https://github.com/spring-projects/spring-framework: Spring Context (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2017 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
 *
 *      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 org.springframework.context;

import java.util.Locale;

import org.springframework.lang.Nullable;


Strategy interface for resolving messages, with support for the parameterization
and internationalization of such messages.

Spring provides two out-of-the-box implementations for production:



Author:Rod Johnson, Juergen Hoeller
See Also:
/**
 * Strategy interface for resolving messages, with support for the parameterization
 * and internationalization of such messages.
 *
 * <p>Spring provides two out-of-the-box implementations for production:
 * <ul>
 * <li>{@link org.springframework.context.support.ResourceBundleMessageSource},
 * built on top of the standard {@link java.util.ResourceBundle}
 * <li>{@link org.springframework.context.support.ReloadableResourceBundleMessageSource},
 * being able to reload message definitions without restarting the VM
 * </ul>
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see org.springframework.context.support.ResourceBundleMessageSource
 * @see org.springframework.context.support.ReloadableResourceBundleMessageSource
 */
public interface MessageSource {

	
Try to resolve the message. Return default message if no message was found.

Params:
  • code – the code to lookup up, such as 'calculator.noRateSet'. Users of
this class are encouraged to base message names on the relevant fully
qualified class name, thus avoiding conflict and ensuring maximum clarity.
  • args – an array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message), or null if none.
  • defaultMessage – a default message to return if the lookup fails
  • locale – the locale in which to do the lookup
See Also:
Returns:the resolved message if the lookup was successful;
otherwise the default message passed as a parameter
/**
	 * Try to resolve the message. Return default message if no message was found.
	 * @param code the code to lookup up, such as 'calculator.noRateSet'. Users of
	 * this class are encouraged to base message names on the relevant fully
	 * qualified class name, thus avoiding conflict and ensuring maximum clarity.
	 * @param args an array of arguments that will be filled in for params within
	 * the message (params look like "{0}", "{1,date}", "{2,time}" within a message),
	 * or {@code null} if none.
	 * @param defaultMessage a default message to return if the lookup fails
	 * @param locale the locale in which to do the lookup
	 * @return the resolved message if the lookup was successful;
	 * otherwise the default message passed as a parameter
	 * @see java.text.MessageFormat
	 */
	@Nullable
	String getMessage(String code, @Nullable Object[] args, @Nullable String defaultMessage, Locale locale);

	
Try to resolve the message. Treat as an error if the message can't be found.

Params:
  • code – the code to lookup up, such as 'calculator.noRateSet'
  • args – an array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message), or null if none.
  • locale – the locale in which to do the lookup
Throws:
See Also:
Returns:the resolved message
/**
	 * Try to resolve the message. Treat as an error if the message can't be found.
	 * @param code the code to lookup up, such as 'calculator.noRateSet'
	 * @param args an array of arguments that will be filled in for params within
	 * the message (params look like "{0}", "{1,date}", "{2,time}" within a message),
	 * or {@code null} if none.
	 * @param locale the locale in which to do the lookup
	 * @return the resolved message
	 * @throws NoSuchMessageException if the message wasn't found
	 * @see java.text.MessageFormat
	 */
	String getMessage(String code, @Nullable Object[] args, Locale locale) throws NoSuchMessageException;

	
Try to resolve the message using all the attributes contained within the MessageSourceResolvable argument that was passed in. 
NOTE: We must throw a NoSuchMessageException on this method since at the time of calling this method we aren't able to determine if the defaultMessage property of the resolvable is null or not. 
Params:
  • resolvable – the value object storing attributes required to resolve a message
  • locale – the locale in which to do the lookup
Throws:
See Also:
Returns:the resolved message
/**
	 * Try to resolve the message using all the attributes contained within the
	 * {@code MessageSourceResolvable} argument that was passed in.
	 * <p>NOTE: We must throw a {@code NoSuchMessageException} on this method
	 * since at the time of calling this method we aren't able to determine if the
	 * {@code defaultMessage} property of the resolvable is {@code null} or not.
	 * @param resolvable the value object storing attributes required to resolve a message
	 * @param locale the locale in which to do the lookup
	 * @return the resolved message
	 * @throws NoSuchMessageException if the message wasn't found
	 * @see java.text.MessageFormat
	 */
	String getMessage(MessageSourceResolvable resolvable, Locale locale) throws NoSuchMessageException;

}