feat: adding mandatory flag to string input

spring-shell-core/src/main/java/org/springframework/shell/component/StringInput.java

@@ -26,7 +26,6 @@
 import org.jline.utils.AttributedString;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.springframework.shell.component.StringInput.StringInputContext;
 import org.springframework.shell.component.context.ComponentContext;
 import org.springframework.shell.component.support.AbstractTextComponent;
@@ -44,21 +43,28 @@ public class StringInput extends AbstractTextComponent<String, StringInputContex
 	private final String defaultValue;
 	private StringInputContext currentContext;
 	private Character maskCharacter;
+	private boolean required;
 
 	public StringInput(Terminal terminal) {
-		this(terminal, null, null, null);
+		this(terminal, null, null, null, false);
 	}
 
 	public StringInput(Terminal terminal, String name, String defaultValue) {
-		this(terminal, name, defaultValue, null);
+		this(terminal, name, defaultValue, null, false);
 	}
 
 	public StringInput(Terminal terminal, String name, String defaultValue,
 			Function<StringInputContext, List<AttributedString>> renderer) {
+		this(terminal, name, defaultValue, renderer, false);
+	}
+
+	public StringInput(Terminal terminal, String name, String defaultValue,
+			Function<StringInputContext, List<AttributedString>> renderer, boolean required) {
 		super(terminal, name, null);
 		setRenderer(renderer != null ? renderer : new DefaultRenderer());
 		setTemplateLocation("classpath:org/springframework/shell/component/string-input-default.stg");
 		this.defaultValue = defaultValue;
+		this.required = required;
 	}
 
 	/**
@@ -70,12 +76,21 @@ public void setMaskCharacter(Character maskCharacter) {
 		this.maskCharacter = maskCharacter;
 	}
 
+	/**
+	 * Sets a required flag to check that the result is not empty
+	 *
+	 * @param required if input is required
+	 */
+	public void setRequired(boolean required) {
+		this.required = required;
+	}
+
 	@Override
 	public StringInputContext getThisContext(ComponentContext<?> context) {
 		if (context != null && currentContext == context) {
 			return currentContext;
 		}
-		currentContext = StringInputContext.of(defaultValue, maskCharacter);
+		currentContext = StringInputContext.of(defaultValue, maskCharacter, required);
 		currentContext.setName(getName());
 		context.stream().forEach(e -> {
 			currentContext.put(e.getKey(), e.getValue());
@@ -116,6 +131,9 @@ protected boolean read(BindingReader bindingReader, KeyMap<String> keyMap, Strin
 				}
 				else if (context.getDefaultValue() != null) {
 					context.setResultValue(context.getDefaultValue());
+				} else if (required) {
+					context.setMessage("This field is mandatory", TextComponentContext.MessageLevel.ERROR);
+					break;
 				}
 				return true;
 			default:
@@ -175,13 +193,27 @@ public interface StringInputContext extends TextComponentContext<String, StringI
 		 */
 		Character getMaskCharacter();
 
+		/**
+		 * Sets flag for mandatory input.
+		 *
+		 * @param required true if input is required
+		 */
+		void setRequired(boolean required);
+
+		/**
+		 * Returns flag if input is required.
+		 *
+		 * @return true if input is required, false otherwise
+		 */
+		boolean isRequired();
+
 		/**
 		 * Gets an empty {@link StringInputContext}.
 		 *
 		 * @return empty path input context
 		 */
 		public static StringInputContext empty() {
-			return of(null, null);
+			return of(null, null, false);
 		}
 
 		/**
@@ -190,7 +222,16 @@ public static StringInputContext empty() {
 		 * @return path input context
 		 */
 		public static StringInputContext of(String defaultValue, Character maskCharacter) {
-			return new DefaultStringInputContext(defaultValue, maskCharacter);
+			return of(defaultValue, maskCharacter, false);
+		}
+
+		/**
+		 * Gets an {@link StringInputContext}.
+		 *
+		 * @return path input context
+		 */
+		public static StringInputContext of(String defaultValue, Character maskCharacter, boolean required) {
+			return new DefaultStringInputContext(defaultValue, maskCharacter, required);
 		}
 	}
 
@@ -199,10 +240,12 @@ private static class DefaultStringInputContext extends BaseTextComponentContext<
 
 		private String defaultValue;
 		private Character maskCharacter;
+		private boolean required;
 
-		public DefaultStringInputContext(String defaultValue, Character maskCharacter) {
+		public DefaultStringInputContext(String defaultValue, Character maskCharacter, boolean required) {
 			this.defaultValue = defaultValue;
 			this.maskCharacter = maskCharacter;
+			this.required = required;
 		}
 
