Introduce default completion provider supporting enumeration values if option is of enum type

Resolves #1282

Signed-off-by: czpilar <[email protected]>

Author: czpilar

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

@@ -17,7 +17,6 @@
 
 import java.io.PrintWriter;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 
@@ -28,6 +27,7 @@
 import org.springframework.shell.core.ParameterValidationException;
 import org.springframework.shell.core.command.availability.Availability;
 import org.springframework.shell.core.command.availability.AvailabilityProvider;
+import org.springframework.shell.core.command.completion.DefaultCompletionProvider;
 import org.springframework.shell.core.command.exit.ExitStatusExceptionMapper;
 import org.springframework.shell.core.command.completion.CompletionProvider;
 
@@ -54,7 +54,7 @@ public abstract class AbstractCommand implements Command {
 
 	@Nullable private ExitStatusExceptionMapper exitStatusExceptionMapper;
 
-	private CompletionProvider completionProvider = context -> Collections.emptyList();
+	private CompletionProvider completionProvider = new DefaultCompletionProvider();
 
 	private List<CommandOption> options = new ArrayList<>();
 

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

@@ -27,6 +27,7 @@
 import org.springframework.shell.core.command.adapter.ConsumerCommandAdapter;
 import org.springframework.shell.core.command.adapter.FunctionCommandAdapter;
 import org.springframework.shell.core.command.availability.AvailabilityProvider;
+import org.springframework.shell.core.command.completion.DefaultCompletionProvider;
 import org.springframework.shell.core.command.exit.ExitStatusExceptionMapper;
 import org.springframework.shell.core.command.completion.CompletionProvider;
 import org.springframework.util.Assert;
@@ -108,7 +109,7 @@ default AvailabilityProvider getAvailabilityProvider() {
 	 * @return the completion provider of the command
 	 */
 	default CompletionProvider getCompletionProvider() {
-		return context -> Collections.emptyList();
+		return context -> new DefaultCompletionProvider().apply(context);
 	}
 
 	/**
@@ -147,7 +148,7 @@ final class Builder {
 
 		private AvailabilityProvider availabilityProvider = AvailabilityProvider.alwaysAvailable();
 
-		private CompletionProvider completionProvider = context -> Collections.emptyList();
+		private CompletionProvider completionProvider = new DefaultCompletionProvider();
 
 		@Nullable ExitStatusExceptionMapper exitStatusExceptionMapper;
 

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

@@ -19,7 +19,6 @@
 import java.lang.reflect.Parameter;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import jakarta.validation.Validator;
@@ -42,6 +41,7 @@
 import org.springframework.shell.core.command.adapter.MethodInvokerCommandAdapter;
 import org.springframework.shell.core.command.annotation.Option;
 import org.springframework.shell.core.command.availability.AvailabilityProvider;
+import org.springframework.shell.core.command.completion.DefaultCompletionProvider;
 import org.springframework.shell.core.command.exit.ExitStatusExceptionMapper;
 import org.springframework.shell.core.command.completion.CompletionProvider;
 import org.springframework.shell.core.utils.Utils;
@@ -142,7 +142,7 @@ private List<CommandOption> getCommandOptions() {
 	}
 
 	private CompletionProvider getCompletionProvider(String completionProviderBeanName) {
-		CompletionProvider completionProvider = CompletionContext -> Collections.emptyList();
+		CompletionProvider completionProvider = new DefaultCompletionProvider();
 		if (!completionProviderBeanName.isEmpty()) {
 			try {
 				completionProvider = this.applicationContext.getBean(completionProviderBeanName,

