Introducing Maven and testing

It is well known and accepted that the Maven build system from Apache is very powerful and capable. It is also easy to use and hard to master.

Countless plugins to extend its functionality can be found.

One of the main functionalities offered by Maven is assisting in various levels of testing, made possible by some powerful plugins.

In building and testing software, individual software components and classes should be unit tested using mockup objects and at a level of granularity that is independent of any services being available, both internal and external.

In this case Maven offers very good solutions, such as the ubiquitous Surefire plugin. Using this plugin unit testing with a variety of testing frameworks is quite straightforward and easy.

On the other hand, Integration Testing is done at a higher level, verifying that the integration between components, both internal and external is done correctly and to help identify problematic areas. Once a faulty integration is discovered, its unit test results can be examined in detail or if it is an external system, further diagnostics on it can be run.

Good judgement on the programmer is key to apply testing at the most convenient levels though on large enterprise systems usually a combination of unit testing and integration testing is most appropriate.

Though less well known than Surefire, Maven offers the Failsafe plugin, designed specifically for integration testing.

It is interesting to note that the name has been chosen to emphasize that failures don’t stop the Maven lifecycle allowing for gracefully cleaning up any resources used during the testing. As resources can be external it i risky -and rather inelegant- not to clean them up correctly.

According to the Failsafe documentation, it needs to be attached to the integration-test and verify phases (though it seems to work if attached only to the integration-phase). In any case, once invoked it runs through the relevant goals and relevant tests are run.

Testing FTP and SFTP functionality under Maven

We have discussed instances of problems where powerful, established plugins are available to do what we want (in this case, testing). However, we need to do something in Maven for where there are no plugins or they are not easy to find. Look it up twice as it is quite likely someone else has solved the problem before though it may be the case no solution exists.

One of such problems is testing systems that depend on external services such as FTP or SFTP. Say we have a client that downloads some data off such a server, such as XML files or large binaries and no other interface is available.

A good non-legacy example of such a service is YouTube’s API.

Even though YouTube offers programmatic APIs in Java for instance, to use more advanced functionality and for efficient bulk uploading an SFTP interface needs to be used. There are many other examples of such services, using both FTP and SFTP.

Unit tests on the system can be done with mockup objects as usual. However, to do integration testing things get more interesting.

We could, of course, use our YouTube production service to do some integration tests using dummy files, etc. Using production for testing is usually not a very good idea, with potential for disaster. Therefore, using the YouTube production service is not advisable.

Ideally, we should be able to create a mock but fully functional FTP environment, containing exactly the files we need where we can upload and download whatever is necessary and if needed, a small script (say, groovy or something) that simulates whatever it is that YouTube does with your files behind the scenes.

The basic workflow would look like this:

Therefore, we need a plugin that fires up a FTP server and points users to specific areas of the target folder. Ideally, it fires up during the pre-integration-test phase and shuts down on the post-integration-test. Easy as a cake.
A google search of ‘maven ftp server plugin‘ yields no significant results and looking up on the official list of plugins here. Also doing a google code search is of no use, either. Lots of stuff to perform FTPs and file transfers but no starting up servers.

Instead of giving up or firing up some server using Ant or even worse, manually(!), we go on and do it the Maven way.

Namely, we develop a plugin that fires up an (S)FTP server on the desired integration test phases.

Firstly, we need a FTP backbone written in Java so it can be integrated easily and of a suitable license. The Apache FtpServer is perfect for that purpose. It is a high-performance server based on Apache MINA for I/O and it is ridiculously easy to embed from any Java app.

Creating the Maven plugin basics

Firstly, we create a plugin skeleton project using the Maven Archetype plugin:

mvn org.apache.maven.plugins:maven-archetype-plugin:1.0-alpha-7:create -DgroupId=cat.calidos.maven.ftpserver -DartifactId=ftpserver-maven-plugin -DarchetypeArtifactId=maven-archetype-plugin -DarchetypeGroupId=org.apache.maven.archetypes

This creates an empty Maven plugin project ready to start adding stuff such as code and tests. We also need to run

mvn eclipse:eclipse

to create Eclipse settings for the project. We also need to run it whenever we add new dependencies to the POM file so they are also included in the Eclipse world.

Firstly, we add the dependencies for the Apache Ftp server (*):

	
		org.apache.ftpserver
		ftpserver-core
		1.0.6
	
	
		org.apache.ftpserver
		ftplet-api
		1.0.6
	
	
		org.slf4j
		slf4j-api
		1.6.1
	
	
		org.slf4j
		slf4j-log4j12
		1.6.1
	

We can find the details on dependencies and versions on a Maven repo such as MVNrepository.

In this case, we also add the Simple Logging Facade for Java ‘Log4j’ implementation< so the ftp server can output logs.

This means that whenever we use the maven plugin we should provide a log4j configuration file through the usual methods. Plugin will still work but will complain about the missing configuration. In any case, should we desire to use another logging framework we only need to change the dependency to our chosen implementation artifact.

Adding our first mojo

Next, we need to start adding some ‘mojos‘, or ‘Maven plain Old Java Object’, which are the fine-grained goals we need to run (or what is the same, tasks that we want Maven to execute). For more information, read the Introduction to the Build Lifecycle article on the official documentation which is very clarifying and chock full of valuable information.

Examining the source of other Maven plugins, we observe a common enough pattern which is to have an abstract superclass with some of the attributes needed by our mojos.

public abstract class AbstractFtpServerMojo extends AbstractMojo {

On this class we can add common attributes to our mojos such as the Maven project instance

/** Encompassing maven project
*	@parameter default-value="${project}"
* 	@required
* 	@readonly
*/
protected MavenProject mavenProject;

To the attributes we add the revelant annotations which let the Maven runtime inject following the popular Inversion of Control pattern. More documentation on the annotations can be found on the Mojo API Specification.

Basically, we need one mojo to start the server at the ‘pre-integration-test’ phase and another to stop it at the ‘post-integration-test’ phase, which gives us this a class hierarchy like this:

Ok, so now we need to take a look at the Apache Ftp Server documentation to discover how to embed it.

Fortunately it is pretty straightforward. A server factory instance is created from which a server instance can be created and attached to a specific port. Any such configuration such as adding users, setting up SSL keystores or port and interface attachment are configured using ‘listeners‘, which are configuration classes. Multiple listener instances can be set onto the same instance, to allow for multiple interfaces, etc. In the case of this example plugin we aim to configure a subset of all setup possibilities as it is only for integration testing and shouldn’t be used to deploy production FTP servers. For proper deployment, it can be run and configured fully from the command line or as a Windows service very easily.

