Re: Large Data Set problems
Well, looks like paging it is. Thanks everyone. Oh, and Hi Tom! -Joe --~--~-~--~~~---~--~~ 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 google-web-toolkit+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/Google-Web-Toolkit?hl=en -~--~~~~--~~--~--~---
Re: Large Data Set problems
Hi!
The problem is that in your function public void showUsers() { you
create a entry into FlexTable for each user, including the non-visible
ones.
Some browsers have problems displaying a huge data.
To solve this you have 2 options:
Create some kind of pagination into your flextable, creating a set of
your users and display only the possible visible ones(Something like
50), and remove/add the users as the user navigate through it.
Other option as Tom Hjeliming said, is to use some framework like
SmartGWT(http://code.google.com/p/smartgwt/). SmartGWT have a lot of
features and Widgets that makes life easier.
One of them is the Live Grid(http://www.smartclient.com/smartgwt/
showcase/#featured_grid_live), in the example it have around 700
records, but only render the visible ones, so it runs smooth on IE and
Firefox.
SmartGWT can load only a partial set of the data and ask server for
more when needed or load everything, depends on your requirement.
Regards
On Jun 11, 2:13 pm, Tom Hjellming thjellm...@riverglassinc.com
wrote:
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 FlexTable panel;
public Button loadBtn;
public Button displayBtn;
public ListBox listBox;
public Label label;
public ArrayListString usernames = 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();
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) {
