From b6869c1b17c65594f65c3ad5e53461082e5c3088 Mon Sep 17 00:00:00 2001 From: pacien Date: Fri, 29 Mar 2019 01:31:15 +0100 Subject: initial impl --- .../lemonad/validation/ValidationResult.java | 129 +++++++++++++++++++++ .../validation/ValidationResultContainer.java | 40 +++++++ .../org/pacien/lemonad/validation/Validator.java | 80 +++++++++++++ 3 files changed, 249 insertions(+) create mode 100644 src/main/java/org/pacien/lemonad/validation/ValidationResult.java create mode 100644 src/main/java/org/pacien/lemonad/validation/ValidationResultContainer.java create mode 100644 src/main/java/org/pacien/lemonad/validation/Validator.java (limited to 'src/main/java/org/pacien/lemonad/validation') diff --git a/src/main/java/org/pacien/lemonad/validation/ValidationResult.java b/src/main/java/org/pacien/lemonad/validation/ValidationResult.java new file mode 100644 index 0000000..65bb389 --- /dev/null +++ b/src/main/java/org/pacien/lemonad/validation/ValidationResult.java @@ -0,0 +1,129 @@ +/* + * lemonad - Some functional sweetness for Java + * Copyright (C) 2019 Pacien TRAN-GIRARD + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see . + */ + +package org.pacien.lemonad.validation; + +import org.pacien.lemonad.attempt.Attempt; + +import java.util.Arrays; +import java.util.List; +import java.util.Objects; +import java.util.function.BiConsumer; +import java.util.function.Consumer; +import java.util.function.Function; +import java.util.stream.Stream; + +import lombok.NonNull; + +import static java.util.stream.Collectors.toUnmodifiableList; +import static org.pacien.lemonad.attempt.Attempt.failure; +import static org.pacien.lemonad.attempt.Attempt.success; + +/** + * Wraps the result of the validation of a subject. + * + * @param the subject type, + * @param the error type. + * @author pacien + */ +public interface ValidationResult { + /** + * @return whether no error have been reported during the validation. + */ + boolean isValid(); + + /** + * @return whether some error have been reported during the validation. + */ + boolean isInvalid(); + + /** + * @return the subject of the validation. + */ + S getSubject(); + + /** + * @return the potentially empty list of reported validation errors. + */ + List getErrors(); + + /** + * @param consumer a subject consumer called if the validation is successful. + * @return the current object. + */ + default ValidationResult ifValid(@NonNull Consumer consumer) { + if (isValid()) consumer.accept(getSubject()); + return this; + } + + /** + * @param consumer the consumer called with the validation subject and reported errors if the validation is failed. + * @return the current object. + */ + default ValidationResult ifInvalid(@NonNull BiConsumer> consumer) { + if (!isValid()) consumer.accept(getSubject(), getErrors()); + return this; + } + + /** + * @return an {@link Attempt} with a state corresponding to the one of the validation. + */ + default Attempt> toAttempt() { + return isValid() ? success(getSubject()) : failure(getErrors()); + } + + /** + * @param mapper a function transforming a {@link ValidationResult}. + * @return the transformed {@link ValidationResult}. + */ + default ValidationResult flatMap(@NonNull Function, ? extends ValidationResult> mapper) { + //noinspection unchecked + return (ValidationResult) mapper.apply(this); + } + + /** + * @param subject an overriding subject. + * @param validationResults a {@link Stream} of {@link ValidationResult}s to merge. + * @return the merged {@link ValidationResult} containing all errors from the supplied ones. + */ + static ValidationResult merge(S subject, @NonNull Stream> validationResults) { + return new ValidationResultContainer<>( + subject, + validationResults.flatMap(res -> res.getErrors().stream()).collect(toUnmodifiableList())); + } + + /** + * @param subject the suject of the validation. + * @return a successful {@link ValidationResult}. + */ + static ValidationResult valid(S subject) { + return new ValidationResultContainer<>(subject, List.of()); + } + + /** + * @param subject the suject of the validation. + * @param