Typically, one of the basic tasks of managing a broker network is to partition the network so that certain queues and topics are restricted to a sub-domain, while messages on other queues and topics are allowed to cross domains. This kind of domain management can be achieved by applying filters at certain points in the network. Fuse Message Broker lets you define filters on network connectors in order to control the flow of messages throughout the network.
Fuse Message Broker allows you to control the flow of messages in two ways:
specifying which destinations' messages can pass through a connector
excluding messages for specific destinations from passing through a connector
Destination names are often segmented to denote how they are related. For example,
an application may use the prefix PRICE.STOCK to denote all of the destinations
that handle stock quotes. The application may then further segment the destination names
such that all stock quotes from the New York Stock Exchange were prefixed with
PRICE.STOCK.NYSE and stock quotes from NASDAQ used the prefix
PRICE.STOCK.NASDAQ. Using wildcards would be a natural way to create filters
for specific types of destinations.
Table 4.1 describes the characters can be used to define wildcard matches for destination names.
Table 4.1. Destination Name Wildcards
| Wildcard | Description |
|---|---|
. | Separates segments in a path name. |
* | Matches any single segment in a path name. |
> | Matches any number of segments in a path name. |
Table 4.2 shows some examples of destination wildcards and the names they would match.
Table 4.2. Example Destination Wildcards
| Destination wildcard | What it matches |
|---|---|
PRICE.> | Any price for any product on any exchange. |
PRICE.STOCK.> | Any price for a stock on any exchange. |
PRICE.STOCK.NASDAQ.* | Any stock price on NASDAQ. |
PRICE.STOCK.*.IBM | Any IBM stock price on any exchange. |
The default behavior of a network connector is to allow messages for all destinations to pass. You can, however, configure a network connector to only allow messages for specific destinations to pass. If you use segmented destination names, you can use wildcards to filter groups of destinations.
You do this by adding a dynamicallyIncludedDestinations child
to the network connector's networkConnector element. The included
destinations are specified using queue and
topic children. Example 4.1
shows configuration for a network connector that only passes messages destined for queues
with names that match TRADE.STOCK.> and topics with names that match
PRICE.STOCK.>.
Example 4.1. Network Connector Using Inclusive Filtering
<networkConnectors>
<networkConnector name="linkToBrokerB"
uri="static:(tcp://localhost:61002)"
networkTTL="3">
<dynamicallyIncludedDestinations>
<queue physicalName="TRADE.STOCK.>"/>
<topic physicalName="PRICE.STOCK.>"/>
</dynamicallyIncludedDestinations>
</networkConnector>
</networkConnectors>![[Important]](imagesdb/important.gif) | Important |
|---|---|
Once you add the |
Another way of partitioning a network and create filters is to explicitly specify a list destinations whose messages are not allowed to pass through a network connector. If you use segmented destination names, you can use wildcards to filter groups of destinations.
You do this by adding a excludedDestinations child
to the network connector's networkConnector element. The excluded
destinations are specified using queue and
topic children. Example 4.2
shows configuration for a network connector that blocks messages destined for queues
with names that match TRADE.STOCK.NYSE.* and topics with names that match
PRICE.STOCK.NYSE.*.
Example 4.2. Network Connector Using Exclusive Filtering
<networkConnectors>
<networkConnector name="linkToBrokerB"
uri="static:(tcp://localhost:61002)"
networkTTL="3">
<excludedDestinations>
<queue physicalName="TRADE.STOCK.NYSE.*"/>
<topic physicalName="PRICE.STOCK.NYSE.*"/>
</excludedDestinations>
</networkConnector>
</networkConnectors>You can combine inclusive and exclusive filtering to create complex network partitions. Example 4.3 shows a network connector that is configured to transmit stock prices from any exchange except the NYSE and transmits orders to trade stocks for any exchange except the NYSE.
Example 4.3. Combining Exclusive and Inclusive Filters
<networkConnectors>
<networkConnector name="linkToBrokerB"
uri="static:(tcp://localhost:61002)"
networkTTL="3">
<dynamicallyIncludedDestinations>
<queue physicalName="TRADE.STOCK.>"/>
<topic physicalName="PRICE.STOCK.>"/>
</dynamicallyIncludedDestinations>
<excludedDestinations>
<queue physicalName="TRADE.STOCK.NYSE.*"/>
<topic physicalName="PRICE.STOCK.NYSE.*"/>
</excludedDestinations>
</networkConnector>
</networkConnectors> |  | |
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