What is Dvare?

The dvare-framework is a Java business rule expression language. The dvare-framework contains set of predefined which helps non-technical background peoples to describe business logic in the real domain.

Dependency

The artifact dvare-framework is published is a central repository. In order to use snapshot versions, you need to add the following maven repository in your pom.xml:

<repository>
    <id>ossrh</id>
    <url>https://oss.sonatype.org/content/repositories/snapshots</url>
</repository> 

<dependency>
    <groupId>org.dvare</groupId>
    <artifactId>dvare-framework</artifactId>
    <version>2.3.0</version>
</dependency>
    

Configuration

Java config:

RuleConfiguration ruleConfiguration= new RuleConfiguration(new String[]{"org.dvare.function"});

Spring Integration:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="ruleEngine" class="org.dvare.spring.DvareConfigFactoryBean">
        <property name="functions">
        </property>
            <list>
                 <value>org.dvare.function</value>
            </list>
    </bean>
</beans>

Rule Engine

ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");
RuleConfiguration ruleConfiguration = context.getBean(RuleConfiguration.class);

Data Types & Predefined Operations

Data Types

The dvare framework has all common data types. Following is the table giving details about all the data types available in the dvare framework.

Predefined Operations

The dare framework defines a number of operations on the data types. Following is the table giving details of the predefined operations on the data types.

Operators

The dvare framework is rich in built-in operators and provides the arithmetic, relational, logical, assignment operations.

Arithmetic Operations

Logical Operations

Relational Operations

Function Invocation

The Dvare Frameworkallows to invoke java methods inside the rule. For Invocation you need to register class methods. For Registration annotate Java class with @FunctionService and annotate method with @FunctionMethod with return type and parameters elements. You also need to define package in rule configuration which use to scan these classes at run time.

RuleConfiguration factory = new RuleConfiguration(new String[]{"org.dvare.function"});

package org.dvare.function;
@FunctionService
public class TestFunction {
    @FunctionMethod(returnType = DataType.IntegerType, list = false, parameters = {DataType.IntegerType})
    public Integer testFunction(Integer variable) {
        System.out.println("inside testFunction with argument value: " + variable);
        return variable;
    }
}

Example

      public class DvareRuleTest extends TestCase {
            SimpleDateFormat dateTimeFormat = new SimpleDateFormat("dd-MM-yyyy-HH:mm:ss");
            SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");

            @Test
             public void testApp() throws ExpressionParseException, InterpretException, ParseException {
                RuleConfiguration factory = new RuleConfiguration(new String[]{"org.dvare.function"});

                String exp = "Variable2 = (1 + 2) " +
                " And Variable0 <= fun( testFunction , 10 ) " +
                " And Variable1 in ['A','B'] " +
                " And Variable2 between [2,4]" +
                " And Variable3 > 3.0 " +
                " And Variable4 = false " +
                " And Variable5 in [12-05-2016,13-05-2016] " +
                " And Variable6 in [12-05-2016-15:30:00,13-05-2016-15:30:00] " +
                " And Variable7 in [R'B1.*',R'A1.*'] ";

                Expression expression = factory.getParser().fromString(exp, EqualOperation.class);
                Rule rule = new org.dvare.binding.rule.Rule(expression);

                EqualOperation equalOperation = new EqualOperation();
                equalOperation.setVariable0(10);
                equalOperation.setVariable1("A");
                equalOperation.setVariable2(3);
                equalOperation.setVariable3(3.2f);
                equalOperation.setVariable4(false);
                equalOperation.setVariable5(dateFormat.parse("12-05-2016"));
                equalOperation.setVariable6(dateTimeFormat.parse("12-05-2016-15:30:00"));
                equalOperation.setVariable7("A1B2");

                RuleEvaluator evaluator = factory.getEvaluator();
                boolean result = evaluator.evaluate(rule, equalOperation);
                assertTrue(result);
             }
      }

      package org.dvare.function;
      @FunctionService
      public class TestFunction {
        @FunctionMethod(returnType = DataType.IntegerType, list = false, parameters = {DataType.IntegerType})
         public Integer testFunction(Integer variable) {
               System.out.println("inside testFunction with argument value: " + variable);
               return variable;
        }
      }