Federated Query Processor Status Listeners

This page describes the listener interface which developers may implement and pass along to the Federated Query Processing Engine to recieve notifications when important query related events happen.

The fully qualified Java classname of the interface is gov.nih.nci.cagrid.fqp.processor.FQPProcessingStatusListener.  Its public API is as follows:

• public void processingStatusChanged(ProcessingStatus status, String message)
  • Indicates a change in the overall Federated Query Processing status
  • status: The new status of query processing.  The ProcessingStatus class is an Axis bean, and may have one of the following values:
    • Waiting_To_Begin: Set when a query has been recieved but no action has been taken on it yet.
    • Processing: Set when query processing has begun.
    • Complete: Set when a query has ran to completion and no errors were found.
    • Complete_With_Error: Set when a query has finished processing, but one or more errors occured.
  • message: A more specific detail message, which may or may not be null.
• public void targetServiceOk(String serviceURL)
  • Indicates that the target service successfully processed the query
  • serviceURL: The URL of the target data service which completed query processing
• public void targetServiceReturnedResults(String serviceURL, ResultsRange range)
  • Indicates that the target service returned results, and when aggregated, those results will be in the given range of indices.
  • serviceURL: The URL of the target data service which completed query processing and returned object results
  • range: The range of indices of the eventual result set which were returned by this data service
• public void targetServiceConnectionRefused(String serviceURL)
  • Indicates that the target service did not respond to connections
  • serviceURL: The URL of the target data service which refused a connection
• public void targetServiceThrowsException(String serviceURL, Exception ex)
  • Indicates that the target service threw some exception while processing
  • serviceURL: The URL of the target data service which threw an exception
  • ex: The exception thrown by the service
• public void targetServiceReturnedInvalidResult(String serviceURL, FederatedQueryProcessingException ex)
  • Indicates that the target service returned some invalid result
  • serviceURL: The URL of the target data service which returned some invalid result
  • ex: An exception detailing the problem