D-Blog

Gwt-Ext example “loading data from database”

Sep 28th, 2008 by Dariusz

After seen a good example of how to save data into the database. I decided to write an example how to fetch data coming from a database.

For this example I will use hibernate to make it more easy for loading the data. In this example I won’t go too much in detail how hibernate works, instead how a server call populates data on front end.

If you take a look on my previous posts, you should be able to follow this application. I will just populate the data in the grid, as soon the user see the page. Basically, I will just present the manager class, which is responsible for getting the data and make it accessible in my Service class.

The example shown here is based on the demo, you can see on GWT-Ext Showcase.

If you are interested in my first posts (Setting up & Login example), here are the links:

Lets do it…

Database

My ‘contacts‘ database is setup as follow:

And here are the tables:

user:

gender:

Values of user table:

Values of gender table:

Eclipse structure

First of all I want to show the end result, after the application is up and running. Here is the structure of my ‘Data Grid’ application.

My libraries I’m using are as follow:

CSS (under: org.mypackage.public.css) grid.css:

.db_icon
{
background-image: url(../js/ext/resources/icons/database.gif) !important;
padding-right: 5px;
margin: 0 !important;
}

Main module Main.gwt.xml:

<module>
<!– Inherit the core Web Toolkit stuff. –>
<inherits name=‘com.google.gwt.user.User’/>
<!– Inherit the GWTExt Toolkit library configuration. –>
<inherits name=‘com.gwtext.GwtExt’ />
<!– Set our own css file –>
<stylesheet src="css/grid.css" />
<!– Specify the app entry point class. –>
<entry-point class=‘org.mypackage.client.Main’/>
<stylesheet src="js/ext/resources/css/ext-all.css" />
<script src="js/ext/adapter/ext/ext-base.js" />
<script src="js/ext/ext-all.js" />
</module>

Java:

Here is my Main.java class, which is the main module:

