001// Copyright 2006, 2008, 2009, 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
015package org.apache.tapestry5.internal.services;
016
017import org.apache.tapestry5.ioc.Resource;
018import org.apache.tapestry5.services.InvalidationEventHub;
019import org.apache.tapestry5.services.ResourceDigestGenerator;
020
021/**
022 * Caches information about resources on the classpath. In addition, acts as an invalidation hub for any resources for
023 * which information is obtained (when any of the resources are changed, invalidation listeners are notified so they can
024 * clear their caches).
025 * <p>
026 * Note that the name and role of this class changed (and diminished) quite a bit in Tapestry 5.3. It is now focused on
027 */
028public interface ResourceDigestManager extends InvalidationEventHub
029{
030    /**
031     * Returns true if the path requires that the client URL for the resource include a digest to validate that the
032     * client is authorized to access the resource.
033     * 
034     * @param resource
035     * @return true if digest is required for the resource
036     * @see ResourceDigestGenerator#requiresDigest(String)
037     */
038    boolean requiresDigest(Resource resource);
039
040    /**
041     * Returns the digest for the given path.
042     * 
043     * @param resource
044     * @return the digest, or null if the resource does not exist
045     */
046    String getDigest(Resource resource);
047}