Building Your Event-Driven Architecture : Universal Messaging Administration Guide : Universal Messaging Enterprise Manager : Administration Using Enterprise Manager : Scheduling : Universal Messaging Scheduling : Conditional Triggers
Universal Messaging Scheduling : Conditional Triggers
Conditional triggers execute tasks when specific conditions occur. Each defined trigger has a number of attributes that can be used as part of the trigger expression and evaluated to determine whether the tasks are executed. For basic information on the grammar for conditional triggers, please read the section on conditional triggers in the writing scripts help file (see Universal Messaging Scheduling : Writing Schedule Scripts). The conditional triggers are signified by using the 'when' keyword. The expression entered after the keyword represent the trigger object(s) and the values to be checked against.
This section will describe in detail the triggers that are available and how to use them within a trigger expression :
*Trigger Expressions
*Store Triggers
*Interface Triggers
*Memory Triggers
*Realm Triggers
*Cluster Triggers
*Counter Triggers
*Timer Triggers
*Config Triggers
To view examples of scheduling scripts, see Scheduler Examples.
Trigger Expressions
A trigger expression is constructed from the definition of the trigger object(s) to be evaluated and the values that will be used in the comparison. The trigger used in the expression can be either the actual trigger object, or the declared name of the trigger from the declarations section of the script (see Universal Messaging Scheduling : Writing Schedule Scripts). Multiple triggers can be used in the expression using conditional operators (AND | OR).
For example, the following expression can be used to evaluate when a Realm's Interface accept threads are exhausted 5 times. When this happens, the accept threads will be increased by 10. This schedule will continually monitor the state of the interface and self-manage the accept threads so the realm server is always able to accept connections from clients.
scheduler realmInterfaceSchedule {

declare Interface myNHP ("nhp0");
declare Counter myCounter("myExhaustedThreads");

when (myNHP.idleThreads == 0) {

Logger.report("NHP0 Interface has no idles Threads");
myCounter.inc();

}

when (myCounter >= 5) {

Logger.report("Increasing the accept thread count on NHP0");
myNHP.threads("+10");
myCounter.reset();

}

}
The above schedule will monitor the number of times the accept threads are exhausted and when the counter trigger hits 5 times, the number of threads will be increased by 10.
The next section will describe the available trigger objects and the available triggers on those objects that can be used within
Store Triggers - Channel / Queue based triggers
Store triggers are declared using the following syntax as an example:
declare Store myChannel("/customer/sales");
The table below lists those triggers that can be evaluated on a Store object, such that the trigger expression will look like :
when (myChannel.connections > 100) {

}
Trigger Object
Parameters
Description
connections
None
Trigger on the number of connections for the channel or queue
freeSpace
None
Trigger on the amount of free space available in the store (used space - size of all purged events)
usedSpace
Trigger on the amount of used space available in the store (size of all event on disk or memory)
numOfEvents
None
Trigger on the number of events on the channel / queue
filter
Valid filter String
Trigger when an event that matches the filter is published to the channel / queue
Interface Triggers - Universal Messaging Interface based triggers
Interface triggers are declared using the following syntax as an example:
declare Interface myNHP("nhp0");
The table below lists those triggers that can be evaluated on an Interface object, such that the trigger expression will look like :
when (myNHP.connections > 100) {

}
Trigger Object
Parameters
Description
connections
None
Trigger on the number of connections for the interface
authentication
None
Trigger on the average authentication time for clients on an interface
failedConnections
None
Trigger on the number of failed authentication attempts
exhaustedTime
None
Trigger on the average amount of time the interface accept thread pool has been exhausted
idleThreads
None
Trigger on the number of idle interface accept pool threads
exhaustedCount
None
Trigger on the number of times an interface accept thread pool is exhausted (i.e. idle == 0)
state
None
Trigger when an interface is in a certain state
MemoryManager Triggers - Universal Messaging JVM Memory Management based triggers
MemoryManager triggers are declared using the following syntax as an example:
declare MemoryManager mem;
The table below lists those triggers that can be evaluated on the memory management object, such that the trigger expression will look like :
when (mem.freeMemory < 1000000) {

