You can promote a node property to the message flow level to simplify
the maintenance of the message flow and its nodes, and to provide common values
for multiple nodes within the flow by converging promoted properties.
Before
you start
To complete this task, you must have completed the following
task:
- Switch to the Broker Application Development
perspective.
- Open the message flow for which you want to promote properties
by double-clicking the message flow in the Navigator view. You
can also open the message flow by right-clicking it in the Navigator view
and clicking Open The message flow
contents are displayed in the editor view.
If this is the first message
flow that you have opened, the message flow control window and the list of
available built-in message flow nodes are also displayed, to the left of the
editor view.
- In the editor view, right-click the symbol of the message flow
node whose properties you want to promote, and click Promote Property. The Property Promotion dialog is displayed. The left side of the dialog
lists all available properties for all the nodes within the message flow.
The properties for the node that you highlighted are expanded.
You can
access all node properties from this dialog, regardless of the node that you
selected when you first opened the dialog, by expanding the properties for
all the other nodes in the flow (these are initially collapsed).
The
right side lists all the properties that are currently promoted to the message
flow. If you have not yet promoted any properties, only the message flow name
as the root of the promoted property tree is displayed on the right.
The
majority of message flow node properties are available for promotion, but
you cannot promote:
- The properties that name ESQL and Mapping modules.
- A property group, but you can promote an individual property.
- A property that you cannot edit (for example, the Fix property
in the Validate group of properties for the MQInput node).
- The description properties (Short Description and Long Description).
- Create new groups and properties for promotion. Above
the list of promoted properties on the right, three icons are displayed: the
new group icon (on the left), the new property icon (in the middle), and the
delete icon (on the right):
When you create a new promoted property, the
name that you enter is the name by which the property is known within the
system, and must meet certain Java and XML naming restrictions. These are
enforced by the dialog, and a message is displayed if you enter a name that
includes a non-valid character. For example, you cannot include a space or
the double quote symbol.
If you are developing a message
flow within a user-defined project that will be delivered as an Eclipse plug-in,
you can add translation for the promoted properties that you have added. Translated
names can contain characters, such as space, that are restricted for system
names. The option to provide translated strings for promoted properties is
not available if you are working with a message flow within a message flow
project.
- Click the new group icon
to add a new group to the promoted properties. The group is added below the message flow root and is given the default
name Group1 (unless you have already created groups that have default names,
in which case the new group name has the next highest number). The name
field is highlighted; type over it to rename the group when it is created.
You can also rename the group at any later time by double-clicking the name.
- Click the new property icon
to add a new promoted property under the currently selected
group (or following the currently-selected property). The property
is added below the highlighted group and is given the default name Property1
(unless you have already created properties that have default names, in which
case the new property name has the next highest number). The name field
is highlighted; type over it to rename the property when it is created. You
can also rename the property at any time by double-clicking the name.
- Click the delete icon
to delete the currently-selected group or property. If you delete a group, all promoted properties within the group are
deleted from the list on the right. There is no confirmation of the delete
action. The deleted promoted properties are, however, returned to the list
on the left, where they are again available for promotion.
- Select the property that you want to promote to the message flow
level from the list of available properties on the left of the Property Promotion
dialog. The list on the left initially shows the expanded list
of all available properties for the selected node. If you have already promoted
properties from this node, they do not appear on the left, but on the right.
The
list on the left also includes the remaining nodes in this message flow. You
can expand the properties listed under each node and work with all these properties
at the same time. You do not have to close the dialog and select another node
from the editor view to continue promoting properties.
- Drag its entry from the list on the left of the Property Promotion
dialog to the list on the right, to promote a property from a message flow
node to the message flow:
- You can drop the property in an empty space. A
new group is automatically created for the message flow, and the property
is placed within it, with the original name of the property and the name of
the message flow node from which it came displayed beneath the property entry.
The
new group is given a name that defaults to Group1. If the group Group1 already
exists, the next default name is Group2, and so on. Rename the group by double-clicking
it and entering new text.
- You can drop it onto a group that already exists, to group together
related properties from the same or different nodes in the message flow. For example, you might want to group all promoted properties that relate
to database interactions.
- You can drop it onto a property that already exists, to converge
related properties from the same or different nodes in the message flow (this
is further described in Converging multiple properties) For example, you might want to create a single promoted property that
overrides the property on each node that defines a data source.
You can rename the promoted property (see Renaming a promoted property), but you cannot update its original identification. This
ensures that you can always determine the specific node or nodes that are
the origin of each promoted property, regardless of the name of the promoted
property.
- When you have selected the properties that you want to promote
to the message flow, click OK Your updates
are committed, and the dialog is closed. If you click Apply,
this commits the changes but leaves the Property Promotion dialog open.
When
you have promoted a property, you can no longer make any changes to that property
through the node properties dialog. You can only update its value at the message
flow level.
The message flow node properties are now promoted to the message
flow. If you want to confirm this, right-click the message flow in the Navigator
view, or right-click the editor view, and select Properties.
The
Properties dialog of the message flow is displayed, showing the message flow
node properties that you have promoted, organized in the groups that you have
created. If you now set a value for one of these properties, that value appears
as the default value for the property whenever the message flow is itself
included in other message flows.
When you select an embedded message
flow within another message flow (a subflow) and view its properties, you
see the promoted property values. If you look inside the embedded flow (that
is, if you select Open Subflow), you see the original
values for the properties. The value of a promoted property does not replace
the original property, but it takes precedence when you deploy the message
flow.