Add generic custom constraint using SpEL expression

build.gradle

@@ -56,7 +56,7 @@ subprojects { Project subproject ->
     sourceCompatibility = "17"
 
     java {
-      ["envers", "reactor", "web", "webMvc", "webFlux", "hibernate"].forEach {
+      ["envers", "reactor", "web", "webMvc", "webFlux", "hibernate", "spel"].forEach {
         registerFeature(it) {
           usingSourceSet(sourceSets.main)
         }

nrich-validation-api/src/main/java/net/croz/nrich/validation/api/constraint/SpelExpression.java

@@ -0,0 +1,71 @@
+/*
+ *  Copyright 2020-2023 CROZ d.o.o, 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 net.croz.nrich.validation.api.constraint;
+
+import jakarta.validation.Constraint;
+import jakarta.validation.Payload;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Repeatable;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
+import static java.lang.annotation.ElementType.CONSTRUCTOR;
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE_USE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+
+/**
+ * The annotated element is validated against a provided SpEL expression
+ */
+@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE })
+@Retention(RUNTIME)
+@Repeatable(SpelExpression.List.class)
+@Documented
+@Constraint(validatedBy = {})
+public @interface SpelExpression {
+
+    String message() default "{nrich.constraint.spelExpression.invalid.message}";
+
+    Class<?>[] groups() default {};
+
+    /**
+     * SpEL expression that is evaluated
+     *
+     * @return SpEL expression
+     */
+    String value();
+
+    Class<? extends Payload>[] payload() default {};
+
+    /**
+     * Defines several {@link SpelExpression} annotations on the same element.
+     *
+     * @see SpelExpression
+     */
+    @Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE })
+    @Retention(RUNTIME)
+    @Documented
+    @interface List {
+
+        SpelExpression[] value();
+    }
+}

nrich-validation-spring-boot-starter/README.md

@@ -65,6 +65,7 @@ and default ones disabled then through `nrich.validation.register-messages` prop
 | `@MaxSizeInBytes`         | Validates that the annotated element size in bytes must be less than specified maximum                                                                                                            |
 | `@NotNullWhen`            | Validates that the annotated element must not be null when condition is satisfied                                                                                                                 |
 | `@NullWhen`               | Validates that the annotated element must be null when condition is satisfied                                                                                                                     |
+| `@SpellExpression`        | Validates the annotated element with the defined SpEL expression                                                                                                                                  |
 | `@ValidFile`              | Validates that the annotated element matches specified content type list, allowed extension list and/or allowed regex                                                                             |
 | `@ValidFileResolvable`    | Validates that the annotated element matches specified content type list, allowed extension list and/or allowed regex                                                                             |
 | `@ValidOib`               | Validates that the annotated element is valid OIB (Personal Identification number)                                                                                                                |

