001    /*
002     * Copyright 2004 Niclas Hedhman.
003     *
004     * Licensed  under the  Apache License,  Version 2.0  (the "License");
005     * you may not use  this file  except in  compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *   http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed  under the  License is distributed on an "AS IS" BASIS,
012     * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
013     * implied.
014     *
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package net.dpml.transit.monitor;
020    
021    import java.io.File;
022    
023    import java.net.URL;
024    
025    import net.dpml.transit.Artifact;
026    
027    /**
028     * A monitor of a Transit cache activity.
029     *
030     * <p>
031     *   The CacheMonitor must be thread safe.
032     * </p>
033     *
034     * @author <a href="http://www.dpml.net">Digital Product Meta Library</a>
035     * @version 1.0.1
036     * @see Monitor
037     */
038    public interface CacheMonitor extends Monitor
039    {
040       /**
041        * Notify the monitor that an artifact has been requested.
042        * @param artifact the requested artifact
043        */
044        void resourceRequested( Artifact artifact );
045    
046       /**
047        * Notify the monitor that an artifact has been added to the local cache.
048        * @param resource the url of the resource added to the local cache
049        * @param localFile the local file resident in the cache
050        */
051        void addedToLocalCache( URL resource, File localFile );
052    
053       /**
054        * Notify the monitor that an artifact in the local cache has been updated.
055        * @param resource the url of the resource updating the local cache
056        * @param localFile the local file that has been updated
057        */
058        void updatedLocalCache( URL resource, File localFile );
059    
060       /**
061        * Notify the monitor that an artifact has been removed from the local cache.
062        * @param resource the url of the resource removed from the local cache
063        * @param localFile the local file removed from the cache
064        */
065        void removedFromLocalCache( URL resource, File localFile );
066    
067       /**
068        * Notify the monitor of a failed download attempt relative to an identified host.
069        * @param host the host raising the fail status
070        * @param artifact the requested artifact
071        * @param cause the exception causing the failure
072        */
073        void failedDownloadFromHost( String host, Artifact artifact, Throwable cause );
074    
075       /**
076        * Notify the monitor of a failed download attempt.
077        * @param artifact the requested artifact
078        */
079        void failedDownload( Artifact artifact );
080    
081    }