IBM Integration Bus, Version 9.0.0.8 Operating Systems: AIX, HP-Itanium, Linux, Solaris, Windows, z/OS

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DecisionService node

Use the DecisionService node to create a set of business rules.

The following sections describe the DecisionService node:

Purpose
How to use this node in a message flow
Terminals
Properties
Local environment fields

Purpose

A decision service is a collection of business rules that process a message. A DecisionService node implements those business rules to provide operations like routing, validation, and transformation. An example of a business rule for a bank is that a credit check is not required when an account is opened for an existing customer. These business rules are organized in a decision service file (.rules). When you deploy the BAR file that contains your decision service, the decision service is compiled into a rule set (.ruleset). You can store a decision service in an application, library, or integration project.

Note: The DecisionService node allows IBM® Integration Bus to call business rules that run on a component of IBM Decision Server that is provided with IBM Integration Bus. The IBM Integration Bus license entitles you to use this component only through the DecisionService node and only for development and functional test. To use the IBM Decision Server component beyond development and functional test, you must purchase a separate license entitlement for either IBM Decision Server or IBM Decision Server Rules Edition for Integration Bus. For more information, see Developing business rules.

The DecisionService node is contained in the Business Decisions drawer of the message flow node palette, and is represented in the IBM Integration Toolkit by the following icon:

How to use this node in a message flow

The New Decision Service wizard, which is used to create a decision service, can be opened in the following ways:

Double-click the DecisionService node.
Click File > New > Decision Service.
Right-click an application, library, or integration project, then click New > Decision Service.
In the Application Development view, click New, then click Decision Service.

If you open the wizard from a DecisionService node, the decision service is associated with that node. You can then use the node in a message flow to control operations like routing, validation, or transformation. If you create the decision service from a menu option, you can drag the decision service onto a DecisionService node to configure the node. You can also associate an existing decision service with a node by using the Decision Service property of the node.

Look at the following sample to see how to use this node:

Business Rules

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.

Terminals

The DecisionService node terminals are described in the following table.

Terminal	Description
In	The input terminal that accepts a message for processing by the node.
Out	The output terminal to which the original message can be routed when processing completes successfully.
Failure	The output terminal to which the message is routed if a failure is detected during processing.

Properties

When you put an instance of the DecisionService node into a message flow, you can configure it. For more information, see Configuring a message flow node. The properties of the node are displayed in the Properties view. All mandatory properties for which you must enter a value (those properties that do not have a default value defined) are marked with an asterisk.

If you double-click the DecisionService node, and it does not have an associated decision service file, you open the New Decision Service wizard. If the node does have an associated decision service file, double-clicking the node opens the file in the Decision Service editor, where you edit your rules.

The following tables describe the node properties. The column headed M indicates whether the property is mandatory (marked with an asterisk if you must enter a value when no default is defined). The column headed C indicates whether the property is configurable (you can change the value when you add the message flow to the BAR file to deploy it).

The DecisionService node Description properties are described in the following table.

Property	M	C	Default	Description
Node name	Yes	No	The node type, DecisionService	The name of the node.
Short Description	No	No		A brief description of the node.
Long Description	No	No		Text that describes the purpose of the node in the message flow.

The DecisionService node Basic properties are described in the following table.

Property	M	C	Default	Description
Decision Service Name	Yes	No	None	To select an existing decision service, click Browse, then select the appropriate file from the available files. To create a decision service, double-click the node to open the New Decision Service wizard. When you complete the wizard, the Decision Service Name property is set to the name of the new decision service file.
Ruleset	Yes	No	None	This property is populated automatically when you select a decision service. A decision service that you create in IBM Integration Bus contains a single rule set. A decision service that is created from an imported rule application archive can contain multiple rule sets. In this case, you can select a rule set to view its parameters.
Parameters	Yes	No	None	A decision service rule set can contain one or more parameters. Most parameter values are read-only, except for the Data location value, where you must enter an XPath expression. The XPath expression specifies the location in the inbound message of the data for each parameter; for example, `$Root`. To set the data location, select a parameter, then click Edit. For help, open the XPath Expression Builder by clicking Edit or pressing Ctrl+Space. When you add data location XPath expressions, avoid accessing parent and child nested fields in a message tree. (A change that you make to a nested structure can be overwritten by a change to the parent structure.) The direction of the parameters can be IN, OUT, or INOUT. For decision services that are created in the IBM Integration Toolkit, only INOUT parameters are supported. For decision services that are created by importing a rule application archive from IBM Operational Decision Manager, IN, OUT, and INOUT parameters are supported. The Verbalization column contains a natural language name (or alias) for the parameter; for example, "the customer". This value is used to refer to the parameter when you write a rule. If the decision service was created by importing a rule application archive, the verbalization value is not visible. If the parameters in the decision service file change, an error message is shown in the Problems view to indicate that the parameters on the node do not match the parameters in the decision service file. To correct this error, reselect the decision service file and the rule set on the node.
Use DecisionServiceRepository configurable service	No	Yes	Cleared	If you are using rules that were created in IBM Operational Decision Manager, you can retrieve those rules at run time from an external repository. To connect to an external repository, you must configure the DecisionServiceRepository configurable service and select this property. If this check box is selected, the node retrieves rules from the external repository. If the check box is cleared, the node uses the local decision service. For more information, see Retrieving business rules at run time from an IBM Operational Decision Manager repository.

The Monitoring properties of the node are described in the following table.

Property	M	C	Default	Description
Events	No	No	None	Events that you have defined for the node are displayed on this tab. By default, no monitoring events are defined on any node in a message flow. Use Add, Edit, and Delete to create, change or delete monitoring events for the node; see Configuring monitoring event sources using monitoring properties for details. You can enable and disable events that are shown here by selecting or clearing the Enabled check box.

Local environment fields

When you run a decision service, information is written to the local environment in the LocalEnvironment.DecisionServices subtree. This information is described in the following table.

Element name	Data type	Description
decisionService	String	The fully qualified name of the decision service that is referenced by the node. If the decision service is in an application or library, this fully qualified name is prefixed with the application or library name.
ruleSet	String	The name of the rule set that is contained in the decision service.
rulesMatched	Integer	The number of rules that are triggered (matched) by the messages that are processed by the decision service.

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Last updated Friday, 21 July 2017