package ch.werner_randelshofer.activation;

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

/**
A content type detector is able to guess the
data type of a data stream by inspecting a
few bytes at the beginning of the stream.

@author	Werner Randelshofer, Staldenmattweg 2, CH-6405 Immensee, Switzerland.
@version	1998-06-12	Created.
*/
public interface ContentTypeDetector
	{
	/**
	This value is returned by #getContentType(byte[])
	when the detector was not able to determine the
	content type of the data snippet.
	*/
	public final static String CONTENT_TYPE_UNKNOWN = "application/octet-stream";

	/**
	Return the number of bytes needed to
	determine the content type.
	*/ 
	public int getMinimalDeterminableDataLength();

	/**
	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);
	}