In general, in source code, you do reference inner classes with the dot notation. However, in this case, you are providing the name of the class file as a string, and class files use the $ notation instead. (You can verify this by looking at the directory in which javac creates your class files.)
Yep, I knew how the class got named when compiled... I guess I didn't realize I was giving it the name of a class file.
The inner classes need to be static because non-static inner classes can only exist within an instance of their enclosing class, and cannot be instantiated on their own. (I think this is probably one of the most misunderstood aspects of inner classes. ;)
Hmmm... I think it's safe to say had such a question been on my SCJP test I would have gotten it wrong! I don't think I was aware of that, I didn't think there was any problem doing:
OuterClass.InnerClass ic = new OuterClass.InnerClass()
...regardless of whether InnerClass was static or not.
Thanks for teaching me something today Martin! :)
Frank
-- Martin Cooper
Frank
Martin Cooper wrote:
On Tue, 22 Mar 2005 16:34:35 -0500 (EST), Frank W. Zammetti <[EMAIL PROTECTED]> wrote:
One small problem remains...
Does Digester not allow you to use inner classes as the target object? I found that I could only get this to work when I made the inner ConfigData class NOT an inner class. I realized too I had to fully-qualify the class, but it didn't seem to matter being an inner class, it wouldn't work no matter what I put.
Is this a shortcoming? Is there a reason if it is? Thanks!
As long as the inner class is public and static, and you use a '$' as the separator, you should be fine. I'm pretty sure I've done this myself.
-- Martin Cooper
-- Frank W. Zammetti Founder and Chief Software Architect Omnytex Technologies http://www.omnytex.com
On Tue, March 22, 2005 4:11 pm, Frank W. Zammetti said:
Ugh. I got it...
The rules were set up wrong. The root of the XML document is AppAvailabilityFilterConfig, not AppAvailabilityFilter as I had.
My head HURTS.
-- Frank W. Zammetti Founder and Chief Software Architect Omnytex Technologies http://www.omnytex.com
On Tue, March 22, 2005 3:43 pm, Frank W. Zammetti said:
Hey all... I'm trying to use Digester myself for the first time and I'm getting very frustrated... Here's what I have:
Digester digester = new Digester(); digester.setValidating(false); digester.addObjectCreate("AppAvailabilityFilter", "AppAvailabilityFilter.ConfigData"); digester.addBeanPropertySetter("AppAvailabilityFilter/mondayStartTime", "mondayStartTime"); digester.addBeanPropertySetter("AppAvailabilityFilter/mondaEndTime", "mondayEndTime"); // I get InputStream isConfigFile here, I have verified I have it by printing out the contents configData = (ConfigData)digester.parse(isConfigFile); configData.setConfigDataSet();
configData is a static member of the class this code belongs to. ConfigData is a inner class. Here's the relevant snippet:
private int mondayStartTime; private int mondayEndTime; public void setMondayStartTime(String mondayStartTime) { this.mondayStartTime = Integer.parseInt(mondayStartTime); } public int getMondayStartTime() { return mondayStartTime; }
As you can probably guess, I have the same things for every day of the week. Lastly, here's the XML file:
<?xml version="1.0" encoding="UTF-8"?> <AppAvailabilityFilterConfig> <mondayStartTime>0100</mondayStartTime> <mondayEndTime>2300</mondayEndTime> </AppAvailabilityFilterConfig>
The problem is that it gets all the way to the line:
configData.setConfigDataSet();
...no exceptions are thrown, no messages from Digester, etc. But, that line causes a NullPointerException, so I can only assume that means Digester did not create the object and/or could not populate it properly so returned null (or ate an exception and didn't report it?)
Anyone spot a problem here? I'm getting ready to throw myself out a window. Thanks all!
-- Frank W. Zammetti Founder and Chief Software Architect Omnytex Technologies http://www.omnytex.com
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