package org.mypackage.client;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.rpc.ServiceDefTarget;
import com.google.gwt.user.client.ui.RootPanel;
import com.gwtext.client.core.TextAlign;
import com.gwtext.client.data.BooleanFieldDef;
import com.gwtext.client.data.FieldDef;
import com.gwtext.client.data.IntegerFieldDef;
import com.gwtext.client.data.JsonReader;
import com.gwtext.client.data.Record;
import com.gwtext.client.data.RecordDef;
import com.gwtext.client.data.Store;
import com.gwtext.client.data.StringFieldDef;
import com.gwtext.client.widgets.MessageBox;
import com.gwtext.client.widgets.Panel;
import com.gwtext.client.widgets.grid.CellMetadata;
import com.gwtext.client.widgets.grid.ColumnConfig;
import com.gwtext.client.widgets.grid.ColumnModel;
import com.gwtext.client.widgets.grid.GridPanel;
import com.gwtext.client.widgets.grid.Renderer;
public class Main implements EntryPoint {
private DataServiceAsync dataService = ( DataServiceAsync )GWT.create( DataService.class );
private Panel dataPanel = new Panel();
private String jsonData = null;
private Store store = null;
public void onModuleLoad() {
ServiceDefTarget endpoint = ( ServiceDefTarget )dataService;
String moduleRelativeURL = GWT.getModuleBaseURL()+"data";
endpoint.setServiceEntryPoint( moduleRelativeURL );
loadData();
dataPanel.setBorder( false );
dataPanel.setPaddings( 15 );
final RecordDef recordDef = new RecordDef( new FieldDef[] {
new StringFieldDef( "firstName", "firstName" ),
new StringFieldDef( "lastName", "lastName" ),
new IntegerFieldDef( "age", "age" ),
new StringFieldDef( "gender", "gender" ),
new BooleanFieldDef( "married", "married"),
});
JsonReader reader = new JsonReader( recordDef );
reader.setRoot( "users" );
reader.setTotalProperty( "totalCount" );
store = new Store( reader );
ColumnModel columnModel = new ColumnModel( getColumnConfig() );
GridPanel grid = new GridPanel();
grid.setTitle( "Loading content from Database" );
grid.setStore( store );
grid.setColumnModel( columnModel );
grid.setFrame( true );
grid.setWidth( 440 );
grid.setHeight( 350 );
grid.stripeRows( true );
grid.setIconCls( "db_icon" );
dataPanel.add( grid );
RootPanel.get( "grid_widget" ).add( dataPanel );
}
/** Method responsible for loading data */
private void loadData() {
AsyncCallback callback = new AsyncCallback()
{
public void onSuccess( Object result )
{
jsonData = null;
jsonData = result.toString();
store.loadJsonData( jsonData, true );
// must commit changes to see the data
// inside the grid!!!
store.commitChanges();
}
public void onFailure( Throwable ex )
{
MessageBox.alert( "Error", "Error while loading data" );
}
};
dataService.getUsers( callback );
}
/**
* Column config setup
* @return the column config
*/
private ColumnConfig[] getColumnConfig() {
ColumnConfig fNameCol = new ColumnConfig( "First Name", "firstName", 100, true );
ColumnConfig lNameCol = new ColumnConfig( "Last Name", "lastName", 100, true );
ColumnConfig ageCol = new ColumnConfig( "Age", "age", 50, true );
ColumnConfig genderCol = new ColumnConfig( "Gender", "gender", 100, true );
genderCol.setRenderer( new Renderer() {
public String render( Object value, CellMetadata cellMetadata,
Record record, int rowIndex, int colNum, Store store ) {
String openStatus = "style=\"font-weight: bold; color: blue;\"";
String closeStatus = "style=\"font-weight: bold; color: #CC0066;\"";
if( value.toString().equals( "Male" ) )
{
cellMetadata.setHtmlAttribute( openStatus );
}
else
{
cellMetadata.setHtmlAttribute( closeStatus );
}
return value.toString();
}
});
ColumnConfig marriedCol = new ColumnConfig( "Married", "married", 70, true );
marriedCol.setAlign( TextAlign.CENTER );
marriedCol.setRenderer( new Renderer() {
public String render(Object value, CellMetadata cellMetadata,
Record record, int rowIndex, int colNum, Store store) {
boolean checked = ( ( Boolean )value ).booleanValue();
return "<img class="\" src="\" alt="" />";
}
});
ColumnConfig[] columnConfigs = {
fNameCol,
lNameCol,
ageCol,
genderCol,
marriedCol
};
return columnConfigs;
}
}

My peristent classes User.java and Gender.java classes, are regular objects with getters and setters. No need to go deeper into it.

DataService.java looks like this:

package org.mypackage.client;
import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.rpc.RemoteService;
import com.google.gwt.user.client.rpc.ServiceDefTarget;
public interface DataService extends RemoteService {
public static final String SERVICE_URI = "/data";
public static class Util {
public static DataServiceAsync getInstance() {
DataServiceAsync instance = (DataServiceAsync) GWT
.create(DataService.class);
ServiceDefTarget target = (ServiceDefTarget) instance;
target.setServiceEntryPoint(GWT.getModuleBaseURL() + SERVICE_URI);
return instance;
}
}
// Gets the JSON data
public String getUsers();
}

DataServiceAsync.java :

package org.mypackage.client;
import com.google.gwt.user.client.rpc.AsyncCallback;
public interface DataServiceAsync {
// Gets the JSON data
public void getUsers( AsyncCallback callback );
}

The manager class (UserManager.java) takes care of creating a JSON object to be able to populate it on the front end. I decided to use JSON simple, with a nice documentation. You can download it here:

