001    // Copyright 2004, 2005 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.tapestry;
016    
017    import java.util.Locale;
018    
019    import org.apache.tapestry.services.Infrastructure;
020    import org.apache.tapestry.services.WebRequestServicer;
021    
022    /**
023     * Defines the core, session-persistant object used to run a Tapestry application for a single
024     * client (each client will have its own instance of the engine).
025     * <p>
026     * The engine exists to provide core services to the pages and components that make up the
027     * application. The engine is a delegate to the {@link ApplicationServlet}.
028     * <p>
029     * Starting in release 4.0, the engine is kept around only for compatibility (with release 3.0).
030     * It's functions have been moved over into a collection of HiveMind services (or are in the process
031     * of doing so).
032     * 
033     * @author Howard Lewis Ship
034     */
035    
036    public interface IEngine extends WebRequestServicer
037    {
038        /**
039         * Returns the locale for the engine. This locale is used when selecting templates and assets.
040         */
041    
042        Locale getLocale();
043    
044        /**
045         * Changes the engine's locale. Any subsequently loaded pages will be in the new locale (though
046         * pages already loaded stay in the old locale). Generally, you should render a new page after
047         * changing the locale, to show that the locale has changed.
048         */
049    
050        void setLocale(Locale value);
051    
052        /**
053         * Returns the encoding to be used to generate the responses and accept the requests.
054         * 
055         * @since 3.0
056         */
057    
058        String getOutputEncoding();
059    
060        /**
061         * Returns the {@link org.apache.tapestry.services.Infrastructure}&nbsp;object, a central
062         * registry of key HiveMind services used by Tapestry.
063         * 
064         * @since 4.0
065         */
066    
067        Infrastructure getInfrastructure();
068    }