Introduce command lookup

.editorconfig

@@ -0,0 +1,5 @@
+root = true
+
+[*.{java,xml,gradle}]
+indent_style = tab
+indent_size = 4

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2022 the original author or authors.
+ * Copyright 2016-present 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.
@@ -29,6 +29,7 @@
  * parameters.
  *
  * @author Eric Bottard
+ * @author Piotr Olaszewski
  */
 public class EnumValueProvider implements ValueProvider {
 
@@ -37,7 +38,7 @@ public List<CompletionProposal> complete(CompletionContext completionContext) {
 		List<CompletionProposal> result = new ArrayList<>();
 		CommandOption commandOption = completionContext.getCommandOption();
 		if (commandOption != null) {
-			ResolvableType type = commandOption.getType();
+			ResolvableType type = commandOption.type();
 			if (type != null) {
 				Class<?> clazz = type.getRawClass();
 				if (clazz != null) {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 the original author or authors.
+ * Copyright 2017-present 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.
@@ -24,6 +24,7 @@
  * Represents the input buffer to the shell.
  *
  * @author Eric Bottard
+ * @author Piotr Olaszewski
  */
 public interface Input {
 
@@ -42,7 +43,7 @@ public interface Input {
 	 * single "word")
 	 */
 	default List<String> words() {
-		return "".equals(rawText()) ? Collections.emptyList() : Arrays.asList(rawText().split(" "));
+		return rawText().isEmpty() ? Collections.emptyList() : Arrays.asList(rawText().split(" "));
 	}
 
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2023 the original author or authors.
+ * Copyright 2022-present 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.
@@ -20,202 +20,13 @@
 import org.springframework.shell.core.completion.CompletionResolver;
 
 /**
- * Interface representing an option in a command.
+ * Represents an option of a command.
  *
  * @author Janne Valkealahti
  * @author Piotr Olaszewski
  */
-// TODO this is better defined as a record.
-public interface CommandOption {
-
-	/**
-	 * Gets a long name of an option.
-	 * @return long name of an option
-	 */
-	String getLongName();
-
-	/**
-	 * Gets a modified long names of an option. Set within a command registration if
-	 * option name modifier were used to have an info about original names.
-	 * @return modified long names of an option
-	 */
-	String getLongNameModified();
-
-	/**
-	 * Gets a short names of an option.
-	 * @return short names of an option
-	 */
-	Character getShortName();
-
-	/**
-	 * Gets a description of an option.
-	 * @return description of an option
-	 */
-	@Nullable String getDescription();
-
-	/**
-	 * Gets a {@link ResolvableType} of an option.
-	 * @return type of an option
-	 */
-	@Nullable ResolvableType getType();
-
-	/**
-	 * Gets a flag if option is required.
-	 * @return the required flag
-	 */
-	boolean isRequired();
-
-	/**
-	 * Gets a default value of an option.
-	 * @return the default value
-	 */
-	@Nullable String getDefaultValue();
-
-	/**
-	 * Gets a positional value.
-	 * @return the positional value
-	 */
-	int getPosition();
-
-	/**
-	 * Gets a minimum arity.
-	 * @return the minimum arity
-	 */
-	int getArityMin();
-
-	/**
-	 * Gets a maximum arity.
-	 * @return the maximum arity
-	 */
-	int getArityMax();
-
-	/**
-	 * Gets a completion function.
-	 * @return the completion function
-	 */
-	@Nullable CompletionResolver getCompletion();
-
-	/**
-	 * Gets an instance of a default {@link CommandOption}.
-	 * @param longName the long name
-	 * @param longNameModified the modified long name
-	 * @param shortName the short name
-	 * @param description the description
-	 * @param type the type
-	 * @param required the required flag
-	 * @param defaultValue the default value
-	 * @param position the position value
-	 * @param arityMin the min arity
-	 * @param arityMax the max arity
-	 * @param label the label
-	 * @param completion the completion
-	 * @return default command option
-	 */
-	static CommandOption of(String longName, String longNameModified, Character shortName, String description,
-			ResolvableType type, boolean required, String defaultValue, Integer position, Integer arityMin,
-			Integer arityMax, String label, CompletionResolver completion) {
-		return new DefaultCommandOption(longName, longNameModified, shortName, description, type, required,
-				defaultValue, position, arityMin, arityMax, label, completion);
-	}
-
-	/**
-	 * Default implementation of {@link CommandOption}.
-	 */
-	class DefaultCommandOption implements CommandOption {
-
-		private String longName;
-
-		private String longNameModified;
-
-		private Character shortName;
-
-		private String description;
-
-		private ResolvableType type;
-
-		private boolean required;
-
-		private String defaultValue;
-
-		private int position;
-
-		private int arityMin;
-
-		private int arityMax;
-
-		private CompletionResolver completion;
-
-		public DefaultCommandOption(String longName, String longNameModified, Character shortName, String description,
-				ResolvableType type, boolean required, String defaultValue, Integer position, Integer arityMin,
-				Integer arityMax, String label, CompletionResolver completion) {
-			this.longName = longName;
-			this.longNameModified = longNameModified;
-			this.shortName = shortName;
-			this.description = description;
-			this.type = type;
-			this.required = required;
-			this.defaultValue = defaultValue;
-			this.position = position != null && position > -1 ? position : -1;
-			this.arityMin = arityMin != null ? arityMin : -1;
-			this.arityMax = arityMax != null ? arityMax : -1;
-			this.completion = completion;
-		}
-
-		@Override
-		public String getLongName() {
-			return longName;
-		}
-
-		@Override
-		public String getLongNameModified() {
-			return longNameModified;
-		}
-
-		@Override
-		public Character getShortName() {
-			return shortName;
-		}
-
-		@Override
-		public String getDescription() {
-			return description;
-		}
-
-		@Override
-		public ResolvableType getType() {
-			return type;
-		}
-
-		@Override
-		public boolean isRequired() {
-			return required;
-		}
-
-		@Override
-		public String getDefaultValue() {
-			return defaultValue;
-		}
-
-		@Override
-		public int getPosition() {
-			return position;
-		}
-
-		@Override
-		public int getArityMin() {
-			return arityMin;
-		}
-
-		@Override
-		public int getArityMax() {
-			return arityMax;
-		}
-
-		@Override
-		public CompletionResolver getCompletion() {
-			return completion;
-		}
-
-	}
+public record CommandOption(String longName, String longNameModified, Character shortName, @Nullable String description,
+		@Nullable ResolvableType type, boolean required, @Nullable String defaultValue, int position, int arityMin,
+		int arityMax, @Nullable String label, @Nullable CompletionResolver completion) {
 
