3 Quality Of Service and Admin Properties

3.1 Quality Of Service and Admin Properties

This chapter explains the allowed properties it is possible to set for this application.

Quality Of Service

The cosEventDomain application supports the following QoS settings:

QoS	Range	Default
CycleDetection	AuthorizeCycles/ForbidCycles	ForbidCycles
DiamondDetection	AuthorizeDiamonds/ForbidDiamonds	ForbidDiamonds

Table 3.1: Supported QoS settings

Comments on the table 'Supported QoS Settings':

CycleDetection: If a cycle is created, the user must be aware of the fact that unless they set timeout on events, events that are not filtered will loop endlessly through the topology.
DiamondDetection: A Diamond in this context, means that the same event may reach a point in the graph by more than one route (i.e. transitive). Hence, it is possible that multiple copies are delivered.

Setting Quality Of Service

Assume we have a Consumer Admin object which we want to change the current Quality of Service. Typical usage:

QoS = 
   [#'CosNotification_Property'
    {name='CosEventDomainAdmin':'DiamondDetection'(), 
     value=any:create(orber_tc:short(),
     'CosEventDomainAdmin':'AuthorizeDiamonds'())},
    #'CosNotification_Property'
    {name='CosEventDomainAdmin':'CycleDetection'(), 
     value=any:create(orber_tc:short(),
     'CosEventDomainAdmin':'ForbidCycles'())}],
'CosEventDomainAdmin_EventDomain':set_qos(ED, QoS),

If it is not possible to set the requested QoS the UnsupportedQoS exception is raised, which includes a sequence of PropertyError's describing which QoS, possible range and why is not allowed. The error codes are:

UNSUPPORTED_PROPERTY - QoS not supported for this type of target object.
UNAVAILABLE_PROPERTY - due to current QoS settings the given property is not allowed.
UNSUPPORTED_VALUE - property value out of range; valid range is returned.
UNAVAILABLE_VALUE - due to current QoS settings the given value is not allowed; valid range is returned.
BAD_PROPERTY - unrecognized property.
BAD_TYPE - type of supplied property is incorrect.
BAD_VALUE - illegal value.

The CosEventDomainAdmin_EventDomain interface also supports an operation called validate_qos/2. The purpose of this operations is to check if a QoS setting is supported by the target object and if so, the operation returns additional properties which could be optionally added as well.

Admin Properties

The OMG specification do not contain any definitions of Admin Properties. Hence, the cosEventDomain application currently does not support any Admin Properties.