Die The Rule-Engine stellt die Basis-Technologien für die regelbasierte Verarbeitung einiger Komponenten bereit.
Diese wird unter anderem von der Rewrite-Komponente und der Transformations-Komponente verwendetprovides basic concepts for a rule-based processing for other compoents. For instance, it is used during rewriting and transformation of queries.

Components and semantics

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• If none of the rules of the current rule flow group was executed, the rule flow group is finished and the next rule flow group is started
• If at least one of the rules of the current group was executed, the current run of the grouped is discontinued and the whole group is started from the beginning. This means, rules that were not executable before are tested again.

Rules

Jede Regel ist einer RuleFlowGroup zugeordnet.
Bei einem Durchlauf der RuleFlowGroup wird folgendes für jede Regel in der RuleFlowGroup gemacht:

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• Nein: Prüfe das nächste Objekt im Working Memory
• Ja: führe die Methode isExecutable der Regel mit dem Objekt aus

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Each rules belongs to a RuleFlowGroup. Furthermore, each rule is responsible for a dedicated type, which is defined by a generic within the rule (this might be, for example, a certain operator).

For each run of a RuleFlowGroup, the following steps are performed for each rule of the group:

• It is checked, if one of the objects in the working memory fits to the dedicated type of the rule
  • If it does not match the type: check the next object in the working memory
  • If it matches the type: run the isExecutable method
    • if isExecutable returns false, break and run the rule for the next object in the working memory
    • if isExecutable returns true, run execute and (like it is written above) the RuleFlowGroup is restarted.

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