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Chapter 8. Working With Rules
8.1. What's in a Rule File
8.1.1. A rule file
A rule file is typically a file with a .drl extension. In a DRL file you can have multiple rules, queries and functions, as well as some resource declarations like imports, globals, and attributes that are assigned and used by your rules and queries. However, you are also able to spread your rules across multiple rule files (in that case, the extension .rule is suggested, but not required) - spreading rules across files can help with managing large numbers of rules. A DRL file is simply a text file.
8.1.2. The structure of a rule file
The overall structure of a rule file is the following:
Example 8.1. Rules file
package package-name
imports
globals
functions
queries
rules
The order in which the elements are declared is not important, except for the package name that, if declared, must be the first element in the rules file. All elements are optional, so you will use only those you need.
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