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BusinessRuleManager

The BusinessRuleManager class is the main class for working with the business rule groups, rule sets and decision tables.

The BusinessRuleManager has methods which allow for retrieving business rule groups by name, target namespace, or custom properties. It also has a method for publishing changes which have been made to business rule groups, rule sets, or decision tables.

The BusinessRuleManager class provides methods that support the following:

• Retrieve all of the business rule groups
• Retrieve business rule groups of a specific target namespace
• Retrieve business rule groups of a specific name
• Retrieve business rule groups of a specific name and target namespace
• Retrieve business rule groups which contain a specific property
• Retrieve business rule groups which contain specific properties
• Publish business rule groups

Figure 1. Class diagram for BusinessRuleManager and package

Rule Group Component Query

The rule group component can have user defined properties (name/value pairs) that can be used to narrow the list of business rule groups returned from the class. The fields that can be used in the query and in any combination are as follows:

• Business rule group component target name space
• Business rule group component name
• Property name
• Property value

Each property name can only be defined once per business rule group component.

The query function supported by this class is a small subset of the full SQL language. The user does not provide the SQL statement, but rather provides the values as parameters for a single property or a tree structure containing the information for a multi-property query in the form of nodes. There are logical operator nodes and property query nodes which all implement the QueryNode interface. The logical operator nodes specify the boolean operators (AND, OR, NOT). These are created through the QueryNodeFactory. As part of the creation of these logical operator nodes, the left and right operators must be specified with additional QueryNode classes. These nodes can either be a property query node or another logical operator node. If a property query node is passed, it will contain the property name, value and operator (EQUAL (==), NOT_EQUAL (!=), LIKE, or NOTLIKE). The overall QueryNode is parsed by the class and a query is performed on the underlying data in persistent storage.

Wildcard searches are supported when the LIKE and NOTLIKE operators are used. Both the ‘%’ and ‘_’ characters are supported in wildcard searches. The ‘%’ character is used when there are an infinite number of characters which are not known or should not be considered when searching.

For example if a search was to be performed for all business rule groups that have a property with a name of Department and value that begins with “North”, the value would be specified as “North%”. Another example, suppose that all Departments with a value ending in “Region” was required. The value would be “%Region”. The ‘%’ character can also be used in the middle of a string.

For example, if there were business rule groups with properties that had values of “NorthCentralRegion”, “NorthEastRegion”, and “NorthWestRegion”, a value of “North%Region” could be specified.

The ‘_’ character is used when there is a single character which is unknown or should not be considered when searching.

For example, if a search for all business rule groups with Department properties with values of “Dept1North”, “Dept2North”, “Dept3North”, and “Dept4North” was required, a value of “Dept_North” could be specified and all 4 of the business rule groups with these properties will be returned. The ‘_’ character can be used multiple times in a search value with each instance indicating a single character to ignore. The ‘_’ character can be used at the beginning or end of a value.

For example if two characters were to be ignored in a value, two ‘_’ could be used such as “Dept__outh”.

In order to treat ‘%’ and ‘_’ as literal characters and not wildcards a ‘\’ escape character must be specified preceding the ‘%’ or ‘_’.

For example if the property name was “%Discount”, in order to use this in a query, “\%Discount” would need to be specified. If the ‘\’ character is to be used as a literal character, another ‘\’ escape character must be used such as “Orders\\Customer”. If a single ‘\’ character is found without a following ‘%’, ‘_’, or ‘\’, an IllegalArgumentException will be thrown.

Wildcard characters can only be used on the left operator (property value). Wildcard characters cannot be used in property name.

During searches on the value of a specific property or a search for values which do not match a property, the absence of a property causes the artifact to be ignored from consideration in the search.

For example, if there are 3 business rule groups (A, B, and C) and only two (A and B) have a property named “Department” with different values (either “Accounting” or “Shipping”) a search for all business rule groups which do not have a “Department” property of “Accounting” will only return the business rule group which has the “Department” property defined but does not equal “Accounting” (business rule group B). The business rule group (C) which does not have the “Department” property, will not be returned as it does not have the property defined in any way.

When using properties for searching, there are two special properties named IBMSystemName and IBMSystemTargetNameSpace which can be used for searching based on the name and namespace of an artifact. These values can also be retrieved with the getName and getTargetNameSpace methods.

The class supports the following methods for query:

List  getBRGsByTNS (string tNSName, Operator op, int skip, int threshold)
List  getBRGByName(string Name, Operator op, int skip, int threshold)
List  getBRGsByTNSAndName (string tNSName, Operator, tNSOp, string
	name, Operator nameOp, int skip, int threshold)
List  getBRGsBySingleProperty (string propertyName, string propertyValue, 	Operator op, int skip, int threshold)
List  getBRGsByProperties (QueryNode queryTree, int skip, int threshold)

The ‘skip’ and ‘threshold’ parameters provide the user the capability of fetching a partial result list up to the specified threshold. A value of zero for both of these parameters will return the full result list. The cursor is not maintained in the result set from a query call. If a skip value is used, it is possible that additions or deletions could have been made to the result set such that a subsequent request will return business rule groups which were in an earlier result set.

Figure 2. Class diagram for QueryNodeFactory and related classes

The nodes in the tree allow the user to specify a search expression using the boolean operators, wild cards (% and escape) and the property/value pair. The operator is only valid for the values, the operator for the property is always equals (==).

Publishing

Publishing of business rule changes is done at the business rule group component level. The user can publish 1…n business rule group components. Before a publish operation is performed, a validate action is performed on the business rule group and the different objects contained in the business rule group (operation selection table, rule sets, decision table, and so on). Each publish request will occur within a single transaction and if any exceptions are encountered during validation or database publishing the transaction is rolled back and no changes for any business rule group are published to the repository. This allows changes that are dependent on each other within a single component (for example, operation selection table and a rule set) or dependencies between components to occur within one atomic operation.

At publishing time, a check will be made to ensure that the items which are to be published have not been changed by another transaction. To reduce the possibilities of a conflict, the publish method will give the user the ability to choose to publish all artifacts whether they are changed or not or only those artifacts that were changed within the business rule group. The default behavior will be to publish all artifacts. If the option is set to publish all artifacts and another transaction had changed the artifacts in the meantime, a ChangeConflictException will be thrown. Specifying to only publish those artifacts which have changed will reduce the chance of conflict. Publishing only those artifacts that were changed could result in two users pushing changes to the repository for two different artifacts within a business rule group (for example, two rule sets) which could introduce incompatible changes within the business rule group. Because this potential situation, this option should be used with caution.

Programming model