Implement interactive completion

- This is a re-implementation of a interactive completion
  with breaking changes as it moves away from a direct use
  of a MethodParameter in favour of a CommandRegistration
  and its option definitions.
- Fixes #449

spring-shell-standard/src/main/java/org/springframework/shell/standard/CommandValueProvider.java

@@ -19,7 +19,6 @@ package org.springframework.shell.standard;
 import java.util.List;
 import java.util.stream.Collectors;
 
-import org.springframework.core.MethodParameter;
 import org.springframework.shell.CompletionContext;
 import org.springframework.shell.CompletionProposal;
 import org.springframework.shell.command.CommandCatalog;
@@ -28,8 +27,9 @@ import org.springframework.shell.command.CommandCatalog;
  * A {@link ValueProvider} that can be used to auto-complete names of shell commands.
  *
  * @author Eric Bottard
+ * @author Janne Valkealahti
  */
-public class CommandValueProvider extends ValueProviderSupport {
+public class CommandValueProvider implements ValueProvider {
 
 	private final CommandCatalog commandRegistry;
 
@@ -38,7 +38,7 @@ public class CommandValueProvider extends ValueProviderSupport {
 	}
 
 	@Override
-	public List<CompletionProposal> complete(MethodParameter parameter, CompletionContext completionContext, String[] hints) {
+	public List<CompletionProposal> complete(CompletionContext completionContext) {
 		return commandRegistry.getRegistrations().keySet().stream()
 			.map(CompletionProposal::new)
 			.collect(Collectors.toList());

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2022 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.
@@ -19,9 +19,10 @@ package org.springframework.shell.standard;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.springframework.core.MethodParameter;
+import org.springframework.core.ResolvableType;
 import org.springframework.shell.CompletionContext;
 import org.springframework.shell.CompletionProposal;
+import org.springframework.shell.command.CommandOption;
 
 /**
  * A {@link ValueProvider} that knows how to complete values for {@link Enum} typed parameters.
@@ -30,21 +31,28 @@ import org.springframework.shell.CompletionProposal;
 public class EnumValueProvider implements ValueProvider {
 
 	@Override
-	public boolean supports(MethodParameter parameter, CompletionContext completionContext) {
-		return Enum.class.isAssignableFrom(parameter.getParameterType());
-	}
-
-	@Override
-	public List<CompletionProposal> complete(MethodParameter parameter, CompletionContext completionContext, String[] hints) {
+	public List<CompletionProposal> complete(CompletionContext completionContext) {
 		List<CompletionProposal> result = new ArrayList<>();
-		for (Object v : parameter.getParameterType().getEnumConstants()) {
-			Enum<?> e = (Enum<?>) v;
-			String prefix = completionContext.currentWordUpToCursor();
-			if (prefix == null) {
-				prefix = "";
-			}
-			if (e.name().startsWith(prefix)) {
-				result.add(new CompletionProposal(e.name()));
+		CommandOption commandOption = completionContext.getCommandOption();
+		if (commandOption != null) {
+			ResolvableType type = commandOption.getType();
+			if (type != null) {
+				Class<?> clazz = type.getRawClass();
+				if (clazz != null) {
+					Object[] enumConstants = clazz.getEnumConstants();
+					if (enumConstants != null) {
+						for (Object v : enumConstants) {
+							Enum<?> e = (Enum<?>) v;
+							String prefix = completionContext.currentWordUpToCursor();
+							if (prefix == null) {
+								prefix = "";
+							}
+							if (e.name().startsWith(prefix)) {
+								result.add(new CompletionProposal(e.name()));
+							}
+						}
+					}
+				}
 			}
 		}
 		return result;

spring-shell-standard/src/main/java/org/springframework/shell/standard/FileValueProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 the original author or authors.
+ * Copyright 2017-2022 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.
@@ -25,7 +25,6 @@ import java.nio.file.Paths;
 import java.util.List;
 import java.util.stream.Collectors;
 
-import org.springframework.core.MethodParameter;
 import org.springframework.shell.CompletionContext;
 import org.springframework.shell.CompletionProposal;
 
@@ -36,29 +35,25 @@ import static java.nio.file.FileVisitOption.FOLLOW_LINKS;
  * current working directory.
  *
  * @author Eric Bottard
+ * @author Janne Valkealahti
  */
 public class FileValueProvider implements ValueProvider {
-    @Override
-    public boolean supports(MethodParameter parameter, CompletionContext completionContext) {
-        return parameter.getParameterType().equals(File.class);
-    }
-
-    @Override
-    public List<CompletionProposal> complete(MethodParameter parameter, CompletionContext completionContext, String[] hints) {
 
