New annotation model

- This is a first commit to add new annotation model
  which eventually will replace old legacy annotations
  like ShellComponent, ShellMethod, @ShellOption, etc.
- Adds subset of features needed for parity with manual
  use of CommandRegistration.
- Relates spring-projects#637
- Relates spring-projects#638
- Relates spring-projects#639
- Relates spring-projects#640
- Relates spring-projects#641

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

@@ -0,0 +1,157 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.command.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.shell.context.InteractionMode;
+
+/**
+ * Annotation marking a method to be a candicate for a shell command target.
+ *
+ * @author Janne Valkealahti
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE, ElementType.METHOD })
+@Documented
+public @interface Command {
+
+	/**
+	 * Define command as an array. Given that command should be
+	 * {@code command1 sub1} it can be defined as:
+	 *
+	 * <pre class="code">
+	 * command = { "command1", "sub1" }
+	 * command = "command1 sub1"
+	 * </pre>
+	 *
+	 * Values are split and trimmed meaning spaces doesn't matter.
+	 *
+	 * <p>
+	 * <b>Supported at the type level as well as at the method level!</b>
+	 * When used at the type level, all method-level mappings inherit this primary
+	 * command to use it as a prefix.
+	 *
+	 * <pre class="code">
+	 * &#64;Command(command = "command1")
+	 * class MyCommands {
+	 *
+	 *   &#64;Command(command = "sub1")
+	 *   void sub1(){}
+	 * }
+	 * </pre>
+	 *
+	 * @return the command as an array
+	 */
+	String[] command() default {};
+
+	/**
+	 * Define alias as an array. Given that alias should be
+	 * {@code alias1 sub1} it can be defined as:
+	 *
+	 * <pre class="code">
+	 * command = { "alias1", "sub1" }
+	 * command = "alias1 sub1"
+	 * </pre>
+	 *
+	 * Values are split and trimmed meaning spaces doesn't matter.
+	 *
+	 * <p>
+	 * <b>Supported at the type level as well as at the method level!</b>
+	 * When used at the type level, all method-level mappings inherit this primary
+	 * alias to use it as a prefix.
+	 *
+	 * <pre class="code">
+	 * &#64;Command(alias = "alias1")
+	 * class MyCommands {
+	 *
+	 *   &#64;Command(alias = "sub1")
+	 *   void sub1(){}
+	 * }
+	 * </pre>
+	 *
+	 * @return the aliases as an array
+	 */
+	String[] alias() default {};
+
+	/**
+	 * Define a command group.
+	 *
+	 * <p>
+	 * <b>Supported at the type level as well as at the method level!</b>
+	 * When used at the type level, all method-level group inherit this primary
+	 * group. Can be overridden on method-level.
+	 *
+	 * @return the command group
+	 */
+	String group() default "";
+
+	/**
+	 * Define a command description.
+	 *
+	 * <p>
+	 * <b>Supported at the type level as well as at the method level!</b>
+	 * When used at the type level, all method-level descriptions inherit this primary
+	 * field. Can be overridden on method-level.
+	 *
+	 * @return the command description
+	 */
+	String description() default "";
+
+	/**
+	 * Define command to be hidden.
+	 *
+	 * <p>
+	 * <b>Supported at the type level as well as at the method level!</b>
+	 * When used at the type level, all method-level mappings inherit this primary
+	 * hidden field.
+	 *
+	 * <pre class="code">
+	 * &#64;Command(hidden = true)
+	 * class MyCommands {
+	 *
+	 *   &#64;Command
+	 *   void sub1(){
+	 *     // sub1 command is hidden
+	 *   }
+	 * }
+	 * </pre>
+	 *
+	 * @return true if command should be hidden
+	 */
+	boolean hidden() default false;
+
+	/**
+	 * Define interaction mode for a command as a hint when command should be
+	 * available. For example presense of some commands doesn't make sense if shell
+	 * is running as non-interactive mode and vice versa.
+	 *
+	 * <p>
+	 * <b>Supported at the type level as well as at the method level!</b>
+	 * When used at the type level, all method-level mappings inherit this primary
+	 * field.
+	 *
+	 * Type is an array to be able to indicate that default don't have anyting defined.
+	 *
+	 * @return interaction modes
+	 */
+	InteractionMode[] interactionMode() default {};
+
+}

