Pretty print bean validation errors

Fixes #137

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

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2017 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
+ *
+ *      http://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;
+
+import javax.validation.ConstraintViolation;
+import java.util.Set;
+
+/**
+ * Thrown when one or more parameters fail bean validation constraints.
+ *
+ * @author Eric Bottard
+ */
+public class ParameterValidationException extends RuntimeException {
+	private final Set<ConstraintViolation<Object>> constraintViolations;
+	private final MethodTarget methodTarget;
+
+	public ParameterValidationException(Set<ConstraintViolation<Object>> constraintViolations, MethodTarget methodTarget) {
+		this.constraintViolations = constraintViolations;
+		this.methodTarget = methodTarget;
+	}
+
+	public Set<ConstraintViolation<Object>> getConstraintViolations() {
+		return constraintViolations;
+	}
+
+	public MethodTarget getMethodTarget() {
+		return methodTarget;
+	}
+}

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

@@ -63,6 +63,9 @@ public class Shell implements CommandRegistry {
 	 */
 	protected static final Object UNRESOLVED = new Object();
 
+	private final ExecutableValidator executableValidator = Validation
+		.buildDefaultValidatorFactory().getValidator().forExecutables();
+
 	public Shell(ResultHandler resultHandler) {
 		this.resultHandler = resultHandler;
 	}
@@ -229,13 +232,13 @@ public class Shell implements CommandRegistry {
 				throw new IllegalStateException("Could not resolve " + methodParameter);
 			}
 		}
-		ExecutableValidator executableValidator = Validation
-			.buildDefaultValidatorFactory().getValidator().forExecutables();
-		Set<ConstraintViolation<Object>> constraintViolations = executableValidator.validateParameters(methodTarget.getBean(),
+		Set<ConstraintViolation<Object>> constraintViolations = executableValidator.validateParameters(
+			methodTarget.getBean(),
 			methodTarget.getMethod(),
-			args);
+			args
+		);
 		if (constraintViolations.size() > 0) {
-			System.out.println(constraintViolations);
+			throw new ParameterValidationException(constraintViolations, methodTarget);
 		}
 	}
 

spring-shell-core/src/main/java/org/springframework/shell/result/ParameterValidationExceptionResultHandler.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2017 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
+ *
+ *      http://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.result;
+
+import org.jline.utils.AttributedString;
+import org.jline.utils.AttributedStringBuilder;
+import org.jline.utils.AttributedStyle;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.MethodParameter;
+import org.springframework.shell.ParameterDescription;
+import org.springframework.shell.ParameterResolver;
+import org.springframework.shell.ParameterValidationException;
+import org.springframework.shell.Utils;
+import org.springframework.stereotype.Component;
+
+import javax.validation.ElementKind;
+import javax.validation.Path;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+/**
+ * Displays validation errors on the terminal.
+ *
+ * @author Eric Bottard
+ */
+@Component
+public class ParameterValidationExceptionResultHandler
+		extends TerminalAwareResultHandler<ParameterValidationException> {
+
+	@Autowired
+	private List<ParameterResolver> parameterResolvers;
+
+	@Override
+	protected void doHandleResult(ParameterValidationException result) {
+		terminal.writer().println(new AttributedString("The following constraints were not met:",
+				AttributedStyle.DEFAULT.foreground(AttributedStyle.RED)).toAnsi());
+		result.getConstraintViolations().stream()
+				.forEach(v -> {
+					Optional<Integer> parameterIndex = StreamSupport.stream(v.getPropertyPath().spliterator(), false)
+							.filter(n -> n.getKind() == ElementKind.PARAMETER)
+							.map(n -> ((Path.ParameterNode) n).getParameterIndex())
+							.findFirst();
+
+					MethodParameter methodParameter = Utils.createMethodParameter(result.getMethodTarget().getMethod(),
+							parameterIndex.get());
+					List<ParameterDescription> descriptions = findParameterResolver(methodParameter)
+							.describe(methodParameter).collect(Collectors.toList());
+					if (descriptions.size() == 1) {
+						ParameterDescription description = descriptions.get(0);
+						AttributedStringBuilder ansi = new AttributedStringBuilder(100);
+						ansi.append("\t").append(description.keys().get(0), AttributedStyle.DEFAULT.foreground(AttributedStyle.RED).bold());
+						ansi.append(" ").append(description.formal(), AttributedStyle.DEFAULT.foreground(AttributedStyle.RED).underline());
+						String msg = String.format(" : %s (You passed '%s')",
+								v.getMessage(),
+								String.valueOf(v.getInvalidValue())
+						);
+						ansi.append(msg, AttributedStyle.DEFAULT.foreground(AttributedStyle.RED));
+
+						terminal.writer().println(ansi.toAnsi(terminal));
+					}
+					// Several formals for one method param, must be framework like JCommander, etc
+					else {
+						// Output toString() for now...
+						terminal.writer().println(new AttributedString(v.toString(),
+								AttributedStyle.DEFAULT.foreground(AttributedStyle.RED)).toAnsi(terminal));
+					}
+
+				});
+	}
+
+	private ParameterResolver findParameterResolver(MethodParameter methodParameter) {
+		return parameterResolvers.stream().filter(pr -> pr.supports(methodParameter)).findFirst().get();
+	}
+}

spring-shell-samples/src/main/java/org/springframework/shell/samples/jcommander/Args.java

@@ -21,6 +21,8 @@ import java.util.List;
 
 import com.beust.jcommander.Parameter;
 
+import javax.validation.constraints.Min;
+
 /**
  * An example straight from the JCommander documentation.
  *
@@ -31,6 +33,7 @@ public class Args {
 	@Parameter
 	private List<String> parameters = new ArrayList<>();
 
+	@Min(3)
 	@Parameter(names = { "-log", "-verbose" }, description = "Level of verbosity")
 	private Integer verbose = 1;
 

spring-shell-samples/src/main/java/org/springframework/shell/samples/jcommander/JCommanderCommands.java

@@ -20,6 +20,8 @@ import org.springframework.shell.standard.ShellComponent;
 import org.springframework.shell.standard.ShellMethod;
 import org.springframework.shell.standard.ShellOption;
 
+import javax.validation.Valid;
+
 /**
  * A class with JCommander commands.
  *
@@ -29,7 +31,7 @@ import org.springframework.shell.standard.ShellOption;
 public class JCommanderCommands {
 
 	@ShellMethod("Bind parameters to JCommander POJO.")
-	public String jcommander(@ShellOption(optOut = true) Args args) {
+	public String jcommander(@ShellOption(optOut = true) @Valid Args args) {
 		return "You said " + args;
 	}
 }

spring-shell-samples/src/main/java/org/springframework/shell/samples/standard/Commands.java

@@ -30,6 +30,8 @@ import org.springframework.shell.standard.ShellOption;
 import org.springframework.shell.standard.ValueProviderSupport;
 import org.springframework.stereotype.Component;
 
+import javax.validation.constraints.Size;
+
 /**
  * Example commands for the Shell 2 Standard resolver.
  *
@@ -44,7 +46,7 @@ public class Commands {
 	}
 
 	@ShellMethod("It's cool.")
-	public String foo(String bar) {
+	public String foo(@Size(min = 2) String bar) {
 		return bar;
 	}