Moderator (MDR): MDR-lisa

Guest Speaker (SPK): SPK-name

MDR-lisa: Hi, my name is Lisa Stapleton, editorial director of the JDC, and our scheduled guest couldn't make it today, but another great expert on applets and the AWT, Kathy Walrath, is here with us to discuss the new AWT and applets. She is the author of these portions of "The Java Tutorial," and she's here to answer your questions today. Welcome, Kathy, and all of our participants.

SPK-walrath: Thanks very much, Lisa. Hi, everyone!

irsan: Hi, Lisa and Kathy. Could you elaborate on the usage of validate() and repaint(). I (and a lot of guys I know) are not very sure on when to call these methods (esp. with lightweight components), and thus are calling the methods "all the time." Thanks.

SPK-walrath: We need to come up with better guidelines for validate and repaint. Theoretically, you never need to call validate if you're adding a component to an already-visible container. However, it does seem to help sometimes. As for repaint, I'd have to know how you're using it. As far as lightweight components go -- all I can say is download JDK 1.1.2 and then try again. A lot of lightweight component bugs were fixed in 1.1.2, in preparation for the release of Swing components.

whitteng: Hello, I would like to know how to wait for "drawImage" to finish, NOT just return. I am drawing a scaled image into an offscreen buffer, and if the image hasn't drawn completely into the buffer before it is rendered onto the screen, a blank or incomplete image is rendered. This is a real problem in 1.0.2 especially.

SPK-walrath: Is the image completely loaded before you do the drawImage? If not, you can use a MediaTracker object to wait for the image data to be loaded.

archers: I have a question about painting from native methods in AWT canvases. I have heard that there is a method of getting a handle to the drawing area, sun.awt.{X11,Win32}DrawingSurfaceInfo, but of course it doesn't actually appear to be documented. Is there really a way of getting at this information? Thanks.

SPK-walrath: We really don't want you to do that from the existing AWT. Have you checked out Java 2D? Look at http://java.sun.com/products/java-media/2D.

irsan: [back to the subject of validate()]: It occurs to me that I have to do a validate() whenever I remove a lightweight component (even in JDK1.1.2). Is this a bug or a feature ;-)

SPK-walrath: I'll check on that.

whitteng: -(waiting for image drawing) Yes, the image is loaded, but it seems that drawImage still iterates for something like scaled drawing, and there appears to be no way to tell when the image drawing has finished. MediaTracker is not documented to track drawing, just loading. Can it be used for monitoring image drawing?

SPK-walrath: Not that I know of. This sounds like another job for Java2D.

irsan: OK, thanks!

irsan: Could you tell us a little bit more about these "Swing components"? What do they do, why do we need them, and when will they be out?

SPK-walrath: The Swing components are pre-fab lightweight components that you can just plug into a program. They're completely implemented in Java, so we're going to be able to release them in preliminary form (to get developer feedback) before the next JDK release. Besides Swing components, the Swing project also includes infrastructure for having a pluggable look and feel, and various classes to make it easy to develop and use lightweight components. Swing is part of the JFC.

werpu: My greatest fear about the swing components is performance. How well will they perform compared to peer components?

SPK-walrath: Good news: They seem to perform really well!

irsan: So, if I get your message right: Swing components are lightweight replacements for the well-known and existing widgets (Button, Radio, List etc)?

SPK-walrath: Yes, Swing will include lightweight versions of existing components. However, it'll also include a huge number of new components. If you went to JavaOne, you saw a lot of them demoed -- full-featured text, color chooser, tables, tabbed panes, etc.

sellhorn: How difficult is it going to be to "upgrade" our JDK1.1-based UI to the new JFC stuff? We kind of need all the new widgets now, but it seems like we might have a to use a third party initially.

SPK-walrath: In theory, it should be pretty easy. Of course, I haven't tried to do it yet. One of the goals of the lightweight versions of existing components is to maintain API compatibility whenever possible.

whitteng: Will Swing components be used instead of peer components so that there will only be one common look and feel?

SPK-walrath: The great thing about Swing components is that they'll all have a pluggable look and feel. So there'll be a common look and feel that you can use across all platforms, or you can choose to have a Windows or Mac (e.g.) look and feel. JavaSoft won't supply every look and feel -- but it'll make it possible for users and developers to plug them in.

sellhorn: When do we get all this cool stuff!?!?! (Please don't say Q3 '97 or some other obscure date)

SPK-walrath: At JavaOne, we promised a release in 60 days, which is right about now. (I suspect this is why Hans couldn't make it here today!) This 60-day release is going to a limited set of customers. We plan another release in early July, and (as far as I know), just about anyone should be able to get a copy of that release.

whitteng: Thanks - what is JFC? I don't recall that particular acronym.

SPK-walrath: JFC stands for Java Foundation Classes. We announced the JFC at JavaOne, in collaboration with Netscape. Besides everything I described above, the JFC will include technology from Netscape's IFC. JFC also includes the existing AWT, Java2D, and other API for creating visual applications. I think of it as the AWT growing up.

sellhorn: How much of Netscape's IFC will be in the JFC? I tried IFC before and it was a memory HOG! (plus some of the widgets were a little too fancy)

SPK-walrath: Well, we're not shoehorning IFC into the JFC. The Netscape developers are right here at JavaSoft, and the AWT team is working with them to figure out how to take the best features of the IFC while remaining true to the Swing vision.

const: It was possible to distribute JDBC with 1.0.2 applets by renaming package from java.sql to something like tempjava.sql (IBM DB2 driver). Will it be possible to distribute EA Swing components with applets like this?

SPK-walrath: Yes, it'll be possible to distribute Swing with 1.1.2. The Swing package is currently named (deep breath) com.sun.java.swing.

const: How will Swing components relate to new additions in the "Glasgow" JavaBeans spec?

SPK-walrath: Maybe we'll have a forum about it later.

MDR-lisa: Yes, I think we're having a rep from the 2D team in about 3 weeks. As for Glasgow, I think that's the Enterprise Beans effort, right? If so, We're working on getting one of its creators to be on a forum soon.

littel: I am not sure if you received my question but here it is again anyway. I am using a TextArea and I want to insert text into different places. I am using the insert() funtion and the getCaretPosition method to acomplish this. The only problem is that it doesn't put the text where the Caret Position is? Can you explain why and how can a fix this problem. Thanks

panrakhi: How do I get the Focus lost event from the textField Ctrl? It does not behave uniformly on different platforms.

SPK-walrath: That, frankly, is why we're doing Swing. The existing peer infrastructure requires lots of platform-specific, non-Java code, and it's practically impossible to get everything working consistently.

panrakhi: How do I set the Tab order of the different components in the container?

SPK-walrath: There's no API for doing this right now, as you probably know. I know that saying "it'll be fixed in Swing" is not going to help you right now, but that's really what's going to solve problems like this. It'll be much easier for us to provide features and fix bugs once we have everything written in Java, rather than having to worry about platform dependencies and native code. I guess you could say we've finally seen the advantage of Java for our own development!

MDR-lisa: That's about all our time for today. This has been a very popular forum, and I'd like to invite everyone back next week, when Georges Saab will be doing Part 2 of our AWT forum series. Thanks to everyone for participating in this forum, and we'll try to pick up where we left off, next week, same bat time, same bat channel!