Ok, so we add a method to the ‘run’ mojo to create the relevant instances

/** Create a server instance with default values
*///////////////////////////////////////////////////////////////////////////////
private void initServer() {

	// add relevant system property variables
	if (systemPropertyVariables!=null) {
		Set propertyNames = systemPropertyVariables.keySet();
		for (Iterator iterator = propertyNames.iterator(); iterator.hasNext();) {
			String propertyName = (String) iterator.next();
			String propertyValue = (String) systemPropertyVariables.get(propertyName);
			getLog().debug("Setting system variable '"+propertyName+"'");
			System.setProperty(propertyName, propertyValue);
		}
	}

	serverFactory = new FtpServerFactory();
	factory = new ListenerFactory();

	// set the port of the listener
	getLog().debug("Using port "+port);
	factory.setPort(port);
	serverFactory.addListener("default", factory.createListener());
	server = serverFactory.createServer();

}	// initServer

Firstly, we add any system variables that our POM wants to have added to our environment. This is a common pattern on many plugins and allows plugin users to fine tune system properties on that particular plugin environment. A very important possibility is to be able to configure a custom location of the log4j configuration using the ‘log4j.configuration’ system variable. For another example of setting system properties you can look at the excellent Jetty Maven plugin.

As properties are just key-value pairs of strings, we allow for the Maven injection to inject them defining the appropriate attribute parameter.

/** Additional system property variables (to pass onto tests, etc.)
*	@parameter
*/
protected Map systemPropertyVariables;

Secondly, we create the factory, listener and server instance. To make use of the more sophisticated features of the Apache Ftp Server we would only need to modify this method a little bit, for instance to allow to bind to a different network interface, etc.

Adding user management

Another common enough configuration that is definitely needed is user setup, including password setup, write permissions, home location, simultaneous logins, etc.

Examining the documentation we see a simple yet very flexible API to manage users. An interface to an user manager class is provided, ‘org.apache.ftpserver.ftplet.UserManager’ and two ready made implementations are available: a properties-based manager and a database-based one. This is very convenient and we could easily have the mojo provide database connection details or a path to a property file. However, we would rather provide configuration details on the POM file itself so all settings are selfcontained in the Maven world.

This means we need a simple factory, user manager and a trivial user class, where all user details are created in Java code.

We start by creating a skeleton factory:

public class SimpleUserManagerFactory implements UserManagerFactory {

And fill the necessary methods, in this case, only the ‘createUserManager’ method.
We follow by creating a simple User class:

public class User implements org.apache.ftpserver.ftplet.User  {

We shouldn’t really use the Ftp Server User implementation ‘BaseUser’ for two reasons: a) it’s in a private implementation package ‘impl’ on ftpserver-core so it can’t really be used (the interface is public and resides in the ftplet-api library) and b) we want to populate its details through the POM file so we need to add appropriate Maven annotations to its attributes.

It is no big deal as it is an easy enough interface to implement, with several key-value pairs, related to the different settings users can have such as maximum number of logins, username, password, etc. We tag the attributes with the Maven annotations and implement all the interface methods.

/** @parameter
*	@required */
protected String name;

/** @parameter
*	@required */
protected String password;

Creating the user manager is also pretty straightforward, implementing the UserManager interface of the ftplet API:

public class SimpleUserManager implements UserManager {

As a ‘repository’ to hold the User data we employ a simple in-memory Map instance:

private HashMap	users;

The resulting class structure is clear in its intent and purpose:

Testing user management code

Both the manager and the manager factory classes are pretty much self-contained it is fairly easy to create tests for most of that functionality. For example. in the case of the user manager, on the setUp() jUnit method we create a sample environment which we use on each test.

/* (non-Javadoc)
* @see junit.framework.TestCase#setUp()
*///////////////////////////////////////////////////////////////////////////////
protected void setUp() throws Exception {

	super.setUp();

	String adminName = "admin";
	userManager = new SimpleUserManager(adminName,new ClearTextPasswordEncryptor(),false);
	saveUser("demo","demo");
	saveUser("demo2","demo");
	saveUser(adminName,"administrator");

}	// setUp

Note that we use the clear text password encryptor both on the test and on the functional code as the passwords are only stored in memory therefore they do not really need to be encrypted and they are in plain view in the POM file anyway.

Using the sample environment we test functionality of the user manager:

/**
* Test method for {@link cat.calidos.maven.ftpserver.users.SimpleUserManager#authenticate(org.apache.ftpserver.ftplet.Authentication)}.
*///////////////////////////////////////////////////////////////////////////////
public void testAuthenticate() {

	loginShouldWork("demo", "demo");
	loginShouldFail("demo", "FAIL");
	loginShouldFail("DOESNTEXIST", "whatever");
	loginShouldWork("admin", "administrator");
	loginShouldFail("admin", "FAIL");

}	// testAuthenticate

Methods ‘saveUser’, ‘loginShouldWork’ and ‘loginShouldFail’ are private convenience methods to aid in testing and make tests more readable, tests are still code and should be readable and well-structured like regular functional code.

Run server mojo

Next, we add some code to have our configured FTP server instance run:

/** Startup the server and store it on the project properties if possible
*	@throws MojoFailureException
*//////////////////////////////////////////////////////////////////////////////
private void runServer() throws MojoFailureException {

	getLog().debug("About to start FTP server...");

	try {

		server.start();
		getLog().info("FTP server started.");

	} catch (FtpException e) {

		getLog().error("Could not start FTP server...");
		throw new MojoFailureException("Could not start FTP server instance", e);

	}

	Properties properties = null;
	if (mavenProject!=null) {
		properties = mavenProject.getProperties();
		properties.put(FtpServerConstants.FTPSERVER_KEY, server);
	} else {
		throw new MojoFailureException("Can't add ftpserver instance as maven project is null");
	}

}	// runServer

The ‘start’ method does not block and creates a new thread, where the server code will run and listen for upcoming connections. We also add the instance to the project properties so the server can be stopped gracefully on the ‘post-integration-test’ phase.

Also, we do not forget to add the annotation to the ‘FtpServerRunMojo’ class that binds the run mojo to the ‘pre-integration-test’ phase:

/** Mojo to start the apache FTP server as an integration instance
*	@goal run
*	@phase pre-integration-test
*///////////////////////////////////////////////////////////////////////////////

Stopping the server mojo

Once our run mojo starts the server, integration tests can be run on the ‘integration-test’ phase. Please bear in mind that client POMs can still be configured to run the server on whatever phases they need through XML tweaking.

