Support option label

- This adds `label` to `CommandOption` which is then used
  in a Help instead of type.
- Fixes #424

spring-shell-core/src/main/java/org/springframework/shell/command/CommandOption.java

@@ -87,6 +87,13 @@ public interface CommandOption {
 	 */
 	int getArityMax();
 
+	/**
+	 * Gets a label.
+	 *
+	 * @return the label
+	 */
+	String getLabel();
+
 	/**
 	 * Gets an instance of a default {@link CommandOption}.
 	 *
@@ -96,7 +103,7 @@ public interface CommandOption {
 	 * @return default command option
 	 */
 	public static CommandOption of(String[] longNames, Character[] shortNames, String description) {
-		return of(longNames, shortNames, description, null, false, null, null, null, null);
+		return of(longNames, shortNames, description, null, false, null, null, null, null, null);
 	}
 
 	/**
@@ -110,7 +117,7 @@ public interface CommandOption {
 	 */
 	public static CommandOption of(String[] longNames, Character[] shortNames, String description,
 			ResolvableType type) {
-		return of(longNames, shortNames, description, type, false, null, null, null, null);
+		return of(longNames, shortNames, description, type, false, null, null, null, null, null);
 	}
 
 	/**
@@ -125,12 +132,14 @@ public interface CommandOption {
 	 * @param position the position value
 	 * @param arityMin the min arity
 	 * @param arityMax the max arity
+	 * @param label the label
 	 * @return default command option
 	 */
 	public static CommandOption of(String[] longNames, Character[] shortNames, String description,
-			ResolvableType type, boolean required, String defaultValue, Integer position, Integer arityMin, Integer arityMax) {
+			ResolvableType type, boolean required, String defaultValue, Integer position, Integer arityMin,
+			Integer arityMax, String label) {
 		return new DefaultCommandOption(longNames, shortNames, description, type, required, defaultValue, position,
-				arityMin, arityMax);
+				arityMin, arityMax, label);
 	}
 
 	/**
@@ -147,10 +156,11 @@ public interface CommandOption {
 		private int position;
 		private int arityMin;
 		private int arityMax;
+		private String label;
 
 		public DefaultCommandOption(String[] longNames, Character[] shortNames, String description,
 				ResolvableType type, boolean required, String defaultValue, Integer position,
-				Integer arityMin, Integer arityMax) {
+				Integer arityMin, Integer arityMax, String label) {
 			this.longNames = longNames != null ? longNames : new String[0];
 			this.shortNames = shortNames != null ? shortNames : new Character[0];
 			this.description = description;
@@ -160,6 +170,7 @@ public interface CommandOption {
 			this.position = position != null && position > -1 ? position : -1 ;
 			this.arityMin = arityMin != null ? arityMin : -1;
 			this.arityMax = arityMax != null ? arityMax : -1;
+			this.label = label;
 		}
 
 		@Override
@@ -206,5 +217,10 @@ public interface CommandOption {
 		public int getArityMax() {
 			return arityMax;
 		}
+
+		@Override
+		public String getLabel() {
+			return label;
+		}
 	}
 }

spring-shell-core/src/main/java/org/springframework/shell/command/CommandRegistration.java

@@ -200,6 +200,14 @@ public interface CommandRegistration {
 		 */
 		OptionSpec arity(OptionArity arity);
 
+		/**
+		 * Define a {@code label} for an option.
+		 *
+		 * @param label the label
+		 * @return option spec for chaining
+		 */
+		OptionSpec label(String label);
+
 		/**
 		 * Return a builder for chaining.
 		 *
@@ -519,6 +527,7 @@ public interface CommandRegistration {
 		private Integer position;
 		private Integer arityMin;
 		private Integer arityMax;
+		private String label;
 
 		DefaultOptionSpec(BaseBuilder builder) {
 			this.builder = builder;
@@ -611,6 +620,12 @@ public interface CommandRegistration {
 			return this;
 		}
 
+		@Override
+		public OptionSpec label(String label) {
+			this.label = label;
+			return this;
+		}
+
 		@Override
 		public Builder and() {
 			return builder;
@@ -651,6 +666,10 @@ public interface CommandRegistration {
 		public Integer getArityMax() {
 			return arityMax;
 		}
+
+		public String getLabel() {
+			return label;
+		}
 	}
 
 	static class DefaultTargetSpec implements TargetSpec {
@@ -820,7 +839,8 @@ public interface CommandRegistration {
 		public List<CommandOption> getOptions() {
 			return optionSpecs.stream()
 				.map(o -> CommandOption.of(o.getLongNames(), o.getShortNames(), o.getDescription(), o.getType(),
-						o.isRequired(), o.getDefaultValue(), o.getPosition(), o.getArityMin(), o.getArityMax()))
+						o.isRequired(), o.getDefaultValue(), o.getPosition(), o.getArityMin(), o.getArityMax(),
+						o.getLabel()))
 				.collect(Collectors.toList());
 		}
 

spring-shell-core/src/test/java/org/springframework/shell/command/CommandParserTests.java

@@ -327,7 +327,7 @@ public class CommandParserTests extends AbstractCommandTests {
 	public void testBooleanWithDefault() {
 		ResolvableType type = ResolvableType.forType(boolean.class);
 		CommandOption option1 = CommandOption.of(new String[] { "arg1" }, new Character[0], "description", type, false,
-				"true", null, null, null);
+				"true", null, null, null, null);
 
 		List<CommandOption> options = Arrays.asList(option1);
 		String[] args = new String[]{};
@@ -359,7 +359,7 @@ public class CommandParserTests extends AbstractCommandTests {
 
 	private static CommandOption longOption(String name, ResolvableType type, boolean required, Integer position, Integer arityMin, Integer arityMax) {
 		return CommandOption.of(new String[] { name }, new Character[0], "desc", type, required, null, position,
-				arityMin, arityMax);
+				arityMin, arityMax, null);
 	}
 
 	private static CommandOption shortOption(char name) {

spring-shell-core/src/test/java/org/springframework/shell/command/CommandRegistrationTests.java

@@ -195,6 +195,7 @@ public class CommandRegistrationTests extends AbstractCommandTests {
 				.shortNames('v')
 				.type(boolean.class)
 				.description("some arg1")
+				.label("mylabel")
 				.and()
 			.withTarget()
 				.function(function1)
@@ -205,6 +206,7 @@ public class CommandRegistrationTests extends AbstractCommandTests {
 		assertThat(registration.getOptions()).hasSize(1);
 		assertThat(registration.getOptions().get(0).getShortNames()).containsExactly('v');
 		assertThat(registration.getOptions().get(0).getType()).isEqualTo(ResolvableType.forType(boolean.class));
+		assertThat(registration.getOptions().get(0).getLabel()).isEqualTo("mylabel");
 	}
 
 	@Test