1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17package org.apache.commons.math.exception.util;
18
19import java.text.MessageFormat;
20import java.util.Locale;
21
22/**
23 * Class for constructing localized messages.
24 *
25 * @since 2.2
26 * @version $Revision$ $Date$
27 */
28public class MessageFactory {
29    /**
30     * Class contains only static methods.
31     */
32    private MessageFactory() {}
33
34    /**
35     * Builds a message string by from a pattern and its arguments.
36     *
37     * @param locale Locale in which the message should be translated.
38     * @param pattern Format specifier.
39     * @param arguments Format arguments.
40     * @return a localized message string.
41     */
42    public static String buildMessage(Locale locale,
43                                      Localizable pattern,
44                                      Object ... arguments) {
45        return buildMessage(locale, null, pattern, arguments);
46    }
47
48    /**
49     * Builds a message string by from two patterns (specific and general) and
50     * an argument list.
51     *
52     * @param locale Locale in which the message should be translated.
53     * @param specific Format specifier (may be null).
54     * @param general Format specifier (may be null).
55     * @param arguments Format arguments. They will be substituted in
56     * <em>both</em> the {@code general} and {@code specific} format specifiers.
57     * @return a localized message string.
58     */
59    public static String buildMessage(Locale locale,
60                                      Localizable specific,
61                                      Localizable general,
62                                      Object ... arguments) {
63        final StringBuilder sb = new StringBuilder();
64        if (general != null) {
65            final MessageFormat fmt = new MessageFormat(general.getLocalizedString(locale), locale);
66            sb.append(fmt.format(arguments));
67        }
68        if (specific != null) {
69            if (general != null) {
70                sb.append(": ");
71            }
72            final MessageFormat fmt = new MessageFormat(specific.getLocalizedString(locale), locale);
73            sb.append(fmt.format(arguments));
74        }
75
76        return sb.toString();
77    }
78}
79