}
Trigger Object
Parameters
Description
freeMemory
None
Trigger when the realm server's JVM has a certain amount of free memory
totalMemory
None
Trigger when the realm server's JVM has a certain amount of total memory
outOfMemory
None
Trigger when the realm server JVM runs out of memory
Realm Triggers - Universal Messaging Realm based triggers
Realm triggers are declared using the following syntax as an example:
declare Realm myRealm("productionmaster");
The table below lists those triggers that can be evaluated on the realm object, such that the trigger expression will look like :
when (realm.connections > 1000) {

}
Trigger Object
Parameters
Description
connections
None
Trigger when the realm server current connections reaches a certain number
eventsSentPerSecond
None
Trigger when the realm server's events per second sent rate reaches a certain value
eventsReceivedPerSecond
None
Trigger when the realm server's events per second sent received reaches a certain value
Cluster Triggers - Universal Messaging Cluster based triggers
Cluster triggers are declared using the following syntax as an example, assuming a cluster is made up of 4 realms:
declare Cluster myNode1("realm1");
declare Cluster myNode2("realm2");
declare Cluster myNode3("realm3");
declare Cluster myNode4("realm4");
The table below lists those triggers that can be evaluated on the cluster object, such that the trigger expression will look like :
when ( Cluster.isOnline("realm1") == true ){

}
Trigger Object
Parameters
Description
hasQuorum
None
Trigger when cluster has quorum == true or false
isMaster
None
Trigger when a cluster realm is voted master
nodeOnline
None
Trigger when a cluster realm is online or offline
Counter Triggers - Counter value based triggers
Counter triggers allow you to keep a local count of events occurring with the Universal Messaging scheduler engine. The values of the Counters can be incremented decremented and reset within the tasks section of a trigger declaration. Counter triggers are declared using the following syntax as an example:
declare Counter counter1 ("myCounter");
The counter trigger can be evaluated by referencing the Counter object itself, such that the trigger expression will look like :
when ( counter1 > 5) {

}
Timer Triggers - Timer based triggers
Timer triggers allow you to start a timer that will keep track of how long (in seconds) it has been running and then evaluate the running time within a trigger expression. Time triggers are declared using the following syntax as an example:
declare Timer reportTimer ("myTimer");
The timer trigger can be evaluated by referencing the timer object itself, such that the trigger expression will look like :
when ( reportTimer == 60 ) {

}
Config Triggers -Universal Messaging configuration triggers
Config triggers refer to any of the configuration values available in the Config panel for a realm. Any configuration value can be used as part of a trigger expression. Config triggers are declared using the following syntax as an example (below example refers to the 'GlobalValues' configuration group:
declare Config myGlobal ("GlobalValues");
The table below lists those triggers that can be evaluated on a Config object, such that the task expression will look like :
when (myGlobal.MaxNoOfConnections == -1) {

