Package org.opennms.netmgt.measurements.impl

Class NullFetchStrategy

java.lang.Object

org.opennms.netmgt.measurements.impl.NullFetchStrategy

All Implemented Interfaces:

MeasurementFetchStrategy

public class NullFetchStrategy
extends java.lang.Object
implements MeasurementFetchStrategy

Used as a fall-back when no known implementations are available.

Author:

Jesse White

Constructor Summary

Constructors

Constructor	Description
NullFetchStrategy()

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.

Methods inherited from class java.lang.Object

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

Constructor Detail

NullFetchStrategy

public NullFetchStrategy()

Method Detail

fetch

public 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.

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:

java.lang.Exception