The stop mojo ‘execute’ method is quite straightforward as well:

public void execute() throws MojoFailureException {

	getLog().debug("Stopping FTP server...");
	Properties properties = null;
	if (mavenProject!=null) {
		properties = mavenProject.getProperties();
	} else {
		throw new MojoFailureException("Can't access maven project to stop FTP server (null)");
	}

	if (properties!=null) {

		FtpServer ftpServer;
		try {
			ftpServer = (FtpServer) properties.get(FtpServerConstants.FTPSERVER_KEY);
		} catch (ClassCastException e) {
			throw new MojoFailureException("Context doesn't contain a valid ftp server instance",e);
		}
		if (ftpServer==null) {
			throw new MojoFailureException("Context doesn't contain any ftp server instance");
		}
		if (!ftpServer.isStopped()) {
			ftpServer.stop();
			getLog().info("FTP server stopped.");
		} else {
			getLog().info("FTP server was stopped already");
		}

	} else {
		throw new MojoFailureException("Maven project has null properties",new NullPointerException());
	}

}	// execute

After error and sanity checks we retrieve the ftp server instance and stop it. Easy.
Bear in mind that, exceptions during the integration-test phase should be instances of ‘MojoFailureException’ which do not cause the build to die (please check the appropriate documentation on the Maven reference book).

So, if for instance a single test fails, the other tests can run and the server is gracefully stopped at the end. Using ‘MojoExecutionException’ would cause the whole build to stop and if done before the stop mojo has a chance to run the server is not stopped. All probable exceptions on the Maven ftp server plugin are of the type ‘MojoFailureException’ as we do not want to stop the whole build if integration tests fail, we report them and it will be up to the client developer to decide what to do.

Testing the mojos the right way

Unit testing mojo code is made easier thanks to the ‘AbstractMojoTestCase’

public class FtpServerMojoTest extends AbstractMojoTestCase {

This superclass contains some methods to help in testing mojos, mainly methods to read POM files and run mojos.

We also need an FTP client to connect to the running instance. The excellent Apache Commons Net library is ideal for that purpose.

To use it we add the relevant test dependencies to our project POM with a ‘test’ scope which means they will only be used on the ‘test’ phase and not when the plugin is ran:

	
		org.apache.maven.plugin-testing
		maven-plugin-testing-harness
		1.2
		test
	
	
	    commons-net
	    commons-net
   		 3.0.1
    	test
    

So what we want to do is run the FTP server startup method on each test setup and stop it on each test teardown.

/** Read pom and start FTP server
*	@throws java.lang.Exception
*///////////////////////////////////////////////////////////////////////////////
public void setUp() throws Exception {

	super.setUp() ;

	pom = getTestFile("src/test/resources/unit/test-project/pom.xml");
	assertNotNull("Test pom not found",pom);
	assertTrue("Test pom not found",pom.exists());

	port = getFreePort();

	FtpServerRunMojo runMojo = (FtpServerRunMojo) lookupMojo("run", pom);

	// all this will be set on a real project (it's not on the test environment)
	runMojo.serverRoot = new File(PlexusTestCase.getBasedir()+"/target");
	runMojo.port = port;
	runMojo.mavenProject = new MavenProject();
	runMojo.mavenProject.getModel().setProperties(new Properties());
	runMojo.execute();
	ftpServer = (FtpServer) runMojo.mavenProject.getProperties().get(FtpServerConstants.FTPSERVER_KEY);

    ftp = new FTPClient();
    ftp.connect("localhost",port);    

}	// setUp

First we call the superclass as it configures stuff we need to call the convenience methods, load up a test pom and find a free port to run the server. Next we lookup the ‘run’ mojo and add the relevant data that it needs to start such as the server root, port, container Maven project, etc. All that data is automatically set on a non-test environment but it is not on a test setup. Last on the setup is to connect to the FTP server.

Teardown needs to cleanup the ftp connection and run the stop mojo:

/** Run stop server mojo
* 	@throws java.lang.Exception
*///////////////////////////////////////////////////////////////////////////////
public void tearDown() throws Exception {

	if (ftp.isAvailable()) {
		if (ftp.isConnected()) {
			ftp.disconnect();
		}
	}

	FtpServerStopMojo stopMojo = (FtpServerStopMojo) lookupMojo("stop",pom);

	Properties properties = new Properties();
	properties.put(FtpServerConstants.FTPSERVER_KEY, ftpServer);
	stopMojo.mavenProject = new MavenProject();
	stopMojo.mavenProject.getModel().setProperties(properties);
	stopMojo.execute();

	super.tearDown();	// called last as it dismantles running mojo stuff

}	// tearDown

Note we create a Maven project instance to store the running FTP instance which will be stopped by the ‘stop’ mojo. We also call ‘super.tearDown()’ last to make sure any superclass resources are cleaned up when we are done cleaning up ourselves.

The test POM should contain appropriate test data so significant tests can be run, therefore we add different configuration settings to the XML

	cat.calidos.maven.ftpserver
	ftpserver-maven-plugin
	1.0
		
			
				admin
admin00
			
			
				
					demo
demo
				
				
					disabled
disabled
					false
				
				
					classes-root
classes-root
					./classes
				
				
					write-disabled
write-disabled
					false
				

			
		
	

This setup lets us test the administrator user, a regular user, a disabled one, home folders and write-disabled users. There are far more features exposed by the Apache FTP Server though it is not the aim of this test to test them all, just to make a general set of features work as expected. Obviously, to get higher code coverage more tests can be added as needed.

After the POM is ready, we add some unit tests such as the regular user test:

/** Demo user should be able to login
*	@throws SocketException
*	@throws IOException
*//////////////////////////////////////////////////////////////////////////////
public void testDemoUser() throws SocketException, IOException {

    ftp.login("demo", "demo");
	int reply = ftp.getReplyCode();
    assertTrue(FTPReply.isPositiveCompletion(reply));
    assertTrue("Can't login with demo user",ftp.isConnected());

	String filename = "test-file";
	putFile(filename);
	boolean found = findRemoteItem(filename);
	assertTrue(filename+" can't be uploaded",found);

    ftp.disconnect();

}	// testDemoUser

We connect, add a test file and ensure it has been uploaded successfully. Both ‘putFile’ and ‘findRemoteItem’ are convenience methods created on the test class.

Adding more test cases is pretty straightforward, like in the test for readonly users:

/**	User shouldn't have write permissions
*	@throws IOException
*//////////////////////////////////////////////////////////////////////////////
public void testCannotWrite() throws IOException {

	ftp.login("write-disabled", "write-disabled");
	int reply = ftp.getReplyCode();
	assertTrue(FTPReply.isPositiveCompletion(reply));
	assertTrue(ftp.isConnected());

	String filename = "test-file2";
	putFile(filename);
	boolean found = findRemoteItem(filename);
	assertFalse(filename+" can be put on nonwrite permissions user",found);

	ftp.disconnect();

}	// testCannotWrite

Using the plugin

Doing integration testing with our completed FTP Server Maven plugin is pretty straightforward using the ‘maven-failsafe-plugin’ to fire up the tests and the ‘ftpserver-maven-plugin’ itself to run the FTP server

	cat.calidos.maven.ftpserver
	ftpserver-maven-plugin
	1.0

		
			
				admin
admin00
			
		
			file:target/test-classes/log4j.properties
		
	

	
	
		
			start-ftpserver
			
				run
			
		
		
			stop-ftpserver
			
				stop
			
		
	

Not that, unlike in unit testing and the ‘maven-surefire-plugin’ the standard test location for the log4j configuration file does not work so we need to specify it on the POM. We also need to specify the goals for the FTP server to startup and shutdown, much along the lines of the Maven Failsafe plugin itself.

