org.opennms.netmgt.measurements.impl

Class AbstractRrdBasedFetchStrategy

java.lang.Object

org.opennms.netmgt.measurements.impl.AbstractRrdBasedFetchStrategy

All Implemented Interfaces:

MeasurementFetchStrategy

Direct Known Subclasses:

JrobinFetchStrategy, JRrd2FetchStrategy, RrdtoolXportFetchStrategy

public abstract class AbstractRrdBasedFetchStrategy
extends Object
implements MeasurementFetchStrategy

Used to fetch measurements from RRD files.

Author:

Jesse White

Constructor Summary

Constructors

Constructor and Description
AbstractRrdBasedFetchStrategy()

Method Summary

Modifier and Type	Method and Description
FetchResults	fetch(long start, long end, long step, int maxrows, Long interval, Long heartbeat, List<Source> sources, boolean relaxed) Fetches the measurements for the given sources.
protected abstract FetchResults	fetchMeasurements(long start, long end, long step, int maxrows, Map<Source,String> rrdsBySource, Map<String,Object> constants, QueryMetadata metadata) Performs the actual retrieval of the values from the RRD/JRB files.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractRrdBasedFetchStrategy

public AbstractRrdBasedFetchStrategy()

Method Detail

fetch

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

Fetches the measurements for the given sources.

Specified by:

fetch in interface MeasurementFetchStrategy

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:

Exception

fetchMeasurements

protected abstract FetchResults fetchMeasurements(long start,
                                                  long end,
                                                  long step,
                                                  int maxrows,
                                                  Map<Source,String> rrdsBySource,
                                                  Map<String,Object> constants,
                                                  QueryMetadata metadata)
                                           throws org.jrobin.core.RrdException

Performs the actual retrieval of the values from the RRD/JRB files.

Throws:

org.jrobin.core.RrdException