Re: Large Data Set problems
Hi Joe,
The trick is to not even try to load that much data into the browser.
We use the SmartGWT widget library which has very good support for
virtual pagination of lists and comboboxes. By default, it only loads
the first 75 rows and then as the user scrolls down, calls are made back
to the server to retrieve the desired data - which is then shown to the
user. There is an occasional delay when the user sees blank space which
is then filled in when the data comes in. But overall, it is a great
solution -we're viewing tables with thousands of rows and seeing better
performance than our old Swing-based application.
Tom
Joe Larson wrote:
I am having a performance problem. I am trying to build a page that
allows the user to select from a fairly large list of objects (up to
20,000). We have filtering capabilities to trim the list so the user
doesn't have to scroll through all of them. It's a reasonable UI.
Unfortunately, I only get decent performance on Safari. IE6 is
exceptionally miserable. It's okay when the list has 100 items, but
it crashes as we exceed 300. So I've been experimenting, and I
haven't found a way around it.
So I created a sample app. All I did was populate an
ArrayListString with 20,000 fairly short strings that I read out of
the HTML file. Under Safari 4 on a G5 Mac Pro, this is almost
instant. Under IE6 on a similar age Windows box, it's taking 4
minutes. Firefox on the G5 runs out of memory.
Is it possible to store large amounts of data in my GWT applications?
Or do I have to store fairly small amounts of data and go back and
forth to the server a lot? If it's the latter, I may as well just go
back to what we used to do (WebObjects).
I'm including my little sample program. Maybe there's something
obvious that I can do?
-Joe
--- GWTMinimum.java ---
package com.missionmode.gwtminimum.client;
import java.util.*;
import com.google.gwt.core.client.*;
import com.google.gwt.user.client.*;
import com.google.gwt.user.client.ui.*;
/**
* Entry point classes define codeonModuleLoad()/code.
*/
public class GWTMinimum implements EntryPoint {
public FlexTablepanel;
public Button loadBtn;
public Button displayBtn;
public ListBox listBox;
public Labellabel;
public ArrayListStringusernames = new ArrayListString();
public String[] parts;
/**
* This is the entry point method.
*/
public void onModuleLoad() {
panel = new FlexTable();
RootPanel.get(web2).add(panel);
loadBtn = new Button(Click to start load);
panel.setWidget(0, 0, loadBtn);
loadBtn.addClickListener(new ClickListener() {
public void onClick(Widget sender) {
loadUsers();
}
});
}
/**
* We've loaded the user table. Set up so they
* can press another button to display the data.
*/
public void setupForDisplay() {
displayBtn = new Button(Click to Display);
panel.setWidget(0, 1, displayBtn);
displayBtn.addClickListener(new ClickListener() {
public void onClick(Widget sender) {
showUsers();
}
});
}
/**
* Load the users from the HTML page.
*/
public void loadUsers() {
if (parts == null) {
String str = stringFromDocument(users);
parts = str.split(===);
loadBtn.setText(Click me again);
}
else {
for (String name : parts) {
name = name.trim();
if (name.length() 0) {
usernames.add(name);
}
}
showCount();
setupForDisplay();
}
}
/**
* Just show how many users were actually loaded.
*/
public void showCount() {
label = new Label(Total user count: + usernames.size());
panel.setWidget(1, 0, label);
}
/**
* Show the loaded users.
*/
public void showUsers() {
try {
listBox = new ListBox();
listBox.setVisibleItemCount(20);
panel.setWidget(2, 0, listBox);
for (String str : usernames) {
listBox.addItem(str);
}
}
catch (Exception e) {
Re: GWT 1.5.2
I found the conflicting class in these jar files:
- jasper-compiler-jdt.jar
- jasper-jdt.jar
The jasper-jdt.jar is a standard jar file shipped with Tomcat 6.0 in the
lib directory.
Once I removed those jar files from my classpath, the problem went away
for me.
Tom
Deep wrote:
Thanks Tom.
I didn't get this part Check your GWT project build path for that jar
file and remove it.. What needs to be removed?
On Nov 6, 9:28 pm, Tom Hjellming [EMAIL PROTECTED] wrote:
I had this same problem last month when I moved to GWT 1.5.2 also.