Download JSON simple

Now, here is the whole UserManager.java

package org.mypackage.manager;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.hibernate.Session;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.mypackage.pojo.Gender;
import org.mypackage.pojo.User;
import org.mypackage.util.HibernateUtil;
public class UserManager {
/** The user list */
private List userList = null;
/** The instance */
private static UserManager instance = null;
/** Class constructor just to defeat instantiation */
protected UserManager() {}
/** Gets the instance. */
public static UserManager getInstance() {
if( instance == null ) {
instance = new UserManager();
}
return instance;
}
/** Gets a json list of all users. */
public JSONObject getUsers() {
userList = new ArrayList();
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
userList = session.createQuery( "from User" ).list();
JSONObject root = new JSONObject();
JSONArray users = new JSONArray();
for( Iterator iterator = userList.iterator(); iterator.hasNext(); )
{
User user = ( User )iterator.next();
Gender gender = user.getGender();
JSONObject jsonUser = new JSONObject();
jsonUser.put( "firstName", user.getFirstName() );
jsonUser.put( "lastName", user.getLastName() );
jsonUser.put( "age", new Integer( user.getAge() ) );
jsonUser.put( "gender", gender.getTitle() );
jsonUser.put( "married", new Boolean( user.getMarried() ) );
users.add( jsonUser );
}
session.close();
root.put( "users", users );
return root;
}
}

A clean JSON output would be this:

{
"users": [
{
"married": false,
"gender": "Male",
"age": 25,
"firstName": "John",
"lastName": "Doe"
},
{
"married": true,
"gender": "Male",
"age": 32,
"firstName": "Foo",
"lastName": "Bar"
},
{
"married": true,
"gender": "Female",
"age": 28,
"firstName": "Mandy",
"lastName": "Boo"
},
{
"married": false,
"gender": "Male",
"age": 45,
"firstName": "Joe",
"lastName": "Black"
}
]
}

If you now open your DataServiceImpl.java, then you can easily start using your manager class to get the data from the database.

package org.mypackage.server;
import org.mypackage.client.DataService;
import org.mypackage.manager.UserManager;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;
public class DataServiceImpl extends RemoteServiceServlet implements DataService {
private UserManager userManager = null;
public String getUsers() {
userManager = UserManager.getInstance();
String users = userManager.getUsers().toString();
return users;
}
}

If you run your application, you should see this result:

I hope this example was helpful.

Dariusz

Posted in Database, Eclipse, Software, gwt-ext, hibernate, java | 51 Comments

51 Responses to “Gwt-Ext example “loading data from database””

on 29 Sep 2008 at 12:36 pm1Arno.Nyhm

this code part looks a little confusing:
- where comes the checkbox?
- the escape of ” looks not ok.

ColumnConfig marriedCol = new ColumnConfig( “Married”, “married”, 70, true );
marriedCol.setAlign( TextAlign.CENTER );
marriedCol.setRenderer( new Renderer() {
public String render(Object value, CellMetadata cellMetadata,
Record record, int rowIndex, int colNum, Store store) {
boolean checked = ( ( Boolean )value ).booleanValue();
return “”;
}
});
on 29 Sep 2008 at 1:21 pm2Dariusz

Arno,
I just saw, that while I was copying the source from my Eclipse, part of them just disappeared… I make the changes now.

By the way, the whole grid comes from the official gwt-ext demo. You can take a look on the source code there: http://www.gwt-ext.com/demo/#localXmlGrid

Thanks,
Dariusz
on 29 Sep 2008 at 2:04 pm3Arno.Nyhm

thx
on 29 Sep 2008 at 5:54 pm4Chuck

How about an eclipse project file or war file? Having trouble getting GWT and Eclipse WTP working together. Thanks for posting this!
on 29 Sep 2008 at 6:19 pm5Dariusz

I’m using this version of Eclipse.

Did you read this post?

And this shows how to start developing GWT with Cypal:

Dariusz
on 04 Oct 2008 at 10:16 am6Pedro

Dariusz, that was a great tutorial, it worked with a few minor corrections.

Few comments:
Main.gwt.xml: replace , with <!– –>
Perhaps Wordpress was fixing those? Maybe you can use & gt; — and & lt;

In “public JSONObject getUSers()”
Instead of:
session.getSessionFactory().close();

It should be:
session.close();
before
root.put( “users”, users );

So that we can keep refreshing the browser window and keep getting valid JSON requests from the server. Once the SessionFactory is closed, we get NullPointerExceptions when requerying.

