/*
 * DataSourceDataContentHandler.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU Java Activation Framework (JAF), a library.
 * 
 * GNU JAF is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAF 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 for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * As a special exception, if you link this library with other files to
 * produce an executable, this library does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * This exception does not however invalidate any other reasons why the
 * executable file might be covered by the GNU General Public License.
 */
package javax.activation;

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Data content handler using an existing DCH and a data source.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 * @version 1.0.2
 */
class DataSourceDataContentHandler
    implements DataContentHandler
{

    private DataSource ds;
    private DataFlavor[] flavors;
    private DataContentHandler dch;

    public DataSourceDataContentHandler(DataContentHandler dch, DataSource ds)
    {
        this.ds = ds;
        this.dch = dch;
    }

    public Object getContent(DataSource ds)
        throws IOException
    {
        if (dch != null)
            return dch.getContent(ds);
        else
            return ds.getInputStream();
    }

    public Object getTransferData(DataFlavor flavor, DataSource ds)
        throws UnsupportedFlavorException, IOException
    {
        if (dch != null)
            return dch.getTransferData(flavor, ds);
        DataFlavor[] flavors = getTransferDataFlavors();
        if (flavors.length > 0 && flavor.equals(flavors[0]))
            return ds.getInputStream();
        else
            throw new UnsupportedFlavorException(flavor);
    }

    public DataFlavor[] getTransferDataFlavors()
    {
        if (flavors == null)
        {
            if (dch != null)
                flavors = dch.getTransferDataFlavors();
            else
            {
                String mimeType = ds.getContentType();
                flavors = new DataFlavor[1];
                flavors[0] = new ActivationDataFlavor(mimeType, mimeType);
            }
        }
        return flavors;
    }

    public void writeTo(Object obj, String mimeType, OutputStream out)
        throws IOException
    {
        if (dch == null)
            throw new UnsupportedDataTypeException(
                    "no DCH for content type " + ds.getContentType());
        dch.writeTo(obj, mimeType, out);
    }
    
}