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.context.support; import java.util.Locale; import org.springframework.context.MessageSource; import org.springframework.context.MessageSourceResolvable; import org.springframework.context.NoSuchMessageException; import org.springframework.context.i18n.LocaleContextHolder; import org.springframework.lang.Nullable; /** * Helper class for easy access to messages from a MessageSource, * providing various overloaded getMessage methods. * * <p>Available from ApplicationObjectSupport, but also reusable * as a standalone helper to delegate to in application objects. * * @author Juergen Hoeller * @since 23.10.2003 * @see ApplicationObjectSupport#getMessageSourceAccessor */ public class MessageSourceAccessor { private final MessageSource messageSource; @Nullable private final Locale defaultLocale; /** * Create a new MessageSourceAccessor, using LocaleContextHolder's locale * as default locale. * @param messageSource the MessageSource to wrap * @see org.springframework.context.i18n.LocaleContextHolder#getLocale() */ public MessageSourceAccessor(MessageSource messageSource) { this.messageSource = messageSource; this.defaultLocale = null; } /** * Create a new MessageSourceAccessor, using the given default locale. * @param messageSource the MessageSource to wrap * @param defaultLocale the default locale to use for message access */ public MessageSourceAccessor(MessageSource messageSource, Locale defaultLocale) { this.messageSource = messageSource; this.defaultLocale = defaultLocale; } /** * Return the default locale to use if no explicit locale has been given. * <p>The default implementation returns the default locale passed into the * corresponding constructor, or LocaleContextHolder's locale as fallback. * Can be overridden in subclasses. * @see #MessageSourceAccessor(org.springframework.context.MessageSource, java.util.Locale) * @see org.springframework.context.i18n.LocaleContextHolder#getLocale() */ protected Locale getDefaultLocale() { return (this.defaultLocale != null ? this.defaultLocale : LocaleContextHolder.getLocale()); } /** * Retrieve the message for the given code and the default Locale. * @param code code of the message * @param defaultMessage the String to return if the lookup fails * @return the message */ public String getMessage(String code, String defaultMessage) { String msg = this.messageSource.getMessage(code, null, defaultMessage, getDefaultLocale()); return (msg != null ? msg : ""); } /** * Retrieve the message for the given code and the given Locale. * @param code code of the message * @param defaultMessage the String to return if the lookup fails * @param locale the Locale in which to do lookup * @return the message */ public String getMessage(String code, String defaultMessage, Locale locale) { String msg = this.messageSource.getMessage(code, null, defaultMessage, locale); return (msg != null ? msg : ""); } /** * Retrieve the message for the given code and the default Locale. * @param code code of the message * @param args arguments for the message, or {@code null} if none * @param defaultMessage the String to return if the lookup fails * @return the message */ public String getMessage(String code, @Nullable Object[] args, String defaultMessage) { String msg = this.messageSource.getMessage(code, args, defaultMessage, getDefaultLocale()); return (msg != null ? msg : ""); } /** * Retrieve the message for the given code and the given Locale. * @param code code of the message * @param args arguments for the message, or {@code null} if none * @param defaultMessage the String to return if the lookup fails * @param locale the Locale in which to do lookup * @return the message */ public String getMessage(String code, @Nullable Object[] args, String defaultMessage, Locale locale) { String msg = this.messageSource.getMessage(code, args, defaultMessage, locale); return (msg != null ? msg : ""); } /** * Retrieve the message for the given code and the default Locale. * @param code code of the message * @return the message * @throws org.springframework.context.NoSuchMessageException if not found */ public String getMessage(String code) throws NoSuchMessageException { return this.messageSource.getMessage(code, null, getDefaultLocale()); } /** * Retrieve the message for the given code and the given Locale. * @param code code of the message * @param locale the Locale in which to do lookup * @return the message * @throws org.springframework.context.NoSuchMessageException if not found */ public String getMessage(String code, Locale locale) throws NoSuchMessageException { return this.messageSource.getMessage(code, null, locale); } /** * Retrieve the message for the given code and the default Locale. * @param code code of the message * @param args arguments for the message, or {@code null} if none * @return the message * @throws org.springframework.context.NoSuchMessageException if not found */ public String getMessage(String code, @Nullable Object[] args) throws NoSuchMessageException { return this.messageSource.getMessage(code, args, getDefaultLocale()); } /** * Retrieve the message for the given code and the given Locale. * @param code code of the message * @param args arguments for the message, or {@code null} if none * @param locale the Locale in which to do lookup * @return the message * @throws org.springframework.context.NoSuchMessageException if not found */ public String getMessage(String code, @Nullable Object[] args, Locale locale) throws NoSuchMessageException { return this.messageSource.getMessage(code, args, locale); } /** * Retrieve the given MessageSourceResolvable (e.g. an ObjectError instance) * in the default Locale. * @param resolvable the MessageSourceResolvable * @return the message * @throws org.springframework.context.NoSuchMessageException if not found */ public String getMessage(MessageSourceResolvable resolvable) throws NoSuchMessageException { return this.messageSource.getMessage(resolvable, getDefaultLocale()); } /** * Retrieve the given MessageSourceResolvable (e.g. an ObjectError instance) * in the given Locale. * @param resolvable the MessageSourceResolvable * @param locale the Locale in which to do lookup * @return the message * @throws org.springframework.context.NoSuchMessageException if not found */ public String getMessage(MessageSourceResolvable resolvable, Locale locale) throws NoSuchMessageException { return this.messageSource.getMessage(resolvable, locale); } }