Polish "Use MessageSource to interpolate bean validation messages"

See gh-17530

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -57,8 +57,7 @@ public class ValidationAutoConfiguration {
 	@ConditionalOnMissingBean(Validator.class)
 	public static LocalValidatorFactoryBean defaultValidator(ApplicationContext applicationContext) {
 		LocalValidatorFactoryBean factoryBean = new LocalValidatorFactoryBean();
-		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory();
-		interpolatorFactory.setMessageSource(applicationContext);
+		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory(applicationContext);
 		factoryBean.setMessageInterpolator(interpolatorFactory.getObject());
 		return factoryBean;
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/validation/ValidatorAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -25,6 +25,7 @@ import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.boot.validation.MessageInterpolatorFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.MessageSource;
 import org.springframework.validation.Errors;
 import org.springframework.validation.SmartValidator;
 import org.springframework.validation.Validator;
@@ -130,11 +131,10 @@ public class ValidatorAdapter implements SmartValidator, ApplicationContextAware
 		}
 	}
 
-	private static Validator create(ApplicationContext applicationContext) {
+	private static Validator create(MessageSource messageSource) {
 		OptionalValidatorFactoryBean validator = new OptionalValidatorFactoryBean();
 		try {
-			MessageInterpolatorFactory factory = new MessageInterpolatorFactory();
-			factory.setMessageSource(applicationContext);
+			MessageInterpolatorFactory factory = new MessageInterpolatorFactory(messageSource);
 			validator.setMessageInterpolator(factory.getObject());
 		}
 		catch (ValidationException ex) {

spring-boot-project/spring-boot-docs/src/docs/asciidoc/io/validation.adoc

@@ -10,3 +10,7 @@ For instance, the following service triggers the validation of the first argumen
 ----
 include::{docs-java}/features/validation/MyBean.java[]
 ----
+
+The application's `MessageSource` is used when resolving +`{parameters}`+ in constraint messages.
+This allows you to use <<features.adoc#features.internationalization,your application's `messages.properties` files>> for Bean Validation messages.
+Once the parameters have been resolved, message interpolation is completed using Bean Validation's default interpolator.

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationPropertiesJsr303Validator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -65,9 +65,7 @@ final class ConfigurationPropertiesJsr303Validator implements Validator {
 
 		Delegate(ApplicationContext applicationContext) {
 			setApplicationContext(applicationContext);
-			MessageInterpolatorFactory factory = new MessageInterpolatorFactory();
-			factory.setMessageSource(applicationContext);
-			setMessageInterpolator(factory.getObject());
+			setMessageInterpolator(new MessageInterpolatorFactory(applicationContext).getObject());
 			afterPropertiesSet();
 		}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/MessageInterpolatorFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -28,7 +28,6 @@ import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.context.MessageSource;
-import org.springframework.context.MessageSourceAware;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -39,7 +38,7 @@ import org.springframework.util.ClassUtils;
  * @author Phillip Webb
  * @since 1.5.0
  */
-public class MessageInterpolatorFactory implements ObjectFactory<MessageInterpolator>, MessageSourceAware {
+public class MessageInterpolatorFactory implements ObjectFactory<MessageInterpolator> {
 
 	private static final Set<String> FALLBACKS;
 
@@ -49,25 +48,28 @@ public class MessageInterpolatorFactory implements ObjectFactory<MessageInterpol
 		FALLBACKS = Collections.unmodifiableSet(fallbacks);
 	}
 
-	private MessageSource messageSource;
+	private final MessageSource messageSource;
+
+	public MessageInterpolatorFactory() {
+		this(null);
+	}
 
