/annotation/support/CommandFactoryBean.java

@@ -77,7 +77,7 @@ public Command getObject() {
 
 		// get command metadata
 		String name = String.join(" ", command.name());
-		name = name.isEmpty() ? this.method.getName() : name;
+		name = name.isEmpty() ? Utils.unCamelify(this.method.getName()) : name;
 		String description = command.description();
 		description = description.isEmpty() ? "N/A" : description;
 		String help = command.help();

spring-shell-core/src/main/java/org/springframework/shell/core/utils/Utils.java

@@ -39,6 +39,23 @@
  */
 public class Utils {
 
+	/**
+	 * Turn CamelCaseText into gnu-style-lowercase.
+	 */
+	public static String unCamelify(CharSequence original) {
+		StringBuilder result = new StringBuilder(original.length());
+		boolean wasLowercase = false;
+		for (int i = 0; i < original.length(); i++) {
+			char ch = original.charAt(i);
+			if (Character.isUpperCase(ch) && wasLowercase) {
+				result.append('-');
+			}
+			wasLowercase = Character.isLowerCase(ch);
+			result.append(Character.toLowerCase(ch));
+		}
+		return result.toString();
+	}
+
 	/**
 	 * Get a formatted string of available non-hidden commands from the command registry.
 	 * @param commandRegistry the command registry

spring-shell-core/src/test/java/org/springframework/shell/core/UtilsTests.java

@@ -23,6 +23,8 @@
 import org.springframework.shell.core.command.CommandRegistry;
 import org.springframework.shell.core.utils.Utils;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
 /**
  * Tests for {@link Utils}.
  *
@@ -31,6 +33,14 @@
  */
 class UtilsTests {
 
+	@Test
+	public void testUnCamelify() throws Exception {
+		assertThat(Utils.unCamelify("HelloWorld")).isEqualTo("hello-world");
+		assertThat(Utils.unCamelify("helloWorld")).isEqualTo("hello-world");
+		assertThat(Utils.unCamelify("helloWorldHowAreYou")).isEqualTo("hello-world-how-are-you");
+		assertThat(Utils.unCamelify("URL")).isEqualTo("url");
+	}
+
 	@Test
 	void testFormatAvailableCommands() {
 		CommandRegistry commandRegistry = new CommandRegistry();