 }

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

@@ -16,7 +16,10 @@
 package org.springframework.shell.core.command;
 
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import org.jspecify.annotations.Nullable;
@@ -38,6 +41,8 @@ public class CommandRegistry implements SmartInitializingSingleton, ApplicationC
 
 	private final Set<Command> commands;
 
+	private final CommandTree.Node root = new CommandTree.Node();
+
 	@SuppressWarnings("NullAway.Init")
 	private ApplicationContext applicationContext;
 
@@ -53,31 +58,76 @@ public Set<Command> getCommands() {
 		return Set.copyOf(commands);
 	}
 
-	@Nullable public Command getCommandByName(String name) {
+	public @Nullable Command getCommandByName(String name) {
 		return commands.stream().filter(command -> command.getName().equals(name)).findFirst().orElse(null);
 	}
 
-	public void registerCommand(Command command) {
-		commands.add(command);
-	}
+	public @Nullable Command lookupCommand(List<String> args) {
+		Command command = null;
 
-	public void unregisterCommand(Command command) {
-		commands.remove(command);
-	}
+		CommandTree.Node current = root;
+		for (String arg : args) {
+			CommandTree.Node next = current.getChild().get(arg);
+			if (next == null) {
+				return command;
+			}
+			current = next;
+
+			Command cmd = current.getCommand();
+			if (cmd != null) {
+				command = cmd;
+			}
+		}
 
-	public void clearCommands() {
-		commands.clear();
+		return command;
 	}
 
 	@Override
 	public void afterSingletonsInstantiated() {
-		Collection<Command> commandCollection = this.applicationContext.getBeansOfType(Command.class).values();
+		Collection<Command> commandCollection = applicationContext.getBeansOfType(Command.class).values();
 		commands.addAll(commandCollection);
+
+		for (Command command : commandCollection) {
+			CommandTree.Node current = root;
+			String[] names = command.getName().split(" ");
+			for (String name : names) {
+				current = current.child(name);
+			}
+			current.setCommand(command);
+		}
 	}
 
 	@Override
 	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
 		this.applicationContext = applicationContext;
 	}
 
+	private static class CommandTree {
+
+		private static class Node {
+
+			private final Map<String, Node> child = new HashMap<>();
+
+			private @Nullable Command command;
+
+			private Map<String, Node> getChild() {
+				return child;
+			}
+
+			private Node child(String name) {
+				return child.computeIfAbsent(name, n -> new Node());
+			}
+
+			private @Nullable Command getCommand() {
+				return command;
+			}
+
+			private void setCommand(Command command) {
+				this.command = command;
+			}
+
+		}
+
+	}
+
 }