If any of the integration tests fails the stop goal is still ran and the server shuts down gracefully.

Additionally, if running the FTP server is needed on phases other than the integration testing ones the goals be attached to the relevant phases through our client POM.

Wrapping up: creation of an FTP server plugin

We have identified a need of using a fully functional FTP and SFTP server in integration testing using Maven. Looking up available plugins on the Web does not yield any already available plugins. We have gone ahead and built a plugin from scratch using the Apache FTP Server opensource library.

You can download the source code of version 1.0 of the maven-ftpserver-plugin as well as a sample client project. Enjoy and comments are welcome.

(*) Between completing the code and writing the article Apache FtpServer came out with a new release (1.0.6). Thanks to Maven and the fair amount testing it was ridiculously easy to upgrade the project, just changed the dependency numbers on the pom file and ran a maven build.

For the sake of drama and structure I will go from the most obvious to the slightly less evident and finish with the most subtle of the three.

Firstly, there is Microsoft.

It is common knowledge that the old boys from Redmond are in deep trouble in the mobile arena (and still are). After being a major player in the mobile smartphone arena for quite a long time it has gradually become a so-so player, being met by some skepticism by users and critics alike.

Even though Windows Phone 7 received decent reviews it feels like too little and definitely too late.

The Windows Phone 7 rollout still feels too corporate to me and still part of a lukewarm strategy.

Yeah but Microsoft has conquered or at least made a good dent on other markets before, even if just by brute force, yes? (read XBOX).

So why would a juggernaut like Microsoft be constrained in its long-term strategy? Shouldn’t be.

Well, it’s the systems, stupid.
If anything, Apple has taught the industry one thing with the iPod, iPhone and lately with the iPad. Consumers love SYSTEMS.

Consumers don’t like loosely coupled devices. Consumers don’t like replacing or upgrading components. Consumers don’t like lengthy boot sequences. Consumers don’t like invasive firmware installations. Consumers don’t like the software provider plus OEM combination. Maybe they did in the beginning of the 90′s. We ain’t in the 90′s anymore. XBOX, though successful, has been targeted at hardcore gamers rather than casual ones up until the Kinect.

On top of that Microsoft has learned something on its own, it doesn’t know how to build consumer SYSTEMS at all.

Therefore, to get itself out of the hole, Microsoft considered its options.

Acquisition of a successful company just to go on and destroy it in the process was ruled out, lest it turn into another disaster.

Lesson learned and any acquisitions ruled out, Microsoft then took a look at the OEM market… Err, in the case of MS, it meant HTC, builder of the 80% of cell phones bearing Microsoft’s mobile OS (at least prior the 7th version). Out of 50 partners!

Well, a simple Google search for Android and HTC is quite revealing. HTC didn’t jump ship, not exactly. But it started to be really busy building handsets with that OS.

Well, considering Android had been in the market for a while, a mature product, consumers liking it, with a plethora of apps and -most importantly- being FREE, what do you expect? Considering that MS has been known to thoroughly screw its partners from time to time., who can blame HTC?

Surely, HTC has hedged its bets and is only too happy to license to MS and adopt a wait-and-see attitude to it to see if it sticks and to exploit slow IT corporate policies that still mandate Windows-Everywhere(™). The good old leverage from the fading age of Windows was gone though and Microsoft would feel like second best here.

Choice taken away: traditional OEMs were out.

To add icing on the cake, it would seem that Microsoft had little choice but to license the ARM architecture, surely watched closely by its mobile hardware OEMs who have perceived it as yet another sword hanging over their little necks. A sword that would materialise as Microsoft mobile hardware. Uh-oh. Again, Microsoft has had to take some eggs from the software-only basket and put them on the systems one though only as a last resort (see Kin fiasco).

No pure-OEM model then. No acquisitions. Definitely not Android. SONY? You gotta be kidding. No Microsoft hardware (yet). Samsung maybe? Nay.

Um…

It had to be Nokia then. It’s smartphone marketshare in decline, Microsoft couldn’t go anywhere else.

Which leads nicely to the next big boy, Nokia itself.

Nokia is a giant. Massive with customers, it has created remarkable legendary mobile designs. However, its fortunes -or at least its marketshare lead- got reversed and were showing a worrying trend.

The new CEO put it very well himself, the company is in dire straits indeed, at least in the long term.

Nokia also considered its options.

Nokia understands systems and consumers very well, probably much more than Microsoft does or has ever done. With that in mind, Elop and senior managers understood that Symbian is a thing of the past that. Meego wasn’t ready and perhaps would never be good enough.

But, wait? A company the size of Nokia has lots of engineering talent! Yes, but also lots of middle managers and lacklustre leadership, if one is to believe Nokia’s top brass.

Therefore, culling the company of useless meddlers and taking the time to isolate a dedicated, motivated and driven team to push Meego (much like what Palm managed to do with its WebOS) up to scratch would take time, too long. If I remember correctly, it took Palm the better part of two years or more to get WebOS near 1.0-status and that is an heroic feat. Time though, is not something Nokia had available. Option out.

Acquisition? Nokia doesn’t strike me as an acquisition-crazy company.

Firstly, a nimble startup would understandably have a hard time integrating into a company of 12.000+ employees.

Secondly, while the Trolltech acquisition had some technical merit, it was completed in 2008 and Nokia has’t really made Qt onto the big promised paradise it was intented to. And they have had plenty of time to do it.

And finally, who to buy? RIM? Are you kidding? Making the company bigger and having a huge corporate cultural clash to boot?!? And getting RIM’s loony CEO(s) onboard?

Nay, purchasing its way out of trouble, choice taken away.

Which lead Nokia to consider Android.

One can imagine Nokia seeing Android as the forbidden fruit of sin. Juicy, tempting, free for the taking… and ultimately damning.

Oh, there is the legal swamp. Before taking a bite out of the fruit, Nokia must have had it’s lawyer legions take a good look at it.

If that was not to scare the Nokia strategist what would?

Well, I would argue that the real reason is freedom. Freedom to differentiate. As the Symbian guys put it “[…] surrender too much of the value and differentiation ability, most obviously in services and advertising, to Google.” Exactly. Nokia would play on the same field as all the other OEM. Bummer, from leading systems developer down to mere squabbling OEM.

