Raible's Wiki: CreateManager

In the context of AppFuse, this is called a Manager class. It's main responsibility is converting backend data (POJOs) into front-end data (Struts ActionForms). The main reason I even use Managers, rather than just calling the DAOs directly is testability. It's nice to be able to populate a Form manually (in the test) and call the DAO to persist it, and verify the database gets the proper results. The Business Delegate

pattern from Sun says that these objects are useful for de-coupling your presentation layer from your database layer (i.e. for Swing apps). Managers should also be where you put any business logic for your application.

Let's get started by creating a new ManagerTest and Manager in AppFuse's architecture.

Create a new ManagerTest to run JUnit tests on the Manager [#1]

This class should extend BaseManagerTestCase

, which already exists in the service package. The parent class (BaseManagerTestCase) serves the same functionality as the BaseDaoTestCase - to load a properties file that has the same name as your *Test.class, as well as to initialize Spring's ApplicationContext.

The code below is what we need for a basic JUnit test of our Managers. It created and destroys our PersonManager. The "ctx" object is initialized in the BaseManagerTestCase

class.




package org.appfuse.service;



import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;



import org.appfuse.webapp.form.PersonForm;





public class PersonManagerTest extends BaseManagerTestCase {

    //~ Static fields/initializers =============================================



    private PersonForm personForm;



    //~ Instance fields ========================================================



    private PersonManager mgr = null;

    private Log log = LogFactory.getLog(PersonManagerTest.class);





    //~ Methods ================================================================



    protected void setUp() throws Exception {

        mgr = (PersonManager) ctx.getBean("personManager");

    }



    protected void tearDown() throws Exception {

        mgr = null;

    }



    public static void main(String[] args) {

        junit.textui.TestRunner.run(PersonManagerTest.class);

    }

}

Now that we have the JUnit framework down for this class, let's add the meat: the test methods to make sure everything works in our Manager. Here's a snippet from the DAO Tutorial tutorial to help you understand what we're about to do.




    public void testGetPerson() throws Exception {

        personForm = (PersonForm) mgr.getPerson("1");



        assertTrue("person.firstName not null", 

                   personForm.getFirstName() != null);

    }



    public void testSavePerson() throws Exception {

        personForm = (PersonForm) mgr.getPerson("1");

        String name = personForm.getFirstName();

        personForm.setFirstName("test");



        personForm = (PersonForm) mgr.savePerson(personForm);

        assertTrue("name updated", personForm.getFirstName().equals("test"));



        personForm.setFirstName(name);

        mgr.savePerson(personForm);

    }



    public void testAddAndRemovePerson() throws Exception {

        personForm = new PersonForm();

        personForm = (PersonForm) populate(personForm);



        personForm = (PersonForm) mgr.savePerson(personForm);

        assertTrue(personForm.getFirstName().equals("Abbie"));

        assertTrue(personForm.getId() != null);



        if (log.isDebugEnabled()) {

            log.debug("removing personForm, personId: " +

                    personForm.getId());

        }



        mgr.removePerson(personForm);

        

        try {

            personForm = (PersonForm) mgr.getPerson("1");

            fail("Expected 'Exception' not thrown");

        } catch (Exception e) {

            if (log.isDebugEnabled()) {

                log.debug(e);

            }



            assertTrue(e != null);

        }

    }

This class won't compile at this point because we have not created our PersonManager interface.

Create a new Manager to talk to the DAO [#2]

First off, create a PersonManager.java interface in the src/service/**/service directory and specify the basic CRUD methods for any implementation classes. I've eliminated the JavaDocs in the class below for display purposes.




package org.appfuse.service;



public interface PersonManager {



    public Object getPerson(String id) throws Exception;



    public Object savePerson(Object person) throws Exception;



    public void removePerson(Object Person) throws Exception;

}

Now let's create a PersonManagerImpl class that implements the methods in PersonManager and uses BeanUtils.copyProperties

to convert POJOs → ActionForms and ActionForms → POJOs. To do this, create a new class in src/service/**/service and name it PersonManagerImpl.java. It should extend BaseManager and implement PersonManager.




package org.appfuse.service;



import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;



import org.appfuse.model.Person;

import org.appfuse.persistence.PersonDao;





public class PersonManagerImpl extends BaseManager implements PersonManager {

    private Log log = LogFactory.getLog(PersonManagerImpl.class);

    private PersonDao dao;



    public void setPersonDao(PersonDao dao) {

        this.dao = dao;

    }



    public Object getPerson(String id) throws Exception {

        Person person = dao.getPerson(Long.valueOf(id));



        return convert(person);

    }



    public Object savePerson(Object obj) throws Exception {

        Person person = (Person) convert(obj);

        dao.savePerson(person);



        return convert(person);

    }



    public void removePerson(Object obj) throws Exception {

        Person person = (Person) convert(obj);

        dao.removePerson(person);

    }

}

One thing to note is the setPersonDao method. This is used by Spring to bind the PersonDao to this Manager. This is configured in the applicationContext-service.xml file. We'll get to configuring that in Step 3[3]. You should be able to compile everything now using "ant compile-service"...

Finally, we need to create the PersonManagerTest.properties file in test/service/**/service so that personForm = (PersonForm) populate(personForm); will work in our test.

Now we need to edit Spring's config file for our services layer so it will know about this new Manager.

Configure Spring for this Manager and Transactions [#3]

To notify Spring of this our PersonManager interface and it's implementation, open the src/service/**/service/applicationContext-service.xml file. In here, you will see an existing configuration for the UserManager. You should be able to copy that and change a few things to get the XML fragment below. Add the following to the bottom of this file.




<!-- Person Manager: Struts implementation -->

<bean id="personManagerTarget" class="org.appfuse.service.PersonManagerImpl" singleton="false">

    <property name="personDao"><ref local="personDAO"/></property>

</bean>



<!-- Transaction declarations for business services.  To apply a generic transaction proxy to

     all managers, you might look into using the BeanNameAutoProxyCreator -->

<bean id="personManager" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">

    <property name="transactionManager"><ref local="transactionManager"/></property>

    <property name="target"><ref local="personManagerTarget"/></property>

    <property name="transactionAttributes">

    <props>

        <prop key="save*">PROPAGATION_REQUIRED</prop>

        <prop key="remove*">PROPAGATION_REQUIRED</prop>

        <prop key="*">PROPAGATION_REQUIRED,readOnly</prop>

    </props>

    </property>

</bean>

Run the ManagerTest [#4]

Save all your edited files and try running "ant test-web -Dtestcase=PersonManager" one more time.

Next Up: Part III: Creating Actions and JSPs - A HowTo for creating Actions and JSPs in the AppFuse architecture.

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Table of Contents

Create a new ManagerTest to run JUnit tests on the Manager [#1]

Create a new Manager to talk to the DAO [#2]

Configure Spring for this Manager and Transactions [#3]

Run the ManagerTest [#4]