Support modify option names

- New OptionNameModifier which is just a Function<String,String> to
  modify a name.
- Can be defined per option in CommandRegistration.
- Can be defined as global default as bean.
- Default implementation for common case types is enabled via boot's
  config props under spring.shell.option.naming.case-type
- Support facilities for camel, kebab, snake and pascal conversions.
- Fixes #621

spring-shell-autoconfigure/src/main/java/org/springframework/shell/boot/CommandCatalogAutoConfiguration.java

@@ -20,7 +20,9 @@ import java.util.stream.Collectors;
 
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.shell.MethodTargetRegistrar;
@@ -29,6 +31,8 @@ import org.springframework.shell.command.CommandCatalog;
 import org.springframework.shell.command.CommandCatalogCustomizer;
 import org.springframework.shell.command.CommandRegistration;
 import org.springframework.shell.command.CommandRegistration.BuilderSupplier;
+import org.springframework.shell.command.CommandRegistration.OptionNameModifier;
+import org.springframework.shell.command.support.OptionNameModifierSupport;
 import org.springframework.shell.command.CommandResolver;
 
 @AutoConfiguration
@@ -74,6 +78,40 @@ public class CommandCatalogAutoConfiguration {
 		};
 	}
 
+	@Bean
+	@ConditionalOnBean(OptionNameModifier.class)
+	public CommandRegistrationCustomizer customOptionNameModifierCommandRegistrationCustomizer(OptionNameModifier modifier) {
+		return builder -> {
+			builder.defaultOptionNameModifier(modifier);
+		};
+	}
+
+	@Bean
+	@ConditionalOnMissingBean(OptionNameModifier.class)
+	@ConditionalOnProperty(prefix = "spring.shell.option.naming", name = "case-type")
+	public CommandRegistrationCustomizer defaultOptionNameModifierCommandRegistrationCustomizer(SpringShellProperties properties) {
+		return builder -> {
+			switch (properties.getOption().getNaming().getCaseType()) {
+				case NOOP:
+					break;
+				case CAMEL:
+					builder.defaultOptionNameModifier(OptionNameModifierSupport.CAMELCASE);
+					break;
+				case SNAKE:
+					builder.defaultOptionNameModifier(OptionNameModifierSupport.SNAKECASE);
+					break;
+				case KEBAB:
+					builder.defaultOptionNameModifier(OptionNameModifierSupport.KEBABCASE);
+					break;
+				case PASCAL:
+					builder.defaultOptionNameModifier(OptionNameModifierSupport.PASCALCASE);
+					break;
+				default:
+					break;
+			}
+		};
+	}
+
 	@Bean
 	@ConditionalOnMissingBean
 	public BuilderSupplier commandRegistrationBuilderSupplier(

spring-shell-autoconfigure/src/main/java/org/springframework/shell/boot/SpringShellProperties.java

@@ -33,6 +33,7 @@ public class SpringShellProperties {
 	private Theme theme = new Theme();
 	private Command command = new Command();
 	private Help help = new Help();
+	private Option option = new Option();
 
 	public void setConfig(Config config) {
 		this.config = config;
@@ -98,6 +99,14 @@ public class SpringShellProperties {
 		return help;
 	}
 
+	public Option getOption() {
+		return option;
+	}
+
+	public void setOption(Option option) {
+		this.option = option;
+	}
+
 	public static class Config {
 
 		private String env;
@@ -559,4 +568,38 @@ public class SpringShellProperties {
 			this.enabled = enabled;
 		}
 	}
+
+	public static class Option {
+
+		private OptionNaming naming = new OptionNaming();
+
+		public OptionNaming getNaming() {
+			return naming;
+		}
+
+		public void setNaming(OptionNaming naming) {
+			this.naming = naming;
+		}
+	}
+
+	public static class OptionNaming {
+		private OptionNamingCase caseType = OptionNamingCase.NOOP;
+
+		public OptionNamingCase getCaseType() {
+			return caseType;
+		}
+
+		public void setCaseType(OptionNamingCase caseType) {
+			this.caseType = caseType;
+		}
+	}
+
+	public static enum OptionNamingCase {
+		NOOP,
+		CAMEL,
+		SNAKE,
+		KEBAB,
+		PASCAL
+	}
+
 }

