Builder Pattern Reference - rulii Documentation

Almost everything in rulii is built using the builder pattern. This page is a quick reference for all builders and the static helper methods you'll use most often.

All Builders at a Glance

What You're Building	How to Start
Bindings container	`Bindings.builder().standard()`
Scoped Bindings	`Bindings.builder().scoped()`
Individual Binding	`Binding.builder().with("name").value("Alice").build()`
RuleContext	`RuleContext.builder().build(bindings)`
Condition	`condition((x) -> ...)`
Action	`action(() -> ...)`
Rule (lambda)	`Rule.builder().name("...").given(...).then(...).build()`
Rule (from class)	`Rule.builder().build(MyRule.class)`
Rule (from instance)	`Rule.builder().build(new MyValidationRule("field"))`
RuleSet	`RuleSet.builder().with("Name").rule(...).build()`
RuleFlow (new in 2.0.0)	`RuleFlow.builder().name("Name").run(...).build()`
MessageFormatter	`MessageFormatter.builder().build()`
MessageResolver	`MessageResolver.builder("baseName").build()`
RuleViolation	`RuleViolation.builder().build("rule", "code", "message")`

New Builder Methods in 2.1.0

2.1.0 adds descriptive metadata methods across the builders. None of them affect execution — they land on the built definition for tools that read it (see Introspection & Metadata).

Method	Available On	Purpose
`category(String)` (new in 2.1.0)	Rule, validation rule, value validation rule, rule set, rule flow	At most one descriptive category; `/` separates hierarchy levels (`"Pricing/Discounts"`)
`tags(String...)` / `tags(Collection)` (new in 2.1.0)	Rule, validation rule, value validation rule, rule set, rule flow	Any number of descriptive tags; `tags(...)` adds to what was given before
`source(SourceDefinition)` (new in 2.1.0)	Rule, validation rule, value validation rule, rule set, rule flow	Explicit source for loaders that know where an artifact was declared; create with `SourceDefinition.forFile(fileName, line)` or `forClass(type)`
`param(name, type, required, description)` / `param(name, type, defaultValue, description)` (new in 2.1.0)	Rule set, rule flow	Declare an input parameter with a description, recorded on the definition's `InputParameter`
`returning(Class<T>, Function<T>)` (new in 2.1.0)	Rule flow	Result extractor plus an explicit result type, for when the extractor's declared return type isn't specific enough

Static Helper Imports

These static imports let you write concise lambda-based conditions, actions, and functions:

import static org.rulii.model.condition.Conditions.condition;
import static org.rulii.model.action.Actions.action;
import static org.rulii.model.function.Functions.function;

Usage Examples

condition() — Creates a Condition

// No parameters
condition(() -> true)

// With parameters (matched by name to bindings)
condition((String name) -> name != null)
condition((Integer age, String status) -> age >= 18 && "active".equals(status))

action() — Creates an Action

// No parameters
action(() -> System.out.println("Done!"))

// Modify a binding value
action((Binding<Integer> count) -> count.setValue(count.getValue() + 1))

// Add new bindings
action((Bindings bindings) -> bindings.bind("result", 42))

function() — Creates a Function (returns a value)

// Return a constant
function(() -> "hello world!")

// Return a computed value from bindings
function((String firstName, String lastName) -> firstName + " " + lastName)

Built-in Constants

// A condition that always returns true
Conditions.TRUE()

// An action that does nothing
Actions.EMPTY_ACTION()

Cheat Sheet

// Quick rule with lambda

Rule.builder().name("R1").given(condition(...)).then(action(...)).build()

// Quick rule from annotated class

Rule.builder().build(MyRule.class)

// Quick validation rule

Rule.builder().build(new NotNullValidationRule("field"))

// Quick rule set

RuleSet.builder().with("Name").rule(r1).rule(r2).build()

// Quick rule flow (the recommended way to run rules)

RuleFlow.builder().name("Flow").run(ruleSet).build()

// Quick run with lambda bindings

flow.run(name -> "Alice", age -> 30)