rulii Documentation

Zero

Dependencies

Build Styles

39+

Built-in Validation Rules

Java 17+

Minimum Version

See How Simple It Is

Define business rules in clean, readable Java — then orchestrate them with a RuleFlow.

// Build a Rule using lambdas
Rule rule = Rule.builder()
    .given(condition((Boolean member, BigDecimal total)
        -> member && total.compareTo(BigDecimal.valueOf(100)) > 0))
    .then(action((Binding<BigDecimal> discount)
        -> discount.setValue(BigDecimal.valueOf(0.10))))
    .build();

// Run with auto-matched Bindings
rule.run(member -> true, total -> BigDecimal.valueOf(150));

// Orchestrate rules with a RuleFlow — new in 2.0
RuleFlow<BigDecimal> flow = RuleFlow.builder()
    .name("DiscountFlow")
    .param("member", Boolean.class)
    .param("total", BigDecimal.class)
    .bind(discount -> BigDecimal.ZERO)
    .run(discountRule)
    .<BigDecimal>returning(function((BigDecimal discount) -> discount))
    .build();

// Validated inputs, orchestration & result extraction — built in
BigDecimal discount = flow.run(member -> true, total -> BigDecimal.valueOf(150));

@Rule
public class DiscountRule {

    @Given
    public boolean isEligible(Boolean member, BigDecimal total) {
        return member && total.compareTo(BigDecimal.valueOf(100)) > 0;
    }

    @Then
    public void applyDiscount(Binding<BigDecimal> discount) {
        discount.setValue(BigDecimal.valueOf(0.10));
    }
}