Package org.opennms.netmgt.measurements.api

Interface MeasurementFetchStrategy

All Known Implementing Classes:

AbstractRrdBasedFetchStrategy, JrobinFetchStrategy, JRrd2FetchStrategy, NewtsFetchStrategy, NullFetchStrategy, RrdtoolXportFetchStrategy, TimeseriesFetchStrategy

public interface MeasurementFetchStrategy

Used to retrieve measurements from the current persistence mechanism.

Author:

Jesse White

Method Summary

Modifier and Type	Method	Description
FetchResults	fetch(long start, long end, long step, int maxrows, java.lang.Long interval, java.lang.Long heartbeat, java.util.List<Source> sources, boolean relaxed)	Fetches the measurements for the given sources.

Method Detail

fetch

FetchResults fetch(long start,
                   long end,
                   long step,
                   int maxrows,
                   java.lang.Long interval,
                   java.lang.Long heartbeat,
                   java.util.List<Source> sources,
                   boolean relaxed)
            throws java.lang.Exception

Fetches the measurements for the given sources.

Parameters:

start - timestamp in milliseconds

end - timestamp in milliseconds

step - desired resolution in milliseconds - actual resolution might differ

maxrows - maximum number of rows - no limit when <= 0

interval - duration in milliseconds, used by strategies that implement late aggregation

heartbeat - duration in milliseconds, used by strategies that implement late aggregation

sources - array of sources - these should have unique labels

relaxed - if false a missing source results in a return of null. true on the other hand ignores that source.

Returns:

null when a resource id or attribute cannot be found

Throws:

java.lang.Exception