nrich-validation/README.md

@@ -247,3 +247,31 @@ public class SearchPersonRequest {
 ```
 
 Above request will require that either both firstName and lastName are not null or that id is not null.
+
+#### SpelExpression
+
+Validates property against a provided SpEL Expression
+
+```java
+
+@Setter
+@Getter
+public class ExampleRequest {
+
+    @SpelExpression("@spelValidationTestService.validateUuid(#this)")
+    private String uuid;
+
+}
+
+@Setter
+@Getter
+@SpelExpression("@spelValidationTestService.validateUuid(uuid)")
+public class ExampleTypeRequest {
+
+    private String uuid;
+
+}
+
+```
+
+In an example above the property uuid is required to be a valid UUID format. The format check is achieved by calling `validateUuid` method of `spelValidationTestService` bean.

nrich-validation/build.gradle

@@ -10,6 +10,9 @@ dependencies {
 
   runtimeOnly "org.apache.tomcat.embed:tomcat-embed-el"
 
+  spelImplementation "org.springframework:spring-expression"
+  spelImplementation "org.springframework:spring-context"
+
   webImplementation "org.springframework:spring-web"
 
   testAnnotationProcessor "org.projectlombok:lombok"

nrich-validation/src/main/java/net/croz/nrich/validation/aot/ValidationRuntimeHintsRegistrar.java

@@ -18,6 +18,7 @@
 package net.croz.nrich.validation.aot;
 
 import net.croz.nrich.validation.constraint.mapping.DefaultConstraintMappingContributor;
+import net.croz.nrich.validation.constraint.validator.SpelExpressionValidator;
 import net.croz.nrich.validation.constraint.validator.InListValidator;
 import net.croz.nrich.validation.constraint.validator.MaxSizeInBytesValidator;
 import net.croz.nrich.validation.constraint.validator.NotNullWhenValidator;
@@ -43,7 +44,7 @@ public class ValidationRuntimeHintsRegistrar implements RuntimeHintsRegistrar {
 
     public static final List<TypeReference> TYPE_REFERENCE_LIST = Collections.unmodifiableList(TypeReference.listOf(
         DefaultConstraintMappingContributor.class, ValidOibValidator.class, ValidSearchPropertiesValidator.class, ValidRangeValidator.class, MaxSizeInBytesValidator.class,
-        NotNullWhenValidator.class, NullWhenValidator.class, ValidFileValidator.class, ValidFileResolvableValidator.class, InListValidator.class
+        NotNullWhenValidator.class, NullWhenValidator.class, ValidFileValidator.class, ValidFileResolvableValidator.class, InListValidator.class, SpelExpressionValidator.class
     ));
 
     @Override

nrich-validation/src/main/java/net/croz/nrich/validation/constraint/mapping/DefaultConstraintMappingContributor.java

@@ -17,6 +17,7 @@
 
 package net.croz.nrich.validation.constraint.mapping;
 
+import net.croz.nrich.validation.api.constraint.SpelExpression;
 import net.croz.nrich.validation.api.constraint.InList;
 import net.croz.nrich.validation.api.constraint.MaxSizeInBytes;
 import net.croz.nrich.validation.api.constraint.NotNullWhen;
@@ -26,6 +27,7 @@
 import net.croz.nrich.validation.api.constraint.ValidOib;
 import net.croz.nrich.validation.api.constraint.ValidRange;
 import net.croz.nrich.validation.api.constraint.ValidSearchProperties;
+import net.croz.nrich.validation.constraint.validator.SpelExpressionValidator;
 import net.croz.nrich.validation.constraint.validator.InListValidator;
 import net.croz.nrich.validation.constraint.validator.MaxSizeInBytesValidator;
 import net.croz.nrich.validation.constraint.validator.NotNullWhenValidator;
@@ -50,5 +52,6 @@ public void createConstraintMappings(ConstraintMappingBuilder builder) {
         builder.addConstraintMapping().constraintDefinition(ValidFile.class).validatedBy(ValidFileValidator.class);
         builder.addConstraintMapping().constraintDefinition(ValidFileResolvable.class).validatedBy(ValidFileResolvableValidator.class);
         builder.addConstraintMapping().constraintDefinition(InList.class).validatedBy(InListValidator.class);
+        builder.addConstraintMapping().constraintDefinition(SpelExpression.class).validatedBy(SpelExpressionValidator.class);
     }
 }

nrich-validation/src/main/java/net/croz/nrich/validation/constraint/validator/SpelExpressionValidator.java

@@ -0,0 +1,64 @@
+/*
+ *  Copyright 2020-2023 CROZ d.o.o, 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 net.croz.nrich.validation.constraint.validator;
+
+import net.croz.nrich.validation.api.constraint.SpelExpression;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.expression.BeanFactoryResolver;
+import org.springframework.expression.Expression;
+import org.springframework.expression.ExpressionParser;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.StandardEvaluationContext;
+
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
+