 	/**
-	 * Sets the {@link MessageSource} used to create
-	 * {@link MessageSourceInterpolatorDelegate}.
-	 * @param messageSource the message source that resolves any message parameters before
-	 * final interpolation
+	 * Creates a new {@link MessageInterpolatorFactory} that will produce a
+	 * {@link MessageInterpolator} that uses the given {@code messageSource} to resolve
+	 * any message parameters before final interpolation.
+	 * @param messageSource message source to be used by the interpolator
+	 * @since 2.6.0
 	 */
-	@Override
-	public void setMessageSource(MessageSource messageSource) {
+	public MessageInterpolatorFactory(MessageSource messageSource) {
 		this.messageSource = messageSource;
 	}
 
 	@Override
 	public MessageInterpolator getObject() throws BeansException {
 		MessageInterpolator messageInterpolator = getMessageInterpolator();
-		MessageSource messageSource = this.messageSource;
-		if (messageSource != null) {
-			return new MessageSourceInterpolatorDelegate(messageSource, messageInterpolator);
+		if (this.messageSource != null) {
+			return new MessageSourceMessageInterpolator(this.messageSource, messageInterpolator);
 		}
 		return messageInterpolator;
 	}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/MessageParameterPlaceholderHelper.java

@@ -1,105 +0,0 @@
-/*
- * Copyright 2012-2019 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.boot.validation;
-
-import java.util.LinkedHashSet;
-import java.util.Set;
-import java.util.function.Function;
-
-/**
- * Utility class to extract message parameters ({@code {param}}) from the message. These
- * parameters can be substituted for supplied values.
- *
- * @author Dmytro Nosan
- */
-final class MessageParameterPlaceholderHelper {
-
-	private static final char PREFIX = '{';
-
-	private static final char SUFFIX = '}';
-
-	private static final char ESCAPE = '\\';
-
-	/**
-	 * Replaces all message parameters using the given {@code parameterResolver}.
-	 * <p>
-	 * If returned value has other message parameters, they will be replaced recursively
-	 * until no replacement is performed;
-	 * <p>
-	 * Resolver can return {@code null} to signal that no further actions need to be done
-	 * and replacement should be omitted;
-	 * <p>
-	 * The message parameter can be escaped by the {@code '\'} symbol;
-	 * @param message the value containing the parameters to be replaced
-	 * @param parameterResolver the {@code parameterResolver} to use for replacement
-	 * @return the replaced message
-	 */
-	String replaceParameters(String message, Function<String, String> parameterResolver) {
-		return replaceParameters(message, parameterResolver, new LinkedHashSet<>(4));
-	}
-
-	private static String replaceParameters(String message, Function<String, String> parameterResolver,
-			Set<String> visitedParameters) {
-		StringBuilder buf = new StringBuilder(message);
-		int parentheses = 0;
-		int startIndex = -1;
-		int endIndex = -1;
-		for (int i = 0; i < buf.length(); i++) {
-			if (buf.charAt(i) == ESCAPE) {
-				i++;
-			}
-			else if (buf.charAt(i) == PREFIX) {
-				if (startIndex == -1) {
-					startIndex = i;
-				}
-				parentheses++;
-			}
-			else if (buf.charAt(i) == SUFFIX) {
-				if (parentheses > 0) {
-					parentheses--;
-				}
-				endIndex = i;
-			}
-			if (parentheses == 0 && startIndex < endIndex) {
-				String parameter = buf.substring(startIndex + 1, endIndex);
-				if (!visitedParameters.add(parameter)) {
-					throw new IllegalArgumentException("Circular reference '{" + parameter + "}'");
-				}
-				String value = replaceParameter(parameter, parameterResolver, visitedParameters);
-				if (value != null) {
-					buf.replace(startIndex, endIndex + 1, value);
-					i = startIndex + value.length() - 1;
-				}
-				visitedParameters.remove(parameter);
-				startIndex = -1;
-				endIndex = -1;
-			}
-		}
-		return buf.toString();
-	}
-
-	private static String replaceParameter(String parameter, Function<String, String> parameterResolver,
-			Set<String> visitedParameters) {
-		parameter = replaceParameters(parameter, parameterResolver, visitedParameters);
-		String value = parameterResolver.apply(parameter);
-		if (value != null) {
-			return replaceParameters(value, parameterResolver, visitedParameters);
-		}
-		return null;
-	}
-
-}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/MessageSourceInterpolatorDelegate.java

