CSC365 B-Tree Assignment

• Your program acts as a server daemon, continually waiting for clients connecting at port 23XY. ("XY" is the 2-digit number you selected in class.) Use SimpleService.java for the basic structure. Remember that you need to run this on moxie. (Also remember to kill this program when you are not logged in!)
• A client (your web browser) accesses your server daemon using moxie.oswego.edu:23XY

Basically, you just need to add about 5 or so lines to the original SimpleService.java file.

These lines consist of: initializing your internal B-Tree, and then handling requests for words to spell check. If the word is not found, then you add it to the btree. If the word is preceeded by "-", it means to remove the word if it is found; if it is not found, then you simply report that it was not found.

Your service doesn't really support full HTTP. Instead it treats each "GET" as a lookup request for a word. For example, "GET /pickle" is a request for check spelling of "pickle", and GET /-pickle is a request to remove the word "pickle".

• If a requested word is not in your btree, then it is added, so the next request for the same word will say that it is spelled correctly. (This is a stripped-down version of a mechanism for adding new words to the dictionary.)

• The response page can be html-formatted in any way you like.

This assignment must be done in two phases:

1. In the first phase, you will implement the dictionary as an internal Top-Down Order-8 B-Tree initialized from words.txt, which contains one word per line.

2. In phase two, you must implement a persistent B-Tree. You cannot proceed to phase two until you successfully demo phase one. Simulate a "cache management system" as discussed in class. Document your cache management code to state how you are reusing the cache.
3. The persistent BTree must have the same functionality (add and remove) as the internal BTree.
4. You need to create two files for your persistent B-Tree:
• a file with the extension "btr" - a Fixed-Length Random Access File which contains your persistent B-Tree.
• a header file with the extension "hdr" - which contains all the relevant information about the persistent B-Tree (order, size, number of nodes, number of leaves, number of levels, last written block number, name of persistent B-Tree file).