Event processing

The stanzas, seen in Table 22, must be specified if the bridge is configured for event processing, for example, if the Mode parameter is set to Event or Both.

Stanza EventHandler mainly contains the WebSphere MQ parameters needed to establish a WebSphere MQ connection with a target application that is used to forward FRONT ARENA event notifications to the target application.

Table 22. Stanza EventHandler

Keyword Mandatory/ Optional/ Default value Possible values Description
Name Mandatory The name of an existing AMB client. Client name used for communication with FRONT ARENA. For more information, see Configuring the application.

WMQQueueMan ager

Mandatory The name of an existing WebSphere MQ queue manager. WebSphere MQ queue manager used for communication with target application. For more information, see Communicating with the WBI adapter.
WMQChannel Mandatory

<channel/ <transport>/ hostname(port)

WebSphere MQ channel used for communication with the given queue manager/ Transport (which usually is TCP) / URL of the system hosting the queue manager + queue manager listener port.
For more information, see Configuring the application.

WMQQueue Mandatory The name of an existing WebSphere MQ queue owned by the given queue manager. The WebSphere MQ queue used to forwarding event messages to the target application.
For more information, see Configuring the application.
WMQUserID Optional A user ID which is known to the given queue manager. The user ID to be used in messages sent by the bridge.
WMQRetries Optional
Default: 3
Integer value;
Negative values mean: Retry forever.
The number of retries for the times that the WebSphere MW connection cannot be established or drops.
WMQRetry Interval Optional
Default: 60000
Integer value > 0 The time (in milliseconds) between successive retries to establish a WebSphere MQ connection.

Event subscription and filtering

FRONT ARENA publishes event notifications under topics. A topic consists of the following parts:

Note:
An update to a TRADE object would be published under the topic, AMBA/TRADE (assuming that AMBA is the prefix from 1).

A client application subscribing to this single topic would get notifications about any changes to TRADE objects but would not notice any modifications of INSTRUMENT objects. Instances of stanza EventHandler and Filter are primarily used to tell the bridge component of the adapter which topics it has subscribed to. If the event filtering defined this way is too coarse-grained, additional filtering criteria can be specified in this stanza.

Each event notification message contains the following attributes:

In the example above, the TYPE would be UPDATE_TRADE and the SOURCE could be, for example, ProdAmba. The additional filter criteria which can be specified in this stanza use these two message attributes. They allow the bridge to be configured so that it only forwards event notifications caused by the update of a TRADE object and published by ProdAmba. In our example, this is accomplished with the following settings:

Stanza EventHandler/Filter<n> (<n> being an integer value):

Table 23. Event notifications

Keyword Mandatory/ Optional/ Default Possible Values Description
Topics Mandatory Any FRONT ARENA topic name (for example, EXT/TRADE). FRONT ARENA topics (separated by semicolons) that the bridge will subscribe to.
Sources Optional Any FRONT ARENA source name (for example, AMBA). Only messages from these sources (separated by semicolons) will be considered.
Objects Optional Any FRONT ARENA object (for example, TRADE). These objects (separated by semicolons) shall be considered only. Note: This is the second token from the <operation>_<object type> pair described above.
Verbs Optional Any FRONT ARENA verb (which are INSERT, UPDATE, and DELETE). Only these verbs (separated by semicolons) are considered.
Note: This is the first token from the <operation>_<object type> pair described above.

Several instances of this stanza (with names EventHandler/Filter1, EventHandler2, and so on) can be specified.

As described above, each stanza defines a filter. The set of events subscribed to in the Topics property can be restricted by the following parameters: Sources, Objects, and Verbs. If several stanzas are provided, the set of events forwarded by the bridge component of the adapter is the union of the sets specified by the different stanzas. All properties of this stanza may have multiple values, separated by semicolons.

Copyright IBM Corp. 1997, 2004