+public class SpelExpressionValidator implements ConstraintValidator<SpelExpression, Object> {
+
+    private String spelExpression;
+
+    private ExpressionParser expressionParser;
+
+    private StandardEvaluationContext evaluationContext;
+
+    private ApplicationContext applicationContext;
+
+    public SpelExpressionValidator(ApplicationContext applicationContext) {
+        this.applicationContext = applicationContext;
+    }
+
+    @Override
+    public void initialize(SpelExpression constraintAnnotation) {
+        spelExpression = constraintAnnotation.value();
+        expressionParser = new SpelExpressionParser();
+        evaluationContext = new StandardEvaluationContext();
+        evaluationContext.setBeanResolver(new BeanFactoryResolver(applicationContext));
+    }
+
+    @Override
+    public boolean isValid(Object value, ConstraintValidatorContext context) {
+        // will be validated by other constraints
+        if (value == null) {
+            return true;
+        }
+
+        Expression expression = expressionParser.parseExpression(spelExpression);
+
+        return expression.getValue(evaluationContext, value, Boolean.class);
+    }
+}

nrich-validation/src/test/java/net/croz/nrich/validation/ValidationTestConfiguration.java

@@ -18,6 +18,7 @@
 package net.croz.nrich.validation;
 
 import net.croz.nrich.validation.constraint.stub.NullWhenTestService;
+import net.croz.nrich.validation.constraint.stub.SpelValidationTestService;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.validation.Validator;
@@ -35,4 +36,9 @@ public Validator validator() {
     public NullWhenTestService nullWhenTestService() {
         return new NullWhenTestService();
     }
+
+    @Bean
+    public SpelValidationTestService spelValidationTestService() {
+        return new SpelValidationTestService();
+    }
 }

nrich-validation/src/test/java/net/croz/nrich/validation/constraint/stub/SpelExpressionTestRequest.java

@@ -0,0 +1,31 @@
+/*
+ *  Copyright 2020-2023 CROZ d.o.o, 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 net.croz.nrich.validation.constraint.stub;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import net.croz.nrich.validation.api.constraint.SpelExpression;
+
+@RequiredArgsConstructor
+@Getter
+public class SpelExpressionTestRequest {
+
+    @SpelExpression("@spelValidationTestService.validateUuid(#this)")
+    private final String uuid;
+
+}

nrich-validation/src/test/java/net/croz/nrich/validation/constraint/stub/SpelValidationTestService.java

@@ -0,0 +1,14 @@
+package net.croz.nrich.validation.constraint.stub;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class SpelValidationTestService {
+
+    private static final Pattern PATTERN = Pattern.compile("[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}");
+
+    public boolean validateUuid(String uuid) {
+        Matcher matcher = PATTERN.matcher(uuid);
+        return matcher.find();
+    }
+}

nrich-validation/src/test/java/net/croz/nrich/validation/constraint/validator/SpelExpressionValidatorTest.java

@@ -0,0 +1,56 @@
+package net.croz.nrich.validation.constraint.validator;
+
+import net.croz.nrich.validation.ValidationTestConfiguration;
+import net.croz.nrich.validation.constraint.stub.SpelExpressionTestRequest;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Validator;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@SpringJUnitConfig(ValidationTestConfiguration.class)
+public class SpelExpressionValidatorTest {
+
+    @Autowired
+    private Validator validator;
+
+    @Test
+    void shouldNotReportErrorForNullValue() {
+        // given
+        SpelExpressionTestRequest request = new SpelExpressionTestRequest(null);
+
+        // when
+        Set<ConstraintViolation<SpelExpressionTestRequest>> constraintViolationList = validator.validate(request);
+
+        // then
+        assertThat(constraintViolationList).isEmpty();
+    }
+
+    @Test
+    void shouldNotReportErrorWhenValueIsValid() {
+        // given
+        SpelExpressionTestRequest request = new SpelExpressionTestRequest("4adf9bf9-2656-468b-880a-706ff704e6b4");
+
+        // when
+        Set<ConstraintViolation<SpelExpressionTestRequest>> constraintViolationList = validator.validate(request);
+
+        // then
+        assertThat(constraintViolationList).isEmpty();
+    }
+
+    @Test
+    void shouldReportErrorWhenValueIsNotValid() {
+        // given
+        SpelExpressionTestRequest request = new SpelExpressionTestRequest("4adf9bf9-2656-xxxx-xxxx-706ff704e6b4");
+
+        // when
+        Set<ConstraintViolation<SpelExpressionTestRequest>> constraintViolationList = validator.validate(request);
+
+        // then
+        assertThat(constraintViolationList).isNotEmpty();
+    }
+}