Surely Nokia had been following what happened to Motorola and the Skyhook guys.

Apparently, both Motorola and ‘Company X’ (believed to be Samsung) have been prevented by Google from shipping handsets bearing its location technology. Remeber Navteq? Ever heard of Nokia maps?

Jump onto the Android bandwagon and kiss goodbye to all that.

So Android being out what was left as an option? A company in desperate need?

Microsoft.

Which leads to the idea of Google having courted Nokia precisely for many of the reasons Microsoft ‘bought’ them in the first place.

Finally, Google is the third big one having run out of options on some of its most strategic options.

Consider the official gospel on why Google created Android and released it to the wild. Well, most of it, anyway.

According to Vic Gundotra from Google:

“If Google didn’t act, it faced a draconian future where one man, one phone, one carrier were our choice. That’s a future we don’t want.”

Sounds chivalrous and following the ‘Don’t be evil’ mantra. Google released Android to save us all from that bleak future.

Well, it’s not true.

Consider Google’s business model. It revolves around advertising and to do well in advertising you need eyeballs, lots of them. Furthermore, to do very well you need targeted eyeballs, that is, to show the right adverts to the right people, to maximise chances of these people hitting the ads.

Google’s business model elevator pitch: person would like to get a service or product on the Web. Cool, she fires up Google on her desktop or laptop and does a search for the terms she thinks will help her find that product or service. Maybe clicks on the ads, maybe finds what she is looking for, maybe not. Bonus points: does more searches through Google, refining the terms (translation: getting more targeted ads), finally finds what she is looking for. This happens millions of times. Google makes tons of money.

Whereas if that same person would like to get a service or product on her iPhone, the story is completely different. Cool, she fires up the App Store app, does a search or browses the categories. Looks at the top charts, reads the reviews and how many stars the candidate solutions have, ponders wether to pay or get a free app, etc. Person chooses app and installs it. Google gets zero money. Zaroo, zip, nada, nothing.

There are a few things that need to be considered:

• Not all services are available through the App Store and probably will never be a 100%, but there are zillions of apps (read, services) waiting to be downloaded.
• People trust Google to deliver good search results but how to compare one result from the other can basically only be done by the rank itself or by clicking on the link and spending sometime on the site. The App Store offers a simplified interface allegedly easier the average consumer (ranks, reviews, stars, etc.).
• People trust the App Store as well, it has never allowed malware on people’s devices.
• Apple is very careful and vocal about not having any influence on the ranking, like, erm, Google.
• To get iPhone apps, geeks will do research on Google and the Web. Will look for extended reviews, comparisons and specialised sites. Consumers just use the App Store.

Google knew that smartphones and later tablets would be the devices the mass market consumer will use to access the Internet. iOS was looking good and demolishing the competition at the time. It seems to be doing the same now.

The App Store is a ‘Google search’ replacement.

I would say that Apple wasn’t expecting it to become so successful. I would add that Apple didn’t set out to build a Google search replacement when the App Store was built. Apple engineers and product managers only wanted to create a better experience for consumers than googling vague terms, shuffling through specialised review sites, getting malware off dubious websites, etc. Google is collateral damage.

Google knew it had to act, very fast and with very decisive steps. Apple’s competition was in shambles and couldn’t get their stuff together for the life of them. Microsoft Windows Mobile 6.x was crap and any real future releases years into the future, RIM was -is- a shadow of its former self and Palm was on its last legs. Google couldn’t wait on them.

Android was born and released for free. Had to be. Google didn’t have any other choice. What they really imagined was a mobile future sans Android, where Apple would rule. Imagine if Android didn’t exist what the marketshare of Apple would be on smartphones today and Google wouldn’t be able to continue making money on it. That is the future Google didn’t want.

A corporate strategy is about having a vision and making it happen and the three giants have lost the initiative.

A common feature of Web applications is the need to output structured content, be it XML, XHTML markup, JSON or many others. A number of technologies is used to do that but few seem to be that dynamic, usually only reloading templates when they change or loading them from URLs. Surely we can leverage OSGi to make things more interesting…

Therefore we should be following the OSGi dynamic philosophy as much as possible, exploiting the features made available by the framework such as dynamic discovery, services, bundle headers and the lot.

In the case of our cache app we are violating quite a few basic design principles by having the format embedded in the java code. So we should as well use a template separate from the code and if possible reuse some existing well-known templating engine from somewhere.

Given these basic design principles let’s get started.

Firstly, we need a robust and flexible templating engine. We select the mature Freemarker engine which is reasonably speedy and has the power and flexibility we want. Make sure you check out the license, of course.

We could stop at putting the library JAR in a bundle and package it so it can be used by any other bundle and that is what we do to be able to use it in OSGi. That however doesn’t exploit many of the nicer OSGi capabilities so we will create another bundle called ‘com.calidos.dani.osgi.freemarker-loader’.

What we want is to allow bundles to carry templates inside them and have our freemarker-loader templating bundle discover them automagically. This is the same technique that the Spring dynamic modules use and you can find more info here. The mechanism is described in this diagram:

That is easy enough with a BundleTracker and a BundleTrackerCustomizer implementation. The BundleTracker class tracks bundles being added to the environment like this:

tracker = new BundleTracker(context, Bundle.RESOLVED, templateTracker);
tracker.open();

With this snippet the tracker instance will look for bundles in the RESOLVED state (which lets us track fragments). The ‘templateTracker’ object is an instance of BundleTrackerCustomizer and will receive callbacks whenever bundles are added to the environment.

For instance, when a bundle is added we check for a special header in the bundle which tells us what is the relative path of available templates in the bundle being resolved:

public Object addingBundle(Bundle bundle, BundleEvent event) {

// we look for the header and act accordingly
String templatesLocation = (String) bundle.getHeaders().get(TEMPLATE_HEADER);
if (templatesLocation!=null) {

	Enumeration bundleTemplates = bundle.findEntries(templatesLocation, "*.ftl", true);
	HashSet templatesFromAddedBundle = new HashSet();
	while (bundleTemplates.hasMoreElements()) {

		URL templateURL = bundleTemplates.nextElement();
		addTemplate(bundle, templateURL,templatesLocation);
		templatesFromAddedBundle.add(templateURL);

	}

	templatesOfEachBundle.put(bundle.getBundleId(), templatesFromAddedBundle);

}
return null;

}	// addingBundle

An interesting method being used here is ‘findEntries’ which loads all the entries in the provided templates folder and lets us add them to our holding structure. We also take care to implement the methods to remove the templates and update them accordingly whenever bundles are updated or unloaded from the environment.

