The local environment tree is used
by the broker, and you can refer to and modify this information. You
can also extend the tree to contain information that you create yourself.
You can create subtrees of this tree that you can use as a scratchpad
or working area.
The message flow sets up information in two
subtrees, Destination and WrittenDestination, below the LocalEnvironment
root. You can refer to the content of both of these subtrees, and
you can write to the Destination tree to influence the way in which
the message flow processes your message. However, if you write to
the Destination tree, follow the defined structure to ensure that
the tree remains valid.
The WrittenDestination subtree
contains the addresses to which the message has been written. Its
name is fixed and it is created by the message flow when a message
is propagated through the Out terminal of a request, output, or reply
node. The subtree includes transport-specific information (for example,
if the output message has been put to a
WebSphere® MQ queue, it includes the queue
manager and queue names). You can use one of the following methods
to obtain information about the details of a message after it has
been sent by the nodes:
- Connect a Compute node
to the Out terminal.
- Configure a user exit to process an output message callback event,
as described in Exploiting user exits.
The topic for each node that supports WrittenDestination information
contains details about the data that it contains.
If
you want the local environment tree to be included in the output message
that is propagated by the Compute node,
you must set the Compute node
property Compute mode to
a value that includes the local environment (for example, All). If you do not, the local
environment tree is not copied to the output message.
The information
that you insert into DestinationData or Defaults depends on the characteristic
of the corresponding node property:
- If a node property is represented by a check box (for example, New Message ID), set the Defaults
or DestinationData element to Yes (equivalent
to selecting the check box) or No (equivalent
to clearing the check box).
- If a node property is represented by a drop-down list (for example, Transaction Mode), set the Defaults
or DestinationData element to the appropriate character string (for
example Automatic).
- If a node property is represented by a text entry field (for example, Queue Manager Name), set the Defaults
or DestinationData element to the character string that you would
enter in this field.
If necessary, configure the sending node to indicate where
the destination information is. For example, for the output node MQOutput, set Destination Mode:
- If you set Destination Mode to Queue Name, the output message
is sent to the queue identified in the output node properties Queue Name and Queue Manager Name. Destination
is not referenced by the node.
- If you set Destination Mode to Destination List, the node extracts
the destination information from the Destination subtree. If you use
this value you can send a single message to multiple destinations,
if you configure Destination and a single output node correctly. The
node checks the node properties only if a value is not available in
Destination (as described above).
- If you set Destination Mode to Reply To Queue, the message is
sent to the reply-to queue identified in the MQMD in this message
(field ReplyToQ). Destination is not referenced by the node.
To find more information about ESQL procedures that perform
typical updates to the local environment, see Populating Destination in the local environment tree.
Review the ESQL statements in these procedures to see how to modify
the local environment. You can use these procedures unchanged, or
modify them for your own requirements.
To find more information
about how to extend the contents of this tree for your own purposes,
see Using scratchpad areas in the local environment.
For another
example of how you can use the local environment to modify the behavior
of a message flow, refer to the XML_PassengerQuery message flow in
the following sample program:
The
Compute node in
this message flow writes a list of destinations in the RouterList
subtree of Destination that are used as labels by a later
RouteToLabel node that propagates
the message to the corresponding
Label node.
You can view information about samples only when you use the product documentation that is integrated with the IBM® Integration Toolkit or the online product documentation. You can run samples only when you use the product documentation that is integrated with the IBM Integration Toolkit.
Last updated Friday, 21 July 2017