Make grouping configurable in build-in help

- New option spring.shell.command.help.grouping-mode which can be either flat/group.
- Build-in help command can now choose if to group command or just show flat list.
- Fixes #347

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

@@ -126,6 +126,7 @@ public class SpringShellProperties {
 	public static class HelpCommand {
 
 		private boolean enabled = true;
+		private GroupingMode groupingMode = GroupingMode.GROUP;
 
 		public boolean isEnabled() {
 			return enabled;
@@ -134,6 +135,19 @@ public class SpringShellProperties {
 		public void setEnabled(boolean enabled) {
 			this.enabled = enabled;
 		}
+
+		public GroupingMode getGroupingMode() {
+			return groupingMode;
+		}
+
+		public void setGroupingMode(GroupingMode groupingMode) {
+			this.groupingMode = groupingMode;
+		}
+
+		public enum GroupingMode {
+			GROUP,
+			FLAT
+		}
 	}
 
 	public static class ClearCommand {

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

@@ -29,6 +29,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.shell.boot.SpringShellProperties.VersionCommand;
+import org.springframework.shell.boot.SpringShellProperties.HelpCommand.GroupingMode;
 import org.springframework.shell.boot.condition.OnCompletionCommandCondition;
 import org.springframework.shell.result.ThrowableResultHandler;
 import org.springframework.shell.standard.commands.Clear;
@@ -54,8 +55,12 @@ public class StandardCommandsAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean(Help.Command.class)
 	@ConditionalOnProperty(prefix = "spring.shell.command.help", value = "enabled", havingValue = "true", matchIfMissing = true)
-	public Help help() {
-		return new Help();
+	public Help help(SpringShellProperties properties) {
+		Help help = new Help();
+		if (properties.getCommand().getHelp().getGroupingMode() == GroupingMode.FLAT) {
+			help.setShowGroups(false);
+		}
+		return help;
 	}
 
 	@Bean

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.HelpCommand.GroupingMode;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -38,6 +39,7 @@ public class SpringShellPropertiesTests {
 					assertThat(properties.getTheme().getName()).isEqualTo("default");
 					assertThat(properties.getCommand().getClear().isEnabled()).isTrue();
 					assertThat(properties.getCommand().getHelp().isEnabled()).isTrue();
+					assertThat(properties.getCommand().getHelp().getGroupingMode()).isEqualTo(GroupingMode.GROUP);
 					assertThat(properties.getCommand().getHistory().isEnabled()).isTrue();
 					assertThat(properties.getCommand().getQuit().isEnabled()).isTrue();
 					assertThat(properties.getCommand().getScript().isEnabled()).isTrue();
@@ -67,6 +69,7 @@ public class SpringShellPropertiesTests {
 				.withPropertyValues("spring.shell.theme.name=fake")
 				.withPropertyValues("spring.shell.command.clear.enabled=false")
 				.withPropertyValues("spring.shell.command.help.enabled=false")
+				.withPropertyValues("spring.shell.command.help.grouping-mode=flat")
 				.withPropertyValues("spring.shell.command.history.enabled=false")
 				.withPropertyValues("spring.shell.command.quit.enabled=false")
 				.withPropertyValues("spring.shell.command.script.enabled=false")
@@ -93,6 +96,7 @@ public class SpringShellPropertiesTests {
 					assertThat(properties.getTheme().getName()).isEqualTo("fake");
 					assertThat(properties.getCommand().getClear().isEnabled()).isFalse();
 					assertThat(properties.getCommand().getHelp().isEnabled()).isFalse();
+					assertThat(properties.getCommand().getHelp().getGroupingMode()).isEqualTo(GroupingMode.FLAT);
 					assertThat(properties.getCommand().getHistory().isEnabled()).isFalse();
 					assertThat(properties.getCommand().getQuit().isEnabled()).isFalse();
 					assertThat(properties.getCommand().getScript().isEnabled()).isFalse();

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

@@ -15,6 +15,7 @@
  */
 package org.springframework.shell.boot;
 
