index-group=Unrevised type=page status=published title=Schedule Expression

In this example we exercise the `TimerService`.

>"The TimerService interface provides enterprise bean components with access to the container-provided Timer Service. 
The EJB Timer Service allows entity beans, stateless session beans, and message-driven beans to be registered for timer 
callback events at a specified time, after a specified elapsed time, or after a specified interval."

For a complete description of the TimerService, please refer to the Java EE tutorial dedicated to the 
[Timer Service](http://docs.oracle.com/javaee/6/tutorial/doc/bnboy.html).

## FarmerBrown

At `PostConstruct` we create 5 programmatic timers. First four will most likely not be triggered during the test
execution, however the last one will timeout a couple of times.

Each timer contains an info attribute, which can be inspected at timeout.   

    package org.superbiz.corn;
    
    import javax.annotation.PostConstruct;
    import javax.annotation.Resource;
    import javax.ejb.Lock;
    import javax.ejb.LockType;
    import javax.ejb.ScheduleExpression;
    import javax.ejb.Singleton;
    import javax.ejb.Startup;
    import javax.ejb.Timeout;
    import javax.ejb.Timer;
    import javax.ejb.TimerConfig;
    import javax.ejb.TimerService;
    import java.util.concurrent.atomic.AtomicInteger;
    
    /**
     * This is where we schedule all of Farmer Brown's corn jobs
     *
     * @version $Revision$ $Date$
     */
    @Singleton
    @Lock(LockType.READ) // allows timers to execute in parallel
    @Startup
    public class FarmerBrown {
    
        private final AtomicInteger checks = new AtomicInteger();
    
        @Resource
        private TimerService timerService;
    
        @PostConstruct
        private void construct() {
            final TimerConfig plantTheCorn = new TimerConfig("plantTheCorn", false);
            timerService.createCalendarTimer(new ScheduleExpression().month(5).dayOfMonth("20-Last").minute(0).hour(8), plantTheCorn);
            timerService.createCalendarTimer(new ScheduleExpression().month(6).dayOfMonth("1-10").minute(0).hour(8), plantTheCorn);
    
            final TimerConfig harvestTheCorn = new TimerConfig("harvestTheCorn", false);
            timerService.createCalendarTimer(new ScheduleExpression().month(9).dayOfMonth("20-Last").minute(0).hour(8), harvestTheCorn);
            timerService.createCalendarTimer(new ScheduleExpression().month(10).dayOfMonth("1-10").minute(0).hour(8), harvestTheCorn);
    
            final TimerConfig checkOnTheDaughters = new TimerConfig("checkOnTheDaughters", false);
            timerService.createCalendarTimer(new ScheduleExpression().second("*").minute("*").hour("*"), checkOnTheDaughters);
        }
    
        @Timeout
        public void timeout(Timer timer) {
            if ("plantTheCorn".equals(timer.getInfo())) {
                plantTheCorn();
            } else if ("harvestTheCorn".equals(timer.getInfo())) {
                harvestTheCorn();
            } else if ("checkOnTheDaughters".equals(timer.getInfo())) {
                checkOnTheDaughters();
            }
        }
    
        private void plantTheCorn() {
            // Dig out the planter!!!
        }
    
        private void harvestTheCorn() {
            // Dig out the combine!!!
        }
    
        private void checkOnTheDaughters() {
            checks.incrementAndGet();
        }
    
        public int getChecks() {
            return checks.get();
        }
    }

## FarmerBrownTest

The test class acquires an instance from the context and waits for 5 seconds to give the timers a chance to timeout.

    package org.superbiz.corn;
    
    import junit.framework.TestCase;
    
    import javax.ejb.embeddable.EJBContainer;
    import javax.naming.Context;
    
    import static java.util.concurrent.TimeUnit.SECONDS;
    
    /**
     * @version $Revision$ $Date$
     */
    public class FarmerBrownTest extends TestCase {
    
        public void test() throws Exception {
    
            final Context context = EJBContainer.createEJBContainer().getContext();
    
            final FarmerBrown farmerBrown = (FarmerBrown) context.lookup("java:global/schedule-expression/FarmerBrown");
    
            // Give Farmer brown a chance to do some work
            Thread.sleep(SECONDS.toMillis(5));
    
            final int checks = farmerBrown.getChecks();
            assertTrue(checks + "", checks > 4);
        }
    }

# Running

    
    -------------------------------------------------------
     T E S T S
    -------------------------------------------------------
    Running org.superbiz.corn.FarmerBrownTest
    Apache OpenEJB 4.0.0-beta-1    build: 20111002-04:06
    http://tomee.apache.org/
    INFO - openejb.home = /Users/dblevins/examples/schedule-expression
    INFO - openejb.base = /Users/dblevins/examples/schedule-expression
    INFO - Using 'javax.ejb.embeddable.EJBContainer=true'
    INFO - Configuring Service(id=Default Security Service, type=SecurityService, provider-id=Default Security Service)
    INFO - Configuring Service(id=Default Transaction Manager, type=TransactionManager, provider-id=Default Transaction Manager)
    INFO - Found EjbModule in classpath: /Users/dblevins/examples/schedule-expression/target/classes
    INFO - Beginning load: /Users/dblevins/examples/schedule-expression/target/classes
    INFO - Configuring enterprise application: /Users/dblevins/examples/schedule-expression
    WARN - Method 'lookup' is not available for 'javax.annotation.Resource'. Probably using an older Runtime.
    INFO - Configuring Service(id=Default Singleton Container, type=Container, provider-id=Default Singleton Container)
    INFO - Auto-creating a container for bean FarmerBrown: Container(type=SINGLETON, id=Default Singleton Container)
    INFO - Configuring Service(id=Default Managed Container, type=Container, provider-id=Default Managed Container)
    INFO - Auto-creating a container for bean org.superbiz.corn.FarmerBrownTest: Container(type=MANAGED, id=Default Managed Container)
    INFO - Enterprise application "/Users/dblevins/examples/schedule-expression" loaded.
    INFO - Assembling app: /Users/dblevins/examples/schedule-expression
    INFO - Jndi(name="java:global/schedule-expression/FarmerBrown!org.superbiz.corn.FarmerBrown")
    INFO - Jndi(name="java:global/schedule-expression/FarmerBrown")
    INFO - Jndi(name="java:global/EjbModule481105279/org.superbiz.corn.FarmerBrownTest!org.superbiz.corn.FarmerBrownTest")
    INFO - Jndi(name="java:global/EjbModule481105279/org.superbiz.corn.FarmerBrownTest")
    INFO - Created Ejb(deployment-id=org.superbiz.corn.FarmerBrownTest, ejb-name=org.superbiz.corn.FarmerBrownTest, container=Default Managed Container)
    INFO - Created Ejb(deployment-id=FarmerBrown, ejb-name=FarmerBrown, container=Default Singleton Container)
    INFO - Started Ejb(deployment-id=org.superbiz.corn.FarmerBrownTest, ejb-name=org.superbiz.corn.FarmerBrownTest, container=Default Managed Container)
    INFO - Started Ejb(deployment-id=FarmerBrown, ejb-name=FarmerBrown, container=Default Singleton Container)
    INFO - Deployed Application(path=/Users/dblevins/examples/schedule-expression)
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 6.141 sec
    
    Results :
    
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0