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Walk On

Posted by editor on March 29, 2007 at 10:38 AM PDT


Going mobile with the FileConnection API

Do you think ME should ultimately be a stop-gap while we wait for small devices to eventually catch up with where desktops were when Java was launched, in which case they could start running a variant of SE, or does ME has unique traits that merit existing as a separate and unique form of Java?

What prompts this is the idea that the original persistence model for CLDC, the record store, only gets you so far, which may be why it was thought necessary to devise JSR 75, which offers a more typical filesystem API for Java ME. Wait long enough and the devices will be able to just use something more like java.io.File, right? Or is JSR 75's FileConnection API just right? Or doesn't it matter until and unless all devices support FileConnection?

Today's Feature Article digs further into this ME filesystem API, in Biswajit Sarkar's

Working with the Java ME FileConnection API on Physical Devices.

In this article we'll use the classes in JSR 75 to build a simple application, FileTester, that moves images from a mobile handset into a server. The emphasis here will mainly be on some of the intricacies involved in handling files in real devices.


Moving from the small device to the desktop, today's Forums, are a triple-shot of Swing discussion. ghaneman starts with
Re: Asynchronous drag n drop.
"Am facing a similar problem. I've been using swing workers for all my long running tasks but in this situation, a swing worker will not work because it is asynchronous. In other words, the import method can't return a valid true or false status because the worker runs on a separate thread. I could always return true but this would be wrong if the worker encounters an exception. It looks like this is one situation where I must use a synchronous worker like spin or foxtrot."

lproctor would like to know
How to Use Multiple JXTreeTables with a single TreeTableModel:
"The JavaDoc for JXTreeTable states "A single treetable model instance may be shared among more than one JXTreeTable instances." However, when I create two JXTreeTable instances that share a single model, the second JXTreeTable instance created receives two copies of all events from the model whereas the first JXTreeTable instance receives none. Can the two instances of JXTreeTable be configured so that each instance receives events from the single model? "

osbald has a problem with
SwingWorker going quiet:
"Having some problems with the 5.0 backport of SwingWorker this morning.. actually had problems for a while but only just realised SwingWorker was at the center of things. Whats been happening is intermittently my UI suddenly stops getting information from the server, no exceptions nor error messages, everything still functions but nothing updates.. very odd. What I can tell so far is it's my background tasks that suddenly stop being executed.. I still call worker.execute(), but the accompanying SwingWorker.doInBackground() isn't getting called? "


Moving from Swing to imaging, today's Weblogs kicks off with Fabrizio Giudici's
Let's discuss about Java imaging:
"I was happy to see that Slav Boleslawski's article about a specialized component for rendering photos made its way to the featured articles of this week. Indeed if Java wants to gain attention on the desktop, the whole media segment can't be ignored."

Evan Summers discusses some options for
Screen Capture:
"We might provide built-in support in our application for capturing an image of the whole screen, or a specific component eg. JPanel, or our JFrame with its window decoration, via a screen capture keystroke."

Finally, Alexander Schunk has
A comment on JPC Project at Oxford:
"Oxford University has managed to simulate an x86 PC using pure Java. See the corresponding entry at java.net homepage. This may be the beginning of a new era of emulated PCs that run anywhere which solve migrating problems and ease application development because of a uniform underlying software platform."


In Java Today,
the PropertyTree project offers a Swing component for organizing and editing properties of different types. "The default Swing JTree implementation uses one single JLabel over and over to paint its tree nodes, and it is impossible to use graphical components like a JCheckBox therein. The PropertyTree aimes at solving this problem by using different JPanels instead of one single JLabel to paint the nodes. The result is a nice JTree that takes care of your property hierarchy."

Duke, meet Duchess. "Duchess is a networking group for female Java developers. We are based in the Netherlands, but every Java-coding girl can join. Especially in Holland, female developers are a minority. Because of that it is interesting to meet the other women-programmers. Every couple of months we get together in a pub our restaurant. It is inspiring and fun!"

Wednesday's WebEx discussion of next week's java.net upgrade is available as the Upgrade - Find-a-bug Win-an-iPod file in the "Upgrade Information" folder of the java-net project. Unzipping this file will create an Upgrade.wrf file, which you can play with the WebEx player. The discussion includes details on how you can win one of two iPods if you find bugs on the upgrade staging server. Remember: java.net will be down for 24-48 hours on April 4 for an upgrade to the latest edition of CollabNet's Community Edition software, as described on an upgrade page.


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Going mobile with the FileConnection API