001    /*
002     * Copyright 2006 Stephen McConnell.
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;
020    
021    import java.io.File;
022    
023    import java.net.URL;
024    
025    /**
026     * Transit event monitor.
027     *
028     * @author <a href="http://www.dpml.net">Digital Product Management Library</a>
029     * @version 2.1.1
030     */
031    public interface Monitor
032    {
033        // cache monitoring functions
034        
035       /**
036        * Notify the monitor that an artifact has been requested.
037        * @param artifact the requested artifact
038        */
039        void resourceRequested( Artifact artifact );
040    
041       /**
042        * Notify the monitor that an artifact has been added to the local cache.
043        * @param resource the url of the resource added to the local cache
044        * @param localFile the local file resident in the cache
045        */
046        void addedToLocalCache( URL resource, File localFile );
047    
048       /**
049        * Notify the monitor that an artifact in the local cache has been updated.
050        * @param resource the url of the resource updating the local cache
051        * @param localFile the local file that has been updated
052        */
053        void updatedLocalCache( URL resource, File localFile );
054    
055       /**
056        * Notify the monitor that an artifact has been removed from the local cache.
057        * @param resource the url of the resource removed from the local cache
058        * @param localFile the local file removed from the cache
059        */
060        void removedFromLocalCache( URL resource, File localFile );
061    
062       /**
063        * Notify the monitor of a failed download attempt relative to an identified host.
064        * @param host the host raising the fail status
065        * @param artifact the requested artifact
066        * @param cause the exception causing the failure
067        */
068        void failedDownloadFromHost( String host, Artifact artifact, Throwable cause );
069    
070       /**
071        * Notify the monitor of a failed download attempt.
072        * @param artifact the requested artifact
073        */
074        void failedDownload( Artifact artifact );
075        
076        // network monitoring
077        
078        /**
079         * Notify the monitor of the update in the download status.
080         *
081         * @param resource the name of the remote resource being downloaded.
082         * @param expected the expected number of bytes to be downloaded.
083         * @param count the number of bytes downloaded.
084         */
085        void notifyUpdate( URL resource, int expected, int count );
086    
087        /**
088         * Notify the monitor of the successful completion of a download
089         * process.
090         * @param resource the name of the remote resource.
091         */
092        void notifyCompletion( URL resource );
093        
094    
095    }