spring-shell-autoconfigure/src/test/java/org/springframework/shell/boot/CommandCatalogAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 the original author or authors.
+ * Copyright 2022-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,9 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.shell.command.CommandCatalog;
 import org.springframework.shell.command.CommandRegistration;
 import org.springframework.shell.command.CommandResolver;
+import org.springframework.shell.command.CommandRegistration.Builder;
+import org.springframework.shell.command.CommandRegistration.BuilderSupplier;
+import org.springframework.shell.command.CommandRegistration.OptionNameModifier;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -68,6 +71,82 @@ public class CommandCatalogAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	void builderSupplierIsCreated() {
+		this.contextRunner
+				.run(context -> {
+					BuilderSupplier builderSupplier = context.getBean(BuilderSupplier.class);
+					assertThat(builderSupplier).isNotNull();
+				});
+	}
+
+	@Test
+	void defaultOptionNameModifierIsNull() {
+		this.contextRunner
+				.run(context -> {
+					BuilderSupplier builderSupplier = context.getBean(BuilderSupplier.class);
+					Builder builder = builderSupplier.get();
+					assertThat(builder).extracting("defaultOptionNameModifier").isNull();
+				});
+	}
+
+	@Test
+	void defaultOptionNameModifierIsSet() {
+		this.contextRunner
+				.withUserConfiguration(CustomOptionNameModifierConfiguration.class)
+				.run(context -> {
+					BuilderSupplier builderSupplier = context.getBean(BuilderSupplier.class);
+					Builder builder = builderSupplier.get();
+					assertThat(builder).extracting("defaultOptionNameModifier").isNotNull();
+				});
+	}
+
+	@Test
+	void defaultOptionNameModifierIsSetFromProperties() {
+		this.contextRunner
+				.withPropertyValues("spring.shell.option.naming.case-type=kebab")
+				.run(context -> {
+					BuilderSupplier builderSupplier = context.getBean(BuilderSupplier.class);
+					Builder builder = builderSupplier.get();
+					assertThat(builder).extracting("defaultOptionNameModifier").isNotNull();
+				});
+	}
+
+	@Test
+	void defaultOptionNameModifierNoopNotSetFromProperties() {
+		this.contextRunner
+				.withPropertyValues("spring.shell.option.naming.case-type=noop")
+				.run(context -> {
+					BuilderSupplier builderSupplier = context.getBean(BuilderSupplier.class);
+					Builder builder = builderSupplier.get();
+					assertThat(builder).extracting("defaultOptionNameModifier").isNull();
+					// there is customizer but it doesn't do anything
+					assertThat(context).hasBean("defaultOptionNameModifierCommandRegistrationCustomizer");
+				});
+	}
+
+	@Test
+	void noCustomizerIfPropertyIsNotSet() {
+		this.contextRunner
+				.run(context -> {
+					BuilderSupplier builderSupplier = context.getBean(BuilderSupplier.class);
+					Builder builder = builderSupplier.get();
+					assertThat(builder).extracting("defaultOptionNameModifier").isNull();
+					// no customizer added without property
+					assertThat(context).doesNotHaveBean("defaultOptionNameModifierCommandRegistrationCustomizer");
+				});
+	}
+
+	// defaultOptionNameModifierCommandRegistrationCustomizer
+	@Configuration
+	static class CustomOptionNameModifierConfiguration {
+
+		@Bean
+		OptionNameModifier customOptionNameModifier() {
+			return name -> name;
+		}
+	}
+
 	@Configuration
 	static class CustomCommandResolverConfiguration {
 

spring-shell-autoconfigure/src/test/java/org/springframework/shell/boot/SpringShellPropertiesTests.java

@@ -19,6 +19,7 @@ import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.shell.boot.SpringShellProperties.OptionNamingCase;
 import org.springframework.shell.boot.SpringShellProperties.HelpCommand.GroupingMode;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -67,6 +68,7 @@ public class SpringShellPropertiesTests {
 					assertThat(properties.getHelp().getCommand()).isEqualTo("help");
 					assertThat(properties.getHelp().getLongNames()).containsExactly("help");
 					assertThat(properties.getHelp().getShortNames()).containsExactly('h');
+					assertThat(properties.getOption().getNaming().getCaseType()).isEqualTo(OptionNamingCase.NOOP);
 				});
 	}
 
@@ -107,6 +109,7 @@ public class SpringShellPropertiesTests {
 				.withPropertyValues("spring.shell.help.command=fake")
 				.withPropertyValues("spring.shell.help.long-names=fake")
 				.withPropertyValues("spring.shell.help.short-names=f")
+				.withPropertyValues("spring.shell.option.naming.case-type=camel")
 				.withUserConfiguration(Config1.class)
 				.run((context) -> {
 					SpringShellProperties properties = context.getBean(SpringShellProperties.class);
@@ -144,6 +147,7 @@ public class SpringShellPropertiesTests {
 					assertThat(properties.getHelp().getCommand()).isEqualTo("fake");
 					assertThat(properties.getHelp().getLongNames()).containsExactly("fake");
 					assertThat(properties.getHelp().getShortNames()).containsExactly('f');
+					assertThat(properties.getOption().getNaming().getCaseType()).isEqualTo(OptionNamingCase.CAMEL);
 				});
 	}