resourcebundleeditor.java

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/*
 * 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.beans.propertyeditors;

import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

import java.beans.PropertyEditorSupport;
import java.util.Locale;
import java.util.ResourceBundle;

/**
 * {@link java.beans.PropertyEditor} implementation for
 * {@link java.util.ResourceBundle ResourceBundles}.
 * 
 * <p>Only supports conversion <i>from</i> a String, but not
 * <i>to</i> a String.
 * 
 * Find below some examples of using this class in a 
 * (properly configured) Spring container using XML-based metadata:
 * 
 * <pre class="code"> &lt;bean id="errorDialog" class="..."&gt;
 *    &lt;!--
 *        the 'messages' property is of type java.util.ResourceBundle.
 *        the 'DialogMessages.properties' file exists at the root of the CLASSPATH
 *    --&gt;
 *    &lt;property name="messages" value="DialogMessages"/&gt;
 * &lt;/bean&gt;</pre>
 * 
 * <pre class="code"> &lt;bean id="errorDialog" class="..."&gt;
 *    &lt;!--
 *        the 'DialogMessages.properties' file exists in the 'com/messages' package
 *    --&gt;
 *    &lt;property name="messages" value="com/messages/DialogMessages"/&gt;
 * &lt;/bean&gt;</pre>
 * 
 * <p>A 'properly configured' Spring {@link org.springframework.context.ApplicationContext container}
 * might contain a {@link org.springframework.beans.factory.config.CustomEditorConfigurer}
 * definition such that the conversion can be effected transparently:
 * 
 * <pre class="code"> &lt;bean class="org.springframework.beans.factory.config.CustomEditorConfigurer"&gt;
 *    &lt;property name="customEditors"&gt;
 *        &lt;map&gt;
 *            &lt;entry key="java.util.ResourceBundle"&gt;
 *                &lt;bean class="org.springframework.beans.propertyeditors.ResourceBundleEditor"/&gt;
 *            &lt;/entry&gt;
 *        &lt;/map&gt;
 *    &lt;/property&gt;
 * &lt;/bean&gt;</pre>
 * 
 * <p>Please note that this {@link java.beans.PropertyEditor} is
 * <b>not</b> registered by default with any of the Spring infrastructure.
 * 
 * <p>Thanks to David Leal Valmana for the suggestion and initial prototype.
 *
 * @author Rick Evans
 * @since 2.0
 */
public class ResourceBundleEditor extends PropertyEditorSupport {

	/**
	 * The separator used to distinguish between the base name and the
	 * locale (if any) when {@link #setAsText(String) converting from a String}.
	 */
	public static final String BASE_NAME_SEPARATOR = "_";


	public void setAsText(String text) throws IllegalArgumentException {
		Assert.hasText(text, "'text' must not be empty");
		ResourceBundle bundle;
		String rawBaseName = text.trim();
		int indexOfBaseNameSeparator = rawBaseName.indexOf(BASE_NAME_SEPARATOR);
		if (indexOfBaseNameSeparator == -1) {
			bundle = ResourceBundle.getBundle(rawBaseName);
		} else {
			// it potentially has locale information
			String baseName = rawBaseName.substring(0, indexOfBaseNameSeparator);
			if (!StringUtils.hasText(baseName)) {
				throw new IllegalArgumentException("Bad ResourceBundle name : received '" + text + "' as argument to 'setAsText(String value)'.");
			}
			String localeString = rawBaseName.substring(indexOfBaseNameSeparator + 1);
			Locale locale = StringUtils.parseLocaleString(localeString);
			bundle = (StringUtils.hasText(localeString))
					? ResourceBundle.getBundle(baseName, locale)
					: ResourceBundle.getBundle(baseName);
		}
		setValue(bundle);
	}

}