@@ -1,57 +0,0 @@
-/*
- * Copyright 2012-2019 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.boot.validation;
-
-import java.util.Locale;
-
-import javax.validation.MessageInterpolator;
-
-import org.springframework.context.MessageSource;
-import org.springframework.context.i18n.LocaleContextHolder;
-
-/**
- * Resolves any message parameters via {@link MessageSource} and then interpolates a
- * message using the underlying {@link MessageInterpolator}.
- *
- * @author Dmytro Nosan
- */
-class MessageSourceInterpolatorDelegate implements MessageInterpolator {
-
-	private static final MessageParameterPlaceholderHelper helper = new MessageParameterPlaceholderHelper();
-
-	private final MessageSource messageSource;
-
-	private final MessageInterpolator messageInterpolator;
-
-	MessageSourceInterpolatorDelegate(MessageSource messageSource, MessageInterpolator messageInterpolator) {
-		this.messageSource = messageSource;
-		this.messageInterpolator = messageInterpolator;
-	}
-
-	@Override
-	public String interpolate(String messageTemplate, Context context) {
-		return interpolate(messageTemplate, context, LocaleContextHolder.getLocale());
-	}
-
-	@Override
-	public String interpolate(String messageTemplate, Context context, Locale locale) {
-		String message = helper.replaceParameters(messageTemplate,
-				(parameter) -> this.messageSource.getMessage(parameter, null, null, locale));
-		return this.messageInterpolator.interpolate(message, context, locale);
-	}
-
-}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/MessageSourceMessageInterpolator.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2012-2021 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.boot.validation;
+
+import java.util.LinkedHashSet;
+import java.util.Locale;
+import java.util.Set;
+
+import javax.validation.MessageInterpolator;
+
+import org.springframework.context.MessageSource;
+import org.springframework.context.i18n.LocaleContextHolder;
+
+/**
+ * Resolves any message parameters via {@link MessageSource} and then interpolates a
+ * message using the underlying {@link MessageInterpolator}.
+ *
+ * @author Dmytro Nosan
+ */
+class MessageSourceMessageInterpolator implements MessageInterpolator {
+
+	private static final char PREFIX = '{';
+
+	private static final char SUFFIX = '}';
+
+	private static final char ESCAPE = '\\';
+
+	private final MessageSource messageSource;
+
+	private final MessageInterpolator messageInterpolator;
+
+	MessageSourceMessageInterpolator(MessageSource messageSource, MessageInterpolator messageInterpolator) {
+		this.messageSource = messageSource;
+		this.messageInterpolator = messageInterpolator;
+	}
+
+	@Override
+	public String interpolate(String messageTemplate, Context context) {
+		return interpolate(messageTemplate, context, LocaleContextHolder.getLocale());
+	}
+
+	@Override
+	public String interpolate(String messageTemplate, Context context, Locale locale) {
+		String message = replaceParameters(messageTemplate, locale);
+		return this.messageInterpolator.interpolate(message, context, locale);
+	}
+
+	/**
+	 * Recursively replaces all message parameters.
+	 * <p>
+	 * The message parameter prefix <code>&#123;</code> and suffix <code>&#125;</code> can
+	 * be escaped using {@code \}, e.g. <code>\&#123;escaped\&#125;</code>.
+	 * @param message the message containing the parameters to be replaced
+	 * @param locale the locale to use when resolving replacements
+	 * @return the message with parameters replaced
+	 */
+	private String replaceParameters(String message, Locale locale) {
+		return replaceParameters(message, locale, new LinkedHashSet<>(4));
+	}
+
+	private String replaceParameters(String message, Locale locale, Set<String> visitedParameters) {
+		StringBuilder buf = new StringBuilder(message);
+		int parentheses = 0;
+		int startIndex = -1;
+		int endIndex = -1;
+		for (int i = 0; i < buf.length(); i++) {
+			if (buf.charAt(i) == ESCAPE) {
+				i++;
+			}
+			else if (buf.charAt(i) == PREFIX) {
+				if (startIndex == -1) {
+					startIndex = i;
+				}
+				parentheses++;
+			}
+			else if (buf.charAt(i) == SUFFIX) {
+				if (parentheses > 0) {
+					parentheses--;
+				}
+				endIndex = i;
+			}
+			if (parentheses == 0 && startIndex < endIndex) {
+				String parameter = buf.substring(startIndex + 1, endIndex);
+				if (!visitedParameters.add(parameter)) {
+					throw new IllegalArgumentException("Circular reference '{" + String.join(" -> ", visitedParameters)
+							+ " -> " + parameter + "}'");
+				}
+				String value = replaceParameter(parameter, locale, visitedParameters);
+				if (value != null) {
+					buf.replace(startIndex, endIndex + 1, value);
+					i = startIndex + value.length() - 1;
+				}
+				visitedParameters.remove(parameter);
+				startIndex = -1;
+				endIndex = -1;
+			}
+		}
+		return buf.toString();
+	}
+
+	private String replaceParameter(String parameter, Locale locale, Set<String> visitedParameters) {
+		parameter = replaceParameters(parameter, locale, visitedParameters);
+		String value = this.messageSource.getMessage(parameter, null, null, locale);
+		return (value != null) ? replaceParameters(value, locale, visitedParameters) : null;
+	}
+
+}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/validation/MessageInterpolatorFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -42,11 +42,10 @@ class MessageInterpolatorFactoryTests {
 
