README.md

Yatomata Camel integration

This project aims to provide the ability to use Yatomata along with Camel.

User Guide

Setup

Add the following dependency to pom.xml of your Camel project:

    <dependency>
        <groupId>ru.yandex.qatools</groupId>
        <artifactId>yatomata-camel</artifactId>
        <version>1.0</version>
    </dependency>

Basics

Create the FSM class (for more information see Yatomata docs):

    @FSM(start = Stopped.class)
    @Transitions({
            @Transit(from = Stopped.class, on = Run.class, to = Running.class),
            @Transit(from = Running.class, on = Stop.class, to = Stopped.class, stop = true),
    })
    public class MyFSM {

    }

Add the aggregator bean to your Spring context:

    <bean id="myFSM" class="ru.yandex.qatools.fsm.camel.YatomataAggregationStrategy">
        <constructor-arg value="com.me.MyFSM"/>
    </bean>

Now you can use myFSM as an ordinary aggregation strategy:

    <aggregate strategyRef="myFSM">
        <correlationExpression>
            <simple>${in.body.uuid}</simple>
        </correlationExpression>
        <completionPredicate>
            <method bean="myFSM" method="isCompleted"/>
        </completionPredicate>
        <to uri="seda:queue:done"/>
    </aggregate>

You can also use the more declarative processors with the @Processor annotation. Create the processor class, declaring the separate methods for every body type of your message:

public class MyProcessor {
    @Processor(bodyType = String.class)
    public String process(@Body String body) {
        return body + "processed";
    }
}

Add the processor bean to your Spring context:

    <bean id="myProcessor" class="ru.yandex.qatools.fsm.camel.PluggableProcessor">
        <constructor-arg>
            <bean class="com.me.MyProcessor"/>
        </constructor-arg>
    </bean>

Now you can use myProcessor as an ordinary processor in your camel routes:

    <process ref="myProcessor"/>

Camel context injection

You can use @InjectHeader and @InjectHeaders annotations to inject the current exchange context into your FSM:

    @InjectHeader("headerName")
    String headerValue;

    @InjectHeaders
    Map<String, Object> headers;

You can also inject the Camel producer templates using @Producer annotation like in the ordinary Camel beans:

    @Produce(uri = "seda:queue:done")
    private ProducerTemplate doneQueue;

It is also possible to inject the CamelContext using the CamelContextAware interface:

   @FSM(start = InitialState.class)
   @Transitions
   public class TestStateMachine implements CamelContextAware {
       private CamelContext camelContext;

       @Override
       public void setCamelContext(CamelContext camelContext) {
           this.camelContext = camelContext;
       }

       @Override
       public CamelContext getCamelContext() {
           return camelContext;
       }
   }