Introduce Conflict Strategy that defines the behavior when a constraint name conflicts (#331)

when adding a constraint.

fixes gh-253

Author: making

src/main/java/am/ik/yavi/builder/ConflictStrategy.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2018-2023 Toshiaki Maki <makingx@gmail.com>
+ *
+ * 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 am.ik.yavi.builder;
+
+import java.util.List;
+
+import am.ik.yavi.core.ConstraintPredicates;
+
+/**
+ * Conflict Strategy that defines the behavior when a constraint name conflicts when
+ * adding a constraint.
+ *
+ * @since 0.13.0
+ */
+@FunctionalInterface
+public interface ConflictStrategy {
+	/**
+	 * Define how to resolve conflicts of a constraint name when adding a constraint.
+	 *
+	 * @param predicatesList existing predicates list
+	 * @param predicates new (conflicting) predicate
+	 * @param <T> target type
+	 */
+	<T> void resolveConflict(List<ConstraintPredicates<T, ?>> predicatesList,
+			ConstraintPredicates<T, ?> predicates);
+
+	/**
+	 * Do nothing if a conflict occurs. That means simply appending the predicate.
+	 */
+	ConflictStrategy NOOP = new ConflictStrategy() {
+		@Override
+		public <T> void resolveConflict(
+				List<ConstraintPredicates<T, ?>> constraintPredicates,
+				ConstraintPredicates<T, ?> predicates) {
+			// NOOP
+		}
+	};
+
+	/**
+	 * If there is a conflict, remove the existing predicates and adopt the new predicate.
+	 */
+	ConflictStrategy OVERRIDE = new ConflictStrategy() {
+		@Override
+		public <T> void resolveConflict(
+				List<ConstraintPredicates<T, ?>> constraintPredicates,
+				ConstraintPredicates<T, ?> predicates) {
+			constraintPredicates.clear();
+		}
+	};
+}

src/main/java/am/ik/yavi/builder/ValidatorBuilder.java

@@ -29,6 +29,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Deque;
+import java.util.LinkedHashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
@@ -125,6 +126,8 @@ public class ValidatorBuilder<T> implements Cloneable {
 
 	boolean failFast = false;
 
+	ConflictStrategy conflictStrategy = ConflictStrategy.NOOP;
+
 	public ValidatorBuilder() {
 		this(DEFAULT_SEPARATOR);
 	}
@@ -188,7 +191,8 @@ public static <X> ValidatorBuilder<X> of() {
 	}
 
 	public Validator<T> build() {
-		return new Validator<>(messageKeySeparator, this.predicatesList,
+		return new Validator<>(messageKeySeparator,
+				new PredicatesList<>(this.conflictStrategy, this.predicatesList).toList(),
 				this.collectionValidators, this.conditionalValidators,
 				this.messageFormatter == null ? new SimpleMessageFormatter()
 						: this.messageFormatter,
@@ -903,6 +907,20 @@ public ValidatorBuilder<T> failFast(boolean failFast) {
 		return this;
 	}
 
