Base Semantic Module

The Base Semantics Module provides a base language for building a RuleSet in XML. By itself, the base semantic module is not capable of writing a complete and valid rule file. It must be used in conjunction with other semantic modules. This can be the Java semantic module, the Groovy semantic module, the Python semantic module, or a custom, domain-specific semantic module you've written specifically for your problem domain.

Syntax Guide

rule-set element

Each DRL file must have exactly one rule-set element, which must be uniquely named in the rule base and declare the appropriate namespace bindings for semantic module lookup and schema validation; see Semantics Module Framework and Schema Validation.

import element

Imports can be specified which are then available to any element that references a Class.

The body of the element can be either a fully qualified import :

Or a dynamic on demand import:

application-data element

Application Data elements allow objects to be made available to conditions and consequences without the need to assert them into the Working Memory.

Application data cannot be set that is not declared in the{{rule-set}} of the rule base. To set application data:

To declare application data inside a rule-set:

rule element

Each rule-set must contain at least one rule element. Each rule element must be uniquely named in the rule-set, and may contain optional salience and no-loop attributes. no-loop is currently ignored if the duration element is specified.

parameter element

Each rule element must contain at least one parameter element, which must use a unique name for the identifer attribute within the rule scope. By itself, the parameter element can do nothing. It requires a nested element representing an ObjectType, like class, class-field and semaphore object (or one from your own semantic module).

class element

The class element is an ObjectType implementation to be used inside a parameter element. It has no attributes and its contents is either a fully qualified class or a class name available from a previously imported package.

class-field element

The class-field element is an ObjectType implementation to be used inside a parameter element. It not only constrains the parameter to a Class, like the class element, but it also constrains to a given value for the specified field. The field is limited to String types and the value is also a static String.

This is akin to saying:

semaphore element

The semaphore element is a specialised ObjectType implementation to be used inside a parameter element. It provides global named variables, where the identifier is the global name, for use within rules; this can be useful for control execution.

To assert a semaphore without an initial value:

To assert a semaphore with an initial value:

To specify a semaphore within a parameter

The following supported semaphore types are:

• CharSemaphore
• DoubleSemaphore
• FloatSemaphore
• IntegerSemaphore
• ListSemaphore
• LongSemaphore
• MapSemaphore
• SetSemaphore
• ShortSemaphore
• StringSemaphore

duration element

The duration element enables Temporal Rules where Activations fire after a given time if they are still true. A duration can have can have one or more unit of time, but must specify atleast one. no-loop is currently ignored if the duration element is specified.

See Also

Base Semantic Module
Java Semantic Module
Groovy Semantic Module
Python Semantic Module