/*

 * Copyright 1997-2005 Sun Microsystems, Inc.  All Rights Reserved.

 * 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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.activation;

import java.awt.datatransfer.DataFlavor;

import java.awt.datatransfer.UnsupportedFlavorException;

import java.io.InputStream;

import java.io.IOException;

import java.io.OutputStream;

import javax.activation.DataSource;

/**

 * The DataContentHandler interface is implemented by objects that can

 * be used to extend the capabilities of the DataHandler's implementation

 * of the Transferable interface. Through <code>DataContentHandlers</code>

 * the framework can be extended to convert streams in to objects, and

 * to write objects to streams. <p>

 *

 * Applications don't generally call the methods in DataContentHandlers

 * directly. Instead, an application calls the equivalent methods in

 * DataHandler. The DataHandler will attempt to find an appropriate

 * DataContentHandler that corresponds to its MIME type using the

 * current DataContentHandlerFactory. The DataHandler then calls

 * through to the methods in the DataContentHandler.

 *

 * @since 1.6

 */

public interface DataContentHandler {

    /**

     * Returns an array of DataFlavor objects indicating the flavors the

     * data can be provided in. The array should be ordered according to

     * preference for providing the data (from most richly descriptive to

     * least descriptive).

     *

     * @return The DataFlavors.

     */

    public DataFlavor[] getTransferDataFlavors();

    /**

     * Returns an object which represents the data to be transferred.

     * The class of the object returned is defined by the representation class

     * of the flavor.

     *

     * @param df The DataFlavor representing the requested type.

     * @param ds The DataSource representing the data to be converted.

     * @return The constructed Object.

     * @exception UnsupportedFlavorException    if the handler doesn't

     *                                          support the requested flavor

     * @exception IOException   if the data can't be accessed

     */

    public Object getTransferData(DataFlavor df, DataSource ds)

                                throws UnsupportedFlavorException, IOException;

    /**

     * Return an object representing the data in its most preferred form.

     * Generally this will be the form described by the first DataFlavor

     * returned by the <code>getTransferDataFlavors</code> method.

     *

     * @param ds The DataSource representing the data to be converted.

     * @return The constructed Object.

     * @exception IOException   if the data can't be accessed

     */

    public Object getContent(DataSource ds) throws IOException;

    /**

     * Convert the object to a byte stream of the specified MIME type

     * and write it to the output stream.

     *

     * @param obj       The object to be converted.

     * @param mimeType  The requested MIME type of the resulting byte stream.

     * @param os        The output stream into which to write the converted

     *                  byte stream.

     * @exception IOException   errors writing to the stream

     */

    public void writeTo(Object obj, String mimeType, OutputStream os)

                                                       throws IOException;

}