 		@Override
@@ -220,6 +263,11 @@ public void setMaskCharacter(Character maskCharacter) {
 			this.maskCharacter = maskCharacter;
 		}
 
+		@Override
+		public void setRequired(boolean required) {
+			this.required = required;
+		}
+
 		@Override
 		public String getMaskedInput() {
 			return maybeMask(getInput());
@@ -240,6 +288,11 @@ public Character getMaskCharacter() {
 			return maskCharacter;
 		}
 
+		@Override
+		public boolean isRequired() {
+			return required;
+		}
+
 		@Override
 		public Map<String, Object> toTemplateModel() {
 			Map<String, Object> attributes = super.toTemplateModel();
@@ -248,6 +301,7 @@ public Map<String, Object> toTemplateModel() {
 			attributes.put("maskedResultValue", getMaskedResultValue());
 			attributes.put("maskCharacter", getMaskCharacter());
 			attributes.put("hasMaskCharacter", hasMaskCharacter());
+			attributes.put("required", isRequired());
 			Map<String, Object> model = new HashMap<>();
 			model.put("model", attributes);
 			return model;

spring-shell-core/src/main/java/org/springframework/shell/component/flow/BaseStringInput.java

@@ -21,7 +21,6 @@
 import java.util.function.Function;
 
 import org.jline.utils.AttributedString;
-
 import org.springframework.shell.component.StringInput.StringInputContext;
 import org.springframework.shell.component.flow.ComponentFlow.BaseBuilder;
 import org.springframework.shell.component.flow.ComponentFlow.Builder;
@@ -38,6 +37,7 @@ public abstract class BaseStringInput extends BaseInput<StringInputSpec> impleme
 	private ResultMode resultMode;
 	private String defaultValue;
 	private Character maskCharacter;
+	private boolean required = false;
 	private Function<StringInputContext, List<AttributedString>> renderer;
 	private List<Consumer<StringInputContext>> preHandlers = new ArrayList<>();
 	private List<Consumer<StringInputContext>> postHandlers = new ArrayList<>();
@@ -79,6 +79,12 @@ public StringInputSpec maskCharacter(Character maskCharacter) {
 		return this;
 	}
 
+	@Override
+	public StringInputSpec required() {
+		this.required = true;
+		return this;
+	}
+
 	@Override
 	public StringInputSpec renderer(Function<StringInputContext, List<AttributedString>> renderer) {
 		this.renderer = renderer;
@@ -146,6 +152,10 @@ public Character getMaskCharacter() {
 		return maskCharacter;
 	}
 
+	public boolean isRequired() {
+		return required;
+	}
+
 	public Function<StringInputContext, List<AttributedString>> getRenderer() {
 		return renderer;
 	}
@@ -169,4 +179,4 @@ public boolean isStoreResult() {
 	public Function<StringInputContext, String> getNext() {
 		return next;
 	}
-}
+}

spring-shell-core/src/main/java/org/springframework/shell/component/flow/ComponentFlow.java

@@ -31,19 +31,18 @@
 import org.jline.terminal.Terminal;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.springframework.core.OrderComparator;
 import org.springframework.core.Ordered;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.shell.component.ConfirmationInput;
+import org.springframework.shell.component.ConfirmationInput.ConfirmationInputContext;
 import org.springframework.shell.component.MultiItemSelector;
 import org.springframework.shell.component.MultiItemSelector.MultiItemSelectorContext;
 import org.springframework.shell.component.PathInput;
 import org.springframework.shell.component.PathInput.PathInputContext;
 import org.springframework.shell.component.SingleItemSelector;
 import org.springframework.shell.component.SingleItemSelector.SingleItemSelectorContext;
 import org.springframework.shell.component.StringInput;
-import org.springframework.shell.component.ConfirmationInput.ConfirmationInputContext;
 import org.springframework.shell.component.StringInput.StringInputContext;
 import org.springframework.shell.component.context.ComponentContext;
 import org.springframework.shell.component.support.SelectorItem;
@@ -445,7 +444,7 @@ else if (n.isPresent()) {
 
 		private Stream<OrderedInputOperation> stringInputsStream() {
 			return stringInputs.stream().map(input -> {
-				StringInput selector = new StringInput(terminal, input.getName(), input.getDefaultValue());
+				StringInput selector = new StringInput(terminal, input.getName(), input.getDefaultValue(), null, input.isRequired());
 				Function<ComponentContext<?>, ComponentContext<?>> operation = (context) -> {
 						if (input.getResultMode() == ResultMode.ACCEPT && input.isStoreResult()
 								&& StringUtils.hasText(input.getResultValue())) {
@@ -465,6 +464,7 @@ private Stream<OrderedInputOperation> stringInputsStream() {
 							if (input.getResultMode() == ResultMode.VERIFY && StringUtils.hasText(input.getResultValue())) {
 								selector.addPreRunHandler(c -> {
 									c.setDefaultValue(input.getResultValue());
+									c.setRequired(input.isRequired());
 								});
 							}
 							selector.addPostRunHandler(c -> {

spring-shell-core/src/main/java/org/springframework/shell/component/flow/StringInputSpec.java