Having TEMPLATE_HEADER with a value of ‘Freemarker-Templates’ means that bundles having a header such as Freemarker-Templates: /templates will have any templates within that folder (please note that the ‘/templates’ bit is not added to template URLs!).

The next thing we need to do is make the loaded templates available to the environment. To do that we make a freemarker Configuration object accessible as an OSGi service object. That Configuration instance is the main object Freemarker to load and use templates and has an interesting mechanism to override its template loading mechanism we use to make available our OSGi environment templates.

freemarkerConfig.setTemplateLoader( new URLTemplateLoader() {

@Override
protected URL getURL(String url) {
Stack templateStack = templates.get(url);
if (templateStack!=null) {
	TemplateEntry templateStackTop = templateStack.peek();
	if (templateStackTop!=null) {
		return templateStackTop.getTemplateURL();
	}
	return null;
}
return null;
}

});

The service Configuration object is set with a template loader inner class that uses our template holding objects to retrieve templates stored in our OSGi context. Cool.

This also allows us to effectively disable the template refreshing cycles that Freemarker does by default (allegedly making it slightly more efficient). Now we only need to refresh a bundle containing the templates to get the new version. This can be modified by using the appropriate methods on the Configuration service of course. (There is another method explained later).

An interesting feature we can add to exploit the dynamic nature of OSGi is to make templates available in a stack. This means different bundles can dynamically overwrite templates by the same name. Moreover, once a template is removed the previous version becomes available. This can be used to make temporary changes to templates to add or remove diagnostics information, test new templates temporarily, etc.

We do that using a Stack of TemplateEntry objects, TemplateEntry being a helper class to store template entries.

This is all very nice but we have a problem when having multiple versions of the same bundle that hold multiple copies of the same template, this means they will stack and we have no way to access a particular version of a template. To solve this problem we store each template in three different stacks by three different URLs:

• ‘path/file.ftl’
• ‘bundle://bundlename/path/file.ftl’
• ‘bundle://bundlename:version/path/file.ftl’

In this manner we can use the more generic URL in most cases but still can access specific versions when needed. It is important to think about the dynamic nature of OSGi as well as the possibility of several versions of the same bundle coexisting peacefully in the same environment.

From the perspective of any bundle using the service in the simplest case it only needs to look for a service named ‘freemarker.template.Configuration’. For convenience, the property ‘dynamicConfiguration’ is set to ‘true’ to coexist peacefully with other Configuration services (maybe coming from an official Freemarker bundle). For instance, if we know for sure our dynamic Configuration service is the only one present we can do:

context.getServiceReference(Configuration.class.getName());

That will give us the highest ranking Configuration service. If there are several such services we can use a call like this to get the one that has the dynamic OSGi loader:

context.getServiceReferences(Configuration.class.getName(), "dynamicConfiguration=true");

There is one last feature which lets bundle users feed an already configured template configuration object to the bundle by publishing a Configuration service with property ‘preparedConfiguration’ set to ‘true’. This will get picked up by the bundle and its template loader put in sequence with the dynamic OSGi template loader. This means that any original Configuration settings are maintained (For further information on service filtering based on properties please check the BundleContext javadoc.).

Best thing to do is to go and try it by downloading the bundles here. Source is also available.

In the case of integration testing, it is manly used in a pre-production environment, with a valid build that has all unit tests passed. It can even be used in production to just after a deployment is made, taking care not to have destructive checks or massive load tests in the integration test code. YMMV.

To achieve integration testing we need to check the various OSGi components deployed interact in the way that is expected of them. Therefore we need to test the components in a group and not in isolation. To do that in the OSGi world means we need to have access to the OSGi context from within the tests to access services, call them and check their responses, etc.

To allow for this kind of integration testing within the OSGi environment, we make a slight modification to the excellent test.extender we have already patched in the previous installment.

Basically, the basic test.extender seeks out any JUnit test classes within the fragment bundle, creates an instance using an empty constructor and then fires up the tests. This is activated either by default when the fragment is loaded or by using ‘test ‘ in the console. For further information please see the previous post about this subject.

For our integration testing, we add an extra command to test.extender:

public Object _integrationTest(CommandInterpreter intp) {
        String nextArgument = intp.nextArgument();
    	testExtender.integrationTest(Long.parseLong(nextArgument));
    	return null;
}

And we refactor the TestExtender to add the integrationTest method which reuses some of the code to instantiate test cases using a constructor that accepts the OSGi context as a parameter.

Constructor[] constructors = clazz.getConstructors();
boolean foundConstructor = false;
for (int i = 0; i < constructors.length && !foundConstructor; i++) {
	Constructor constructor = constructors[i];
	Class[] types = constructor.getParameterTypes();
	if (types.length==1 && types[0].isInstance(context)) {
		foundConstructor = true;
		EClassUtils.testClass(inspectClass, constructor.newInstance(context));
	}
} // for

The OSGi context is passed onto the constructor and then the test class is run. It is obviously up to the test class to use the context appropriately for its integration testing.

In our cache project setup, we can do some useful integration testing on the cache.controller component, basically checking if the interaction with the provider components is behaving as we expect it. The integration testing is also added to a fragment that can be deployed optionally, of course.

We start by creating the fragment and adding a testing class like this:

Next, we add the constructor that accepts an OSGi context, which is very simple:

public CacheIntegrationTest(BundleContext ctx) {
	super();
	this.context = ctx;
}

In the setup and teardown methods we get and unget the cache service to perform the testing:

public void setUp() throws Exception {
	serviceReference = context.getServiceReference(Cache.class.getName());
	controller = (CacheControllerCore) context.getService(serviceReference);

}

public void tearDown() throws Exception {
	context.ungetService(serviceReference);
	controller = null;
}

In this case we get the controller cache service and store it in an instance used to perform the tests. This is quite simple and fulfills our intended purpose but we still have the flexibility to make more complex integration testing if needed.

Next we create as many test cases as needed:

public void testGet() {
	try {
		controller.init();
		double v = Math.random();
		String k = "/k"+v;
		controller.set(k, v);
		assertEquals(v, controller.get(k));
	} catch (CacheProviderException e) {
		e.printStackTrace();
		fail(e.getMessage());
	}

}

It should be noted that while the code looks like regular testing code, it is actually using real services from the OSGi environment as opposed to mockups. This means we are testing the real integration between components as well as the individual controller component code. The disadvantage here is that if there is an error in the controller we might mistake the problem with an issue with the services used. In conclusion, having integration code doesn’t negate the need to have unit tests.

