package ch.werner_randelshofer.activation;

/*
Copyright (C) 1999-99 Werner Randelshofer
werner.randelshofer@mythen.ch
http://www.mythen.ch/w.randelshofer/
    
Permission to use this release of URLConnectionCTD is hereby
granted without fee provided that the complete copyright
notice and this permission notice appear in all copies
and in supporting documentation.
*/

import java.io.*;
import java.net.*;

/**
This content type detector uses
java.net.URLConnection#guessContentTypeFromStream()
to determine the type of data.

@author	Werner Randelshofer, Staldenmattweg 2, CH-6405 Immensee, Switzerland.
@version	1998-06-12	Created.
*/
public class URLConnectionCTD
implements ContentTypeDetector
	{
	/**
	Return the number of bytes needed to
	determine the content type.
	*/ 
	public int getMinimalDeterminableDataLength()
		{
		return 10;
		}

	/**
	Return the base MIME Type of this data. This method is
	expected to ALWAYS return a valid (non-null) MIME Type.
	I suggest that if the DataTypeDetector implementation cannot 
	determine the type of the data, it use the convention of
	returning "application/octet-stream".

	@param	the first few bytes of the data file.
	@return MIME Type
	*/
	public String getContentType(byte[] dataSnippet)
		{
		String contentType = null;
		try	{
			ByteArrayInputStream stream = new ByteArrayInputStream(dataSnippet);
			contentType = URLConnection.guessContentTypeFromStream(stream);
			}
		catch (IOException e)
			{ }
		finally
			{
			if (contentType != null)
				{ return contentType; }
			else
				{ return ContentTypeDetector.CONTENT_TYPE_UNKNOWN; }
			}
		}
	}