Data Crawler

Java Interface

/

• A DataCrawler accesses the physical source represented by a DataSource
• and delivers a stream of DataObjects representing the individual items
• in that source. */

public interface DataCrawler {

/

• Constants used to indicate why a scan was stopped. */

public static enum ExitCode {

COMPLETED, the scan procedure terminated normally BY_REQUEST, the DataCrawler was requested to abort the scan procedure FATAL_EXCEPTION an error occurred that made further scanning impossible

};

/

• Returns the DataSource crawler by this DataCrawler. */

public DataSource getDataSource();

/

• Starts a scan for DataObjects over the configured domain defined
• in the DataSource. If this is not the first run of this DataCrawler,
• it will only report the differences with the previous run, unless the
• previous scan results have been cleared. /

public void scan();

/

• Stops a running scan operation as fast as possible. This method
• may return before the operation has actually been stopped. /

public void stopScanning();

/

• Clears all stored scan results. Any listeners registered with
• this data source will be notified of the removal of the data
• objects. The next call to scan() will again report all
• data objects in the configured domain. /

public void clearScanResults();

/

• Gets the ScanReport of the last performed scan, or the current
• scan when a scan is in progress. Returns null when
• no scan was performed in this session and there is no scan report
• available from the previous session.
• @return The ScanReport of the last session, or null when
• this is not available. /

public ScanReport getLastScanReport();

/

• Adds a DataSourceListener to which this data source should
• report any scanned or cleared data objects. *
• @param listener The DataCrawlerListener to add. /

public void addListener(DataCrawlerListener listener);

/

• Removes a DataSourceListener from this data source. *
• @param listener The DataCrawlerListener to remove. /

public void removeListener(DataCrawlerListener listener);

}