The database.gif icon was not found in the ExtJS 2.0.2 distribution.
I used this one instead:
../js/ext/resources/images/default/dd/drop-yes.gif

And with all those changes, I got rid of all errors and warnings.

Thanks Dariusz!
Keep up with the great work!!!
on 06 Oct 2008 at 7:01 pm7Dariusz

Thanks Pedro!
I made the changes in the Main.gwt.xml. It should be fine now.
You can download great icons on this page.

I see the point with closing session, but if I take a look in the log file I can see that the way I did it, I’m closing the hibernate session. If I do your way, I can’t see the closing statement.
Could you tell me the advantage of using it your way?

Thanks a lot!
on 09 Oct 2008 at 9:56 am8Dariusz

OK, never mind. I made the changes in closing the hibernate session before I add users to the root.

Thanks Pedro!
on 31 Oct 2008 at 7:56 pm9pakcikkantin

Dear Dar,
I received this error
[ERROR] Unable to instantiate ‘org.mypackage.server.DataServiceImpl’
Do i miss something
Please help, tq
on 31 Oct 2008 at 8:52 pm10Dariusz

Hi!
If you could send the whole exception message, that would be a help. Did you check the web.xml file? Maybe it’s not mentioned in it. Are you using Cypal Plugin?
on 05 Nov 2008 at 5:06 am11pedro

Hi Dariusz,

I don’t come to this web page often, so it’s hard to get your question.
I happen to revisit your site, and find your question now.
I would be very glad to answer it here.

You probably have some code that creates the SessionFactory in HibernateUtil.

There should be a single SessionFactory for the lifecyle of the Servlet:
http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/Servlets4.html
http://www.stardeveloper.com/articles/display.html?article=2001111901&page=1
That’s where you should create and destroy SessionFactory.

Hibernate’s SessionFactory can create many instances of Session.
For every HttpServletRequest, there should be a single Session with a short lifespan.
Another possibility is attaching the Hibernate Session to the HttpSession, and making sure the Session is destroyed when the HttpSession is destroyed (use and register HttpSessionListener)
You should register all the appropriate in the web.xml file.

You can take a look at the Spring framework to get cleaner dependency injection for more complicated and realistic cases. That’s another big subject =)

I hope I have answered your question.
Your tutorials on gwt-ext are really good contributions to the many developers.

Regards,
Pedro
on 05 Nov 2008 at 5:09 am12pedro

In the line:
You should register all the appropriate in the web.xml file.

It should be:
You should register all the appropriate “listeners” in the web.xml file.

Wordpress deleted my word, since I used the “greater than” and “less than” symbols conflicting with HTML.

Cheers,
Pedro
on 05 Nov 2008 at 8:57 am13Dariusz

Pedro,

Thanks a lot. I’m glad you answered my question. I think I have to improve my hibernate implementation in future.

Cheers,
Dariusz
on 05 Nov 2008 at 6:09 pm14pedro

Dariusz,

Think of SessionFactory as a database connection pool, and Hibernate\’s Session as database transactions where you want to finish your database operations quickly with commit/rollback.
SessionFactory is an expensive object to create, Session\’s are cheap.

I have been addicted to iBATIS for some years, but now I\’m looking into Hibernate and Spring.
Persistence in Java is moving too fast with too many options:
Hibernate, JPA, Spring 2.5 integration, and options to use JDK 5 annotations or not.

I recommend a really good practical book on Hibernate: \"Harnessing Hibernate\",
and for Spring 2.5: \"Spring Recipes\".

Happy learning,
Pedro
on 25 Nov 2008 at 5:40 pm15usman

hi,
this tutorial is very nice.but for me the grid headings are coming but data inside are not coming and also i am not getting any error.i checked the database part also for data,please tell me what is the problem

thanks
usman.sk
on 25 Nov 2008 at 5:57 pm16Dariusz

I had the same problem, but it was due to a function I didn’t call after loading data. Take a look in the Main.java.

