Requirements

1. Prompt for the name of the file to be validated. Create a Scanner for the file and pass it to your validator.

2. Your validator should use a stack to check for correct nesting of tags. The algorithm is similar to the algorithm for checking for balanced parentheses in our textbook. Open tags are pushed onto the stack. Each close tag is compared with the top of the stack to check for a match.

3. Don't forget that some tags have no close tag.

4. Create class for tags. This class should not have set or get methods. The Tag class should contain the list of tags with no end tag and a method to test whether a tag has no end tag. Your tag class should also have a method to test whether a pair of tags are matching start and end tags. You will probably need some additional methods in the Tag class.

5. You need to extract the tags from the input file. Attributes are not stacked. My advice is to write your own "split" method that will take a line of the input file and return an array or ArrayList of the tags (modified to remove attributes) in a line of input. A good place for this method is to make it a static method in the Tag class.