EventTracker

java.lang.Object
- org.qbroker.jms.EventTracker

All Implemented Interfaces:

EventEscalation
```
public class EventTracker
extends java.lang.Object
implements EventEscalation
```
EventTracker aggregates incoming events and keeps tracking their state according to the predefined policies and the content of the aggregated events. In case of the state changes up to the escalation point, it generates a new event as the escalation and returns it. EventTracker maitains the session for all aggregated events. The session will expire if it reaches the expiration time, or reset by certain incoming events. If the Type is set to MessageTracker, it will return a TextEvent as a JMS Message.

EventTracker caches the aggregated events based on their keys and the shared TimeToLive. If the cache time for the key exceeds the TTL, it will expire and a new event will be generated for aggregations. EventTracker uses MinTimeSpan to suppress those events occurred immediately after the escalated event. MinTimeSpan is the seconds measured from the time of previous escalated event. In case that MinTimeSpan is defined as a positive value, any events within the time span will not trigger escalations. But they will be aggregated.

EventTracker implements EventEscalation. It provides a way for us to correlate events across the time line.

Author:

yannanlu@yahoo.com

Field Summary
- Fields inherited from interface org.qbroker.event.EventEscalation
  ORDER_FIRST, ORDER_LAST, ORDER_NONE

Constructor Summary

Constructors
Constructor and Description

EventTracker(java.util.Map props)

Constructors
Constructor and Description
`EventTracker(java.util.Map props)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`java.util.Map<java.lang.String,java.lang.Object>`	`checkpoint()` returns the checkpoint Map for the escalation
`void`	`clear()` cleans up all internal caches and releases all resources
`Event`	`escalate(int status, long currentTime, Event event)` It examines the event and returns a new event as the escalation or null if no escalation.
`int`	`getEscalationOrder()` It returns an integer as the escalation order that determines if the escalation event to be processed before the original event or not.
`java.lang.String`	`getName()` returns the name of the escalation
`int`	`getSessionSize()` returns the size of current session
`long`	`getSessionTime()` returns the start time of current session
`int`	`resetSession(long currentTime)` resets the internal session returns number of items being reset
`void`	`restoreFromCheckpoint(java.util.Map<java.lang.String,java.lang.Object> chkpt)` restores the state of the escalation from the checkpoint Map

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - EventTracker
```
public EventTracker(java.util.Map props)
```
- Method Detail
  - escalate
```
public Event escalate(int status,
                      long currentTime,
                      Event event)
```
    Description copied from interface: EventEscalation
    
    It examines the event and returns a new event as the escalation or null if no escalation.
    
    Specified by:
    
    escalate in interface EventEscalation
  - resetSession
```
public int resetSession(long currentTime)
```
    Description copied from interface: EventEscalation
    
    resets the internal session returns number of items being reset
    
    Specified by:
    
    resetSession in interface EventEscalation
  - getSessionTime
```
public long getSessionTime()
```
    Description copied from interface: EventEscalation
    
    returns the start time of current session
    
    Specified by:
    
    getSessionTime in interface EventEscalation
  - getSessionSize
```
public int getSessionSize()
```
    Description copied from interface: EventEscalation
    
    returns the size of current session
    
    Specified by:
    
    getSessionSize in interface EventEscalation
  - getName
```
public java.lang.String getName()
```
    Description copied from interface: EventEscalation
    
    returns the name of the escalation
    
    Specified by:
    
    getName in interface EventEscalation
  - getEscalationOrder
```
public int getEscalationOrder()
```
    Description copied from interface: EventEscalation
    
    It returns an integer as the escalation order that determines if the escalation event to be processed before the original event or not. If the escalation order is ORDER_FISRT, the escalation event should be processed before the original event. If it is ORDER_LAST, the escalation event should be processed after. If it is ORDER_NONE, which one is the first does not matter.
    
    Specified by:
    
    getEscalationOrder in interface EventEscalation
  - clear
```
public void clear()
```
    Description copied from interface: EventEscalation
    
    cleans up all internal caches and releases all resources
    
    Specified by:
    
    clear in interface EventEscalation
  - checkpoint
```
public java.util.Map<java.lang.String,java.lang.Object> checkpoint()
```
    Description copied from interface: EventEscalation
    
    returns the checkpoint Map for the escalation
    
    Specified by:
    
    checkpoint in interface EventEscalation
  - restoreFromCheckpoint
```
public void restoreFromCheckpoint(java.util.Map<java.lang.String,java.lang.Object> chkpt)
```
    Description copied from interface: EventEscalation
    
    restores the state of the escalation from the checkpoint Map
    
    Specified by:
    
    restoreFromCheckpoint in interface EventEscalation

Class EventTracker

Field Summary

Fields inherited from interface org.qbroker.event.EventEscalation

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

EventTracker

Method Detail

escalate

resetSession

getSessionTime

getSessionSize

getName

getEscalationOrder

clear

checkpoint

restoreFromCheckpoint