Leonardo França » Java

Lazy Loading with Adobe Flex and BlazeDS

Leonardo França — Tue, 31 Aug 2010 11:05:08 +0000

BlazeDS is an implementation in Java for working with the protocol AMF (Action Message Format) and facilitate communication between the swf and your server-side Java.
When you begin to use a resource unlike most people, you may find some problems difficult to solve. Flex with Java and the problem is the old Lazy Loading, which already was the subject of several conversations between me and Wenderson. I left this issue aside to focus on other things. However the Wenderson managed to find a solution, see the full article with the solution.
Adobe Flex, BlazeDS, Gilead, LazyLoading Resolvido(LazyLoading Solved)

Recommended books:

Options for Mobile Development

Leonardo França — Thu, 19 Aug 2010 21:07:56 +0000

The mobile market is one of the fastest growing lately, and with it the demand for applications for this growing niche also bringing one more option for anyone who is a developer and new business opportunities. You developer who likes to keep up, you know exactly what I’m talking about. In this article I gathered some links that those who want to start with mobile development in at least three different platform in which I had lately demands.

The mobile market is one of the fastest growing lately, and with it the demand for applications for this growing niche also bringing one more option for anyone who is a developer and new business opportunities

Among the platforms available for mobile development, we can highlight:

Java with JME
Nokia Qt, besides being able to use WRT(Web RunTime)
Flash Lite
Android SDK from Google with the addition of Adobe AIR and Flash Player 10.1
IPhone

‘ll Comment a little bit of each:

Java with JME
JME (Java Micro Edition) is the version that Sun offers for you to program in Java for mobile devices. It offers an enormous range of API’s that were made specifically. Has a very complete documentation and several examples. I leave a link how to set up your environment for development JME.

Nokia Qt
Nokia offers Qt, Cross-plaftorm application and UI framework, with specific libraries for mobile devices (such as QTMobility). You program in C++ and there is an interface language like MXML. Has its own IDE and has emulators for Symbian S60, 40 and Symbian^3 beyond Maemo and Meego.

Adobe Flash Lite
Adobe Flash Lite still has space on the market, with a different version of the Flash player with some features specific to mobile devices. The development environment is to own Adobe Flash Professional and Adobe Device Central.

Google Android
Google offers for the Android platform a set of SDK’s and emulators for the different versions of its operating system with each passing day it becomes more popular. It has a plugin for you to program in Eclipse, the Android Development Tools(ADT). The language used is Java. From Android 2.2 (Froyo) you have the option to create applications in Adobe AIR, the AIR runtime is installed on the device and you create the application using Adobe Flash Professional (which has an extension to create the files .apk) or Adobe Flash Builder.

Apple IPhone
Who wants to program for iPhone, ipad and the like, Apple provides an SDK. You use the Objective-C language, derived from C, and some interesting libraries developed for working with muiltitouch like Cocoa. We’ll find a list of frameworks.

Well, we have options, it behooves us to analyze only that can best serve our customers. Should stay something about Windows Phone 7 because it seems to me very promising and deserves attention too.

Nokia Qt, C++, Symbian, Meego
Qt for Symbian
S60 (Software Platform): Qt, Nokia 5800 Xpressmusic, S60, Nokia Pc Suite, Python for S60, the Core Pocket Media Player, Nokia E75
Beginning Nokia Apps Development: Using MeeGo, Mobile QT and OpenSymbian
Porting to the Symbian Platform: Open Mobile Development in C/C++ (Symbian Press)

Adobe Flash Lite
AdvancED Flash on Devices: Mobile Development with Flash Lite and Flash 10
Professional Flash Lite Mobile Development (Wrox Programmer to Programmer)
Foundation Flash Applications for Mobile Devices

Android
Hello, Android: Introducing Google’s Mobile Development Platform (Pragmatic Programmers)
Android Application Development: Programming with the Google SDK
Professional Android 2 Application Development (Wrox Programmer to Programmer)

IPhone
Beginning iPhone 3 Development: Exploring the iPhone SDK
iPhone Programming: The Big Nerd Ranch Guide (Big Nerd Ranch Guides)
The iPhone Developer’s Cookbook: Building Applications with the iPhone 3.0 SDK (2nd Edition)

Windows Phone 7
Learning Windows Phone Programming
Windows Mobile Game Development: Building games for the Windows Phone and other mobile devices (Expert’s Voice in .NET)
Programming Windows Phone 7

Radicalism?

