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- /*
- * Copyright 2000-2016 Vaadin Ltd.
- *
- * 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 com.vaadin.data;
-
- import java.io.Serializable;
- import java.util.Objects;
- import java.util.function.BiFunction;
-
- import com.vaadin.server.SerializablePredicate;
- import com.vaadin.shared.ui.ErrorLevel;
-
- /**
- * A functional interface for validating user input or other potentially invalid
- * data. When a validator instance is applied to a value of the corresponding
- * type, it returns a <i>result</i> signifying that the value either passed or
- * failed the validation.
- * <p>
- * For instance, the following validator checks if a number is positive:
- *
- * <pre>
- * Validator<Integer> v = num -> {
- * if (num >= 0)
- * return ValidationResult.ok();
- * else
- * return ValidationResult.error("number must be positive");
- * };
- * </pre>
- *
- * @author Vaadin Ltd.
- *
- * @since 8.0
- *
- * @param <T>
- * the type of the value to validate
- *
- * @see ValidationResult
- */
- @FunctionalInterface
- public interface Validator<T>
- extends BiFunction<T, ValueContext, ValidationResult>, Serializable {
-
- /**
- * Validates the given value. Returns a {@code ValidationResult} instance
- * representing the outcome of the validation.
- *
- * @param value
- * the input value to validate
- * @param context
- * the value context for validation
- * @return the validation result
- */
- @Override
- public ValidationResult apply(T value, ValueContext context);
-
- /**
- * Returns a validator that passes any value.
- *
- * @param <T>
- * the value type
- * @return an always-passing validator
- */
- public static <T> Validator<T> alwaysPass() {
- return (value, context) -> ValidationResult.ok();
- }
-
- /**
- * Builds a validator out of a conditional function and an error message. If
- * the function returns true, the validator returns {@code Result.ok()}; if
- * it returns false or throws an exception,
- * {@link ValidationResult#error(String)} is returned with the given message
- * and error level {@link ErrorLevel#ERROR}.
- * <p>
- * For instance, the following validator checks if a number is between 0 and
- * 10, inclusive:
- *
- * <pre>
- * Validator<Integer> v = Validator.from(num -> num >= 0 && num <= 10,
- * "number must be between 0 and 10");
- * </pre>
- *
- * @param <T>
- * the value type
- * @param guard
- * the function used to validate, not null
- * @param errorMessage
- * the message returned if validation fails, not null
- * @return the new validator using the function
- */
- public static <T> Validator<T> from(SerializablePredicate<T> guard,
- String errorMessage) {
- Objects.requireNonNull(errorMessage, "errorMessage cannot be null");
- return from(guard, ctx -> errorMessage);
- }
-
- /**
- * Builds a validator out of a conditional function and an error message. If
- * the function returns true, the validator returns {@code Result.ok()}; if
- * it returns false or throws an exception,
- * {@link ValidationResult#error(String)} is returned with the given message
- * and error level.
- * <p>
- * For instance, the following validator checks if a number is between 0 and
- * 10, inclusive:
- *
- * <pre>
- * Validator<Integer> v = Validator.from(num -> num >= 0 && num <= 10,
- * "number must be between 0 and 10", ErrorLevel.ERROR);
- * </pre>
- *
- * @param <T>
- * the value type
- * @param guard
- * the function used to validate, not null
- * @param errorMessage
- * the message returned if validation fails, not null
- * @param errorLevel
- * the error level for failures from this validator, not null
- * @return the new validator using the function
- *
- * @since 8.2
- */
- public static <T> Validator<T> from(SerializablePredicate<T> guard,
- String errorMessage, ErrorLevel errorLevel) {
- Objects.requireNonNull(errorMessage, "errorMessage cannot be null");
- return from(guard, ctx -> errorMessage, errorLevel);
- }
-
- /**
- * Builds a validator out of a conditional function and an error message
- * provider. If the function returns true, the validator returns
- * {@code Result.ok()}; if it returns false or throws an exception,
- * {@code Result.error()} is returned with the message from the provider.
- *
- * @param <T>
- * the value type
- * @param guard
- * the function used to validate, not null
- * @param errorMessageProvider
- * the provider to generate error messages, not null
- * @return the new validator using the function
- */
- public static <T> Validator<T> from(SerializablePredicate<T> guard,
- ErrorMessageProvider errorMessageProvider) {
- return from(guard, errorMessageProvider, ErrorLevel.ERROR);
- }
-
- /**
- * Builds a validator out of a conditional function and an error message
- * provider. If the function returns true, the validator returns
- * {@code Result.ok()}; if it returns false or throws an exception,
- * {@code Result.error()} is returned with the message from the provider.
- *
- * @param <T>
- * the value type
- * @param guard
- * the function used to validate, not null
- * @param errorMessageProvider
- * the provider to generate error messages, not null
- * @param errorLevel
- * the error level for failures from this validator, not null
- * @return the new validator using the function
- *
- * @since 8.2
- */
- public static <T> Validator<T> from(SerializablePredicate<T> guard,
- ErrorMessageProvider errorMessageProvider, ErrorLevel errorLevel) {
- Objects.requireNonNull(guard, "guard cannot be null");
- Objects.requireNonNull(errorMessageProvider,
- "errorMessageProvider cannot be null");
- Objects.requireNonNull(errorLevel, "errorLevel cannot be null");
- return (value, context) -> {
- try {
- if (guard.test(value)) {
- return ValidationResult.ok();
- } else {
- return ValidationResult.create(
- errorMessageProvider.apply(context), errorLevel);
- }
- } catch (Exception e) {
- return ValidationResult.create(
- errorMessageProvider.apply(context), errorLevel);
- }
- };
- }
- }
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