README.md

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JARE

Just Another Rules Engine

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What is JARE?

JARE is just another rules engine! It is minimalistic library to provide a rules engine (JAREngine) to software clients. Clients are able to run individual rules or multiple rules using JAREngine.

Examples

1. Using simple rules:

Provide the class to the given method and feed the rule when you run it:

Rule rule = RuleBuilder.given(String.class)
        .then(s -> System.out.println("Hello " + s));

rule.run("JARE");

With a when clause:

Rule rule = RuleBuilder.given(String.class)
    .when(s -> "JARE".equals(s))
    .then(s -> System.out.println("Hello " + s));
    
rule.run("JARE");

We can also run in the same statement:

StringBuilder test = new StringBuilder();

RuleBuilder.given(StringBuilder.class)
    .when(s -> s.toString().isEmpty())
    .then(s -> s.append("Hello JARE"))
    .run(test);

System.out.println(test);

Let's throw an exception:

RuleBuilder.given(Boolean.class)
    .when(Boolean::booleanValue)
    .thenThrow(RuntimeException::new)
    .run(true);

2. Using JAREngine

You can chain multiple rules and fire the engine:

JAREngine.feed("JARE")
    .addRule(r -> r.when(String::isEmpty).then(s -> System.out.println("Oh no!")))
    .addRule(r -> r.when(s -> !s.isEmpty()).then(s -> System.out.println("Hello " + s)))
    .fire();

You can also feed the engine with multiple inputs using a List or variable arguments:

JAREngine.feed("JARE", "", "me")
    .addRule(r -> r.when(String::isEmpty).then(s -> System.out.println("Oh no!")))
    .addRule(r -> r.when(s -> !s.isEmpty()).then(s -> System.out.println("Hello " + s)))
    .fire();

Thank you for using JARE!

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