Monthly Archives: May 2009

Image submit in Tapestry 5.1

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This just took me a really long time to figure out, so I’m writing it down. Tapestry 5.1 adds support for submit buttons with an image (I think it was added in 5.1). In any case, you just use the normal tag, but you add an image attribute which is an “asset”. I added an Asset property to my page class and used @Inject and @Path to inject the asset. I used that property name in the image attribute, and it didn’t work. It turns out, you don’t need to declare the asset as a property in your page class. You just specify the path in the image attribute just like you would in the @Path annotation. So, it looks something like this:

<t:submit image=”context:images/submit.gif”/>

Much simpler than I was thinking. Sometimes I get really frustrated with these little Tapestry issues…

Tabs vs spaces in Netbeans

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I work with some people that like spaces and some people that like tabs in their code. I don’t really care, so I try to follow whatever the project is using. I ran into a big problem with Netbeans, though, in that it seems like getting it to use tabs only is impossible. It turns out they appear to be following a weird part of the Java Code Conventions spec:

Four spaces should be used as the unit of indentation. The exact construction of the indentation (spaces vs. tabs) is unspecified. Tabs must be set exactly every 8 spaces (not 4).

http://java.sun.com/docs/codeconv/html/CodeConventions.doc3.html#262

So, Netbeans sort of has two different “numbers” around tabs. There is a number that says how many spaces a tab should appear as, and a number that says how many spaces should be used when you indent something. By default a tab appears as 8 spaces, but a level of indentation is 4 (like the spec says above). As a result, it inserts four hard spaces when you indent one level, and a tab if you indent two levels. The solution is to set the two numbers to the same value. Just a wee bit confusing for a new user.

Here’s a bug report where someone describes it:

http://www.netbeans.org/issues/show_bug.cgi?id=52053