Java Server-side Breakout

Fabian Urban

© FORTIS IT-SERVICES GMBH

Fabian UrbanFORTIS

Using Ext JS with a Java Back-end

>> SenchaCon 2011

Wednesday, November 2, 11

Fabian Urban


Ext JS / Sencha Touch with a Java back-end is a perfect combination

Having a container has many advantages.

Web applications must as run smoothly as desktop applications.

Using better technologies means writing less error prone code.

Theoretically I can do everything, and in practice it is as simple as in theory :-)


Fabian Urban


What is perfect???>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

Perfect!performanceoptimized

easy

application runs

smoothly

write less code

save time

minimize risk of writing

error prone code


Fabian Urban


Having a container has many advantages>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

Request Scoped Beans

Session Scoped Beans

Application Scoped Beans




Session Scoped Beans

Client 1Request A

Client 1Request B

Client 2Request A

Client 2Request B

No need to persist data across requests. Use different scopes.Better performance: No need to recreate instances for every request. No unnecessary database access.


Fabian Urban


If an application is declared to be final, then it has to be final

>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

Application

database=DEVuser=foopassword=bar

DatabaseDEV

DatabasePROD

Development Server

Production Server


Fabian Urban


… so we don’t have to update the configuration before every deployment


Application

DataSource=MyDS DatabaseDEV

DatabasePROD

Development Server

Production Server

MyDSdatabase=DEVuser=foopassword=bar

MyDSdatabase=PRODuser=abcpassword=def


Fabian Urban


The less we have to do the earlier it’s done


Without Connection Pooling (open / close database connection for each request)

With Connection Pooling


Fabian Urban


Having a container has many advantages>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

Java Application Server (Development)

Database Dev

ApplicationDataSource

ConfigurationDataSource: MyDs

ConnectionPooling

Java Application Server (Prod)

ApplicationDataSource

ConfigurationDataSource: MyDs

ConnectionPooling

Database Prod

No open / close database connection for each request.Better Database performance(No session overhead).

Deploy application without spending time on updating login credentials


Fabian Urban


Web applications must run as smoothlyas desktop applications


Server-side Rendering

Client-side RenderingNETWORK SERVER

No rendering is done on the server side: less network traffic.Web applications run smoothly like desktop applications.


Fabian Urban


Using better technologies means writing less error prone code


JAX-RS: Easy way to map HTTP requests to a class/method, using annotations. Jackson: Easy way to apply JSON marshalling/unmarshalling. (http://

jackson.codehaus.org/)

CDI: Easy way to fire/observe events (loosely coupled).

Easy way to apply interceptors (AOP). Easy way to write portable extensions (code reuse).


http://http:/jackson.codehaus.org/




Fabian Urban


Using better technologies means: writing less code


@ApplicationScopedpublic class SomeApplicationScopedBean {

private String fooText;

public String getFooText() { return fooText; }

public void setFooText(String fooText) { this.fooText = fooText; }}

@SessionScopedpublic class SomeSessionScopedBean { @Inject private SomeApplicationScopedBean someApplicationScopedBean;

public void doSomething() { String fooText = someApplicationScopedBean.getFooText(); // do something with fooText }}

We do not want to worry about doing stuff like bean injection.someApplicationScopedBean = … // where do I get this from???Bean injection is done automatically when using the @Inject annotation.

Thanks to CDI, we don‘t waste time writing unnecessary code.


Fabian Urban


Java data transfer object (DTO)>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

public class UserDto { private String firstName; private String lastName; private Integer age;

public UserDto() {} // getter and setter}


Fabian Urban


Marshalling and unmarshalling JSON data using Jackson is very easy


UserDto youngFabian = objectMapper.readValue( "{\"firstName\":\"Fabian\", \"lastName\":\"Urban\“, \"age\":19}", UserDto.class);

youngFabian.getAge(); > 19

ObjectMapper objectMapper = new ObjectMapper();

UserDto fabian = new UserDto("Fabian", "Urban", 27); String json = objectMapper.writeValueAsString(fabian); > {"firstName":"Fabian","lastName":"Urban","age":27}

OK, that‘s simple … but you do not really want to worry about writing that … do you?


Fabian Urban


Applying JAX-RS resources can be that simple


@Path(“user“)public class UserResource { @POST @Path(“doSomething") @Consumes(MediaType.APPLICATION_JSON) @Produces(MediaType.APPLICATION_JSON) public UserDto doSomething(UserDto user) { // do something return user; } }

@javax.ws.rs.ApplicationPath(“resources“)public class UserManagerApp extends javax.ws.rs.core.Application {}

Why spend time on writing complicated code that does some routing and JSON marshalling/ unmarshalling if JAX-RS and Jackson can do that for you?