Once we load the fragment onto the environment, first we need to obtain the bundle id of the integration fragment and then launch the integration testing in this manner:


osgi> integrate 125
Bundle : [125] : com.calidos.dani.osgi.cache.controller.integration
_
CLASS : [com.calidos.dani.osgi.cache.controller.CacheIntegrationTest]
___________________________________________________________________________
Method : [ testInit ] PASS
Method : [ testInitInt ] PASS
Method : [ testSize ] PASS
14:21:43,077 WARN CacheControllerCore Couldn't clear some of the provider caches as operation is unsupported
14:21:43,077 WARN CacheControllerCore Couldn't clear some of the provider caches as operation is unsupported
Method : [ testClear ] PASS
Method : [ testSet ] PASS
Method : [ testGet ] PASS
Method : [ testGetStatus ] PASS
___________________________________________________________________________


The results tell us that all operations are OK but we need to bear in mind that the clear operation is not supported in some backend caches. If this is what is expected by the operator then all is fine.

We take advantage of the new integration testing functionality to make some extensive changes to logging and exception handling of the controller code. By running the integration tests we make sure all seems to work fine (even though we still need some proper unit testing of the controller). Modifications are made quite quickly thanks to the integration tests.

To recap, we’ve added integration testing support to the existing ‘test.extender’ bundle and created integration testing code for the cache controller component. This has allowed us to make code changes quickly with less risk of mistakes.

Here you can find a patch for the test extender project as well as the patched testing bundle already compiled. Enjoy!

La idea és anar amb molt de compte en enllaçar els posts i updates de microblogging entre els diferents serveis, no sempre és lo òptim. Com diu el mateix Roger:

Un clam al cel perquè la gent deixi de reaprofitar el mateix missatge per a totes les xarxes socials. Crea soroll innecesari, molts cops perd context (hashtags a facebook, etc…) i molesta. Ok a que em diguis “avui he dinat molt bé”, però no necessito rebre-ho per triplicat.

Both J.G. and L.G. have brought up many valid points: Adobe dragged their heels on Flash for mobile for a looooong time. There have been countless detabes and blog posts.

I’ll bring two further arguments, one logical and one historical, the latter being one that I believe hasn’t been brought up yet.

Logical argument: the fallacy of Flash being cross-platform

Moreover, why should we choose to lock ourselves onto Adobe’s propietary API instead of Apple’s propietary API? Why is Adobe’s API, specs and runtime superior to any others? Many would say the main reason (the only?) is that it’s crossplatform?

Wikipedia says that cross-platform means:

“an attribute conferred to computer software or computing methods and concepts that are implemented and inter-operate on multiple computer platforms”.

Oh, okay, so multiple means Windows, Mac and Linux desktops. Hello?!? Anyone there?!? This is 2010 and the 90′s called because they want their meaning of “platform” back. Nowadays, multiple means desktop and mobile. Therefore:

• Flash Lite is a joke. Where are the multiplicity of mobile devices supporting proper Flash 10.1 today?
• Where is the pervasive Android support today? HTC Hero buyers are screwed, a phone bought as little as less than a year ago won’t be supported.
• Where is the support for Windows Mobile devices? Not there until WinMo7. You mean it will be supported on a OS that it’s not even there yet?

Well, you could say that the Open Screen Project and the releasing of the FLV, SWF and the lot specs are true multiplatformness… Well, so far so good but where is the real market traction? Where are the tried-and-true implementations? Adobe has released this technology but until it gains traction it’s no more than a glorified press release. Apple can play this game too, with tech such as WebKit which is used in a zillion places including Adobe’s own Air platform. Press releases and freeing technologies are irrelevant until adopted. A good initiative which I applaud, but still not widely used.

No, Flash is not cross-platform anymore. What is the marketshare of the mobile devices capable of running Flash 10.1? Nowhere big enough for Adobe to be pulling muscle and demanding anything. It seems Adobe is using Flash devs and aficionados as cannon fodder or -as Gerbarg more aptly puts it-, “Adobe used its userbase and their livelihood as a bargaining chip”. Adobe dragged its feet for years in the mobile arena and now is paying for its mistakes.

Historical argument: Macromedia Adobe has screwed its own developers like this before

In the nineties Macromedia had a great product already. It was cross-platform (as per 90′s definition), had powerful scripting capabilities, an powerful extension architecture, a great browser plug-in runtime that was also cross-platform, video capabilities, awesome rapid development tools, stellar graphics integration, built-in debugger, great performance, etc. It was called Director and it was really cool.

Then Macromedia bought FutureSplash in 1996 which would be later renamed to Flash. It had far less capabilities that Director at the time (no real scripting at the beginning, etc.) and would remain technically inferior for sometime, having no debugging and many other features being missing for a long while. However, it had three distinct advantages. Strike one: having less features and being a newer codebase meant it could have a more lightweight runtime than the Director one. Strike two: it had support for vector graphics, which desktop CPUs at the time were just capable of displaying and animating adequately. Director came from a less CPU-intensive bitmap background, faster but consuming more space than vector definitions and looking less sleek in many cases.

One “advantage” remained. So what did Macromedia do? Take advantage of the FutureSplash technology acquisition and the Director established developer base? It could have easily added the vector drawing technology into Director (it supported many types of media already). Refactoring the code and runtime would be no trivial feat but doable. Any Director developer would have been OK with a new restriction being put into place that meant only vector-graphics resources being allowed any new Director web runtime, would have welcomed and embraced such a change.

Strike three: Macromedia realised that with the maturity and feature-complete of Director no long-winded upgrade path was in sight. Just adding vector graphics and a streamlined runtime would do for one or two Director upgrades, no more. They thoroughly screwed the existing loyal developer base royally and released a sleek new 1.0 Flash product. Then they spent years releasing upgrades that added features that had already been present in Director for some time. They created another cash cow, a cow that would ride the wave of the Web explosion of the .com era. Director out. And no, I’m not buying any of the “official” reasons for its languishing and Flash emergence. It was all about money.

I am not crying for Director’s demise -or rather, being put into life-support mode. It was a good platform and many (myself included) made good money using it. This doesn’t mean Adobe didn’t screw up many of its own developers and went in for the next cash cow.

I am not buying Flash developers and supporters taking offense and the moral high ground, the company (now Adobe) you support has done a much worse thing to its own developers. Why should Apple even care for developers of other platforms? Just because you learned a framework and are scared of it fading away doesn’t mean anything… Some of us have done this many times before and moved on…

Final word: put your code where your mouth is

Okay. Time to recap, folks. If Flash is such a great platform -it’s actually not bad but not that good either- go ahead and develop these killer apps on Android or WinMo7 whenever that comes out. With killer apps being available on competing platforms making a huge difference Apple will simply change the clause and allow you in. They’re not stupid.

Now stop crying and start coding. Myself, will try to put this out of my mind.

I això que teòricament estaven en “peu de guerra“. Serà que han enterrat la destral…?

