An explanation of the most common terms that are used in this scenario.
- Message maps
- The data map type that you can create and edit in WebSphere® Message Broker Version 6.1 and Version
7.0. The file extension for a message map is .msgmap. Message maps are based on
ESQL code. They can be deployed, but they cannot be edited in WebSphere Message
Broker Version 8.0 or later.
- Graphical data maps
- The data map type that you can create and edit in WebSphere Message
Broker Version 8.0. The file extension for a
graphical data map is .map. The Graphical Data Mapping editor has a dedicated
runtime execution engine, instead of being just an ESQL code generation tool. Compared with message
maps, graphical data maps have the following benefits:
- Faster at runtime
- Increased reliability and stability
- Greater range of options for transforms
- Easier to create and edit in the Graphical Data Mapping editor
- Are created in a common component across other IBM®
products, such as WebSphere Application Server.
- Graphical Data Mapping editor
- The editor for graphical data maps. The Graphical Data Mapping editor is a component that is
part of WebSphere Message
Broker Version 8.0 and WebSphere Message Broker or later versions. It is also
available as a stand-alone component, and as a component in other IBM products, such as WebSphere
Application Server. The Graphical Data Mapping editor has a dedicated runtime execution engine that
uses the broker Java virtual machine, whereas message mapping used ESQL statements.
This change in underlying logic enables you to use a wider variety of transformations.
- Mapping node
- You can use the Mapping
node to construct one or more new messages and populate them with various types of information. The
Mapping node can transform a
message from one format to another, by using a message map or graphical data map. The Mapping node that is used in
Version 6.1 and Version 7.0 of WebSphere Message Broker is different from the Mapping node that is used in the
later versions. It must be replaced by the latest type to accept graphical data maps.
- Transforms
- Transforms that are used in the Graphical Data Mapping editor use different underlying logic
when compared to the types used in the message mapping editor. This change provides a wider range of
transforms. You might find that you have to think differently about what transforms you might need
in your messaging solutions, because ESQL map (esql:) functions are not used in graphical data
maps.
For example, a For statement in a message map that produces one output for
each input is converted to a ForEach transform in a graphical data map. It is flagged for review and
is explained in more detail on the Documentation tab of the
Properties view.
When a converted message map includes calls to
predefined ESQL map (esql:) functions, each of these calls is converted to an XPath
or Custom XPath transform. If there is no XPath equivalent of an ESQL map function, it is replaced
with a Task transform in your graphical data map. You must replace each of these Task transforms
with a Custom XPath, Custom Java, or Custom ESQL transform that re-creates the required
behavior.
- Task transforms
- Task transforms in a converted graphical data map indicate that further configuration is
required before the map can operate as intended. The Task transform is ignored at runtime.
Some
information is provided on the
Documentation tab to indicate the problem. When
you click a Task transform, in the
General tab you can define what problem
requires resolving by selecting from one of four options:
If the map is complex, you can use the Task transform like code comments to indicate
what further work needs to be done.