It turned out to be a conflict between GWT's dev library and the Jasper
2 JSP engine which apparently uses the Eclipse JDT Java compiler. The
jasper-compiler-jdt.jar had conflicting versions of the
org.eclipse.jdt.internal.compiler.Compiler class. Check your GWT
project build path for that jar file and remove it.
Hope this helps...
Tom
Deep wrote:
I'm using Mac OS 10.5.5 Eclipse 3.3.2 and I migrated my project from
GWT 1.4.61 to 1.5.2 and getting following error. Please help me.
INFO] [gwt:compile {execution: default}]
Exception in thread main java.lang.NoSuchMethodError:
org.eclipse.jdt.internal.compiler.Compiler.init(Lorg/eclipse/jdt/
internal/compiler/env/INameEnvironment;Lorg/eclipse/jdt/internal/
compiler/IErrorHandlingPolicy;Lorg/eclipse/jdt/internal/compiler/impl/
CompilerOptions;Lorg/eclipse/jdt/internal/compiler/
ICompilerRequestor;Lorg/eclipse/jdt/internal/compiler/
IProblemFactory;)V
at com.google.gwt.dev.javac.JdtCompiler
$CompilerImpl.init(JdtCompiler.java:93)
at com.google.gwt.dev.javac.JdtCompiler.init(JdtCompiler.java:231)
at
com.google.gwt.dev.javac.JdtCompiler.compile(JdtCompiler.java:193)
at
com.google.gwt.dev.javac.CompilationState.compile(CompilationState.java:
115)
at com.google.gwt.dev.GWTCompiler.distill(GWTCompiler.java:327)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:564)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:554)
at com.google.gwt.dev.GWTCompiler.main(GWTCompiler.java:214)
Exception in thread main java.lang.NoSuchMethodError:
org.eclipse.jdt.internal.compiler.Compiler.init(Lorg/eclipse/jdt/
internal/compiler/env/INameEnvironment;Lorg/eclipse/jdt/internal/
compiler/IErrorHandlingPolicy;Lorg/eclipse/jdt/internal/compiler/impl/
CompilerOptions;Lorg/eclipse/jdt/internal/compiler/
ICompilerRequestor;Lorg/eclipse/jdt/internal/compiler/
IProblemFactory;)V
at com.google.gwt.dev.javac.JdtCompiler
$CompilerImpl.init(JdtCompiler.java:93)
at com.google.gwt.dev.javac.JdtCompiler.init(JdtCompiler.java:231)
at
com.google.gwt.dev.javac.JdtCompiler.compile(JdtCompiler.java:193)
at
com.google.gwt.dev.javac.CompilationState.compile(CompilationState.java:
115)
at com.google.gwt.dev.GWTCompiler.distill(GWTCompiler.java:327)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:564)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:554)
at com.google.gwt.dev.GWTCompiler.main(GWTCompiler.java:214)
Exception in thread main java.lang.NoSuchMethodError:
org.eclipse.jdt.internal.compiler.Compiler.init(Lorg/eclipse/jdt/
internal/compiler/env/INameEnvironment;Lorg/eclipse/jdt/internal/
compiler/IErrorHandlingPolicy;Lorg/eclipse/jdt/internal/compiler/impl/
CompilerOptions;Lorg/eclipse/jdt/internal/compiler/
ICompilerRequestor;Lorg/eclipse/jdt/internal/compiler/
IProblemFactory;)V
at com.google.gwt.dev.javac.JdtCompiler
$CompilerImpl.init(JdtCompiler.java:93)
at com.google.gwt.dev.javac.JdtCompiler.init(JdtCompiler.java:231)
at
com.google.gwt.dev.javac.JdtCompiler.compile(JdtCompiler.java:193)
at
com.google.gwt.dev.javac.CompilationState.compile(CompilationState.java:
115)
at com.google.gwt.dev.GWTCompiler.distill(GWTCompiler.java:327)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:564)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:554)
at com.google.gwt.dev.GWTCompiler.main(GWTCompiler.java:214)
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Re: GWT 1.5.2
I had this same problem last month when I moved to GWT 1.5.2 also.
It turned out to be a conflict between GWT's dev library and the Jasper
2 JSP engine which apparently uses the Eclipse JDT Java compiler. The
jasper-compiler-jdt.jar had conflicting versions of the
org.eclipse.jdt.internal.compiler.Compiler class. Check your GWT
project build path for that jar file and remove it.