+	/**
+	 * Sets the {@link ConflictStrategy} that defines the behavior when a constraint name
+	 * conflicts when adding a constraint. By default, {@link ConflictStrategy#NOOP} is
+	 * used.
+	 *
+	 * @param conflictStrategy Conflict Strategy
+	 * @return validator builder (self)
+	 * @since 0.13.0
+	 */
+	public ValidatorBuilder<T> conflictStrategy(ConflictStrategy conflictStrategy) {
+		this.conflictStrategy = conflictStrategy;
+		return this;
+	}
+
 	public <N> ValidatorBuilder<T> nest(Function<T, N> nested, String name,
 			Validator<N> validator) {
 		return this.nest(nested, name, validator, NullAs.INVALID);
@@ -1197,4 +1215,46 @@ public interface ToYearMonthConstraint<T> extends Function<T, YearMonth> {
 	public interface ValidatorBuilderConverter<T>
 			extends Function<ValidatorBuilder<T>, ValidatorBuilder<T>> {
 	}
+
+	/**
+	 * An internal class that manages predicate conflicts
+	 *
+	 * @param <T> target type
+	 * @since 0.13.0
+	 */
+	static final class PredicatesList<T> {
+		private final ConflictStrategy conflictStrategy;
+
+		private final Map<String, List<ConstraintPredicates<T, ?>>> predicatesListMap = new LinkedHashMap<>();
+
+		public PredicatesList(ConflictStrategy conflictStrategy) {
+			this.conflictStrategy = conflictStrategy;
+		}
+
+		public PredicatesList(ConflictStrategy conflictStrategy,
+				List<ConstraintPredicates<T, ?>> predicatesList) {
+			this(conflictStrategy);
+			predicatesList.forEach(this::add);
+		}
+
+		public void add(ConstraintPredicates<T, ?> predicates) {
+			final List<ConstraintPredicates<T, ?>> predicatesList = this.predicatesListMap
+					.computeIfAbsent(predicates.name(), s -> new ArrayList<>());
+			if (!predicatesList.isEmpty()) {
+				this.conflictStrategy.resolveConflict(predicatesList, predicates);
+			}
+			predicatesList.add(predicates);
+		}
+
+		public List<ConstraintPredicates<T, ?>> toList() {
+			final int length = predicatesListMap.values().stream().mapToInt(List::size)
+					.sum();
+			final List<ConstraintPredicates<T, ?>> list = new ArrayList<>(length);
+			for (List<ConstraintPredicates<T, ?>> predicates : predicatesListMap
+					.values()) {
+				list.addAll(predicates);
+			}
+			return list;
+		}
+	}
 }

src/main/java/am/ik/yavi/core/ErrorHandler.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright (C) 2018-2023 Toshiaki Maki <makingx@gmail.com>
+ *
+ * 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 am.ik.yavi.core;
 
 /**

src/test/java/am/ik/yavi/arguments/Car.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright (C) 2018-2023 Toshiaki Maki <makingx@gmail.com>
+ *
+ * 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 am.ik.yavi.arguments;
 
 import am.ik.yavi.builder.IntegerValidatorBuilder;

src/test/java/am/ik/yavi/core/Gh249Test.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright (C) 2018-2023 Toshiaki Maki <makingx@gmail.com>
+ *
+ * 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 am.ik.yavi.core;
 
 import java.util.Collections;

src/test/java/am/ik/yavi/core/Gh253Test.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2018-2023 Toshiaki Maki <makingx@gmail.com>
+ *
+ * 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 am.ik.yavi.core;
+
+import am.ik.yavi.builder.ConflictStrategy;
+import am.ik.yavi.builder.ValidatorBuilder;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class Gh253Test {
+
+	ValidatorBuilder<Car> baseValidatorBuilder = ValidatorBuilder.<Car> of()
+			.constraint(Car::getManufacturer, "manufacturer", c -> c.notNull())
+			.constraint(Car::getSeatCount, "seatCount", c -> c.greaterThanOrEqual(2));
+
+	@Test
+	void overrideConstraint() {
+		final Car target = new Car("foo", "AAA", 2);
+		final Validator<Car> baseValidator = baseValidatorBuilder.build();
+		final ConstraintViolations violations1 = baseValidator.validate(target);
+		assertThat(violations1.isValid()).isTrue();
+
+		final Validator<Car> overwrittenValidator = baseValidatorBuilder
+				.constraint(Car::getManufacturer, "manufacturer", c -> c.isNull())
+				.conflictStrategy(ConflictStrategy.OVERRIDE).build();
+		final ConstraintViolations violations2 = overwrittenValidator.validate(target);
+		assertThat(violations2.isValid()).isFalse();
+		assertThat(violations2).hasSize(1);
+		assertThat(violations2.get(0).message())
+				.isEqualTo("\"manufacturer\" must be null");
+	}
+
+	public static class Car {
+		private final String manufacturer;
+
+		private final String licensePlate;
+
+		private final int seatCount;
+
+		public Car(String manufacturer, String licencePlate, int seatCount) {
+			this.manufacturer = manufacturer;
+			this.licensePlate = licencePlate;
+			this.seatCount = seatCount;
+		}
+
+		public String getManufacturer() {
+			return manufacturer;
+		}
+
+		public String getLicensePlate() {
+			return licensePlate;
+		}
+
+		public int getSeatCount() {
+			return seatCount;
+		}
+	}
+}