
Mastering JBoss Drools 6
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As we already know, the right-hand side of a rule in Drools may contain a combination of the following elements:
Java sentences: Any regular Java sentence that is allowed in a Java method can also be used on the right-hand side of a rule in Drools.
MVEL expressions: If the dialect of the rule is set to mvel
, MVEL expressions are enabled on the right-hand side of the rule in Drools.
Predefined variables and methods: Variables such as drools
and kcontext
and methods such as insert
, update
, and delete
are also allowed. The special modify(){}
structure could also be used on the right-hand side of the rule in Drools.
In the previous section, we introduced the notion of how, when compiled, the left-hand side of all the rules in a KIE Base is converted into a network of nodes. For the right-hand side of the rules, the situation is different. When a KIE Base is compiled, the right-hand side of each of the rules that it contains is converted into a Java class....