Hope this helps...
Tom
Deep wrote:
I'm using Mac OS 10.5.5 Eclipse 3.3.2 and I migrated my project from
GWT 1.4.61 to 1.5.2 and getting following error. Please help me.
INFO] [gwt:compile {execution: default}]
Exception in thread main java.lang.NoSuchMethodError:
org.eclipse.jdt.internal.compiler.Compiler.init(Lorg/eclipse/jdt/
internal/compiler/env/INameEnvironment;Lorg/eclipse/jdt/internal/
compiler/IErrorHandlingPolicy;Lorg/eclipse/jdt/internal/compiler/impl/
CompilerOptions;Lorg/eclipse/jdt/internal/compiler/
ICompilerRequestor;Lorg/eclipse/jdt/internal/compiler/
IProblemFactory;)V
at com.google.gwt.dev.javac.JdtCompiler
$CompilerImpl.init(JdtCompiler.java:93)
at com.google.gwt.dev.javac.JdtCompiler.init(JdtCompiler.java:231)
at com.google.gwt.dev.javac.JdtCompiler.compile(JdtCompiler.java:193)
at
com.google.gwt.dev.javac.CompilationState.compile(CompilationState.java:
115)
at com.google.gwt.dev.GWTCompiler.distill(GWTCompiler.java:327)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:564)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:554)
at com.google.gwt.dev.GWTCompiler.main(GWTCompiler.java:214)
Exception in thread main java.lang.NoSuchMethodError:
org.eclipse.jdt.internal.compiler.Compiler.init(Lorg/eclipse/jdt/
internal/compiler/env/INameEnvironment;Lorg/eclipse/jdt/internal/
compiler/IErrorHandlingPolicy;Lorg/eclipse/jdt/internal/compiler/impl/
CompilerOptions;Lorg/eclipse/jdt/internal/compiler/
ICompilerRequestor;Lorg/eclipse/jdt/internal/compiler/
IProblemFactory;)V
at com.google.gwt.dev.javac.JdtCompiler
$CompilerImpl.init(JdtCompiler.java:93)
at com.google.gwt.dev.javac.JdtCompiler.init(JdtCompiler.java:231)
at com.google.gwt.dev.javac.JdtCompiler.compile(JdtCompiler.java:193)
at
com.google.gwt.dev.javac.CompilationState.compile(CompilationState.java:
115)
at com.google.gwt.dev.GWTCompiler.distill(GWTCompiler.java:327)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:564)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:554)
at com.google.gwt.dev.GWTCompiler.main(GWTCompiler.java:214)
Exception in thread main java.lang.NoSuchMethodError:
org.eclipse.jdt.internal.compiler.Compiler.init(Lorg/eclipse/jdt/
internal/compiler/env/INameEnvironment;Lorg/eclipse/jdt/internal/
compiler/IErrorHandlingPolicy;Lorg/eclipse/jdt/internal/compiler/impl/
CompilerOptions;Lorg/eclipse/jdt/internal/compiler/
ICompilerRequestor;Lorg/eclipse/jdt/internal/compiler/
IProblemFactory;)V
at com.google.gwt.dev.javac.JdtCompiler
$CompilerImpl.init(JdtCompiler.java:93)
at com.google.gwt.dev.javac.JdtCompiler.init(JdtCompiler.java:231)
at com.google.gwt.dev.javac.JdtCompiler.compile(JdtCompiler.java:193)
at
com.google.gwt.dev.javac.CompilationState.compile(CompilationState.java:
115)
at com.google.gwt.dev.GWTCompiler.distill(GWTCompiler.java:327)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:564)
at com.google.gwt.dev.GWTCompiler.run(GWTCompiler.java:554)
at com.google.gwt.dev.GWTCompiler.main(GWTCompiler.java:214)
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Re: what GUI creator are you using ?
IntelliJ does not have a d-n-d GUI designer for GWT. I think they were referring to the pretty-basic GWT plug-in that doesn't provide a GWT GUI builder. Tom JacoGr wrote: I use IntelliJ IDEA. I actually wan't aware that IDEA had a drag-n-drop GUI designer for GWT. (I know about the GWT support, but though that was just contextual.) GWT Designer for me - not perfect, but more or less does the job. Jaco --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To post to this group, send email to Google-Web-Toolkit@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/Google-Web-Toolkit?hl=en -~--~~~~--~~--~--~---
Re: Best GWT canvas (vector graphics) library?
