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CreateManager


Part II: Creating new Managers - A HowTo for creating Business Facades that talk to the database tier (DAOs) and handle transaction management.

This tutorial depends on Part I: Creating new DAOs and Objects in AppFuse.

About this Tutorial

This tutorial will show you how to create a Business Facade class (and a JUnit Test) to talk to the DAO we created in Part I.

In the context of AppFuse, this is called a Manager class. Its main responsibility is to act as a bridge between the persistence (DAO) layer and the web layer. It's also 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.

I will tell you how I do stuff in the Real World in text like this.

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

Table of Contents

  • [1] Create a new ManagerTest to run JUnit tests on the Manager
  • [2] Create a new Manager to talk to the DAO
  • [3] Configure Spring for this Manager and Transactions
  • [4] Run the ManagerTest

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

In Part I, we created a Person object and PersonDao - so let's continue developing this entity. First, let's create a JUnit test for the PersonManager. Create PersonManagerTest in the test/service/**/service directory. We'll want to test the same basic methods (get, save, remove) that our DAO has.
This may seem redundant (why all the tests!), but these tests are GREAT to have 6 months down the road.

This class should extend BaseManagerTestCase, which already exists in the service package. The parent class (BaseManagerTestCase) serves similar functionality as the BaseDaoTestCase.

I usually copy (open → save as) an existing test (i.e. UserManagerTest.java) and find/replace [Uu]ser with [Pp]erson, or whatever the name of my object is.

The code below is what you need for a basic JUnit test of your Manager. Unlike the DaoTest, this test uses jMock to isolate the Manager from its dependencies and make it a true "unit" test. This can be very helpful because it allows you to test your business logic w/o worrying about other dependencies. The code below simply sets up the Manger and its dependencies (as Mocks) for testing.


package org.appfuse.service;

import java.util.List;
import java.util.ArrayList;

import org.appfuse.dao.PersonDao;
import org.appfuse.model.Person;
import org.appfuse.service.impl.PersonManagerImpl;

import org.jmock.Mock;
import org.springframework.orm.ObjectRetrievalFailureException;

public class PersonManagerTest extends BaseManagerTestCase {
    private final String personId = "1";
    private PersonManager personManager = new PersonManagerImpl();
    private Mock personDao = null;
    private Person person = null;

    protected void setUp() throws Exception {
        super.setUp();
        personDao = new Mock(PersonDao.class);
        personManager.setPersonDao((PersonDaopersonDao.proxy());
    }

    protected void tearDown() throws Exception {
        super.tearDown();
        personManager = null;
    }
}

Now that you have the skeleton done for this class, you need to add the meat: the test methods to make sure everything works. Here's a snippet from the DAO Tutorial tutorial to help you understand what we're about to do.

...we create methods that begin with "test" (all lower case). As long as these methods are public, have a void return type and take no arguments, they will be called by our <junit> task in our Ant build.xml file. Here's some simple tests for testing CRUD. An important thing to remember is that each method (also known as a test), should be autonomous.

Add the following methods to your PersonManagerTest.java file:


    public void testGetPerson() throws Exception {
        // set expected behavior on dao
        personDao.expects(once()).method("getPerson")
            .will(returnValue(new Person()));
        person = personManager.getPerson(personId);
        assertTrue(person != null);
        personDao.verify();
    }

    public void testSavePerson() throws Exception {
        // set expected behavior on dao
        personDao.expects(once()).method("savePerson")
            .with(same(person)).isVoid();

        personManager.savePerson(person);
        personDao.verify();
    }    

    public void testAddAndRemovePerson() throws Exception {
        person = new Person();

        // set required fields
        person.setFirstName("firstName");
        person.setLastName("lastName");

        // set expected behavior on dao
        personDao.expects(once()).method("savePerson")
            .with(same(person)).isVoid();
        personManager.savePerson(person);
        personDao.verify();

        // reset expectations
        personDao.reset();

        personDao.expects(once()).method("removePerson").with(eq(new Long(personId)));
        personManager.removePerson(personId);
        personDao.verify();

        // reset expectations
        personDao.reset();
        // remove
        Exception ex = new ObjectRetrievalFailureException(Person.class, person.getId());
        personDao.expects(once()).method("removePerson").isVoid();            
        personDao.expects(once()).method("getPerson").will(throwException(ex));
        personManager.removePerson(personId);
        try {
            personManager.getPerson(personId);
            fail("Person with identifier '" + personId + "' found in database");
        catch (ObjectRetrievalFailureException e) {
            assertNotNull(e.getMessage());
        }
        personDao.verify();
    }

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

I think it's funny how I've followed so many patterns to allow extendibility in AppFuse. In reality, on most projects I've been on - I learn so much in a year that I don't want to extend the architecture - I want to rewrite it. Hopefully by keeping AppFuse up to date with my perceived best practices, this won't happen as much. Each year will just be an upgrade to the latest AppFuse, rather than a re-write. ;-)

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. The setPersonDao() method is not used in most cases - its just exists so the PersonManagerTest can set the DAO on the interface.

As usual, I usually duplicate (open → save as) an existing file (i.e. UserManager.java).


package org.appfuse.service;

import org.appfuse.model.Person;
import org.appfuse.dao.PersonDao;

public interface PersonManager {
    public void setPersonDao(PersonDao dao);
    public Person getPerson(String id);
    public void savePerson(Person person);
    public void removePerson(String id);
}

Now let's create a PersonManagerImpl class that implements the methods in PersonManager. To do this, create a new class in src/service/**/service/impl and name it PersonManagerImpl.java. It should extend BaseManager and implement PersonManager.


package org.appfuse.service.impl;

import org.appfuse.model.Person;
import org.appfuse.dao.PersonDao;
import org.appfuse.service.PersonManager;

public class PersonManagerImpl extends BaseManager implements PersonManager {
    private PersonDao dao;

    public void setPersonDao(PersonDao dao) {
        this.dao = dao;
    }

    public Person getPerson(String id) {
        return dao.getPerson(Long.valueOf(id));
    }

    public void savePerson(Person person) {
        dao.savePerson(person);
    }

    public void removePerson(String id) {
        dao.removePerson(Long.valueOf(id));
    }
}

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".

Now you 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 its implementation, open the src/service/**/service/applicationContext-service.xml file. Add the following to the bottom of this file.


    <bean id="personManager" class="org.appfuse.service.impl.PersonManagerImpl">
        <property name="personDao" ref="personDao"/>
    </bean>

This bean must have a name that ends in "Manager". This is because there is AOP advice applied at the top of this file for all *Manager beans.

<aop:advisor id="managerTx" advice-ref="txAdvice" pointcut="execution(* *..service.*Manager.*(..))" order="2"/>
For more information on transactions with Spring, see Spring's documentation.

Run the ManagerTest [#4]

Save all your edited files and try running ant test-service -Dtestcase=PersonManager.

Yeah Baby, Yeah: BUILD SUCCESSFUL
Total time: 9 seconds


The files that were modified and added to this point are available for download.

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



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This page last changed on 06-Nov-2006 13:52:58 MST by MattRaible.