Leonardo França — Thu, 25 Feb 2010 14:38:47 +0000

This post was originally written several years ago, it was only as a draft and strangely remains current.

Sometimes I see on the Internet some movement “anti-Flash”, something really strange, it seems religion. There is a culture of saying that Flash is a program “to make a ball go” or that “Flash has accessibility zero, this is very far from the truth. it is possible to make extremely complex applications with Flash. And when there is a kind of “dispute” between ~~AJAX X FLASH~~ ~~Flash x Silverlight~~ Flash x HTML5. From time to time there is a new “Flash-killer”, I think they are different technologies and complement. I see the same kind of radicalism in relation to PHP X Cold Fusion, ASP X PHP, PHP X PHYTON, Open Source X Proprietary etc.
I have also been very radical, defending PHP tooth and nail, spoke ill of any other language that was not PHP without even know it, but I realized that those who still think that way, limits their opportunities to major world today no matter what tool you use but how you use the tool, who heard “The bad employee blames his tools work”?.
Always worked with Flash and PHP, when I entered the BANCOOB, I felt compelled to learn Java, was a challenge that could overcome. Shortly after I entered the migration project, which would have to program in C # and Visual Basic, many of my friends simply do not accept into the project. I heard things like, “look at my curriculum and see if it is VB” and called the loose, but the end result was a great experience for me, I was able to grow much.
I have already been many philosophical discussions, and today I have no more patience for it when I see that this conversation tends to radicalism or religion, I lose the will to fully discuss.
Working with Flash since version 5, I followed closely the development of the tool, and the long ceased to be just a “plugin” to become a development platform for several devices. Of course with that, disrespect the competition, which is great. After all we must always move.

Developers who do not work with Flash, underestimate the power he has.

I’m not the only one who thinks this story that “one will replace the other” makes no sense, to own Adobe preaches that the two work perfectly together, so that the Adobe Dreamweaver CS5 already has support HTML5.
The launch of the iPad was the trigger for the so-called “anti-Flash”. it mounted the perfect setting for a healthy discussion, where we could point out the strengths and weaknesses of a given technology and how it can be improved. But what we have seen is just the opposite, I’ve seen several articles and comments from people simply saying “I hate Flash”, sites with sensational headlines(what they did to the post of Lee was disgusting!!!), Each week a different rumor that people believe without checking the sources and the same conversation 5 years ago.

Meanwhile, the client ta little matter if you use this tool or that, what matters to him is that you do the job.

The bad employee blames his tools work.

Integrating Flex with Java using BlazeDS – first steps

Leonardo França — Fri, 21 Aug 2009 19:30:45 +0000

Adobe Flex has become a trend when it comes to view layer between developers, analyst, managers and especially users, and can integrate with virtually any language programming. In the layer of business have a good race between Java and .NET(ok ok Java takes advantage).
For the Flex can integrate seamlessly with Java, you need a gateway(a device that works in any layer of the ISO/OSI to win "differences" between networks, manipulating and converting data). that can convert the native data types of Flex to data types native to Java and vice versa using AMF protocol..
In the following link we have the data types of Flex and its counterpart in Java:
http://livedocs.adobe.com/flex/3/html/help.html?content=data_access_4.html
The AMF(Action Message Format) is protocol with open specification, compact and tranvels in binary format, and the ActionScript 3.0, will be the AMF3 supported data type specific to AS3.
Today we have several implementations that support AMF3, we use BlazeDS as a gateway for communication in ActionScript 3 and Java.
The database named "contacts" will be used MySQL with the following structure:

PLAIN TEXT

SQL:

CREATE TABLE `tabela` (                 
          `id` int(11) NOT NULL,                
          `nome` varchar(30) DEFAULT NULL,      
          `email` varchar(100) DEFAULT NULL,    
          PRIMARY KEY  (`id`)                   
        ) ENGINE=InnoDB DEFAULT CHARSET=latin1

As application server we use the JBoss Application Server and will use the Eclipse and Flex Builder for coding respectively (you can to use Eclipse for Flex and Java in same IDE).
BlazeDS comes by default witn Tomcat, ~~but it is only container servlet~~. With JBoss can use later ejb3, JPA, Hibernate etc.
Download the latest version of BlazeDS this link
Having everything and properly configured, let's enconding:

Create a new project type "Dynamic Web Project" and name it "Contacts".
Select the "Target Runtime" as JBoss and "Configurations" with "Default Configuration for JBoss v4.2.
In "Projects Facets" does not need to change anything, just click next.
In "Web Module" does not need to change anything, click Finish.

