001// Copyright 2007, 2008, 2009 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
015package org.apache.tapestry5.services;
016
017import java.util.Locale;
018
019/**
020 * Manages the persistent locale stored in the browser (inside the URL).
021 *
022 * @see LocalizationSetter#setLocaleFromLocaleName(String)
023 * @see org.apache.tapestry5.services.LocalizationSetter
024 * @see org.apache.tapestry5.services.ComponentEventLinkEncoder
025 */
026public interface PersistentLocale
027{
028    /**
029     * Sets the locale value that will be encoded into the response. This must match a locale configured via {@link
030     * org.apache.tapestry5.SymbolConstants#SUPPORTED_LOCALES}.
031     *
032     * @throws IllegalArgumentException if the locale is not valid
033     */
034    void set(Locale locale);
035
036    /**
037     * Gets the locale obtained from the request, or null if the response did not indicate a specific locale (in which
038     * case the active locale may have been determined from request headers).
039     */
040    Locale get();
041
042    /**
043     * @return true if a locale was present in the request URL; false otherwise.
044     */
045    boolean isSet();
046}