001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *  http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    
020    package javax.activation;
021    
022    import java.io.File;
023    
024    /**
025     * FileTypeMap is an abstract class that provides a data type interface for files.
026     *
027     * @version $Rev: 467742 $ $Date: 2006-10-25 15:30:38 -0400 (Wed, 25 Oct 2006) $
028     */
029    public abstract class FileTypeMap {
030        // we use null here rather than a default because
031        // the constructor for MimetypesFileTypeMap does a lot of I/O
032        private static FileTypeMap defaultFileTypeMap = null;
033    
034        /**
035         * Sets the default FileTypeMap for the system.
036         * @param fileMap the new default FileTypeMap
037         * @throws SecurityException if the caller does not have "SetFactory" RuntimePermission
038         */
039        public static void setDefaultFileTypeMap(FileTypeMap fileMap) {
040            SecurityManager sm = System.getSecurityManager();
041            if (sm != null) {
042                sm.checkSetFactory();
043            }
044            defaultFileTypeMap = fileMap;
045        }
046    
047        /**
048         * Returns the default FileTypeMap
049         * @return the default FileTYpeMap; if null returns a MimetypesFileTypeMap
050         */
051        public synchronized static FileTypeMap getDefaultFileTypeMap() {
052            if (defaultFileTypeMap == null) {
053                defaultFileTypeMap = new MimetypesFileTypeMap();
054            }
055            return defaultFileTypeMap;
056        }
057    
058        public FileTypeMap() {
059        }
060    
061        public abstract String getContentType(File file);
062    
063        public abstract String getContentType(String filename);
064    }