Add automatic command grouping

Fixes #163

Introduce Command and Command.Help

spring-shell-core/src/main/java/org/springframework/shell/Command.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.shell;
+
+import java.util.Objects;
+
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+public interface Command {
+
+	/**
+	 * Encapsulates help metadata about a shell command.
+	 *
+	 * @author Eric Bottard
+	 */
+	class Help {
+
+		/**
+		 * Optional group to gather related commands together.
+		 */
+		private final String group;
+
+		/**
+		 * A required, short one sentence description of the command. Should start with a capital and end with a dot
+		 * for consistency.
+		 */
+		private final String description;
+
+		public Help(String description) {
+			this(description, null);
+		}
+
+		public Help(String description, String group) {
+			Assert.isTrue(StringUtils.hasText(description), "Command description cannot be null or empty");
+			this.description = description;
+			this.group = StringUtils.hasText(group) ? group : "";
+		}
+
+		public String getDescription() {
+			return description;
+		}
+
+		public String getGroup() {
+			return group;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (this == o) return true;
+			if (o == null || getClass() != o.getClass()) return false;
+			Help help = (Help) o;
+			return Objects.equals(group, help.group) &&
+					Objects.equals(description, help.description);
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash(group, description);
+		}
+	}
+
+}

spring-shell-core/src/main/java/org/springframework/shell/MethodTarget.java

@@ -29,15 +29,13 @@ import org.springframework.util.ReflectionUtils;
  *
  * @author Eric Bottard
  */
-public class MethodTarget {
+public class MethodTarget implements Command {
 
 	private final Method method;
 
 	private final Object bean;
 
-	private final String help;
-
-	private final String group;
+	private final Help help;
 
 	/**
 	 * If not null, returns whether or not the command is currently available. Implementations must be idempotent.
@@ -45,22 +43,21 @@ public class MethodTarget {
 	private final Supplier<Availability> availabilityIndicator;
 
 	public MethodTarget(Method method, Object bean, String help) {
-		this(method, bean, help, null, null);
+		this(method, bean, new Help(help, null), null);
 	}
 
 	public MethodTarget(Method method, Object bean, String help, Supplier<Availability> availabilityIndicator) {
-		this(method, bean, help, null, availabilityIndicator);
+		this(method, bean, new Help(help, null), availabilityIndicator);
 	}
 
-	public MethodTarget(Method method, Object bean, String help, String group, Supplier<Availability> availabilityIndicator) {
+	public MethodTarget(Method method, Object bean, Help help, Supplier<Availability> availabilityIndicator) {
 		Assert.notNull(method, "Method cannot be null");
 		Assert.notNull(bean, "Bean cannot be null");
-		Assert.hasText(help, String.format("Help cannot be blank when trying to define command based on '%s'", method));
+		Assert.hasText(help.getDescription(), String.format("Help cannot be blank when trying to define command based on '%s'", method));
 		ReflectionUtils.makeAccessible(method);
 		this.method = method;
 		this.bean = bean;
 		this.help = help;
-		this.group = group != null ? group : "";
 		this.availabilityIndicator = availabilityIndicator != null ? availabilityIndicator : () -> Availability.available();
 	}
 
@@ -68,30 +65,22 @@ public class MethodTarget {
 	 * Construct a MethodTarget for the unique method named {@literal name} on the given object. Fails with an exception
 	 * in case of overloaded method.
 	 */
-	public static MethodTarget of(String name, Object bean, String help) {
-		return of(name, bean, help, null, null);
+	public static MethodTarget of(String name, Object bean, Help help) {
+		return of(name, bean, help, null);
 	}
 
 	/**
 	 * Construct a MethodTarget for the unique method named {@literal name} on the given object. Fails with an exception
 	 * in case of overloaded method.
 	 */
-	public static MethodTarget of(String name, Object bean, String help, String group) {
-		return of(name, bean, help, group, null);
-	}
-
-	/**
-	 * Construct a MethodTarget for the unique method named {@literal name} on the given object. Fails with an exception
-	 * in case of overloaded method.
-	 */
-	public static MethodTarget of(String name, Object bean, String help, String group, Supplier<Availability> availabilityIndicator) {
+	public static MethodTarget of(String name, Object bean, Help help, Supplier<Availability> availabilityIndicator) {
 		Set<Method> found = new HashSet<>();
 		ReflectionUtils.doWithMethods(bean.getClass(), found::add, m -> m.getName().equals(name));
 		if (found.size() != 1) {
 			throw new IllegalArgumentException(String.format("Could not find unique method named '%s' on object of class %s. Found %s",
 				name, bean.getClass(), found));
 		}
-		return new MethodTarget(found.iterator().next(), bean, help, group, availabilityIndicator);
+		return new MethodTarget(found.iterator().next(), bean, help, availabilityIndicator);
 	}
 
 	public Method getMethod() {
@@ -103,11 +92,11 @@ public class MethodTarget {
 	}
 
 	public String getHelp() {
-		return help;
+		return help.getDescription();
 	}
 
 	public String getGroup() {
-		return group;
+		return help.getGroup();
 	}
 
 	public Availability getAvailability() {
@@ -123,7 +112,7 @@ public class MethodTarget {
 
 		if (!method.equals(that.method)) return false;
 		if (!bean.equals(that.bean)) return false;
-		if (!group.equals(that.group)) return false;
+		if (!help.equals(that.help)) return false;
 		return help.equals(that.help);
 
 	}
@@ -133,7 +122,7 @@ public class MethodTarget {
 		int result = method.hashCode();
 		result = 31 * result + bean.hashCode();
 		result = 31 * result + help.hashCode();
-		result = 31 * result + group.hashCode();
+		result = 31 * result + help.hashCode();
 		return result;
 	}