error a validation error. + * @param errors additional validation errors. + * @return a failed {@link ValidationResult} for the supplied subject. + */ + @SafeVarargs static ValidationResult invalid(S subject, E error, E... errors) { + return new ValidationResultContainer<>( + subject, + Stream.concat(Stream.of(error), Arrays.stream(errors)).map(Objects::requireNonNull).collect(toUnmodifiableList())); + } +} diff --git a/src/main/java/org/pacien/lemonad/validation/ValidationResultContainer.java b/src/main/java/org/pacien/lemonad/validation/ValidationResultContainer.java new file mode 100644 index 0000000..2c752f6 --- /dev/null +++ b/src/main/java/org/pacien/lemonad/validation/ValidationResultContainer.java @@ -0,0 +1,40 @@ +/* + * lemonad - Some functional sweetness for Java + * Copyright (C) 2019 Pacien TRAN-GIRARD + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see . + */ + +package org.pacien.lemonad.validation; + +import java.util.List; + +import lombok.NonNull; +import lombok.Value; + +/** + * @author pacien + */ +@Value class ValidationResultContainer implements ValidationResult { + S subject; + @NonNull List errors; + + @Override public boolean isValid() { + return errors.isEmpty(); + } + + @Override public boolean isInvalid() { + return !isValid(); + } +} diff --git a/src/main/java/org/pacien/lemonad/validation/Validator.java b/src/main/java/org/pacien/lemonad/validation/Validator.java new file mode 100644 index 0000000..a8a9e3f --- /dev/null +++ b/src/main/java/org/pacien/lemonad/validation/Validator.java @@ -0,0 +1,80 @@ +/* + * lemonad - Some functional sweetness for Java + * Copyright (C) 2019 Pacien TRAN-GIRARD + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see . + */ + +package org.pacien.lemonad.validation; + +import java.util.Arrays; +import java.util.List; +import java.util.Objects; +import java.util.function.Function; +import java.util.function.Predicate; + +import lombok.NonNull; +import lombok.val; + +import static java.util.stream.Collectors.toUnmodifiableList; +import static org.pacien.lemonad.validation.ValidationResult.invalid; +import static org.pacien.lemonad.validation.ValidationResult.valid; + +/** + * A function which applies validation rules on a subject and reports possible errors. + * + * @param the subject type + * @param the error type + * @author pacien + */ +@FunctionalInterface public interface Validator { + /** + * @param subject the subject to validate, which can potentially be null. + * @return the non-null result of the validation of the supplied subject. + */ + ValidationResult validate(S subject); + + /** + * @param predicate the validation predicate testing the validity of a subject. + * @param negativeError an error to return if the subject does not pass the test. + * @return a {@link Validator} based on the supplied predicate and error. + */ + static Validator ensuringPredicate(@NonNull Predicate predicate, @NonNull E negativeError) { + return subject -> predicate.test(subject) ? valid(subject) : invalid(subject, negativeError); + } + + /** + * @param validators the {@link Validator}s to combine, to be evaluated in order of listing. + * @return a {@link Validator} based on the supplied ones. + */ + @SafeVarargs static Validator validatingAll(@NonNull Validator... validators) { + val validatorList = Arrays.stream(validators).map(Objects::requireNonNull).collect(toUnmodifiableList()); + return subject -> new ValidationResultContainer<>( + subject, + validatorList.stream() + .flatMap(validator -> validator.validate(subject).getErrors().stream()) + .collect(toUnmodifiableList())); + } + + /** + * @param getter the field getter mapping the validation subject. + * @param validator the {@link Validator} validating the field. + * @return a {@link Validator} validating the parent object. + */ + static Validator validatingField(@NonNull Function getter, + @NonNull Validator validator) { + //noinspection unchecked + return subject -> new ValidationResultContainer<>(subject, (List) validator.validate(getter.apply(subject)).getErrors()); + } +} -- cgit v1.2.3