 	@Test
 	void getObjectShouldReturnMessageSourceMessageInterpolatorDelegateWithResourceBundleMessageInterpolator() {
-		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory();
 		MessageSource messageSource = mock(MessageSource.class);
-		interpolatorFactory.setMessageSource(messageSource);
+		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory(messageSource);
 		MessageInterpolator interpolator = interpolatorFactory.getObject();
-		assertThat(interpolator).isInstanceOf(MessageSourceInterpolatorDelegate.class);
+		assertThat(interpolator).isInstanceOf(MessageSourceMessageInterpolator.class);
 		assertThat(interpolator).hasFieldOrPropertyWithValue("messageSource", messageSource);
 		assertThat(ReflectionTestUtils.getField(interpolator, "messageInterpolator"))
 				.isInstanceOf(ResourceBundleMessageInterpolator.class);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/validation/MessageInterpolatorFactoryWithoutElIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -55,11 +55,10 @@ class MessageInterpolatorFactoryWithoutElIntegrationTests {
 
 	@Test
 	void getObjectShouldUseMessageSourceMessageInterpolatorDelegateWithFallback() {
-		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory();
 		MessageSource messageSource = mock(MessageSource.class);
-		interpolatorFactory.setMessageSource(messageSource);
+		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory(messageSource);
 		MessageInterpolator interpolator = interpolatorFactory.getObject();
-		assertThat(interpolator).isInstanceOf(MessageSourceInterpolatorDelegate.class);
+		assertThat(interpolator).isInstanceOf(MessageSourceMessageInterpolator.class);
 		assertThat(interpolator).hasFieldOrPropertyWithValue("messageSource", messageSource);
 		assertThat(ReflectionTestUtils.getField(interpolator, "messageInterpolator"))
 				.isInstanceOf(ParameterMessageInterpolator.class);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/validation/MessageParameterPlaceholderHelperTests.java

