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 CTDFileTypeMap 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 javax.activation.*;
/**
This file data source uses a ContentTypeDetector to
determine the content type of the file.

@author	Werner Randelshofer, Staldenmattweg 2, CH-6405 Immensee, Switzerland.
@version	1998-06-12	Created.
*/
public class CTDFileTypeMap
extends FileTypeMap
	{
	private ContentTypeDetector detector_;

	/**
	Creates a new instance
	No ContentTypeDetector will be used to determine the
	content type of the file (#getContentType will always
	return "application/octet-stream".
	*/
	public CTDFileTypeMap()
		{ }
	/**
	Creates a new instance.
	The specified ContentTypeDetector will be used to determine the
	content type of the file.
	*/
	public CTDFileTypeMap(ContentTypeDetector detector)
		{
		detector_ = detector;
		}

	/**
	Sets the ContentTypeDetector that will be
	used for determining the content type of the file.
	*/
	public void setCTD(ContentTypeDetector detector)
		{
		detector_ = detector;
		}

	/**
	Returns the ContentTypeDetector that will be
	used for determining the content type of the file.
	*/
	public ContentTypeDetector getCTD()
		{
		return detector_;
		}

	/**
	Return the base MIME Type of this data. This method is
	expected to ALWAYS return a valid (non-null) MIME Type.
	We suggest that if the DataSource implementation cannot 
	determine the type of the data, it use the convention of
	returning "application/octet-stream".
	
	@return MIME Type
	*/
	public String getContentType(File file)
		{
		InputStream in = null;
		ContentTypeDetector d = getCTD();
		String contentType = ContentTypeDetector.CONTENT_TYPE_UNKNOWN;
		if (d == null)
			{ return contentType; }
		try	{
			byte[] snippet = new byte[d.getMinimalDeterminableDataLength()];
			in = new FileInputStream(file);
			in.read(snippet);
			contentType = d.getContentType(snippet);
			}
		catch (IOException e)
			{ }
		finally
			{
			try	{
				if (in != null)
					{ in.close(); }
				}
			catch (IOException e)
				{}
			}
		return contentType;
		}
	/**
	Return the base MIME Type of this data. This method is
	expected to ALWAYS return a valid (non-null) MIME Type.
	We suggest that if the DataSource implementation cannot 
	determine the type of the data, it use the convention of
	returning "application/octet-stream".
	
	@return MIME Type
	*/
	public String getContentType(String filename)
		{
		return ContentTypeDetector.CONTENT_TYPE_UNKNOWN;
		}
	}