Done that we can begin our coding, but we will insert into project the BlazeDS libraries, if you downloaded the bin BlazeDS, just unzip the "blazeds.war" with some winrar and copy the diretory "WEB-INF\lib" into our project in "WebContent\WEB-INF\lib", so then d the same thing with the directory "WEB-INF\flex" and the file "WEB-INF\web.xml".
Configure JBoss to start the eclipse project and add the "Contacts" to be publised automatically on start JBoss (if you have not configured yet, follow the steps in this link).
Now let's test our BlazeDS is properly configured, simply open the browser and enter the following address:

http://localhost:8080/Contatos/messagebroker/amf

if you see a blank page, it means that BlazeDS is ready to be used

Let our VO, create a package called "br.com.leonardofranca.vo" and create a class called "ContatosVO", your code is as follow:

PLAIN TEXT

JAVA:

package br.com.leonardofranca.vo;
 
public class ContatosVO 
{
    private int id;
    private String nome;
    private String email;
    
    public int getId() 
    {
        return id;
    }
    
    public void setId(int id) 
    {
        this.id = id;
    }
    
    public String getNome() 
    {
        return nome;
    }
    
    public void setNome(String nome) 
    {
        this.nome = nome;
    }
    
    public String getEmail() 
    {
        return email;
    }
    
    public void setEmail(String email) 
    {
        this.email = email;
    }
}

Until now, no mystery, we have a simple object to be typed using Java. Let our main class that will do all the work.

PLAIN TEXT

JAVA:

package br.com.leonardofranca;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
 
import br.com.leonardofranca.vo.ContatosVO;
 
public class Contatos 
{
    Connection conn; 
    Statement stm;
    ResultSet rs;
 
    public Contatos()
    {
        try
        {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/meubanco","root","minhasenha");
            stm = conn.createStatement();
        }
        catch (Exception e) 
        {
            e.printStackTrace();
        }
    }
 
    public List<ContatosVO> getData()
    {
        List<ContatosVO> list = new ArrayList<ContatosVO>();
        try 
        {
            rs = stm.executeQuery("SELECT id, nome, email FROM tabela");
            while (rs.next()) 
            {
                ContatosVO contatosVO = new ContatosVO();
                contatosVO.setId(rs.getInt("id"));
                contatosVO.setNome(rs.getString("nome"));
                contatosVO.setEmail(rs.getString("email"));
                list.add(contatosVO);
            }
        } 
        catch (SQLException e) 
        {
            e.printStackTrace();
        }
        return list;
    }
    
    public Boolean insertData(ContatosVO contatosVO)
    {
        try 
        {
            String sql = "INSERT INTO tabela (nome, email) VALUES('"+contatosVO.getNome()+"','"+contatosVO.getEmail()+"')";
            if(stm.execute(sql))
            {
                return true;
            }
        } 
        catch (SQLException e) 
        {
            e.printStackTrace();
        }
        return false;
    }
    
    public Boolean deleteData(ContatosVO contatosVO)
    {
        try 
        {
            stm = conn.createStatement();
            String sql = "DELETE FROM tabela WHERE id = '"+contatosVO.getId()+"'";
            if(stm.execute(sql))
            {
                return true;
            }
        } 
        catch (SQLException e) 
        {
            e.printStackTrace();
        }
        return false;
    }
    
    public Boolean updateData(ContatosVO contatosVO)
    {
        try 
        {
            stm = conn.createStatement();
            String sql = "UPDATE tabela SET nome = '"+contatosVO.getNome()+"', email = '"+contatosVO.getEmail()+"' WHERE id = '"+contatosVO.getId()+"'";
            if(stm.execute(sql))
            {
                return true;
            }
        } 
        catch (SQLException e) 
        {
            e.printStackTrace();
        }
        return false;
    }
}

In the constructr instantiate the class from the database, the following method is to list the data from the database, returning a List of Java that fed my DataGrid in Flex, the rest of the methods (insertm update and delete) just let me return a Boolean.