@@ -1,100 +0,0 @@
-/*
- * Copyright 2012-2019 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.boot.validation;
-
-import java.util.LinkedHashMap;
-import java.util.Map;
-
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
-
-/**
- * Tests for {@link MessageParameterPlaceholderHelper}.
- *
- * @author Dmytro Nosan
- */
-class MessageParameterPlaceholderHelperTests {
-
-	private final MessageParameterPlaceholderHelper resolver = new MessageParameterPlaceholderHelper();
-
-	@Test
-	void recursionInParameters() {
-		Map<String, String> props = new LinkedHashMap<>();
-		props.put("a", "{b}");
-		props.put("b", "{c}");
-		props.put("c", "{a}");
-		assertThatIllegalArgumentException().isThrownBy(() -> this.resolver.replaceParameters("{a}", props::get))
-				.withMessage("Circular reference '{a}'");
-	}
-
-	@Test
-	void replaceParameters() {
-		Map<String, String> props = new LinkedHashMap<>();
-		props.put("foo", "fooValue");
-		props.put("bar", "");
-		assertThat(this.resolver.replaceParameters("{foo}{bar}", props::get)).isEqualTo("fooValue");
-	}
-
-	@Test
-	void replaceNestedParameters() {
-		Map<String, String> props = new LinkedHashMap<>();
-		props.put("top", "{child}+{child}");
-		props.put("child", "{{differentiator}.grandchild}");
-		props.put("differentiator", "first");
-		props.put("first.grandchild", "actualValue");
-		assertThat(this.resolver.replaceParameters("{top}", props::get)).isEqualTo("actualValue+actualValue");
-	}
-
-	@Test
-	void unresolvedParameters() {
-		Map<String, String> props = new LinkedHashMap<>();
-		props.put("top", "{child}+{child}");
-		assertThat(this.resolver.replaceParameters("{foo}{top}{bar}", props::get))
-				.isEqualTo("{foo}{child}+{child}{bar}");
-	}
-
-	@Test
-	void unbalancedParentheses() {
-		Map<String, String> props = new LinkedHashMap<>();
-		props.put("top", "topValue");
-		assertThat(this.resolver.replaceParameters("\\{top}", props::get)).isEqualTo("\\{top}");
-		assertThat(this.resolver.replaceParameters("{top\\}", props::get)).isEqualTo("{top\\}");
-		assertThat(this.resolver.replaceParameters("{{top}", props::get)).isEqualTo("{{top}");
-		assertThat(this.resolver.replaceParameters("{top}}", props::get)).isEqualTo("topValue}");
-	}
-
-	@Test
-	void resolveEscapeParameters() {
-		Map<String, String> props = new LinkedHashMap<>();
-		props.put("foo", "fooValue");
-		props.put("bar", "\\{foo}");
-		props.put("bazz\\}", "bazzValue");
-		assertThat(this.resolver.replaceParameters("{foo}", props::get)).isEqualTo("fooValue");
-		assertThat(this.resolver.replaceParameters("{foo}\\a", props::get)).isEqualTo("fooValue\\a");
-		assertThat(this.resolver.replaceParameters("\\\\{foo}", props::get)).isEqualTo("\\\\fooValue");
-		assertThat(this.resolver.replaceParameters("\\\\\\{foo}", props::get)).isEqualTo("\\\\\\{foo}");
-		assertThat(this.resolver.replaceParameters("\\{foo}", props::get)).isEqualTo("\\{foo}");
-		assertThat(this.resolver.replaceParameters("{foo\\}", props::get)).isEqualTo("{foo\\}");
-		assertThat(this.resolver.replaceParameters("\\{foo\\}", props::get)).isEqualTo("\\{foo\\}");
-		assertThat(this.resolver.replaceParameters("{foo}\\", props::get)).isEqualTo("fooValue\\");
-		assertThat(this.resolver.replaceParameters("{bar}", props::get)).isEqualTo("\\{foo}");
-		assertThat(this.resolver.replaceParameters("{bazz\\}}", props::get)).isEqualTo("bazzValue");
-	}
-
-}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/validation/MessageSourceMessageInterpolatorIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -35,14 +35,17 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
- * Tests for {@link MessageSourceInterpolatorDelegate}.
+ * Integration tests for {@link MessageSourceMessageInterpolator}.
  *
  * @author Dmytro Nosan
  */
-class MessageSourceInterpolatorDelegateTests {
+class MessageSourceMessageInterpolatorIntegrationTests {
 
 	private final Validator validator = buildValidator();
 
