How to fix 1

[Miros]

My program is working nicely, thank you everyone.

However, being a total maniac, I'm trying to jam several thousand rows into a JTable. Naturally, after about 1100, it runs out of memory.

I think it's happening when the JTable tries to do the insert, not when I add the row class to my ArrayList (although it could happen then as well).

Is there anything I can do to make more memory available?

 

[stefanwagner]

How much data do your rows contain?

And yes, you can start the jvm with special parameters.

java -X

shows special parameters.

java -Xms128M -Xmx256M YourMainClass

will start the jvm with 128MB RAM initially, and a maximum of 256MB i.e.



seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[Miros]

Here's the data from my row class.

private int itemNumber ;
private String itemName ;
private String itemCreator ;
private int itemRevision ;
private int itemSetNumber ;
private String itemSetItems ;
private String itemRecommendedItems ;
private String itemRequiredItems ;
private Boolean itemRecolors ;
private Boolean itemDownloaded ;
private Boolean itemFree ;

itemSetItems, itemRecommendedItems, and itemRequiredItems are quite often "0", but could possibly be quite long (up to 256 characters).

Null or "" caused my input routine to crash, so I changed the default value to "0".

I don't think it's an excessive amount per record, it's just the number of records that's excessive...

 

[Miros]

Thanks!

I was able to read almost 5000 records, much better than 1100!

Gonna up the max a little more and I should be able to read my whole file, with room for expansion.

 

[timw]

You're better putting next/previous type controls with the table and having 'pages' of results in it. No user is going to thank you for gobbling up that much of their memory.

Tim

 

[Miros]

I'm probably the only person who will ever use this program.

I was thinking about doing my own sort, so then I could do next/previous controls.

Do you just send a "cell contents changed" for every visible cell when the next/previous button gets hit?

I also thought that the JTable itself only used memory for the visible cells, basically using the scroll bar as a next/previous control... Am I mistaken?

I really don't have an easy way to leave the data on disk and just load what I need, so my ArrayList of my objects still needs to sit in memory.

 

[timw]

JTable uses a TableModel to contain the actual data (namely a DefaultTableModel unless you provide your own implementation). The JTable itself is a 'view' on the data in this model. The DefaultTableModel will hold ALL the data regardless of which portion is currently displayed.

You could modify this behaviour by writing your own; either implement TableModel, subclass AbstractTableModel or DefaultTableModel, depending on your needs.

The Swing controls which process collections of data all use a view/model paradigm like this, and it's my experience that the default models in each case are coded to hold all the data all the time.

Tim

 

[Miros]

Too much trouble, especially if I'm the only person who's going to use it!

 

[timw]

Too much trouble, especially if I'm the only person who's going to use it.

Yes, I got that. I'm just responding to your thought that JTable only stored visible cells.

Tim