OptionValues supports multiple resolvers

- Change ref field in OptionValues to providers
  takin an array.
- Relates #637

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

@@ -33,8 +33,9 @@ import java.lang.annotation.Target;
 public @interface OptionValues {
 
 	/**
-	 * Reference to a bean name
-	 * @return a bean name
+	 * Names of beans for {@link CompletionProvider}.
+	 *
+	 * @return names of CompletionProvider beans
 	 */
-	String ref() default "";
+	String[] provider() default {};
 }

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

@@ -17,6 +17,7 @@ package org.springframework.shell.command.annotation.support;
 
 import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -38,6 +39,8 @@ import org.springframework.core.annotation.MergedAnnotations.SearchStrategy;
 import org.springframework.messaging.handler.invocation.InvocableHandlerMethod;
 import org.springframework.shell.Availability;
 import org.springframework.shell.AvailabilityProvider;
+import org.springframework.shell.CompletionContext;
+import org.springframework.shell.CompletionProposal;
 import org.springframework.shell.Utils;
 import org.springframework.shell.command.CommandExceptionResolver;
 import org.springframework.shell.command.CommandHandlingResult;
@@ -52,6 +55,7 @@ import org.springframework.shell.command.annotation.Option;
 import org.springframework.shell.command.annotation.OptionValues;
 import org.springframework.shell.command.invocation.InvocableShellMethod;
 import org.springframework.shell.completion.CompletionProvider;
+import org.springframework.shell.completion.CompletionResolver;
 import org.springframework.shell.context.InteractionMode;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
@@ -277,12 +281,25 @@ class CommandRegistrationFactoryBean implements FactoryBean<CommandRegistration>
 				}
 
 				OptionValues ovAnn = mp.getParameterAnnotation(OptionValues.class);
-				if (ovAnn != null && StringUtils.hasText(ovAnn.ref())) {
-					CompletionProvider cr = this.applicationContext.getBean(ovAnn.ref(), CompletionProvider.class);
-					if (cr != null) {
-						optionSpec.completion(ctx -> cr.apply(ctx));
+				if (ovAnn != null) {
+					String[] providerBeanNames = ovAnn.provider();
+					if (providerBeanNames.length > 0) {
+						final List<CompletionProvider> resolvers = Arrays.stream(providerBeanNames)
+							.map(beanName -> this.applicationContext.getBean(beanName, CompletionProvider.class))
+							.collect(Collectors.toList());
+						optionSpec.completion(ctx -> {
+							return resolvers.stream()
+								.flatMap(resolver -> resolver.apply(ctx).stream())
+								.collect(Collectors.toList());
+						});
 					}
 				}
+				// if (ovAnn != null && StringUtils.hasText(ovAnn.ref())) {
+				// 	CompletionProvider cr = this.applicationContext.getBean(ovAnn.ref(), CompletionProvider.class);
+				// 	if (cr != null) {
+				// 		optionSpec.completion(ctx -> cr.apply(ctx));
+				// 	}
+				// }
 
 			}
 		}

spring-shell-core/src/test/java/org/springframework/shell/command/annotation/support/CommandRegistrationFactoryBeanTests.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.shell.command.annotation.support;
 
+import java.util.Collections;
+
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
@@ -25,6 +27,8 @@ import org.springframework.shell.command.CommandRegistration;
 import org.springframework.shell.command.annotation.Command;
 import org.springframework.shell.command.annotation.CommandAvailability;
 import org.springframework.shell.command.annotation.Option;
+import org.springframework.shell.command.annotation.OptionValues;
+import org.springframework.shell.completion.CompletionProvider;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -209,6 +213,35 @@ class CommandRegistrationFactoryBeanTests {
 		}
 	}
 
+	@Test
+	void setsOptionWithCompletion() {
+		configCommon(OptionWithCompletion.class, new OptionWithCompletion(), "command1", new Class[] { String.class })
+				.run((context) -> {
+					CommandRegistrationFactoryBean fb = context.getBean(FACTORYBEANREF,
+							CommandRegistrationFactoryBean.class);
+					assertThat(fb).isNotNull();
+					CommandRegistration registration = fb.getObject();
+					assertThat(registration).isNotNull();
+					assertThat(registration.getOptions().get(0).getCompletion()).isNotNull();
+		});
+	}
+
+	@Command
+	private static class OptionWithCompletion {
+
+		@Command
+		void command1(@Option(longNames = "arg") @OptionValues(provider = "completionProvider") String arg) {
+		}
+
+		@Bean
+		CompletionProvider completionProvider() {
+			return ctx -> {
+				return Collections.emptyList();
+			};
+		}
+
+	}
+
 	private <T> ApplicationContextRunner configCommon(Class<T> type, T bean) {
 		return configCommon(type, bean, "command", new Class[0]);
 	}

spring-shell-samples/src/main/java/org/springframework/shell/samples/e2e/InteractiveCompletionCommands.java

@@ -62,8 +62,8 @@ public class InteractiveCompletionCommands {
 
 		@Command(command = "interactive-completion-1")
 		public String testRequiredValueAnnotation(
-				@Option(longNames = "arg1", required = true) @OptionValues(ref = "test1CompletionProvider") String arg1,
-				@Option(longNames = "arg2", required = true) @OptionValues(ref = "test2CompletionProvider")	String arg2
+				@Option(longNames = "arg1", required = true) @OptionValues(provider = "test1CompletionProvider") String arg1,
+				@Option(longNames = "arg2", required = true) @OptionValues(provider = "test2CompletionProvider") String arg2
 		) {
 				return "Hello " + arg1;
 		}
@@ -79,8 +79,8 @@ public class InteractiveCompletionCommands {
 		@Bean
 		CompletionProvider test2CompletionProvider() {
 			return ctx -> {
-				Test1ValuesProvider test1ValuesProvider = new Test1ValuesProvider();
-				return test1ValuesProvider.complete(ctx);
+				Test2ValuesProvider test2ValuesProvider = new Test2ValuesProvider();
+				return test2ValuesProvider.complete(ctx);
 			};
 		}
 	}