Now let the party in Flex.
We begin by VO part of Flex, note that it is necessary to put the "RemoteClass":

PLAIN TEXT

ACTIONSCRIPT3:

package br.com.leonardofranca.vo
{
    [Bindable]
    [RemoteClass(alias="br.com.leonardofranca.vo.ContatosVO")]
    public class ContatosVO
    {
        public var id:uint;
        public var nome:String;
        public var email:String;
        
        public function ContatosVO()
        {
        }
 
    }
}

We now implement our presentation layer, we need a form with two fields name and emai, and a DataGrid to list the email database, we still nedd three buttons, one for insert, update and delete records from database.

PLAIN TEXT

MXML:

"1.0" encoding="utf-8"?>
 xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
 x="0" y="0" width="100%" height="100%">
         width="338" height="389" layout="absolute">
             x="0" y="0" width="100%" height="100%">
                 label="Nome:">
                     id="input_nome"/>
                >
                 label="Email:">
                     id="input_email"/>
                >
                >
                     id="btnCadastrar" label="Cadastrar" />
                >
                >
                     label="Excluir"/>
                >
                >
                     label="Atualizar" />
                >
            >
        >
         height="390" id="dg">
            >
                 headerText="id" dataField="id"/>
                 headerText="Nome" dataField="nome"/>
                 headerText="Email" dataField="email"/>
            >
        >
    >
>

Usually now we would need to configure the services-config.xml for the swf know where to get the service. But do differently, i will set right in the endpoint of RemoteObject:

PLAIN TEXT

MXML:

 id="ro" destination="blazeds" source="br.com.leonardofranca.Contatos"  endpoint="http://localhost:8080/Contatos/messagebroker/amf">
         name="getData" result="onResult(event);" fault="onFault(event);"/>
         name="insertData" result="onResultData(event);" fault="onFault(event);"/>
         name="deleteData" result="onResultData(event);" fault="onFault(event);"/>
         name="updateData" result="onResultData(event);" fault="onFault(event);"/>
>

And the tag method,mlet configured to call the methods in my Java class, Now just write the functions that will receive the returns of success or failure, note that i left the same method in case of failure.

PLAIN TEXT

ACTIONSCRIPT3:

import mx.controls.Alert;
            import mx.events.ListEvent;
            import br.com.leonardofranca.vo.ContatosVO;
            import mx.collections.ArrayCollection;
            import mx.rpc.events.FaultEvent;
            import mx.rpc.events.ResultEvent;
            
            public function init():void
            {
                dg.addEventListener(ListEvent.CHANGE,selectedItems);
            }
            
            public function onResult(re:ResultEvent):void
            {
                var data:Object = re.message.body;
                dg.dataProvider = data;
            }
            
            public function onFault(fault:FaultEvent):void
            {
                trace("Code: "+fault.fault.faultCode);
                trace("Detail: "+fault.fault.faultDetail);
                trace("String: "+fault.fault.faultString);
            }
            
            public function insertData():void
            {
                var contatosVO:ContatosVO = new ContatosVO();
                contatosVO.nome = input_nome.text;
                contatosVO.email = input_email.text;
                ro.insertData(contatosVO);
            }
            
            public function onResultData(re:ResultEvent):void
            {
                ro.getData();
            }
            
            public function deleteData():void
            {
                if(dg.selectedItem != null)
                {
                    var contatosVO:ContatosVO = new ContatosVO();
                    contatosVO.id = dg.selectedItem.id;
                    ro.deleteData(contatosVO);
                }
                else
                {
                    Alert.show("Selecione um item da tabela!!!");
                }
            }
            
            public function selectedItems(evt:ListEvent):void
            {
                input_nome.text = dg.selectedItem.nome;
                input_email.text = dg.selectedItem.email;
            }
            
            public function updateData():void
            {
                if(dg.selectedItem != null)
                {
                    var contatosVO:ContatosVO = new ContatosVO();
                    contatosVO.id = dg.selectedItem.id;
                    contatosVO.nome = input_nome.text;
                    contatosVO.email = input_email.text;
                    ro.updateData(contatosVO);
                }
                else
                {
                    Alert.show("Selecione um item da tabela!!!");
                }
            }