Initially, Firefox for N900 does not support browser plug-ins. Due to performance problems using Adobe Flash within Firefox on many websites, especially those with multiple plug-ins on them, we have disabled plugins for Firefox for Maemo 1.0. We plan to provide a browser add-on that will enable you to selectively enable plugins on certain sites, because some sites, like YouTube, work well.

So the good folks of the Mozilla Foundation have gone and released the thing. Given the recent turn of events, it’s interesting to see the reality brick hitting the Adobe head, so to speak. Couldn’t think of a more appropriate support for the Apple iPad, really.

Even if the eventually release it with plug-in support enabled, they will probably stick with letting users enable Flash selectively… This is yet another nail in the Flash coffin.

Ens parla dels compromisos inherents en qualsevol decisió de disseny. També del mal que pot fer el disseny d’aplicacions en un comité on tothom hi diu la seva. També planteja la idea d’objectivar les decisions que es prenguin i construïr si cal una taula amb les avantatges i les consequències de cadascuna de les decisions.

Lectura obligada si ens dediquem al disseny i conceptualització de productes. Bookmark afegit.

Please make sure you read the previous installments before you continue with this article…

To ensure greater flexibility, performance and encapsulation, we will be using OSGi fragments.

http://static.springsource.org/osgi/docs/1.1.3/reference/html/appendix-tips.html

OSGi fragments attach to “host” bundles and can be used to extend functionality, provide configuration and even extra manifest entries.

On the first part, we move our unit tests to fragments. This has the benefit of being able to separate tests from actual code as well as allowing us to deploy using a smaller footprint in situations where we don’t want test code such as production deployments.

If we start with the cache code we’ve got so far we need to separate the test code from two bundles: ‘com.calidos.dani.osgi.cache.provider.memory’ and ‘com.calidos.dani.osgi.cache.provider.memcached’. That is easy enough.

We create a new OSGi bundle fragment project like this:

We specify the bundle the new fragment is attaching to:

The next step is to move the JUnit code from the main bundle onto the fragment. If we run the test independently we see that it passes as the classpath of the host and fragment bundles is merged into one.

We then add the fragment to our existing run configuration and it will be loaded onto our environment. So far so good, but there is no way to run the tests outside our controlled Eclipse.

Slim Ouertani at Javalobby shows us how to run fragment tests from within the OSGi environment in a great article. His code uses the new bundle tracker feature to discover any test fragments and exposing functionality to be able to run the tests.

You can get the source at kenai: http://kenai.com/projects/testosgifragment

We read the article thoroughly, fetch the source and build test.extender using maven:


mvn install


The code works great but has a bug which is triggered when the code looks for the host of the fragment by reading the ‘Fragment-Host:’ header. If the value specifies any kind of version qualifier it fails. It also crashes when trying to test a bundle or a fragment that doesn’t have the ‘Unit-Test’ custom header.

The ‘Unit-Test’ custom header lives on the fragment manifest and is used by test.extender to control who is able to be tested and if tests are done manually or automatically.

If no ‘Unit-Test’ header is present or if its value is empty, test.extender will refuse to run any tests present on the bundle. If the value is ‘true’ then test.extender will run the tests automatically whenever the test fragment bundle is loaded. If the value is anything else the tests won’t run automatically but you can still run them using the ‘test’ and ‘testall’ commands.

I have patched the code to accept a version qualifier for the fragment host as well as giving out an informative error message when attempting to test the wrong bundle.

Once this is done, we play with the test.extender by obtaining the fragment bundle id and issuing ‘test <id>’ on the console:


osgi> test 80
Bundle : [80] : com.calidos.dani.osgi.cache.provider.memory.test
_
CLASS : [com.calidos.dani.osgi.cache.provider.memory.test.MemoryCacheTest]
___________________________________________________________________________
Method : [ testClear ] PASS
Method : [ testInit ] PASS
Method : [ testInitInt ] PASS
Method : [ testSize ] PASS
Method : [ testSet ] PASS
Method : [ testGet ] PASS
Method : [ testGetStatus ] PASS
___________________________________________________________________________
_


We can also use the ‘testall’ command which will look for all the testable fragment bundles and run the test there.

Having tested that functionality, we separate the tests from the memcached bundle and move them onto their own bundle.

Here you can download the two test fragments and the patch to modify test.extender, neat.

Ok then, we move onto the next thing that is looking closely at the Servlet Bridge and its behaviour. What we are interested in is what happens when the container deploys and inits the Web app itself, starting up the servlet bridge. The bridge uses the container temporary folder to deploy the OSGi environment in a subfolder, copying any bundles into that subfolder. If the subfolder exists and there are bundles that have the same names, they won’t be copied. I have found this behaviour to be very confusing for newbies to the platform and very annoying for veterans. I’m not entirely sure if this is deliberate and has performance reasons or what. Calling the framework controls to prevent that is not optimal and manually removing the temporary folder isn’t, either. One possible solution would be to use a building system that increments the micro number every time there is a build and remember to clear up the container temporary folder from time to time. That is not always desirable or possible but fortunately, the servlet bridge implementation provides a way to customize it to our heart’s content.

Basically we have the following code in the bridge init() method:

	framework.init(getServletConfig());
	framework.deploy();
	framework.start();
	frameworkStarted = true;

In this case, ‘framework’ is a instance of the FrameworkLauncher class which is created just before this code snippet. The FrameworkLauncher is the class responsible for deploying and launching OSGi. We note that the object is created by default as a plain FrameworkLauncher instance. However, the class to be used can be customized by specifying it in the web.xml file using the ‘frameworkLauncherClass’ servlet initialization parameter. As long as that class is a subclass of FrameworkLauncher the appropriate contract is fulfilled.

This means we can override some behaviour and delete the framework deployment folders upon startup:

@Override
public void init() {

super.init();

File servletTemp = (File) context.getAttribute("javax.servlet.context.tempdir");
File platformDirectory = new File(servletTemp, "eclipse");

if (platformDirectory.exists()) {
	deleteDirectory(platformDirectory);
}

}

Cool, so we need to export this as a jar file named dani-frameworklauncher.jar into the package project lib folder:

Next we change the servletbridge web.xml configuration parameter to load the new framework launcher:


<init-param>
<param-name>frameworkLauncherClass</param-name>
<param-value>com.calidos.dani.osgi.servletbridge.FrameworkLauncher2</param-value>
</init-param>


To test, we can add a file onto the $APACHE_TOMCAT/work/Catalina/localhost//eclipse folder and restart Tomcat. Before this new launcher was in place, the file would be kept but now it is deleted alongside the rest. Any other methods can also be extended to customize the bridge behaviour without having to modify the launcher class.

Here you can download the framework launcher project, put it on the WEB-INF/lib folder alongside the servlet bridge and enjoy!