    001    // Copyright 2006, 2007 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    //     http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.ioc;
    016
    017    /**
    018     * Provides access to a messages catalog, a set of properties files that provide localized messages for a particular
    019     * locale. The message catalog consists of keys and values and follows the semantics of a Java {@link
    020     * java.util.ResourceBundle} with some changes.
    021     */
    022    public interface Messages
    023    {
    024        /**
    025         * Returns true if the bundle contains the named key.
    026         */
    027        boolean contains(String key);
    028
    029        /**
    030         * Returns the localized message for the given key. If catalog does not contain such a key, then a modified version
    031         * of the key is returned (converted to upper case and enclosed in brackets).
    032         *
    033         * @param key
    034         * @return localized message for key, or placeholder
    035         */
    036        String get(String key);
    037
    038        /**
    039         * Returns a formatter for the message, which can be used to substitute arguments (as per {@link
    040         * java.util.Formatter}).
    041         *
    042         * @param key
    043         * @return formattable object
    044         */
    045        MessageFormatter getFormatter(String key);
    046
    047        /**
    048         * Convienience for accessing a formatter and formatting a localized message with arguments.
    049         */
    050
    051        String format(String key, Object... args);
    052    }