+import java.lang.reflect.Field;
 import java.util.function.Function;
 
 import org.junit.jupiter.api.Test;
@@ -22,6 +23,8 @@ import org.junit.jupiter.api.Test;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.shell.standard.commands.Completion;
+import org.springframework.shell.standard.commands.Help;
+import org.springframework.util.ReflectionUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -48,6 +51,21 @@ public class StandardCommandsAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	public void testHelpCommand() {
+		this.contextRunner
+				.with(disableCommands("clear", "quit", "stacktrace", "script", "history", "completion"))
+				.withPropertyValues("spring.shell.command.help.grouping-mode=flat")
+				.run(context -> {
+					assertThat(context).hasSingleBean(Help.class);
+					Help help = context.getBean(Help.class);
+					Field showGroupsField = ReflectionUtils.findField(Help.class, "showGroups");
+					ReflectionUtils.makeAccessible(showGroupsField);
+					ReflectionUtils.getField(showGroupsField, help);
+					assertThat(ReflectionUtils.getField(showGroupsField, help)).isEqualTo(false);
+				});
+	}
+
 	private static Function<ApplicationContextRunner, ApplicationContextRunner> disableCommands(String... commands) {
 		return (cr) -> {
 			for (String command : commands) {

spring-shell-standard-commands/src/main/java/org/springframework/shell/standard/commands/Help.java

@@ -78,6 +78,7 @@ public class Help extends AbstractShellComponent {
 	}
 
 	private MessageInterpolator messageInterpolator = Utils.defaultValidatorFactory().getMessageInterpolator();
+	private boolean showGroups = true;
 
 	public Help() {
 	}
@@ -101,6 +102,16 @@ public class Help extends AbstractShellComponent {
 
 	}
 
+	/**
+	 * Sets if groups should be shown in a listing, defaults to true. If not enabled
+	 * a simple list is shown without groups.
+	 *
+	 * @param showGroups the flag to show groups
+	 */
+	public void setShowGroups(boolean showGroups) {
+		this.showGroups = showGroups;
+	}
+
 	/**
 	 * Return a description of a specific command. Uses a layout inspired by *nix man pages.
 	 */
@@ -263,32 +274,34 @@ public class Help extends AbstractShellComponent {
 	private CharSequence listCommands() {
 		Map<String, MethodTarget> commandsByName = getCommandRegistry().listCommands();
 
-		SortedMap<String, Map<String, MethodTarget>> commandsByGroupAndName = commandsByName.entrySet().stream()
-				.collect(groupingBy(e -> e.getValue().getGroup(), TreeMap::new, // group by and sort by command group
-						toMap(Entry::getKey, Entry::getValue)));
-
 		AttributedStringBuilder result = new AttributedStringBuilder();
 		result.append("AVAILABLE COMMANDS\n\n", AttributedStyle.BOLD);
 
+		SortedMap<String, Map<String, MethodTarget>> commandsByGroupAndName = commandsByName.entrySet().stream()
+				.collect(groupingBy(e -> e.getValue().getGroup(), TreeMap::new, // group by and sort by command group
+						toMap(Entry::getKey, Entry::getValue)));
 		// display groups, sorted alphabetically, "Default" first
 		commandsByGroupAndName.forEach((group, commandsInGroup) -> {
-			result.append("".equals(group) ? "Default" : group, AttributedStyle.BOLD).append('\n');
-
+			if (showGroups) {
+				result.append("".equals(group) ? "Default" : group, AttributedStyle.BOLD).append('\n');
+			}
 			Map<MethodTarget, SortedSet<String>> commandNamesByMethod = commandsInGroup.entrySet().stream()
 					.collect(groupingBy(Entry::getValue, // group by command method
 							mapping(Entry::getKey, toCollection(TreeSet::new)))); // sort command names
-
 			// display commands, sorted alphabetically by their first alias
 			commandNamesByMethod.entrySet().stream().sorted(sortByFirstCommandName()).forEach(e -> {
+				String prefix = showGroups ? "      " : "";
+				prefix = prefix + (isAvailable(e.getKey()) ? "  " : " *");
 				result
-						.append(isAvailable(e.getKey()) ? "        " : "      * ")
+						.append(prefix)
 						.append(String.join(", ", e.getValue()), AttributedStyle.BOLD)
 						.append(": ")
 						.append(e.getKey().getHelp())
 						.append('\n');
 			});
-
-			result.append('\n');
+			if (showGroups) {
+				result.append('\n');
+			}
 		});
 
 		if (commandsByName.values().stream().distinct().anyMatch(m -> !isAvailable(m))) {