org.hd.d.pg2k.test.dev
Class SystemVariablesTest.EventValueRequestMonitor

java.lang.Object
  org.hd.d.pg2k.svrCore.datasource.SimpleExhibitPipelineFilter
      org.hd.d.pg2k.test.dev.SystemVariablesTest.EventValueRequestMonitor

All Implemented Interfaces:

SimpleExhibitPipelineIF, BasicVarMgrInterface, SimpleVariablePipelineIF

Enclosing class:

SystemVariablesTest

static final class SystemVariablesTest.EventValueRequestMonitor
extends SimpleExhibitPipelineFilter

Observe upstream accesses to event values. This can optionally veto redundant reads that indicate that a cacheing stage is not working properly.

The EventVariableValue.equals() and hashCode() methods allow us to simply keep a Set of authorised values returned; any duplicate is an error.

vetoRedundantReads

private final boolean vetoRedundantReads

If true, veto attempts to read authoritative values more than once, ie redunantly.

authValueSeen

private final java.util.Set<EventVariableValue> authValueSeen

Set of authoritative responses so far passed downstream; never null.

SystemVariablesTest.EventValueRequestMonitor

SystemVariablesTest.EventValueRequestMonitor(SimpleExhibitPipelineIF upstream,
                                             boolean vetoRedundantReads)

Construct instance wrapped round upstream source.

Parameters:

upstream - datasource; never null

vetoRedundantReads - if true, veto attempts to read authoritative values more than once, ie redunantly; should be safe to use only behind a cache stage

getEventValue

public EventVariableValue getEventValue(SimpleVariableDefinition def,
                                        EventPeriod intervalSelector,
                                        boolean current)

Intercept event requests and look for incorrect redundancy.

Specified by:

getEventValue in interface BasicVarMgrInterface

Overrides:

getEventValue in class SimpleExhibitPipelineFilter

Parameters:

def - event definition (must be for an event); never null

intervalSelector - one of EVENT_INTERVAL_SELECTOR_xxx values

current - if true the current event set is returned, else the previous complete set is returned

Returns:

requested event set; may be null if requested set not available

getEventValues

public EventVariableValue[] getEventValues(SimpleVariableDefinition def,
                                           EventPeriod intervalSelector,
                                           long intervalNumber,
                                           java.util.BitSet whichValues)

Intercept event requests and look for incorrect redundancy.

Specified by:

getEventValues in interface BasicVarMgrInterface

Overrides:

getEventValues in class SimpleExhibitPipelineFilter

Parameters:

def - event definition (must be for an event); never null

intervalSelector - one of EVENT_INTERVAL_SELECTOR_xxx values

intervalNumber - a time (as from System.currentTimeMillis()) which identifies the first interval for which data is potentially required; if too far in the past or future then possibly no data will be available, zero is used to access the "all" bucket

whichValues - each true bit represents a slot for which data is required, bit 0 indicating data from the slot within which firstIntervalTime is located, bit 1 the previous slot, etc; null is treated as the common case equivalent to just bit 0 set

Returns:

as many of the requested values as available, at least long enough to return all the available values, with [0] corresponding to bit 0 in the BitSet; may contain nulls or be zero-length but is never null