Exercise 7.3 A WebPage consists of a

• String header,

• and a Body b.

A Body is a list of HTML elements.
A HTML element is either

• a String word

• or a Link.

A Link consists of

• a String word

• and a WebPage.

Perform the following tasks:

• Draw the UML diagram for the collection of classes that represent web pages.

• Develop the classes.

• Develop the method allWords, which produces a list of all words in the web page

• Develop the method pages, which produces the list of immediate words on a page. That is, it consumes a WebPage and produces a list of String. An immediate word on a list of HTML elements is defined as follows:

  • an HTML element that is a word is the immediate word

  • for an HTML element that is a Link, the method extracts the word from the Link.

• Develop the method occurs, which determines whether the given word occurs in the web page or its embedded pages.