Java tutorial
/* * Copyright 2002-2018 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.validation; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.lang.Nullable; import org.springframework.util.Assert; import org.springframework.util.ObjectUtils; import org.springframework.util.StringUtils; /** * Utility class offering convenient methods for invoking a {@link Validator} * and for rejecting empty fields. * * <p>Checks for an empty field in {@code Validator} implementations can become * one-liners when using {@link #rejectIfEmpty} or {@link #rejectIfEmptyOrWhitespace}. * * @author Juergen Hoeller * @author Dmitriy Kopylenko * @since 06.05.2003 * @see Validator * @see Errors */ public abstract class ValidationUtils { private static final Log logger = LogFactory.getLog(ValidationUtils.class); /** * Invoke the given {@link Validator} for the supplied object and * {@link Errors} instance. * @param validator the {@code Validator} to be invoked * @param target the object to bind the parameters to * @param errors the {@link Errors} instance that should store the errors * @throws IllegalArgumentException if either of the {@code Validator} or {@code Errors} * arguments is {@code null}, or if the supplied {@code Validator} does not * {@link Validator#supports(Class) support} the validation of the supplied object's type */ public static void invokeValidator(Validator validator, Object target, Errors errors) { invokeValidator(validator, target, errors, (Object[]) null); } /** * Invoke the given {@link Validator}/{@link SmartValidator} for the supplied object and * {@link Errors} instance. * @param validator the {@code Validator} to be invoked * @param target the object to bind the parameters to * @param errors the {@link Errors} instance that should store the errors * @param validationHints one or more hint objects to be passed to the validation engine * @throws IllegalArgumentException if either of the {@code Validator} or {@code Errors} * arguments is {@code null}, or if the supplied {@code Validator} does not * {@link Validator#supports(Class) support} the validation of the supplied object's type */ public static void invokeValidator(Validator validator, Object target, Errors errors, @Nullable Object... validationHints) { Assert.notNull(validator, "Validator must not be null"); Assert.notNull(target, "Target object must not be null"); Assert.notNull(errors, "Errors object must not be null"); if (logger.isDebugEnabled()) { logger.debug("Invoking validator [" + validator + "]"); } if (!validator.supports(target.getClass())) { throw new IllegalArgumentException( "Validator [" + validator.getClass() + "] does not support [" + target.getClass() + "]"); } if (!ObjectUtils.isEmpty(validationHints) && validator instanceof SmartValidator) { ((SmartValidator) validator).validate(target, errors, validationHints); } else { validator.validate(target, errors); } if (logger.isDebugEnabled()) { if (errors.hasErrors()) { logger.debug("Validator found " + errors.getErrorCount() + " errors"); } else { logger.debug("Validator found no errors"); } } } /** * Reject the given field with the given error code if the value is empty. * <p>An 'empty' value in this context means either {@code null} or * the empty string "". * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key */ public static void rejectIfEmpty(Errors errors, String field, String errorCode) { rejectIfEmpty(errors, field, errorCode, null, null); } /** * Reject the given field with the given error code and default message * if the value is empty. * <p>An 'empty' value in this context means either {@code null} or * the empty string "". * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode error code, interpretable as message key * @param defaultMessage fallback default message */ public static void rejectIfEmpty(Errors errors, String field, String errorCode, String defaultMessage) { rejectIfEmpty(errors, field, errorCode, null, defaultMessage); } /** * Reject the given field with the given error code and error arguments * if the value is empty. * <p>An 'empty' value in this context means either {@code null} or * the empty string "". * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key * @param errorArgs the error arguments, for argument binding via MessageFormat * (can be {@code null}) */ public static void rejectIfEmpty(Errors errors, String field, String errorCode, Object[] errorArgs) { rejectIfEmpty(errors, field, errorCode, errorArgs, null); } /** * Reject the given field with the given error code, error arguments * and default message if the value is empty. * <p>An 'empty' value in this context means either {@code null} or * the empty string "". * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key * @param errorArgs the error arguments, for argument binding via MessageFormat * (can be {@code null}) * @param defaultMessage fallback default message */ public static void rejectIfEmpty(Errors errors, String field, String errorCode, @Nullable Object[] errorArgs, @Nullable String defaultMessage) { Assert.notNull(errors, "Errors object must not be null"); Object value = errors.getFieldValue(field); if (value == null || !StringUtils.hasLength(value.toString())) { errors.rejectValue(field, errorCode, errorArgs, defaultMessage); } } /** * Reject the given field with the given error code if the value is empty * or just contains whitespace. * <p>An 'empty' value in this context means either {@code null}, * the empty string "", or consisting wholly of whitespace. * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key */ public static void rejectIfEmptyOrWhitespace(Errors errors, String field, String errorCode) { rejectIfEmptyOrWhitespace(errors, field, errorCode, null, null); } /** * Reject the given field with the given error code and default message * if the value is empty or just contains whitespace. * <p>An 'empty' value in this context means either {@code null}, * the empty string "", or consisting wholly of whitespace. * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key * @param defaultMessage fallback default message */ public static void rejectIfEmptyOrWhitespace(Errors errors, String field, String errorCode, String defaultMessage) { rejectIfEmptyOrWhitespace(errors, field, errorCode, null, defaultMessage); } /** * Reject the given field with the given error code and error arguments * if the value is empty or just contains whitespace. * <p>An 'empty' value in this context means either {@code null}, * the empty string "", or consisting wholly of whitespace. * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key * @param errorArgs the error arguments, for argument binding via MessageFormat * (can be {@code null}) */ public static void rejectIfEmptyOrWhitespace(Errors errors, String field, String errorCode, @Nullable Object[] errorArgs) { rejectIfEmptyOrWhitespace(errors, field, errorCode, errorArgs, null); } /** * Reject the given field with the given error code, error arguments * and default message if the value is empty or just contains whitespace. * <p>An 'empty' value in this context means either {@code null}, * the empty string "", or consisting wholly of whitespace. * <p>The object whose field is being validated does not need to be passed * in because the {@link Errors} instance can resolve field values by itself * (it will usually hold an internal reference to the target object). * @param errors the {@code Errors} instance to register errors on * @param field the field name to check * @param errorCode the error code, interpretable as message key * @param errorArgs the error arguments, for argument binding via MessageFormat * (can be {@code null}) * @param defaultMessage fallback default message */ public static void rejectIfEmptyOrWhitespace(Errors errors, String field, String errorCode, @Nullable Object[] errorArgs, @Nullable String defaultMessage) { Assert.notNull(errors, "Errors object must not be null"); Object value = errors.getFieldValue(field); if (value == null || !StringUtils.hasText(value.toString())) { errors.rejectValue(field, errorCode, errorArgs, defaultMessage); } } }