Raible's Wiki: CreateManager

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__Part II:__ [Creating new Managers|CreateManager] - A HowTo for creating [Business Delegates|http://java.sun.com/blueprints/corej2eepatterns/Patterns/BusinessDelegate.html] that talk to the database tier (DAOs) and the web tier (Struts Actions).

__Part II:__ [Creating new Managers|CreateManager] - A HowTo for creating Business Facades that talk to the database tier (DAOs) and handle transaction management.

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

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|CreateDAO].

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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|http://java.sun.com/blueprints/corej2eepatterns/Patterns/BusinessDelegate.html] 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.

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.

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* [3] Run the ManagerTest

* [4] Run the ManagerTest

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This class should extend [BaseManagerTestCase|http://raibledesigns.com/downloads/appfuse/api/org/appfuse/service/BaseManagerTestCase.java.html], 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.

This class should extend [BaseManagerTestCase|http://raibledesigns.com/downloads/appfuse/api/org/appfuse/service/BaseManagerTestCase.java.html], which already exists in the ''service'' package. The parent class (BaseManagerTestCase) serves similar functionality as the BaseDaoTestCase.

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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|http://raibledesigns.com/downloads/appfuse/api/org/appfuse/service/BaseManagerTestCase.java.html] class.

The code below is what you need for a basic JUnit test of your Manager. Unlike the DaoTest, this test uses [jMock|http://jmock.org] 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.

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import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import java.util.List;

import java.util.ArrayList;

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import org.appfuse.webapp.form.PersonForm;

import org.appfuse.dao.PersonDao;

import org.appfuse.model.Person;

import org.appfuse.service.impl.PersonManagerImpl;

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import org.jmock.Mock;

import org.springframework.orm.ObjectRetrievalFailureException;

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

private final String personId = "1";

private PersonManager personManager = new PersonManagerImpl();

private Mock personDao = null;

private Person person = null;

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private PersonForm personForm;

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

private PersonManager mgr = null;

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

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

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

super.setUp();

personDao = new Mock(PersonDao.class);

personManager.setPersonDao((PersonDao) personDao.proxy());

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mgr = null;

super.tearDown();

personManager = null;

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public static void main(String[] args) {

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

}

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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|CreateDAO] tutorial to help you understand what we're about to do.

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|CreateDAO] tutorial to help you understand what we're about to do.

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

assertTrue("person.firstName not null",

personForm.getFirstName() != null);

// set expected behavior on dao

personDao.expects(once()).method("getPerson")

.will(returnValue(new Person()));

person = personManager.getPerson(personId);

assertTrue(person != null);

personDao.verify();

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

String name = personForm.getFirstName();

personForm.setFirstName("test");

// set expected behavior on dao

personDao.expects(once()).method("savePerson")

.with(same(person)).isVoid();

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

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

personManager.savePerson(person);

personDao.verify();

}

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personForm.setFirstName(name);

mgr.savePerson(personForm);

}

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personForm = new PersonForm();

personForm = (PersonForm) populate(personForm);

person = new Person();

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

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

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

// set required fields

person.setFirstName("firstName");

person.setLastName("lastName");

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if (log.isDebugEnabled()) {

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

personForm.getId());

}

// set expected behavior on dao

personDao.expects(once()).method("savePerson")

.with(same(person)).isVoid();

personManager.savePerson(person);

personDao.verify();

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mgr.removePerson(personForm);

try {

personForm = (PersonForm) mgr.getPerson(personForm.getId());

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

} catch (DAOException e) {

if (log.isDebugEnabled()) {

log.debug(e);

}

// reset expectations

personDao.reset();

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assertTrue(e != null);

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());

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personDao.verify();

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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.''

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.

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public interface PersonManager {

import org.appfuse.model.Person;

import org.appfuse.dao.PersonDao;

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public Object getPerson(String id) throws Exception;

public Object savePerson(Object person) throws Exception;

public void removePerson(Object Person) throws Exception;

public interface PersonManager {

public void setPersonDao(PersonDao dao);

public Person getPerson(String id);

public void savePerson(Person person);

public void removePerson(String id);

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Now let's create a PersonManagerImpl class that implements the methods in PersonManager and uses [BeanUtils.copyProperties|http://jakarta.apache.org/commons/beanutils/api/org/apache/commons/beanutils/BeanUtils.html#copyProperties(java.lang.Object,%20java.lang.Object)]

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.

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.

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;:''The [BaseManager|http://raibledesigns.com/downloads/appfuse/api/org/appfuse/service/BaseManager.java.html] is for registering different Converters (i.e. [DateConverter|http://raibledesigns.com/downloads/appfuse/api/org/appfuse/common/util/DateConverter.java.html]) so that BeanUtils.copyProperties knows how to convert Strings → Objects. It also provides a {{convert(Object)}} method that converts POJOs -> Forms and vise-versa. If you have Lists on your POJOs (i.e. for parent-child relationships), you will need to manually convert those if you want to work with indexed properties (see UserManagerImpl.java and the conversion of Roles for an example).''

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package org.appfuse.service;

package org.appfuse.service.impl;

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import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

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import org.appfuse.persistence.PersonDao;

import org.appfuse.dao.PersonDao;

import org.appfuse.service.PersonManager;

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

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public Object getPerson(String id) throws Exception {

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

return convert(person);

public Person getPerson(String id) {

return dao.getPerson(Long.valueOf(id));

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public Object savePerson(Object obj) throws Exception {

Person person = (Person) convert(obj);

public void savePerson(Person person) {

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return convert(person);

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public void removePerson(Object obj) throws Exception {

Person person = (Person) convert(obj);

dao.removePerson(person);

public void removePerson(String id) {

dao.removePerson(Long.valueOf(id));

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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"...

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".

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__Doh!__ I guess not:

{{{

PersonManagerImpl.java:11: cannot resolve symbol

[javac] symbol : class PersonForm

[javac] location: package form

[javac] import org.appfuse.webapp.form.PersonForm;

}}}

We need to add XDoclet tags to the Person.java Object to create our Struts ActionForm. In the JavaDoc for the Person.java file, add the following @struts.form tags (use User.java if you need an example):

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

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[{Java2HtmlPlugin

* @struts.form include-all="true" extends="BaseForm"

}]

;:''We extend org.appfuse.webapp.form.BaseForm because it has a toString() method that allows us to call log.debug(formName) to print out a reader-friendly view of the Form object.''

Now, running "ant compile-web" should work just fine.

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

;:''Duplicating (and renaming) the PersonDaoTest.properties is the easy route. Alternatively, you could set the properties manually.''

{{{firstName=Bill

lastName=Joy}}}

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

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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.

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.

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</bean>

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

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

<props>

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

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

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

</props>

</property>

</bean>

</bean>

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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|http://www.springframework.org/docs/reference/transaction.html].

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

Save all your edited files and try running __ant test-service -Dtestcase=PersonManager__.

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__Yeah Baby, Yeah:__

''Yeah Baby, Yeah:''

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The files that were modified and added to this point are [available for download|https://appfuse.dev.java.net/files/documents/1397/7484/appfuse-tutorial-managers-1.6.zip].

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CreateManager