001    // Copyright 2006, 2007, 2008, 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.internal.services;
016    
017    import org.apache.tapestry5.ioc.Messages;
018    import org.apache.tapestry5.services.InvalidationEventHub;
019    import org.apache.tapestry5.services.UpdateListener;
020    import org.apache.tapestry5.services.pageload.ComponentResourceSelector;
021    
022    public interface MessagesSource extends InvalidationEventHub, UpdateListener
023    {
024        /**
025         * Used to obtain a {@link Messages} instance for a particular component, within a particular locale. If the
026         * component extends from another component, then its localized properties will merge with its parent's properties
027         * (with the subclass overriding the super class on any conflicts).
028         * 
029         * @param bundle
030         *            defines the set of properties files to read, as well as a series of parent bundles to extend and
031         *            override
032         * @param selector
033         *            defines the locale and other axes used to locate the necessary resources
034         * @return the message catalog for the bundle, for the indicated selector
035         */
036        Messages getMessages(MessagesBundle bundle, ComponentResourceSelector selector);
037    }