+	@Override
+	public List<CompletionProposal> complete(CompletionContext completionContext) {
         String input = completionContext.currentWordUpToCursor();
         int lastSlash = input.lastIndexOf(File.separatorChar);
         Path dir = lastSlash > -1 ? Paths.get(input.substring(0, lastSlash+1)) : Paths.get("");
         String prefix = input.substring(lastSlash + 1, input.length());
 
         try {
-            return Files.find(dir, 1, (p, a) -> p.getFileName() != null && p.getFileName().toString().startsWith(prefix), FOLLOW_LINKS)
+            return Files
+                    .find(dir, 1, (p, a) -> p.getFileName() != null && p.getFileName().toString().startsWith(prefix),
+                            FOLLOW_LINKS)
                     .map(p -> new CompletionProposal(p.toString()))
                     .collect(Collectors.toList());
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
-
-    }
-
+	}
 }

spring-shell-standard/src/main/java/org/springframework/shell/standard/StandardMethodTargetRegistrar.java

@@ -23,6 +23,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
@@ -36,13 +37,17 @@ import org.springframework.core.MethodParameter;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.messaging.handler.invocation.InvocableHandlerMethod;
 import org.springframework.shell.Availability;
+import org.springframework.shell.CompletionContext;
+import org.springframework.shell.CompletionProposal;
 import org.springframework.shell.MethodTargetRegistrar;
 import org.springframework.shell.Utils;
 import org.springframework.shell.command.CommandCatalog;
 import org.springframework.shell.command.CommandRegistration;
 import org.springframework.shell.command.CommandRegistration.Builder;
 import org.springframework.shell.command.CommandRegistration.OptionSpec;
+import org.springframework.shell.standard.ShellOption.NoValueProvider;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
@@ -143,6 +148,14 @@ public class StandardMethodTargetRegistrar implements MethodTargetRegistrar, App
 							if (ObjectUtils.nullSafeEquals(so.defaultValue(), ShellOption.NONE)) {
 								optionSpec.required();
 							}
+							if (!ClassUtils.isAssignable(NoValueProvider.class, so.valueProvider())) {
+								Function<CompletionContext, List<CompletionProposal>> completionFunction = ctx -> {
+									ValueProvider valueProviderBean = this.applicationContext.getBean(so.valueProvider());
+									List<CompletionProposal> complete = valueProviderBean.complete(ctx);
+									return complete;
+								};
+								optionSpec.completion(completionFunction);
+							}
 						}
 					}
 					else {

spring-shell-standard/src/main/java/org/springframework/shell/standard/ValueProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2022 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.
@@ -13,23 +13,27 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.shell.standard;
 
 import java.util.List;
 
-import org.springframework.core.MethodParameter;
 import org.springframework.shell.CompletionContext;
 import org.springframework.shell.CompletionProposal;
 
 /**
- * Beans implementing this interface are queried during TAB completion to gather possible values of a parameter.
+ * Beans implementing this interface are queried during TAB completion to gather
+ * possible values of a parameter.
  *
  * @author Eric Bottard
+ * @author Janne Valkealahti
  */
 public interface ValueProvider {
 
-	boolean supports(MethodParameter parameter, CompletionContext completionContext);
-
-	List<CompletionProposal> complete(MethodParameter parameter, CompletionContext completionContext, String[] hints);
+	/**
+	 * Complete completion proposals.
+	 *
+	 * @param completionContext the context
+	 * @return the completion proposals
+	 */
+	List<CompletionProposal> complete(CompletionContext completionContext);
 }

spring-shell-standard/src/main/java/org/springframework/shell/standard/ValueProviderSupport.java

@@ -1,38 +0,0 @@
-/*
- * Copyright 2016 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.standard;
-
-import org.springframework.core.MethodParameter;
-import org.springframework.shell.CompletionContext;
-
-/**
- * Base class for {@link ValueProvider} that match by type. Subclasses {@literal C} will be selected for parameters
- * whose {@literal @}{@link ShellOption#valueProvider()} return the concrete class {@literal C}.
- *
- * @author Eric Bottard
- */
-public abstract class ValueProviderSupport implements ValueProvider {
-
-	@Override
-	public boolean supports(MethodParameter parameter, CompletionContext completionContext) {
-		ShellOption annotation = parameter.getParameterAnnotation(ShellOption.class);
-		if (annotation == null) {
-			return false;
-		}
-		return annotation.valueProvider().isAssignableFrom(this.getClass());
-	}
-}