Spring Framework example source code file (LocalizedResourceHelper.java)

This example Spring Framework source code file (LocalizedResourceHelper.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

default_separator, default_separator, defaultresourceloader, extension, locale, localizedresourcehelper, localizedresourcehelper, name, resource, resourceloader, resourceloader, string, string, util

The Spring Framework LocalizedResourceHelper.java source code

/*
 * Copyright 2002-2006 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.core.io.support;

import java.util.Locale;

import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.util.Assert;

/**
 * Helper class for loading a localized resource,
 * specified through name, extension and current locale.
 *
 * @author Juergen Hoeller
 * @since 1.2.5
 */
public class LocalizedResourceHelper {

	/** The default separator to use inbetween file name parts: an underscore */
	public static final String DEFAULT_SEPARATOR = "_";


	private final ResourceLoader resourceLoader;

	private String separator = DEFAULT_SEPARATOR;


	/**
	 * Create a new LocalizedResourceHelper with a DefaultResourceLoader.
	 * @see org.springframework.core.io.DefaultResourceLoader
	 */
	public LocalizedResourceHelper() {
		this.resourceLoader = new DefaultResourceLoader();
	}

	/**
	 * Create a new LocalizedResourceHelper with the given ResourceLoader.
	 * @param resourceLoader the ResourceLoader to use
	 */
	public LocalizedResourceHelper(ResourceLoader resourceLoader) {
		Assert.notNull(resourceLoader, "ResourceLoader must not be null");
		this.resourceLoader = resourceLoader;
	}

	/**
	 * Set the separator to use inbetween file name parts.
	 * Default is an underscore ("_").
	 */
	public void setSeparator(String separator) {
		this.separator = (separator != null ? separator : DEFAULT_SEPARATOR);
	}


	/**
	 * Find the most specific localized resource for the given name,
	 * extension and locale:
	 * <p>The file will be searched with locations in the following order,
	 * similar to <code>java.util.ResourceBundle's search order:
	 * <ul>
	 * <li>[name]_[language]_[country]_[variant][extension]
	 * <li>[name]_[language]_[country][extension]
	 * <li>[name]_[language][extension]
	 * <li>[name][extension]
	 * </ul>
	 * <p>If none of the specific files can be found, a resource
	 * descriptor for the default location will be returned.
	 * @param name the name of the file, without localization part nor extension
	 * @param extension the file extension (e.g. ".xls")
	 * @param locale the current locale (may be <code>null)
	 * @return the most specific localized resource found
	 * @see java.util.ResourceBundle
	 */
	public Resource findLocalizedResource(String name, String extension, Locale locale) {
		Assert.notNull(name, "Name must not be null");
		Assert.notNull(extension, "Extension must not be null");

		Resource resource = null;

		if (locale != null) {
			String lang = locale.getLanguage();
			String country = locale.getCountry();
			String variant = locale.getVariant();

			// Check for file with language, country and variant localization.
			if (variant.length() > 0) {
				String location =
						name + this.separator + lang + this.separator + country + this.separator + variant + extension;
				resource = this.resourceLoader.getResource(location);
			}

			// Check for file with language and country localization.
			if ((resource == null || !resource.exists()) && country.length() > 0) {
				String location = name + this.separator + lang + this.separator + country + extension;
				resource = this.resourceLoader.getResource(location);
			}

			// Check for document with language localization.
			if ((resource == null || !resource.exists()) && lang.length() > 0) {
				String location = name + this.separator + lang + extension;
				resource = this.resourceLoader.getResource(location);
			}
		}

		// Check for document without localization.
		if (resource == null || !resource.exists()) {
			String location = name + extension;
			resource = this.resourceLoader.getResource(location);
		}

		return resource;
	}

}