Fabian Urban


Live Walkthrough>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

A Simple Chat Application Using JAX-RS and Jackson on

the Server Side

and

Ext.Ajax.request on the Client Side


Fabian Urban


Ext Direct libs for Java>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

No standard lib but different implementations available:

directjngine http://code.google.com/p/directjngine/

extdirectspring http://code.google.com/p/extdirectspring/

extdirect4java http://code.google.com/p/extdirect4java

extdirectj-s2-plugin http://code.google.com/p/extdirectj-s2-plugin/

HQExtDirect http://bitbucket.org/cattus/hqextdirect/


http://code.google.com/p/directjngine/




http://code.google.com/p/extdirectspring/




http://code.google.com/p/extdirect4java




http://code.google.com/p/extdirectj-s2-plugin/




http://bitbucket.org/cattus/hqextdirect/




Fabian Urban


Enable Ext Direct on the Java back-end makes it even simpler


public class UserManager {

@ExtDirectAccess public UserDto doSomething(@Name(“user”) UserDto user) { user.setAge(19); return user; } }

var userDto = { firstName: ‘Fabian’, lastName: ‘Urban’, age: 27};var namedArguments = { user: userDto };UserManager.doSomething(namedArguments, function(returnedUserDto) { Ext.Window.MessageBox.alert(‘Fabians real age’,

returnedUserDto.age); // Fabians real age: 19});


Fabian Urban



Simple Ext Direct Chat Application Using

JAX-RS and Jackson on the Server Side

and

Ext Direct Technology on the Client Side


Fabian Urban


Less dependencies in the code makes maintaining code a lot easier


Today we’ve learned that we do not really want to

worry about anything

We do not worry to

care about JSON

marshalling

We do not want to worry about

JSON unmarshalling

We do not want to worry about routing on the server

side

We do not want to worry about writing complex code to

invoke methods on the server side

But do we then want to worry about which methods are available on the server side?


Fabian Urban


Less dependencies in the code makes maintaining code a lot easier


public class FooController { @Inject private EventController eventController;

public void handleFooEvent(@Observes FooEvent fooEvent) { // do something with event data BarEvent barEvent = new BarEvent(); eventController.fireGlobalEvent(barEvent); } }

@ClientEventpublic class FooEvent { // properties, // getters, // setters}

var fooEvent = { /* some foo event properties */ };eventController.fireGlobalEvent(‘de.fit4ria.event.FooEvent', fooEvent);

eventController.observes(‘de.fit4ria.event.BarEvent’, function(barEvent){ // do something with barEvent data});


Fabian Urban



The Event-based Version of the Chat Application


Fabian Urban


Events vs. Ext Direct>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

Event-based

loosely coupled code

perfectly integrates with CDI

Service-based (Ext Direct)client needs to know the services

perfectly integrates with Ext JS


Fabian Urban


ServerClient

We can easily delegate to methods on the client side


function doSomething() { FooManager.doA(); BarManager.doB(); XyzManager.doC(); doClientSideAction();}

public class FooManager { public void doA() {…}}

public class BarManager { public void doB() {…}}

public class XyzManager{ public void doC() {…}}

function doClientSideAction() { // do something}


Fabian Urban


ServerClient

… or on the server side>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

function doSomething() { SomeManager.doSomething(); doClientSideAction();}

function doClientSideAction() { // do something}

public class SomeManager { @Inject private FooManager fooManager; @Inject private BarManager barManager;

@Inject private XyzManager xyzManager;

public void doSomething() { fooManager.doA(); barManager.doB(); xyzManager.doC(); }}


Fabian Urban


client or server … doesn‘t matter

… or you don’t worry about delegation>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

eventController.fireGlobalEvent(“some.SomeEvent“);// clienteventController.fireGlobalEvent(new SomeEvent()); // server

SomeEvent

Client

eventController.observes(‘some.SomeEvent‘, function() { // do something});

Serverpublic class FooManager { public void handleSomeEvent(@Observes SomeEvent someEvent) { /* do A */ }}

public class BarManager { public void handleSomeEvent(@Observes SomeEvent someEvent) { /* do B */ }}

public class XyzManager { public void handleSomeEvent(@Observes SomeEvent someEvent) { /* do C */ }}


Fabian Urban


Summary>> Ext JS / Sencha Touch with a Java back-end is a perfect combination

Technologies / specifications like JAX-RS, Jackson and CDI simplify the code.

The enterprise Java standards not only support service-based, but also event-based applications. You have the choice!

Ext JS / Sencha Touch with a Java back-end is a perfect combination!


Fabian Urban


Thank you for listening

Contact:Fabian [email protected]

FORTIS IT-Service GmbHDuvenstedter Damm 7222397 Hamburg T: +49(0)40 607 699 22 Altenburger Straße 933699 BielefeldT: +49(0)521 920 198 40

>> Contact

Want to check examples of this talk?http://laboris.fortis-it.de/~urbanfbi/SenchaCon2011/ExtJSJavaHowto.pdf


http://laboris.fortis-it.de/~urbanfbi/SenchaCon2011/ExtJSJavaHowto.pdf

http://laboris.fortis-it.de/~urbanfbi/SenchaCon2011/ExtJSJavaHowto.pdf

Java Server-side Breakout

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