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public interface RulesEngineListener {
    /**
     * Triggered before evaluating the rule set.
     * <strong>When this listener is used with a {@link InferenceRulesEngine},
     * this method will be triggered before the evaluation of each candidate rule
     * set in each iteration.</strong>
     *
     * @param rules to fire
     * @param facts present before firing rules
     */
    default void beforeEvaluate(Rules rules, Facts facts) { }
    /**
     * Triggered after executing the rule set
     * <strong>When this listener is used with a {@link InferenceRulesEngine},
     * this method will be triggered after the execution of each candidate rule
     * set in each iteration.</strong>
     *
     * @param rules fired
     * @param facts present after firing rules
     */
    default void afterExecute(Rules rules, Facts facts) { }
}

public interface RulesEngine {
    /**
     * Return the rules engine parameters.
     *
     * @return The rules engine parameters
     */
    RulesEngineParameters getParameters();
    /**
     * Return the list of registered rule listeners.
     *
     * @return the list of registered rule listeners
     */
    default List<RuleListener> getRuleListeners() {
        return Collections.emptyList();
    }
    /**
     * Return the list of registered rules engine listeners.
     *
     * @return the list of registered rules engine listeners
     */
    default List<RulesEngineListener> getRulesEngineListeners() {
        return Collections.emptyList();
    }
    /**
     * Fire all registered rules on given facts.
     */
    void fire(Rules rules, Facts facts);
    /**
     * Check rules without firing them.
     * @return a map with the result of evaluation of each rule
     */
    default Map<Rule, Boolean> check(Rules rules, Facts facts) {
        return Collections.emptyMap();
    }
}

public class RulesEngineParameters {
    /**
     * Default rule priority threshold.
     */
    public static final int DEFAULT_RULE_PRIORITY_THRESHOLD = Integer.MAX_VALUE;
    
    /**
     * Parameter to skip next applicable rules when a rule is applied.
     */
    private boolean skipOnFirstAppliedRule;
    /**
     * Parameter to skip next applicable rules when a rule is non triggered
     */
    private boolean skipOnFirstNonTriggeredRule;
    /**
     * Parameter to skip next applicable rules when a rule has failed.
     */
    private boolean skipOnFirstFailedRule;
    /**
     * Parameter to skip next rules if priority exceeds a user defined threshold.
     */
    private int priorityThreshold;
    /**
     * Create a new {@link RulesEngineParameters} with default values.
     */
    public RulesEngineParameters() {
        this.priorityThreshold = RulesEngineParameters.DEFAULT_RULE_PRIORITY_THRESHOLD;
    }
    /**
     * Create a new {@link RulesEngineParameters}.
     *
     * @param skipOnFirstAppliedRule parameter to skip next applicable rules on first applied rule.
     * @param skipOnFirstFailedRule parameter to skip next applicable rules on first failed rule.
     * @param skipOnFirstNonTriggeredRule parameter to skip next applicable rules on first non triggered rule.
     * @param priorityThreshold threshold after which rules should be skipped.
     */
    public RulesEngineParameters(final boolean skipOnFirstAppliedRule, final boolean skipOnFirstFailedRule, final boolean skipOnFirstNonTriggeredRule, final int priorityThreshold) {
        this.skipOnFirstAppliedRule = skipOnFirstAppliedRule;
        this.skipOnFirstFailedRule = skipOnFirstFailedRule;
        this.skipOnFirstNonTriggeredRule = skipOnFirstNonTriggeredRule;
        this.priorityThreshold = priorityThreshold;
    }
    public int getPriorityThreshold() {
        return priorityThreshold;
    }
    public void setPriorityThreshold(final int priorityThreshold) {
        this.priorityThreshold = priorityThreshold;
    }
    public RulesEngineParameters priorityThreshold(final int priorityThreshold) {
        setPriorityThreshold(priorityThreshold);
        return this;
    }
    public boolean isSkipOnFirstAppliedRule() {
        return skipOnFirstAppliedRule;
    }
    public void setSkipOnFirstAppliedRule(final boolean skipOnFirstAppliedRule) {
        this.skipOnFirstAppliedRule = skipOnFirstAppliedRule;
    }
    public RulesEngineParameters skipOnFirstAppliedRule(final boolean skipOnFirstAppliedRule) {
        setSkipOnFirstAppliedRule(skipOnFirstAppliedRule);
        return this;
    }
    public boolean isSkipOnFirstNonTriggeredRule() {
        return skipOnFirstNonTriggeredRule;
    }
    public void setSkipOnFirstNonTriggeredRule(final boolean skipOnFirstNonTriggeredRule) {
        this.skipOnFirstNonTriggeredRule = skipOnFirstNonTriggeredRule;
    }
    public RulesEngineParameters skipOnFirstNonTriggeredRule(final boolean skipOnFirstNonTriggeredRule) {
        setSkipOnFirstNonTriggeredRule(skipOnFirstNonTriggeredRule);
        return this;
    }
    public boolean isSkipOnFirstFailedRule() {
        return skipOnFirstFailedRule;
    }
    public void setSkipOnFirstFailedRule(final boolean skipOnFirstFailedRule) {
        this.skipOnFirstFailedRule = skipOnFirstFailedRule;
    }
    public RulesEngineParameters skipOnFirstFailedRule(final boolean skipOnFirstFailedRule) {
        setSkipOnFirstFailedRule(skipOnFirstFailedRule);
        return this;
    }
    @Override
    public String toString() {
        return "Engine parameters { " +
                "skipOnFirstAppliedRule = " + skipOnFirstAppliedRule +
                ", skipOnFirstNonTriggeredRule = " + skipOnFirstNonTriggeredRule +
                ", skipOnFirstFailedRule = " + skipOnFirstFailedRule +
                ", priorityThreshold = " + priorityThreshold +
                " }";
    }
}

void fire(Rules rules, Facts facts);