You see in line: 89 that I am calling: “store.commitChanges();” If I don’t use this method, I don’t see any errors, but neither the data inside the grid.
on 27 Nov 2008 at 7:53 pm17usman

hi,
i got the solution.there is a mismatch between root.put( “users1″, users ); and reader.setRoot( “users” ); .thanks to answered my question
on 27 Nov 2008 at 11:15 pm18Dariusz

Hey Usman,
Glad you sorted it out!
on 05 Dec 2008 at 12:53 am19Mark

Hi Dariusz,
I have an GWT RPC based app where I wanted to replace an old Grid with a nice GridPanel. I’d like to keep the GWT RPC mechanism to fetch the data just like you’ve done it. I also want to use a PagingToolbar to navigate in a large data set, so I thought of subclassing DataProxy [that in my view should be responsible for paging] and possibly Reader. What I can’t figure out is how these messages “next”, “prev”, etc. are communicated from the toolbar to the proxy. I’d appreciate your insight. Or maybe you know how to get to the source code of the classes in the com.gwtext.client.data package. I think I’d be able to figure it out from the source.
Thank you in advance,
Mark
on 04 Jan 2009 at 6:39 pm20extjs-gwt

Hi,
How to setup Ext js-GWT : GXT and Example on Eclipse Ganymede 3.4
Follow this: http://www.gwt-ext.com/wiki/index.php/Using_Eclipse
on 04 Jan 2009 at 6:42 pm21extjs-gwt

like this: http://extjs-gwt.blogspot.com/
on 05 Jan 2009 at 2:34 am22sony

Hi,
I found your description very helpful, can u please tell me how can i setup Hibernate ??
thx
on 13 Feb 2009 at 2:18 pm23xaxera

Hi,I was wondering if u could share your working source because I can\’t set it work!
I am a newbie to GWT and would like to ask for some help!
By the way u can use JPA for making the query:

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

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.unimasters.plc.entities.Gender;
import org.unimasters.plc.entities.User;

public class UserManager {
private static final long serialVersionUID = 370732473547L;
private EntityManager em;
private EntityManagerFactory emf;
private String persistenceUnit = \"TestExample\";

/** The user list */
private List userList = null;

/** The instance */
private static UserManager instance = null;

/** Class constructor just to defeat instantiation */
protected UserManager() {
}

/** Gets the instance. */
public static UserManager getInstance() {
if (instance == null) {
instance = new UserManager();
}
return instance;
}

/** Gets a json list of all users. */
public JSONObject getUsers() {
userList = new ArrayList();
emf = Persistence.createEntityManagerFactory(persistenceUnit);
em = emf.createEntityManager();
Query q = em.createQuery(\"Select u from User u\");
List<User> results = (List<User>)q.getResultList();
userList = (ArrayList<User>) results;

JSONObject root = new JSONObject();
JSONArray users = new JSONArray();
for (Iterator iterator = userList.iterator(); iterator.hasNext();) {
User user = (User) iterator.next();
Gender gender = user.getGenderid();
JSONObject jsonUser = new JSONObject();
jsonUser.put(\"firstName\", user.getFirstname());
jsonUser.put(\"lastName\", user.getLastname());
jsonUser.put(\"age\", new Integer(user.getAge()));
jsonUser.put(\"gender\", gender.getTitle());
jsonUser.put(\"married\", new Boolean(user.getMarried()));
users.add(jsonUser);
}
// session.close();
root.put(\"users\", users);
return root;
}
}
on 10 Jul 2009 at 3:36 pm24Swario

Hi Dariusz,
i’m interested in how to develop a connection pool vith the GWT.
In my project i’m not using Hibernate so, i’m looking for a solution in Tomcat.
Do you know how, or can you redirect me somehow better solution ?