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

@@ -0,0 +1,59 @@
+/*
+ * 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.
+ * 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.core.command.completion;
+
+import org.jspecify.annotations.Nullable;
+import org.springframework.shell.core.command.CommandOption;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * A default implementation of the {@link CompletionProvider} interface that provides
+ * completion proposals for enum-type command options and handles prefix generation for
+ * command options based on the current input context.
+ *
+ * @author David Pilar
+ * @since 4.0.1
+ */
+public class DefaultCompletionProvider implements CompletionProvider {
+
+	@Override
+	public List<CompletionProposal> apply(CompletionContext context) {
+		if (context.getCommandOption() == null || !context.getCommandOption().type().isEnum()) {
+			return Collections.emptyList();
+		}
+		return new EnumCompletionProvider(context.getCommandOption().type(),
+				getPrefix(context.currentWord(), context.getCommandOption()))
+			.apply(context);
+	}
+
+	private String getPrefix(@Nullable String currentWord, CommandOption option) {
+		String prefix = "";
+		if (currentWord == null) {
+			return prefix;
+		}
+
+		if (option.longName() != null && currentWord.startsWith("--" + option.longName() + "=")) {
+			prefix = "--" + option.longName();
+		}
+		else if (option.shortName() != ' ' && currentWord.startsWith("-" + option.shortName() + "=")) {
+			prefix = "-" + option.shortName();
+		}
+		return prefix;
+	}
+
+}

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

@@ -0,0 +1,85 @@
+package org.springframework.shell.core.command.completion;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.springframework.shell.core.command.CommandOption;
+
+import java.util.List;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author David Pilar
+ */
+class DefaultCompletionProviderTests {
+
+	@Test
+	void testApplyWithNoCommandOption() {
+		// given
+		CompletionContext context = mock(CompletionContext.class);
+		when(context.getCommandOption()).thenReturn(null);
+
+		// when
+		List<CompletionProposal> result = new DefaultCompletionProvider().apply(context);
+
+		// then
+		assertTrue(result.isEmpty());
+	}
+
+	@Test
+	void testApplyWithNoEnumCommandOption() {
+		// given
+		CompletionContext context = mock(CompletionContext.class);
+		when(context.getCommandOption()).thenReturn(CommandOption.with().type(String.class).build());
+
+		// when
+		List<CompletionProposal> result = new DefaultCompletionProvider().apply(context);
+
+		// then
+		assertTrue(result.isEmpty());
+	}
+
+	public enum TestEnum {
+
+		VALUE1, VALUE2
+
+	}
+
+	@ParameterizedTest
+	@MethodSource("applyWithEnumCommandOptionData")
+	void testApplyWithEnumCommandOption(String currentWord, String longName, char shortName,
+			List<String> expectedValues) {
+		// given
+		CompletionContext context = mock(CompletionContext.class);
+		when(context.getCommandOption())
+			.thenReturn(CommandOption.with().longName(longName).shortName(shortName).type(TestEnum.class).build());
+		when(context.currentWord()).thenReturn(currentWord);
+
+		// when
+		List<CompletionProposal> result = new DefaultCompletionProvider().apply(context);
+		List<String> resultValues = result.stream().map(CompletionProposal::value).toList();
+
+		// then
+		assertEquals(expectedValues, resultValues);
+	}
+
+	static Stream<Arguments> applyWithEnumCommandOptionData() {
+		return Stream.of(Arguments.of(null, "name", 'n', List.of("VALUE1", "VALUE2")),
+				Arguments.of("", "name", 'n', List.of("VALUE1", "VALUE2")),
+				Arguments.of("different", "name", 'n', List.of("VALUE1", "VALUE2")),
+				Arguments.of("VA", "name", 'n', List.of("VALUE1", "VALUE2")),
+
+				Arguments.of("--name=", "name", 'n', List.of("--name=VALUE1", "--name=VALUE2")),
+				Arguments.of("-n=", "name", 'n', List.of("-n=VALUE1", "-n=VALUE2")),
+
+				Arguments.of("--name=", null, 'n', List.of("VALUE1", "VALUE2")),
+				Arguments.of("-n=", "name", ' ', List.of("VALUE1", "VALUE2")));
+	}
+
+}