}
Trigger Object
Parameters
Description
GlobalValues
SchedulerPoolSize
None
The number of threads assigned to the scheduler
MaxNoOfConnections
None
Sets the maximum concurrent connections to the server, -1 indicates no restriction
StatusUpdateTime
None
The number of ms between status events being written to disk
StatusBroadcast
None
The number of ms between status events being published
fLoggerLevel
None
The server logging level
NHPTimeout
None
The number of milliseconds the server will wait for client authentication
NHPScanTime
None
The number of milliseconds that the server will wait before scanning for client timeouts
HandshakeTimeout
None
The number of milliseconds that the server will wait for the session to be established
StampDictionary
None
Place Universal Messaging details into the dictionary (true/false)
ExtendedMessageSelector
None
If true, allows the server to use the extended message selector syntax (true/false)
ServerTime
None
Allow the server to send the current time to the clients (true/false)
SecureHandshake
None
Performs a security handshake when connecting into a cluster
ConnectionDelay
None
When the server has exceeded the connection count, how long to hold on to the connection before disconnecting
SupportVersion2Clients
None
Allow the server to support older clients (true/false)
SendRealmSummaryStats
None
If true sends the realms status summary updates (true/false)
AuditSettings
RealmMaintenance
None
Log to the audit file any realm maintenance activity
InterfaceManagement
None
Log to the audit file any interface management activity
ChannelMaintenance
None
Log to the audit file any channel maintenance activity
QueueMaintenance
None
Log to the audit file any queue maintenance activity
ServiceMaintenance
None
Log to the audit file any service maintenance activity
JoinMaintenance
None
Log to the audit file any join maintenance activity
RealmSuccess
None
Log to the audit file any successful realm interactions
ChannelSuccess
None
Log to the audit file any successful channel interactions
QueueSuccess
None
Log to the audit file any successful queue interactions
ServiceSuccess
None
Log to the audit file any successful realm interactions
JoinSuccess
None
Log to the audit file any successful join interactions
RealmFailure
None
Log to the audit file any unsuccessful realm interactions
ChannelFailure
None
Log to the audit file any unsuccessful channel interactions
QueueFailure
None
Log to the audit file any unsuccessful queue interactions
ServiceFailure
None
Log to the audit file any unsuccessful service interactions
JoinFailure
None
Log to the audit file any unsuccessful join interactions
RealmACL
None
Log to the audit file any unsuccessful realm acl interactions
ChannelACL
None
Log to the audit file any unsuccessful channel acl interactions
QueueACL
None
Log to the audit file any unsuccessful queue acl interactions
ServiceACL
None
Log to the audit file any unsuccessful service acl interactions
ClientTimeoutValues
EventTimeout
None
The amount of ms the client will wait for a response from the server
DisconnectWait
None
The maximum amount of time to wait when performing an operation when disconnected before throwing session not connected exception
TransactionLifeTime
None
The default amount of time a transaction is valid before being removed from the tx store
KaWait
None
The amount of time the client will wait for keep alive interactions between server before acknowledging disconnected state
LowWaterMark
None
The low water mark for the connection internal queue. When this value is reached the outbound internal queue will again be ready to push event to the server
HighWaterMark
None
The high water mark for the connection internal queue. When this value is reached the internal queue is temporarily suspended and unable to send events to the server. This provides flow control between publisher and server.
QueueBlockLimit
None
The maximum number of milliseconds a queue will have reached HWM before notifying listeners
QueueAccessWaitLimit
None
The maximum number of milliseconds it should take to gain access to a queue to push events before notifying listeners
QueuePushWaitLimit
None
The maximum number of milliseconds it should take to gain access to a queue and to push events before notifying listeners
ClusterConfig
HeartBeatInterval
None
Heart Beat interval in milliseconds
SeparateLog
None
Create a separate log file for cluster events
EventsOutStanding
None
Number of events outstanding
EventStorage
CacheAge
None
The time in ms that cached events will be kept in memory for
ThreadPoolSize
None
The number of threads allocated to perform the management task on the channels
ActiveDelay
None
The time in milliseconds that an active channel will delay between scans
IdleDelay
None
The time in milliseconds that an idle channel will delay between scans
FanoutValues
ConcurrentUser
None
The number of client threads allowed to execute concurrently in the server
KeepAlive
None
The number of milliseconds between the server will wait before sending a heartbeat
QueueHighWaterMark
None
The number of events in a client output queue before the server stops sending events
QueueLowWaterMark
None
The number of events in the clients queue before the server resumes sending events
MaxBufferSize
None
The maximum buffer size that the server will accept
OutputBlockSize
None
The size of the output block size
PublishDelay
None
How long to delay the publisher when subscribers queue start to fill, in milliseconds
RoundRobinDelivery
None
Use a round robin approach to event delivery (true/false)
PublishExpiredEvents
None
Publish expired events at server startup (true/false)
JVMManagement
MemoryMonitoring
None
Number of milliseconds between monitoring memory usage on the realm
WarningThreshold
None
The memory threshold when the server starts to scan for objects to release
EmergencyThreshold
None
The memory threshold when the server starts to aggressively scan for objects to release
ExitOnMemoryError
None
If true, the server will exit if it gets an out of memory exception
ExitOnDiskIOError
None
If true, the server will exit if it gets a I/O Exception
JoinConfig
MaxEventsPerSchedule
None
Number of events that will be sent to the remote server in one run
MaxQueueSizeToUse
None
The maximum events that will be queued on behalf of the remote server
ActiveThreadPoolSize
None
The number of threads to be assigned for the join recovery
IdleThreadPoolSize
None
The number of threads to manage the idle and reconnection to remote servers
RecoveryDaemon
ThreadPool
None
Number of threads to use for client recovery
EventsPerBlock
None
The number of events to send in one block
TransactionManager
MaxTransactionTime
None
Time in milliseconds that a transaction will be kept active
MaxEventsPerTransaction
None
The maximum number of events per transaction, a 0 indicates no limit
TTLThreshold
None
The minimum time in milliseconds, below which the server will not store the Transaction ID
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