+	@NotNull
+	private String defaultMessage;
+
 	@NotNull(message = "{null}")
 	private String nullable;
 
@@ -67,6 +70,11 @@ class MessageSourceInterpolatorDelegateTests {
 	@NotNull(message = "\\\\{null}")
 	private String escapeEscape;
 
+	@Test
+	void defaultMessage() {
+		assertThat(validate("defaultMessage")).containsExactly("must not be null");
+	}
+
 	@Test
 	void nullable() {
 		assertThat(validate("nullable")).containsExactly("must not be null");
@@ -79,7 +87,8 @@ class MessageSourceInterpolatorDelegateTests {
 
 	@Test
 	void recursion() {
-		assertThatThrownBy(() -> validate("recursion")).hasStackTraceContaining("Circular reference '{recursion}'");
+		assertThatThrownBy(() -> validate("recursion"))
+				.hasStackTraceContaining("Circular reference '{recursion -> middle -> recursion}'");
 	}
 
 	@Test
@@ -121,13 +130,14 @@ class MessageSourceInterpolatorDelegateTests {
 		StaticMessageSource messageSource = new StaticMessageSource();
 		messageSource.addMessage("blank", locale, "{null} or {javax.validation.constraints.NotBlank.message}");
 		messageSource.addMessage("null", locale, "{javax.validation.constraints.NotNull.message}");
-		messageSource.addMessage("recursion", locale, "{recursion}");
-		MessageInterpolatorFactory messageInterpolatorFactory = new MessageInterpolatorFactory();
-		messageInterpolatorFactory.setMessageSource(messageSource);
-		LocalValidatorFactoryBean validatorFactory = new LocalValidatorFactoryBean();
-		validatorFactory.setMessageInterpolator(messageInterpolatorFactory.getObject());
-		validatorFactory.afterPropertiesSet();
-		return validatorFactory.getValidator();
+		messageSource.addMessage("recursion", locale, "{middle}");
+		messageSource.addMessage("middle", locale, "{recursion}");
+		MessageInterpolatorFactory messageInterpolatorFactory = new MessageInterpolatorFactory(messageSource);
+		try (LocalValidatorFactoryBean validatorFactory = new LocalValidatorFactoryBean()) {
+			validatorFactory.setMessageInterpolator(messageInterpolatorFactory.getObject());
+			validatorFactory.afterPropertiesSet();
+			return validatorFactory.getValidator();
+		}
 	}
 