Following the complete code:

PLAIN TEXT

MXML:

"1.0" encoding="utf-8"?>
 xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="ro.getData();init();">
    >
        [CDATA[
            import mx.controls.Alert;
            import mx.events.ListEvent;
            import br.com.leonardofranca.vo.ContatosVO;
            import mx.collections.ArrayCollection;
            import mx.rpc.events.FaultEvent;
            import mx.utils.ObjectUtil;
            import mx.rpc.events.ResultEvent;
            
            public function init():void
            {
                dg.addEventListener(ListEvent.CHANGE,selectedItems);
            }
            
            public function onResult(re:ResultEvent):void
            {
                var data:Object = re.message.body;
                dg.dataProvider = data;
            }
            
            public function onFault(fault:FaultEvent):void
            {
                trace("Code: "+fault.fault.faultCode);
                trace("Detail: "+fault.fault.faultDetail);
                trace("String: "+fault.fault.faultString);
            }
            
            public function insertData():void
            {
                var contatosVO:ContatosVO = new ContatosVO();
                contatosVO.nome = input_nome.text;
                contatosVO.email = input_email.text;
                ro.insertData(contatosVO);
            }
            
            public function onResultData(re:ResultEvent):void
            {
                ro.getData();
            }
            
            public function deleteData():void
            {
                if(dg.selectedItem != null)
                {
                    var contatosVO:ContatosVO = new ContatosVO();
                    contatosVO.id = dg.selectedItem.id;
                    ro.deleteData(contatosVO);
                }
                else
                {
                    Alert.show("Selecione um item da tabela!!!");
                }
            }
            
            public function selectedItems(evt:ListEvent):void
            {
                input_nome.text = dg.selectedItem.nome;
                input_email.text = dg.selectedItem.email;
            }
            
            public function updateData():void
            {
                if(dg.selectedItem != null)
                {
                    var contatosVO:ContatosVO = new ContatosVO();
                    contatosVO.id = dg.selectedItem.id;
                    contatosVO.nome = input_nome.text;
                    contatosVO.email = input_email.text;
                    ro.updateData(contatosVO);
                }
                else
                {
                    Alert.show("Selecione um item da tabela!!!");
                }
            }
        ]]>
    >
     id="ro" destination="blazeds" source="br.com.leonardofranca.Contatos"  endpoint="http://localhost:8080/Contatos/messagebroker/amf">
        "getData" result="onResult(event);" fault="onFault(event);"/>
         name="insertData" result="onResultData(event);" fault="onFault(event);"/>
         name="deleteData" result="onResultData(event);" fault="onFault(event);"/>
         name="updateData" result="onResultData(event);" fault="onFault(event);"/>
    >
     x="0" y="0" width="100%" height="100%">
         width="338" height="389" layout="absolute">
             x="0" y="0" width="100%" height="100%">
                 label="Nome:">
                     id="input_nome"/>
                >
                 label="Email:">
                     id="input_email"/>
                >
                >
                     id="btnCadastrar" label="Cadastrar" click="insertData();"/>
                >
                >
                     label="Excluir" click="deleteData();"/>
                >
                >
                     label="Atualizar" click="updateData();"/>
                >
            >
        >
         height="390" id="dg">
            >
                 headerText="id" dataField="id"/>
                 headerText="Nome" dataField="nome"/>
                 headerText="Email" dataField="email"/>
            >
        >
    >
>

If you got this far ok! everything right and working, but you can forget, i will go show a better and efficient to integrate Flex with Java

[UPDATE]
I forgot to mention that you need a directory of the project in eclipses, called "WebContent/WEB-INF/flex" to be included in the files: services-config.xml, remoting-config.xml, proxy-config.xml, messaging-config. xml. the project is only necessary that the remoting-config.xml, whose content should be like the code below

PLAIN TEXT

XML:

 version="1.0" encoding="UTF-8"?>
 id="remoting-service" 
    class="flex.messaging.services.RemotingService">
 
    >
         id="java-object" class="flex.messaging.services.remoting.adapters.JavaAdapter" default="true"/>
    >
 
    >
         ref="my-amf"/>
    >
    
     id="blazeds">  
          >  
             >br.com.leonardofranca.Contatos> 
             >session>
           >
     >  
>

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