MessageFormatter.java

/*
 * Copyright 2008-2010 the T2 Project ant the Others.
 *
 * 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.t2framework.confeito.util;

import java.text.MessageFormat;
import java.util.ResourceBundle;

/**
 * <#if locale="en">
 * <p>
 * Simple message formatter.
 * 
 * </p>
 * <#else>
 * <p>
 * 
 * </p>
 * </#if>
 * 
 * @author shot
 * 
 */
public class MessageFormatter {

	private static final String MESSAGES = "Messages";

	private MessageFormatter() {
	}

	public static String getMessage(String messageCode, Object[] args) {
		if (messageCode == null) {
			messageCode = "";
		}
		return "[" + messageCode + "]" + getSimpleMessage(messageCode, args);
	}

	/**
	 * <#if locale="en">
	 * <p>
	 * get message from message resource without using any caches.
	 * 
	 * </p>
	 * <#else>
	 * <p>
	 * 
	 * </p>
	 * </#if>
	 * 
	 * @param messageCode
	 * @param arguments
	 * @return
	 */
	public static String getSimpleMessageNoCache(String messageCode,
			Object[] arguments) {
		return getSimpleMessage0(messageCode, arguments, false);
	}

	/**
	 * <#if locale="en">
	 * <p>
	 * get message from message resource.
	 * 
	 * </p>
	 * <#else>
	 * <p>
	 * 
	 * </p>
	 * </#if>
	 * 
	 * @param messageCode
	 * @param arguments
	 * @return
	 */
	public static String getSimpleMessage(String messageCode, Object[] arguments) {
		return getSimpleMessage0(messageCode, arguments, true);
	}

	private static String getSimpleMessage0(String messageCode,
			Object[] arguments, boolean cacheable) {
		try {
			String pattern = getPattern(messageCode, cacheable);
			if (pattern != null) {
				return MessageFormat.format(pattern, arguments);
			}
		} catch (Throwable ignore) {
		}
		return getNoPatternMessage(arguments);
	}

	protected static String getPattern(final String messageCode,
			final boolean cacheable) {
		ResourceBundle resourceBundle = getMessages(getSystemName(messageCode),
				cacheable);
		if (resourceBundle != null) {
			return resourceBundle.getString(messageCode);
		}
		return null;
	}

	protected static String getSystemName(String messageCode) {
		if (messageCode.length() <= 4) {
			throw new IllegalStateException(
					"messageCode length is more than 4. Format is [System code(D|I|E|T|W, 1char)][Message file name(any char length)][Message code name(4char)]");
		}
		return messageCode.substring(1, messageCode.length() - 4);
	}

	private static ResourceBundle getMessages(String systemName,
			boolean cacheable) {
		final String baseName = systemName + MESSAGES;
		if (cacheable) {
			return ResourceBundle.getBundle(baseName);
		} else {
			return ResourceBundleUtil.getBundleNoCache(baseName);
		}
	}

	private static String getNoPatternMessage(Object[] args) {
		if (args == null || args.length == 0) {
			return "";
		}
		StringBuilder builder = new StringBuilder();
		for (int i = 0; i < args.length; i++) {
			builder.append(args[i] + ", ");
		}
		builder.setLength(builder.length() - 2);
		return builder.toString();
	}
}