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/validation/MessageSourceMessageInterpolatorTests.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright 2012-2021 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.boot.validation;
+
+import java.util.Locale;
+
+import javax.validation.MessageInterpolator;
+import javax.validation.MessageInterpolator.Context;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.context.support.StaticMessageSource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link MessageSourceMessageInterpolator}.
+ *
+ * @author Dmytro Nosan
+ * @author Andy Wilkinson
+ */
+class MessageSourceMessageInterpolatorTests {
+
+	private final Context context = mock(Context.class);
+
+	private final StaticMessageSource messageSource = new StaticMessageSource();
+
+	private final MessageSourceMessageInterpolator interpolator = new MessageSourceMessageInterpolator(
+			this.messageSource, new IdentityMessageInterpolator());
+
+	@Test
+	void interpolateShouldReplaceParameters() {
+		this.messageSource.addMessage("foo", Locale.getDefault(), "fooValue");
+		this.messageSource.addMessage("bar", Locale.getDefault(), "");
+		assertThat(this.interpolator.interpolate("{foo}{bar}", this.context)).isEqualTo("fooValue");
+	}
+
+	@Test
+	void interpolateWhenParametersAreUnknownShouldLeaveThemUnchanged() {
+		this.messageSource.addMessage("top", Locale.getDefault(), "{child}+{child}");
+		assertThat(this.interpolator.interpolate("{foo}{top}{bar}", this.context))
+				.isEqualTo("{foo}{child}+{child}{bar}");
+	}
+
+	@Test
+	void interpolateWhenParametersAreNestedShouldFullyReplaceAllParameters() {
+		this.messageSource.addMessage("top", Locale.getDefault(), "{child}+{child}");
+		this.messageSource.addMessage("child", Locale.getDefault(), "{{differentiator}.grandchild}");
+		this.messageSource.addMessage("differentiator", Locale.getDefault(), "first");
+		this.messageSource.addMessage("first.grandchild", Locale.getDefault(), "actualValue");
+		assertThat(this.interpolator.interpolate("{top}", this.context)).isEqualTo("actualValue+actualValue");
+	}
+
+	@Test
+	void interpolateWhenParameterBracesAreUnbalancedShouldLeaveThemUnchanged() {
+		this.messageSource.addMessage("top", Locale.getDefault(), "topValue");
+		assertThat(this.interpolator.interpolate("\\{top}", this.context)).isEqualTo("\\{top}");
+		assertThat(this.interpolator.interpolate("{top\\}", this.context)).isEqualTo("{top\\}");
+		assertThat(this.interpolator.interpolate("{{top}", this.context)).isEqualTo("{{top}");
+		assertThat(this.interpolator.interpolate("{top}}", this.context)).isEqualTo("topValue}");
+	}
+
+	@Test
+	void interpolateWhenBracesAreEscapedShouldIgnore() {
+		this.messageSource.addMessage("foo", Locale.getDefault(), "fooValue");
+		this.messageSource.addMessage("bar", Locale.getDefault(), "\\{foo}");
+		this.messageSource.addMessage("bazz\\}", Locale.getDefault(), "bazzValue");
+		assertThat(this.interpolator.interpolate("{foo}", this.context)).isEqualTo("fooValue");
+		assertThat(this.interpolator.interpolate("{foo}\\a", this.context)).isEqualTo("fooValue\\a");
+		assertThat(this.interpolator.interpolate("\\\\{foo}", this.context)).isEqualTo("\\\\fooValue");
+		assertThat(this.interpolator.interpolate("\\\\\\{foo}", this.context)).isEqualTo("\\\\\\{foo}");
+		assertThat(this.interpolator.interpolate("\\{foo}", this.context)).isEqualTo("\\{foo}");
+		assertThat(this.interpolator.interpolate("{foo\\}", this.context)).isEqualTo("{foo\\}");
+		assertThat(this.interpolator.interpolate("\\{foo\\}", this.context)).isEqualTo("\\{foo\\}");
+		assertThat(this.interpolator.interpolate("{foo}\\", this.context)).isEqualTo("fooValue\\");
+		assertThat(this.interpolator.interpolate("{bar}", this.context)).isEqualTo("\\{foo}");
+		assertThat(this.interpolator.interpolate("{bazz\\}}", this.context)).isEqualTo("bazzValue");
+	}
+
+	@Test
+	void interpolateWhenParametersContainACycleShouldThrow() {
+		this.messageSource.addMessage("a", Locale.getDefault(), "{b}");
+		this.messageSource.addMessage("b", Locale.getDefault(), "{c}");
+		this.messageSource.addMessage("c", Locale.getDefault(), "{a}");
+		assertThatIllegalArgumentException().isThrownBy(() -> this.interpolator.interpolate("{a}", this.context))
+				.withMessage("Circular reference '{a -> b -> c -> a}'");
+	}
+
+	private static final class IdentityMessageInterpolator implements MessageInterpolator {
+
+		@Override
+		public String interpolate(String messageTemplate, Context context) {
+			return messageTemplate;
+		}
+
+		@Override
+		public String interpolate(String messageTemplate, Context context, Locale locale) {
+			return messageTemplate;
+		}
+
+	}
+
+}