HW10

Computer Science 111, Fall Semester, 2006
Homework #10

due: by midnight December 6, 2006

Your task in this week's project is expand your Hw7 to use objects instead of strings and to obtain data from amazon.com.

Preliminary Work

Do the following:

If your hw7.py does not work, start with mine, which is in the file hw7demo.py (use getcopy to get this).
If you are using the demo program, do
```
cp hw7demo.py hw10.py
```
otherwise
```
cp hw7.py hw10.py
```
and use emacs to edit hw10.py.

Define a class called Site. The class Site is used to make instances that contain information about web sites. There are three items of data stored in each object:

The name of the artist, a string
The site URL, a string
The site ProductName, a string.

Design and then type in your class definition, using the following criteria and the example on page 402 of the textbook.

The Site instances are created by calling the Site constructor, and passing in the name of the Artist Name, a string. Site will contain five methods, plus the __init__ method. Call these methods getName, setProductName, getProductName, setLink, and getLink.

__init__ takes two parameters. The first is self (always), and the second is the name of the artist. It stores the value of the artist name in the instance variable name.
getName takes in one parameter, self, and returns the value of the instance variable name.
setProductName takes two parameters. The first is self (always), and the second is the ProductName, and should be a string. This method changes all of the letters in ProdcutName to capital letters before storing it in the instance variable.
getProductName takes in one parameter, self, and returns the value of the instance variable used to store the product name.
setLink takes two parameters. The first is self (always), and the second is the URL, a string. It stores the URL value in an instance variable called link.
getLink takes in one parameter (self) and returns the value of the instance variable link.

Get a copy a datafile I made called cdsites.txt. Look at the contents.

Interface to Amazon

Now insert the function definition for getCDsFromArtist from your lab10.py. Modify this function so it creates a list of instances of Site and returns this list, as below.

It does not print out all the sites returned from amazon and stored in musicList.
Instead, it should create either 0, 1, or 2 instances of Site (i.e. the first two on the returned list or fewer if there are either 0 or 1). You may need to use an if-else statement here.
1. It uses the artist string passed in to the function as the name it passes to the Site constructor.
2. It uses the URL returned from amazon as the Site instance URL,
3. and uses the ProductName returned from amazon as the Site instance ProductName.
It appends each instance to the list it returns. But before returning, it prints out the list of sites it is returning. There should be either 0, 1, or 2. Define a function called printSite() that prints out values from a Site object in a tidy way.

get a copy of the file cdsites.txt:

getcopy cdsites.txt

Now in main

Read in the values from this file and make list of Site objects instead of a list of strings (the odl booklist). I call it siteList.

You will have to modify any of the functions that operated on booklist in homework7 so that they work with a list of Site objects.

Before the while loop ask the user if she wants to query amazon by artist name.
The loop condition checks if the answer is "yes" or "Yes".
The body of the loop asks the user which artist name to use. Then it calls getCDsFromArtist, and passes it the user's response. It appends the list returned from getCDsFromArtist to siteList, the list of Sites from the file cdsites.txt. Be careful here. You'll have to append the sites in the amazon list one by one to siteList.
The user can query amazon again, using a different artist name. Fix up the while loop so the working is right.

After the while loop, use your printSite() function to print out each Site object in siteList, then call selSort(), and then print each Site object in siteList again. as in hw7. However, you'll have to change selSort so it sorts the objects by ProductName Also, rewrite the sorted sites out to the file cdsitesSorted.txt. It should have exactly the same format as cdsites.txt. Make sure it doesn't have extra lines in it, and that there is only one value per line.

What to submit. Your program should be in a file called hw10.py. Submit this homework by the due date with the command submit homework10 hw10.py