thanx for the attention.
bye
on 10 Jul 2009 at 5:12 pm25Dariusz

Hi Swario,
I’m not sure what you mean? Can you describe it more in detail? Give me a scenario and I’ll see if I can help you. I can’t promise anything.
on 12 Jul 2009 at 11:29 am26Swario

Well, i want to build an app that it can run in real world…
I mean, right now i’m getting a connection to my Oracle db directly in my servlet class in a “getConnection()” method. But, as you know, this is not a well formed connection implementation.
I wanto to implement a connection pool for the db but i don’t know how…

i hope you understand
thank you again.
on 26 Aug 2009 at 4:10 pm27saranga

hi Dariusz,

below complete error is given——-
com.google.gwt.user.client.rpc.InvocationException:
at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:201)
at com.google.gwt.http.client.Request.fireOnResponseReceivedImpl(Request.java:264)
at com.google.gwt.http.client.Request.fireOnResponseReceivedAndCatch(Request.java:236)
at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:227)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
at com.google.gwt.dev.shell.ie.IDispatchImpl.callMethod(IDispatchImpl.java:126)
at com.google.gwt.dev.shell.ie.IDispatchProxy.invoke(IDispatchProxy.java:155)
at com.google.gwt.dev.shell.ie.IDispatchImpl.Invoke(IDispatchImpl.java:294)
at com.google.gwt.dev.shell.ie.IDispatchImpl.method6(IDispatchImpl.java:194)
at org.eclipse.swt.internal.ole.win32.COMObject.callback6(COMObject.java:117)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW(Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(OS.java:1925)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2966)
at com.google.gwt.dev.SwtHostedModeBase.processEvents(SwtHostedModeBase.java:235)
at com.google.gwt.dev.HostedModeBase.pumpEventLoop(HostedModeBase.java:558)
at com.google.gwt.dev.HostedModeBase.run(HostedModeBase.java:405)
at com.google.gwt.dev.GWTShell.main(GWTShell.java:140)
in the rpc log file it says..
com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException

please help me
on 26 Aug 2009 at 4:44 pm28Dariusz

Where are you running this request? In your web or hosted mode?
If your Exception is in webmode, then you probably forgot to implement your call in the web.xml.

It should be something like this:
<servlet> <servlet-name>AccountService</servlet-name> <servlet-class>org.yourpackage.server.AccountServiceImpl</servlet-class> </servlet> <servlet-mapping> <servlet-name>AccountService</servlet-name> <url-pattern>/accountservice</url-pattern> </servlet-mapping> </code>
on 27 Aug 2009 at 4:15 am29saranga

hi Dariusz,
Thanks for the prompt reply. but I m running this in hosted mode.
please help.
on 27 Aug 2009 at 5:00 am30saranga

I m using GWT 1.7 and GWTEXT 2.0.2
on 04 Sep 2009 at 5:01 am31Angelorum

Congratulations and very much thanks for your article!

so clear, so good, excelent!!

It helps me so much

thankfully, Me =)
on 22 Oct 2009 at 12:32 pm32deo

Thanks you so much dude….. Ur article really helped me alot…
on 31 Jan 2010 at 10:23 am33lida

how can i add paging toolbar this example.
I’ve added paging toolbar to this example but the textfield which shows current page number has not been changed by navigating between pages. how can i access it? what’s it name?
on 12 Apr 2010 at 3:06 pm34John

Can I use SQL Server 2005 as database server in GWT?
on 12 Apr 2010 at 3:35 pm35Dariusz

Hi John,

Of course you can. You can use any database you want. You just need to change the layer, which communicates with your database and hook it up to you business logic. I never used SQL Server, so I can’t really help you out with that.
on 28 May 2010 at 5:52 am36Balu

Excellent Tutorial. Fetched some Idea.
on 08 Jul 2010 at 12:37 pm37narsimha

Hi, could you please help me gwt-ext with struts2 integration sample login application with eclipse. thanks
on 08 Jul 2010 at 12:50 pm38Dariusz

Sorry, but I don’t have any experience with struts(2).
on 09 Jul 2010 at 6:49 am39narsimhamudiraj

Hi Dariusz, ur application integrate with Hybernate is good. i am new to gwt-ext and i need to create multiple jsps in my webproject.i need to do forward and redirect like that.pls let me know if you have experience gwt-ext with any other framework integration. thanks
on 12 Jul 2010 at 8:21 am40Manish

how can i change the total number of records on pagingToolbar on every server call?

is there any way i can do that. Any suggestions?

