org.mycore.datamodel.ifs.extractors
Class MCRDataExtractor

java.lang.Object
  org.mycore.common.events.MCREventHandlerBase
      org.mycore.datamodel.ifs.extractors.MCRDataExtractor

All Implemented Interfaces:

MCREventHandler

Direct Known Subclasses:

MCRDataExtractorJPEG, MCRDataExtractorMP3, MCRDataExtractorPDF

public abstract class MCRDataExtractor
extends MCREventHandlerBase

Event handler that extracts data like technical metadata (ID3 from MP3, EXIF from JPEG etc.) whenever an MCRFile's content is changed. The extracted data is stored in MCRFile's additional xml data.

Version:

$Revision: 13085 $ $Date: 2008-02-06 18:27:24 +0100 (Mi, 06 Feb 2008) $

Author:

Frank Lützenkirchen

See Also:

org.mycore.datamodel.ifs.MCRFilesystemNode#getAdditionalData()

Constructor Summary

MCRDataExtractor()

Method Summary

protected void	addDataValue(Element parent, String name, String value) Adds extracted metadata value to the resulting XML output, if it is not null or empty.
protected abstract void	extractData(Element container, InputStream in) Extracts metadata from a file.
protected abstract String	getSupportedContentTypeIDs() Returns the IDs of the FileContentTypes that are supported by this metadata extractor.
protected void	handleFileCreated(MCREvent evt, MCRFile file) Handles file created events.
protected void	handleFileUpdated(MCREvent evt, MCRFile file) Handles file updated events.
protected String	outputData(Element data) Returns the XML data element as a String
protected void	testLocalFile(String filePath) Convenience method that prints out extracted data of a local file

Methods inherited from class org.mycore.common.events.MCREventHandlerBase

doHandleEvent, doNothing, handleClassificationCreated, handleClassificationDeleted, handleClassificationRepaired, handleClassificationUpdated, handleDerivateCreated, handleDerivateDeleted, handleDerivateRepaired, handleDerivateUpdated, handleFileDeleted, handleFileRepaired, handleObjectCreated, handleObjectDeleted, handleObjectRepaired, handleObjectUpdated, undoClassificationCreated, undoClassificationDeleted, undoClassificationRepaired, undoClassificationUpdated, undoDerivateCreated, undoDerivateDeleted, undoDerivateRepaired, undoDerivateUpdated, undoFileCreated, undoFileDeleted, undoFileRepaired, undoFileUpdated, undoHandleEvent, undoObjectCreated, undoObjectDeleted, undoObjectRepaired, undoObjectUpdated

Methods inherited from class java.lang.Object

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

Constructor Detail

MCRDataExtractor

public MCRDataExtractor()

Method Detail

testLocalFile

protected void testLocalFile(String filePath)

Convenience method that prints out extracted data of a local file

Parameters:

filePath - the path of the file to be tested

outputData

protected String outputData(Element data)

Returns the XML data element as a String

Parameters:

data - the extracted data as XML element

Returns:

the XML pretty-outputted as a String

handleFileCreated

protected void handleFileCreated(MCREvent evt,
                                 MCRFile file)

Description copied from class: MCREventHandlerBase

Handles file created events. This implementation does nothing and should be overwritted by subclasses.

Overrides:

handleFileCreated in class MCREventHandlerBase

Parameters:

evt - the event that occured

file - the MCRFile that caused the event

handleFileUpdated

protected void handleFileUpdated(MCREvent evt,
                                 MCRFile file)

Description copied from class: MCREventHandlerBase

Handles file updated events. This implementation does nothing and should be overwritted by subclasses.

Overrides:

handleFileUpdated in class MCREventHandlerBase

Parameters:

evt - the event that occured

file - the MCRFile that caused the event

extractData

protected abstract void extractData(Element container,
                                    InputStream in)
                             throws Exception

Extracts metadata from a file. This method must be overwritten by subclasses.

Parameters:

container - empty XML element that the extractor should fill with data

in - the InputStream to read the file's content from

Throws:

Exception

getSupportedContentTypeIDs

protected abstract String getSupportedContentTypeIDs()

Returns the IDs of the FileContentTypes that are supported by this metadata extractor. Only if the given file matches one of these types, metadata is extracted.

Returns:

a String of supported MCRFileContentType ID(s), separated by spaces

addDataValue

protected void addDataValue(Element parent,
                            String name,
                            String value)

Adds extracted metadata value to the resulting XML output, if it is not null or empty.