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

@@ -0,0 +1,76 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.command.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Import;
+import org.springframework.core.annotation.AliasFor;
+import org.springframework.shell.command.annotation.support.CommandScanRegistrar;
+
+/**
+ * Configures the base packages used when scanning for {@link Command @Comamnd}
+ * classes. One of {@link #basePackageClasses()}, {@link #basePackages()} or its
+ * alias {@link #value()} may be specified to define specific packages to scan.
+ * If specific packages are not defined scanning will occur from the package of
+ * the class with this annotation.
+ *
+ * @author Janne Valkealahti
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Import(CommandScanRegistrar.class)
+@EnableCommand
+public @interface CommandScan {
+
+	/**
+	 * Alias for the {@link #basePackages()} attribute. Allows for more concise
+	 * annotation declarations e.g.: {@code @CommandScan("org.my.pkg")} instead of
+	 * {@code @CommandScan(basePackages="org.my.pkg")}.
+	 *
+	 * @return the base packages to scan
+	 */
+	@AliasFor("basePackages")
+	String[] value() default {};
+
+	/**
+	 * Base packages to scan for commands. {@link #value()} is an alias for (and
+	 * mutually exclusive with) this attribute.
+	 * <p>
+	 * Use {@link #basePackageClasses()} for a type-safe alternative to String-based
+	 * package names.
+	 *
+	 * @return the base packages to scan
+	 */
+	@AliasFor("value")
+	String[] basePackages() default {};
+
+	/**
+	 * Type-safe alternative to {@link #basePackages()} for specifying the packages
+	 * to scan for commands. The package of each class specified will be scanned.
+	 * <p>
+	 * Consider creating a special no-op marker class or interface in each package
+	 * that serves no purpose other than being referenced by this attribute.
+	 *
+	 * @return classes from the base packages to scan
+	 */
+	Class<?>[] basePackageClasses() default {};
+}

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

@@ -0,0 +1,45 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.command.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Import;
+import org.springframework.shell.command.annotation.support.EnableCommandRegistrar;
+
+/**
+ * Enable support for {@link Command @Command} annotated classes.
+ * {@code @Command} classes can be registered directly on this annotation.
+ *
+ * @author Janne Valkealahti
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Import(EnableCommandRegistrar.class)
+public @interface EnableCommand {
+
+	/**
+	 * Defines candicate classes for shell commands.
+	 *
+	 * @return candidate classes for shell commands
+	 */
+	Class<?>[] value() default {};
+}

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

@@ -21,8 +21,6 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.springframework.aot.hint.annotation.Reflective;
-
 /**
  * Annotation for handling exceptions in specific command classes and/or its methods.
  *
@@ -31,7 +29,6 @@
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)
 @Documented
-@Reflective
 public @interface ExceptionResolver {
 
 	/**

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

@@ -0,0 +1,79 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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.command.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.shell.command.CommandRegistration.OptionArity;
+
+/**
+ * Annotation marking a method parameter to be a candicate for an option.
+ *
+ * @author Janne Valkealahti
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.PARAMETER)
+@Documented
+public @interface Option {
+
+	/**
+	 * Long names of an option. There can be multiple names where first is primary
+	 * one and other are aliases.
+	 *
+	 * @return Option long names, defaults to empty.
+	 */
+	String[] longNames() default {};
+
+	/**
+	 * Short names of an option. There can be multiple names where first is primary
+	 * one and other are aliases.
+	 *
+	 * @return Option short names, defaults to empty.
+	 */
+	char[] shortNames() default {};
+
+	/**
+	 * Mark option required.
+	 *
+	 * @return true if option is required, defaults to false.
+	 */
+	boolean required() default false;
+
+	/**
+	 * Define option default value.
+	 *
+	 * @return default value
+	 */
+	String defaultValue() default "";
+
+	/**
+	 * Return a short description of the option.
+	 *
+	 * @return description of the option
+	 */
+	String description() default "";
+
+	/**
+	 * Define option arity.
+	 *
+	 * @return option arity
+	 */
+	OptionArity arity() default OptionArity.NONE;
+}