001    // Copyright 2006, 2007, 2008 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;
016    
017    /**
018     * Interface for objects which can periodically check for updates.
019     * <p>
020     * Note that this interface has moved from module tapestry-core to tapestry-ioc, but has kept the same package (for
021     * backwards compatibility reasons).
022     * 
023     * @see org.apache.tapestry5.services.UpdateListenerHub
024     * @since 5.1.0.0
025     */
026    public interface UpdateListener
027    {
028        /**
029         * Invoked to force the receiver to check for updates to whatever underlying resources it makes use of.
030         */
031        void checkForUpdates();
032    }