When you mediate a service integration bus destination,
your mediation runs in a bus member and you specify a combination
of mediation points and queue points to handle the messages that are
mediated. When you interoperate with WebSphere® MQ by using WebSphere MQ server, you can use one
of several mediated exchange scenarios.
Queue-type destinations assigned to a WebSphere MQ server bus member can be
mediated in the same way as destinations assigned to other bus members.
In addition to the mediation task described in Mediating a destination by using a WebSphere MQ queue as the mediation point, WebSphere MQ server supports other mediation
scenarios that you also set up by using the administrative console
Mediation wizard.
Note: Although WebSphere MQ server
extends the way in which queue-type destinations can be mediated,
the way in which topic spaces are mediated does not change.
To mediate a service integration bus destination, you must specify
a mediation point, a queue point and a mediation execution point:
- Mediation point
- The location where messages are placed before they are mediated.
It can be either a service integration bus member (an application
server or a cluster) or a WebSphere MQ queue.
- Queue point
- The location where messages are placed after they have been mediated.
It can be either a service integration bus member (an application
server or a cluster) or a WebSphere MQ queue.
If there is a default forward routing path and the destination is
a queue type destination, the queue point is unused. If the destination
is a service type destination, the queue point is absent.
- Mediation execution point
- The server where the mediation process runs. If the mediation
point is a service integration bus member then the mediation execution
point is the same bus member as the mediation point.
For more information, see
WebSphere MQ queue points and mediation points.
WebSphere MQ server supports the
following mediated exchange scenarios:
- Scenario 1: A WebSphere MQ mediation
point and a service integration queue point. In this case, you must
specify the mediation execution point.
- Scenario 2: A WebSphere MQ mediation
point and a WebSphere MQ queue point.
In this case, you can use a service integration mediation; you must
specify the mediation execution point when you configure the mediation,
as for scenario 1.
- Scenario 3: A service integration mediation point and a WebSphere MQ queue point. In this case,
you do not have to specify the mediation execution point; WebSphere Application Server automatically
allocates the bus member in which the mediation runs.
- Scenario 4: Alternatively, you can use a WebSphere MQ application or a message
broker flow to mediate the destination. In this case, the application
or broker flow retrieves messages from the mediation point (which
is a WebSphere MQ queue), mediates
the messages, then places the mediated messages on the queue point
(which is also a WebSphere MQ queue).
You do not specify a mediation execution point when you configure
the mediation; instead, you specify that there is an external mediation
process.
For a queue point, message producers place messages on the queue
point and consumers receive messages from the queue point. For a mediation
point, message producers place messages on the mediation point. The
messages are mediated then put on a post-mediation queue point. Consumers
receive messages from the post-mediation queue point.
Figure 1. Queue-type destinations assigned to a service integration
bus member.
Queue points and mediation points are queues
of service integration messages held in service integration 
For a queue point, message producers place messages on the queue
point and consumers receive messages from the queue point. If the
queue point is a WebSphere MQ queue
point, message producers place messages on the WebSphere MQ queue and consumers receive
the messages from the WebSphere MQ queue.
For a mediation point, message producers place messages on the mediation
point (a WebSphere MQ queue). The
messages are mediated, perhaps by an external message broker flow,
then put on a post-mediation queue point (another WebSphere MQ queue). Consumers receive
messages from the post-mediation queue point.
Figure 2. Queue-type destinations assigned to a WebSphere MQ
server bus member .
Queue points and mediation points
can be queues of WebSphere MQ messages
held in WebSphere MQ. A message broker,
or other WebSphere MQ application,
can run mediations externally. 
Scenario 1
In this scenario, you want to
mediate a conventional queue-type destination where the queue point
is a service integration queue point, and assign a WebSphere MQ queue as the mediation point
(the input side of the destination). As the mediation point is a WebSphere MQ queue, a queue point must
also be specified.
Messages arriving at the WebSphere MQ queue are processed by the
mediation running in an application server. When the messages have
been processed by the mediation, they are placed onto the service
integration queue point. The
mediation itself runs in the service integration bus member that is
assigned as the mediation point.
For this scenario, you must
complete the following steps using the Mediate destination wizard.
These example steps assume that the destination is assigned to a service
integration bus member:
- Navigate to the destinations collection panel for the bus that
hosts the destination you want to mediate.
- Select the queue-type destination that you want to mediate, then
click Mediate. This starts the Mediate destination
wizard.
- Step 1: Select the mediation that you want to use to mediate the
service integration destination.
- Step 2: Select a WebSphere MQ server
bus member to host the mediation point.
- Step 3: Enter details of the WebSphere MQ queue
that will be the mediation point.
- Step 4: Select a bus member where you want the mediation code
to run.
- Step 5: Review the summary of changes you are about to make, then
click Finish.
Scenario 2
In this scenario, you want to
mediate a WebSphere MQ queue type,
with a WebSphere MQ queue point,
and assign a WebSphere MQ queue as
the mediation point (the input side of the destination). As the mediation
point is a WebSphere MQ queue, a
mediation execution point must also be specified.
Messages arriving
at the destination are processed by the mediation, then placed on
the WebSphere MQ queue. The mediation
itself runs in the service integration bus member that is assigned
as the mediation point.
For this scenario, you must complete
the following steps using the Mediate destination wizard. These example
steps assume that the destination is assigned to a
WebSphere MQ server bus member:
- Navigate to the destinations collection panel for the bus that
hosts the destination you want to mediate.
- Select the queue-type destination that you want to mediate, then
click Mediate. This starts the Mediate destination
wizard.
- Step 1: Select the mediation that you want to use to mediate the
service integration destination.
- Step 2: Select a WebSphere MQ server
bus member to host the mediation point.
- Step 3: Enter details of the WebSphere MQ queue
that will act as the mediation point.
- Step 4: Select the service integration bus member where you want
the mediation to run.
- Step 5: Review the summary of changes you are about to make, then
click Finish.
Scenario 3
In this scenario, you want to
mediate a WebSphere MQ queue type
and assign a service integration mediation point.
Messages
arriving at the destination are processed by the mediation, then placed
on the WebSphere MQ queue. The mediation
itself runs in the service integration bus member that is assigned
as the mediation point.
For this scenario, you must complete
the following steps using the Mediate destination wizard. These example
steps assume that the destination is assigned to a WebSphere MQ
server bus member:
- Navigate to the destinations collection panel for the bus that
hosts the destination you want to mediate.
- Select the queue-type destination that you want to mediate, then
click Mediate. This starts the Mediate destination
wizard.
- Step 1: Select the mediation that you want to use to mediate the
service integration destination.
- Step 2: Select the service integration bus member to host the
mediation point. The mediation code also runs in this bus member.
- Step 3: Review the summary of changes you are about to make, then
click Finish.
Scenario 4
In this scenario, you want to
mediate a WebSphere MQ queue type
destination and assign a WebSphere MQ queue
as the mediation point (the input side of the destination).
The
mediation of messages is performed by an external process. Messages
arriving at the WebSphere MQ queue
are processed by the external process, then placed by the external
process on the WebSphere MQ queue-type
destination.
For this scenario, you must complete the following
steps using the Mediate destination wizard. These example steps assume
that the destination is assigned to a WebSphere MQ
server bus member:
- Navigate to the destinations collection panel for the bus that
hosts the destination you want to mediate.
- Select the queue-type destination that you want to mediate, then
click Mediate. This starts the Mediate destination
wizard.
- Step 1: Select an external process to use for mediating the destination.
- Step 2: Enter details of the WebSphere MQ queue
that you want to act as the mediation point.
- Step 3: Review the summary of changes you are about to make, then
click Finish.