001// Copyright 2006, 2007, 2012 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.commons.services;
016
017/**
018 * Interface for objects that may cache information that can be invalidated. Invalidation occurs when external files,
019 * from which in-memory data is cached, is determined to have changed. Granularity is very limited; when any external
020 * file is found to have changed, the event is fired (with the expectation that the cleared cache will be repopulated as
021 * necessary).
022 *
023 * @see org.apache.tapestry5.commons.services.InvalidationEventHub
024 * @since 5.1.0.0
025 * @deprecated In 5.4; use {@link InvalidationEventHub#addInvalidationCallback(Runnable)} instead
026 */
027public interface InvalidationListener
028{
029    /**
030     * Invoked to indicate that some object is invalid. The receiver should clear its cache.
031     */
032    void objectWasInvalidated();
033}