001    // Copyright 2006, 2008, 2009, 2010, 2011 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.services.messages;
016    
017    import org.apache.tapestry5.ioc.Messages;
018    import org.apache.tapestry5.ioc.Resource;
019    import org.apache.tapestry5.ioc.annotations.NotLazy;
020    import org.apache.tapestry5.ioc.annotations.UsesOrderedConfiguration;
021    import org.apache.tapestry5.model.ComponentModel;
022    import org.apache.tapestry5.services.InvalidationEventHub;
023    import org.apache.tapestry5.services.pageload.ComponentResourceSelector;
024    
025    import java.util.Locale;
026    
027    /**
028     * Used to connect a Tapestry component to its message catalog, or to obtain the application catalog (that all
029     * component message catalogs extend from). The application catalog is defined by the collection of {@link Resource}s
030     * contributed to the service. In general, component libraries will contribute a Resource before the "AppCatalog"
031     * resource (representing
032     * the application message catalog, WEB-INF/app.properties) so that the application can override messages of the
033     * component library.
034     */
035    @UsesOrderedConfiguration(Resource.class)
036    public interface ComponentMessagesSource
037    {
038        /**
039         * Used to obtain a {@link Messages} instance for a particular component, within a particular locale. If the
040         * component extends from another component, then its localized properties will merge with its parent's properties
041         * (with the subclass overriding the super class on any conflicts).
042         *
043         * @param componentModel
044         * @param locale
045         * @return the message catalog for the component, in the indicated locale
046         * @deprecated Deprecated in 5.3; use {@link #getMessages(ComponentModel, ComponentResourceSelector)} instead.
047         */
048        Messages getMessages(ComponentModel componentModel, Locale locale);
049    
050        /**
051         * Used to obtain a {@link Messages} instance for a particular component, using a particular selector. If the
052         * component extends from another component, then its localized properties will merge with its parent's properties
053         * (with the subclass overriding the super class on any conflicts).
054         *
055         * @param componentModel
056         * @param selector       determined correct version of messages to obtain
057         * @return the message catalog for the component, in the indicated selector
058         * @since 5.3
059         */
060        Messages getMessages(ComponentModel componentModel, ComponentResourceSelector selector);
061    
062        /**
063         * Gets the Messages derived from the application's message catalog.
064         *
065         * @since 5.2.0
066         */
067        Messages getApplicationCatalog(Locale locale);
068    
069        /**
070         * Returns the event hub that allows listeners to be notified when any underlying message catalog file is changed.
071         *
072         * @since 5.1.0.0
073         */
074        @NotLazy
075        InvalidationEventHub getInvalidationEventHub();
076    }