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how to generate sequenced group number and sub-group number?  RSS feed

 
richard chang
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Hi folks,
I'm new here, really need help!
I need to generate sequence numbers for groups of objects. the sequenced group numbers can have sub-group numbers, the display would be like this:
1. This is header
1.1. This is sub-header
1.1.1. This is sub-sub-hearder
1.2. Thank you
1.3. Welcome
Also I need to auto update the numbers if I change the sequence, for example, if I move "1.3. Welcome" to in front of "1.1. This is sub-hearder", the display would change to:
1. This is header
1.1. Welcome
1.2. This is sub-header
1.2.1. This is sub-sub-hearder
1.3. Thank you
Can anyone give me some hints please?
Thanks a lot
 
Tim West
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One approach to this would be to use the composite pattern for number generation.
Better than this would be to make a composite tree of objects (whatever they may be), and use the visitor pattern to traverse the tree and output the numbers as needed. This assumes that the numbers aren't a fundamental property of the objects, rather it's a property of the object's location in the tree.
That's one approach, anyway. Your design will depend a lot on how complex the whole thing will get and how much functionality each object has - composite & visitor may be overkill for simple situations, but it's a very extensible model.

Cheers,
-Tim
 
Stan James
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How do you get the information to put into the outline? If somebody hands you a tree of data you're most of the way there. Say each node of the tree looks like:

Zat make any sense? You'll have to adjust a bit. I bet your outline has a level "2." so you don't print your root, but 1, 2, 3 are the children of the invisible root. And that's not all exactly Java.
I assumed a tree of data, and standard output. If you're doing another form of input or maybe a Swing display, nearly everything changes.
 
richard chang
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Tim and James,
Thank you very much for your help. I'll look into composit pattern and visitor pattern. And the display will be on web pages, so in my mind I would use JSP to publish the data.
James, yes my outline would have 2.-2.1-2.1.1, 3.-3.1-3.2, etc.
Any more ideas would be appreciated. I'll try above suggestion and let you guys know later.
Cheers
 
Don't get me started about those stupid light bulbs.
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