org.semanticdesktop.aperture.extractor
Class AbstractFileExtractor

java.lang.Object
  org.semanticdesktop.aperture.extractor.AbstractFileExtractor

All Implemented Interfaces:

FileExtractor

Direct Known Subclasses:

MP3FileExtractor

public abstract class AbstractFileExtractor
extends Object
implements FileExtractor

A common superclass for all file extractors. Its purpose is to check if a file exists and if it's readable before the actual extraction can commence.

Constructor Summary

AbstractFileExtractor()

Method Summary

void	extract(URI id, File file, Charset charset, String mimeType, RDFContainer result) Extracts metadata from a file.
protected abstract void	performExtraction(URI id, File file, Charset charset, String mimeType, RDFContainer result)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractFileExtractor

public AbstractFileExtractor()

Method Detail

extract

public void extract(URI id,
                    File file,
                    Charset charset,
                    String mimeType,
                    RDFContainer result)
             throws ExtractorException

Extracts metadata from a file. This method checks if the file exists and if it's readable before calling the method that performs the actual extraction.

Specified by:

extract in interface FileExtractor

Parameters:

id - the URI identifying the object (e.g. a file or web page) from which the file was obtained. The generated statements should describe this URI. Note that it doesn't have to be the URI of the file that is passed as the second argument.

file - the File with the content from which metadata is to be extracted

charset - the charset in which the file is encoded (optional).

mimeType - the MIME type of the file (optional).

result - the container in which this FileExtractor can put the RDF statements it generates

Throws:

ExtractorException - in case of any error during the extraction process.

See Also:

FileExtractor.extract(URI, File, Charset, String, RDFContainer)

performExtraction

protected abstract void performExtraction(URI id,
                                          File file,
                                          Charset charset,
                                          String mimeType,
                                          RDFContainer result)
                                   throws ExtractorException

Throws:

ExtractorException