/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 * questions.

 */

package javax.activation;

import java.io.File;

/**

 * The FileTypeMap is an abstract class that provides a data typing

 * interface for files. Implementations of this class will

 * implement the getContentType methods which will derive a content

 * type from a file name or a File object. FileTypeMaps could use any

 * scheme to determine the data type, from examining the file extension

 * of a file (like the MimetypesFileTypeMap) to opening the file and

 * trying to derive its type from the contents of the file. The

 * FileDataSource class uses the default FileTypeMap (a MimetypesFileTypeMap

 * unless changed) to determine the content type of files.

 *

 * @see javax.activation.FileTypeMap

 * @see javax.activation.FileDataSource

 * @see javax.activation.MimetypesFileTypeMap

 *

 * @since 1.6

 */

public abstract class FileTypeMap {

    private static FileTypeMap defaultMap = null;

    /**

     * The default constructor.

     */

    public FileTypeMap() {

        super();

    }

    /**

     * Return the type of the file object. This method should

     * always return a valid MIME type.

     *

     * @param file A file to be typed.

     * @return The content type.

     */

    abstract public String getContentType(File file);

    /**

     * Return the type of the file passed in.  This method should

     * always return a valid MIME type.

     *

     * @param filename the pathname of the file.

     * @return The content type.

     */

    abstract public String getContentType(String filename);

    /**

     * Sets the default FileTypeMap for the system. This instance

     * will be returned to callers of getDefaultFileTypeMap.

     *

     * @param map The FileTypeMap.

     * @exception SecurityException if the caller doesn't have permission

     *                                  to change the default

     */

    public static void setDefaultFileTypeMap(FileTypeMap map) {

        SecurityManager security = System.getSecurityManager();

        if (security != null) {

            try {

                // if it's ok with the SecurityManager, it's ok with me...

                security.checkSetFactory();

            } catch (SecurityException ex) {

                // otherwise, we also allow it if this code and the

                // factory come from the same class loader (e.g.,

                // the JAF classes were loaded with the applet classes).

                if (FileTypeMap.class.getClassLoader() !=

                        map.getClass().getClassLoader())

                    throw ex;

            }

        }

        defaultMap = map;

    }

    /**

     * Return the default FileTypeMap for the system.

     * If setDefaultFileTypeMap was called, return

     * that instance, otherwise return an instance of

     * <code>MimetypesFileTypeMap</code>.

     *

     * @return The default FileTypeMap

     * @see javax.activation.FileTypeMap#setDefaultFileTypeMap

     */

    public static FileTypeMap getDefaultFileTypeMap() {

        // XXX - probably should be synchronized

        if (defaultMap == null)

            defaultMap = new MimetypesFileTypeMap();

        return defaultMap;

    }

}