Thanks in Advance
on 12 Jul 2010 at 9:15 am41Dariusz

Hi,
If you are talking from the hibernate perspective, you should use setFirstResult and setMaxResults. A typical example would be:

int startingPoint = 50;
int amountOfResults = 50; // this is the number of the results you would like to get
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
List userList = new ArrayList();
Query query = session.createQuery( “from User” );
query.setFirstResult( startingPoint );
query.setMaxResult( );
session.close();

Of course, you need to do some calculation, how many entries in the database you have (for paging) and where the starting point at the given time is.
I hope it helps!
on 12 Jul 2010 at 9:31 am42Manish

Actaully i want to implement the total number of record on Client side by using GWT-Ext PaginationToolbar.
i have implemented the server side code.
after every 1000 record i want to make a server call then display it on the client using GWT-ext.
Scenario:
page size is set to 25 so for page number 1 to 40 i am displaying the 0 to 999 records once the user clicks on next page or last page i am making a server call and getting the response back now the real problem is it pagination toolbar should show me 41 to 80 page(1000 to 2000 record)
this is where i am badly stuck.
on 12 Jul 2010 at 9:57 am43Dariusz

Oh, I see it’s more a client site issue. Unfortunately, I haven’t been working on GWT-Ext for a while and therefore I can’t really tell you the best approach.
I would recommend you try to post this question to the GWT-Ext forum.
on 06 Aug 2010 at 6:55 pm44Mark

The only thing wrong with this is the ordering of development. I don’t think this is the order that you put this together. All of the required data services, hibernate, etc should be explained first. The last thing shown should probably be the completed Main.java. In other words, it should be layed out in the order that the various configuration and code elements were developed.

Still, thanks for your efforts.
on 12 Aug 2010 at 8:06 am45narsimhamudiraj

Hi Dariusz,

can i create the new package in gwt application? i.e com.web.client, com.web.server like new package (com.web.dao)?.please let me know. Thanks
on 12 Aug 2010 at 8:14 am46Dariusz

Hi narsimhamudiraj,
I’m not sure if I understand your question, but you can create any package structure you want. You just need to be sure, that you have ‘client’ and ’server’ package name for the compiler. I assume you want to split your dao layer to ‘com.web.dao’, which is a good approach. Now, if you want to use your dao layer in your gwt components, you need to inherit them in your *.gwt.xml file.
on 12 Aug 2010 at 9:39 am47narsimhamudiraj

Thanks Dariusz.
but i have one question how to inherit require module(com.web.dao package) in *.gwt.xml file. please let me know with small sample.because i am getting following error :
did you forget to inherit a required module? Thanks
on 12 Aug 2010 at 10:52 am48Dariusz

Sorry narsimhamudiraj, but right now I am on vacation, but you should visit the following site and download the sources. Inside, you’ll find a good example how they are doing it.

http://development.lombardi.com/?p=734

I hope it helps!
on 12 Aug 2010 at 1:46 pm49narsimhamudiraj

Thanks Dariusz. I resolved it. thanks
on 23 Aug 2010 at 9:38 am50narsimhamudiraj

Hi Dariusz, please help me ListBox selected Item move up and down sample code.thanks
on 23 Aug 2010 at 9:51 pm51Dariusz

narsimhamudiraj,
I’m not sure if I understand what you are looking for, but it seems like you want to implement a ‘drag and drop’ solution, right?

If this is the case, then you might want to check out this:http://allen-sauer.com/com.allen_sauer.gwt.dnd.demo.DragDropDemo/DragDropDemo.html#FlowPanelExample

Dariusz