001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.vfs2.util;
018
019import java.text.MessageFormat;
020import java.util.MissingResourceException;
021import java.util.ResourceBundle;
022import java.util.concurrent.ConcurrentHashMap;
023import java.util.concurrent.ConcurrentMap;
024
025/**
026 * Formats messages.
027 */
028public final class Messages {
029    /**
030     * Map from message code to MessageFormat object for the message.
031     */
032    private static ConcurrentMap<String, MessageFormat> messageMap = new ConcurrentHashMap<>();
033    private static final ResourceBundle RESOURCES = new CombinedResources("org.apache.commons.vfs2.Resources");
034
035    private Messages() {
036    }
037
038    /**
039     * Formats a message.
040     *
041     * @param code The message code.
042     * @return The formatted message.
043     */
044    public static String getString(final String code) {
045        return getString(code, new Object[0]);
046    }
047
048    /**
049     * Formats a message.
050     *
051     * @param code The message code.
052     * @param param The message parameter.
053     * @return The formatted message.
054     * @deprecated Will be removed in 3.0 in favor of {@link #getString(String, Object[])} When removed, calls to this
055     *             method will automatically recompile to {@link #getString(String, Object[])}
056     */
057    @Deprecated
058    public static String getString(final String code, final Object param) {
059        return getString(code, new Object[] { param });
060    }
061
062    /**
063     * Formats a message.
064     *
065     * @param code The message code.
066     * @param params The message parameters.
067     * @return The formatted message.
068     */
069    public static String getString(final String code, final Object... params) {
070        try {
071            if (code == null) {
072                return null;
073            }
074
075            final MessageFormat msg = findMessage(code);
076            return msg.format(params);
077        } catch (final MissingResourceException mre) {
078            return "Unknown message with code \"" + code + "\".";
079        }
080    }
081
082    /**
083     * Locates a message by its code.
084     */
085    private static MessageFormat findMessage(final String code) throws MissingResourceException {
086        // Check if the message is cached
087        MessageFormat msg = messageMap.get(code);
088        if (msg != null) {
089            return msg;
090        }
091
092        final String msgText = RESOURCES.getString(code);
093        msg = new MessageFormat(msgText);
094        messageMap.putIfAbsent(code, msg);
095        return messageMap.get(code);
096    }
097}