@@ -20,7 +20,6 @@
 import java.util.function.Function;
 
 import org.jline.utils.AttributedString;
-
 import org.springframework.shell.component.StringInput.StringInputContext;
 import org.springframework.shell.component.context.ComponentContext;
 import org.springframework.shell.component.flow.ComponentFlow.Builder;
@@ -72,6 +71,13 @@ public interface StringInputSpec extends BaseInputSpec<StringInputSpec> {
 	 */
 	StringInputSpec maskCharacter(Character maskCharacter);
 
+	/**
+	 * Sets input to required
+	 *
+	 * @return a builder
+	 */
+	StringInputSpec required();
+
 	/**
 	 * Sets a renderer function.
 	 *
@@ -128,4 +134,4 @@ public interface StringInputSpec extends BaseInputSpec<StringInputSpec> {
 	 * @return the parent builder
 	 */
 	Builder and();
-}
+}

spring-shell-core/src/main/resources/org/springframework/shell/component/string-input-default.stg

@@ -1,3 +1,14 @@
+// message
+message(model) ::= <%
+<if(model.message && model.hasMessageLevelError)>
+  <({<figures.error>}); format="style-level-error"> <model.message; format="style-level-error">
+<elseif(model.message && model.hasMessageLevelWarn)>
+  <({<figures.warning>}); format="style-level-warn"> <model.message; format="style-level-warn">
+<elseif(model.message && model.hasMessageLevelInfo)>
+  <({<figures.info>}); format="style-level-info"> <model.message; format="style-level-info">
+<endif>
+%>
+
 // info section after '? xxx'
 info(model) ::= <%
 <if(model.hasMaskCharacter)>
@@ -6,6 +17,8 @@ info(model) ::= <%
   <else>
     <if(model.defaultValue)>
       <("[Default "); format="style-value"><model.defaultValue; format="style-value"><("]"); format="style-value">
+    <elseif(model.required)>
+      <("[Required]"); format="style-value">
     <endif>
   <endif>
 <else>
@@ -14,6 +27,8 @@ info(model) ::= <%
   <else>
     <if(model.defaultValue)>
       <("[Default "); format="style-value"><model.defaultValue; format="style-value"><("]"); format="style-value">
+    <elseif(model.required)>
+      <("[Required]"); format="style-value">
     <endif>
   <endif>
 <endif>
@@ -32,6 +47,7 @@ result(model) ::= <<
 // component is running
 running(model) ::= <<
 <question_name(model)> <info(model)>
+<message(model)>
 >>
 
 // main

spring-shell-core/src/test/java/org/springframework/shell/component/StringInputTests.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.shell.component;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.nio.charset.StandardCharsets;
@@ -28,13 +30,10 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
-
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.shell.component.StringInput.StringInputContext;
 import org.springframework.shell.component.context.ComponentContext;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
 public class StringInputTests extends AbstractShellTests {
 
 	private ExecutorService service;
@@ -166,6 +165,39 @@ public void testResultUserInput() throws InterruptedException {
 		assertThat(run1Context.getResultValue()).isEqualTo("test");
 	}
 
+	@Test
+	public void testResultMandatoryInput() throws InterruptedException {
+		ComponentContext<?> empty = ComponentContext.empty();
+		StringInput component1 = new StringInput(getTerminal());
+		component1.setResourceLoader(new DefaultResourceLoader());
+		component1.setTemplateExecutor(getTemplateExecutor());
+		component1.setRequired(true);
+
+		service.execute(() -> {
+			StringInputContext run1Context = component1.run(empty);
+			result1.set(run1Context);
+			latch1.countDown();
+		});
+
+		TestBuffer testBuffer = new TestBuffer().cr();
+		write(testBuffer.getBytes());
+
+		latch1.await(2, TimeUnit.SECONDS);
+
+		StringInputContext run1Context = result1.get();
+		assertThat(consoleOut()).contains("This field is mandatory");
+		assertThat(run1Context).isNull();
+
+		testBuffer.append("test").cr();
+		write(testBuffer.getBytes());
+
+		latch1.await(2, TimeUnit.SECONDS);
+		run1Context = result1.get();
+
+		assertThat(run1Context).isNotNull();
+		assertThat(run1Context.getResultValue()).isEqualTo("test");
+	}
+
 	@Test
 	public void testPassingViaContext() throws InterruptedException {
 		ComponentContext<?> empty = ComponentContext.empty();