Dojo has a pretty decent GFX library that provides an SVG-like abstraction that works on IE's VML as well as FireFox's native SVG. The tatami project/library provides a GWT wrapper for dojo including the GFX library: http://code.google.com/p/tatami/ The downside is that it pulls in a fair amount of dojo stuff. Tom John Gunther wrote: I've recently used the GWTCanvas widget from the GWT incubator (nothing fancy, just to draw lines--will likely do more canvas stuff later, though) and so far so good. However, a Google search shows there are quite a few GWT canvas libraries out there. Wondering if I'm missing out on a better library... Anyone used (or written) any of them? Care to share your opinions about which ones work best? John --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To post to this group, send email to Google-Web-Toolkit@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/Google-Web-Toolkit?hl=en -~--~~~~--~~--~--~---
Re: GWT Timers - say no to it with IE
Timer works fine for me in both IE and Firefox. Tom Ivan wrote: Hello everybody, I have encountered one problem: it's well known that there's a Timer class: com.google.gwt.user.client.Timer and of cource it is not a secret that it works in Firefox, Opera, and Google Chrome without any problems, but what's about Internet Explorer ? Well, the answer is unfortunately - no! Does anybody have an idea how it is possible to run this function in IE? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To post to this group, send email to Google-Web-Toolkit@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/Google-Web-Toolkit?hl=en -~--~~~~--~~--~--~---
Re: Accessing Location of an iframe from another iframe and Cross Domain Security
You could implement a backend proxy that fetches the html page, parses
the content to patch all link references to go back through the proxy
prior to sending the modified page to the browser. Since the browser
thinks the iFrame pages are loaded form the backend proxy (same domain
as the rest of your GWT app), the cross domain security issues won't be
a problem.
Tom
Jayant wrote:
Hello,
I am trying to create an application where I have to watch the
location and content of an iframe. I wrote a simple prototype where a
top page contains 2 iframes. One is used for the real content and one
just contains a script that watches the content iframe. Now as long as
the pages in the iframe are coming from the same server, this works.
However when the user navigates to a page from another server, the
scheme fails. I cannot stop the user from going to any other page in
that iframe. I only need to know where the iframe is pointing to. I
have gone through a numerous references on the cross domain security
and there does not seem to be an answer to this. I have two questions:
1. Is this impossible to resolve in pure javascript. May be there is
some scheme used by portlets that could help and 2. Can use of flash /
flex help get over this problem.
Following is the code for the four files in the little prorotype.
--main.html---
html
head
titleMain Co-Browser Page/title
script language=javascript
function getContentURL()
{
d = document;
f = d.frames ? d.frames['content'] : d.getElementById('content');
var url = ;
try
{
if (f.getCurrentLocation)
{
url = f.getCurrentLocation();
}
else if (f.contentWindow.getCurrentLocation)
{
url = f.contentWindow.getCurrentLocation();
}
}
catch(e)
{
url = ;
}
returnurl;
}
/script
/head
body
iframe id=content src=sample1.html width=100% height=200px/
iframe
iframe id=tracker src=tracker.html/iframe
/body
/html
---
-sample1.html--
html
head
titleSample1/title
script language=javascript
function getCurrentLocation()
{
returndocument.location;
}
/script
/head
body
pThis is page sample 1
pa href=sample2.htmlSample2/a
pa href=http://www.google.com;Google/a
/body
/html
---
-sample2.html--
html
head
titleSample1/title
script language=javascript
function getCurrentLocation()
{
returndocument.location;
}
/script
/head
body
pThis is page sample 2
pa href=sample1.htmlSample1/a
pa href=http://www.yahoo.com;Yahoo/a
/body
/html
---
-tracker.html--
html
head
titleTracker/title
script language=javascript
function test()
{
var frameUrl = parent.getContentURL();
if (frameUrl == )
{
alert(Content is out of scope);
}
else
{
alert('frameUrl = '+frameUrl);
}
setTimeout(test(), 3000);
}
var timerID = setTimeout(test(), 3000);
/script
/head
body
/body
/html
---
Thanks,
-Jayant.
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