    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
    015    package org.apache.tapestry5.internal.services;
    016
    017    import org.apache.tapestry5.ioc.Resource;
    018    import org.apache.tapestry5.services.InvalidationEventHub;
    019    import 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     */
    028    public 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    }