The Flesch readability index was invented by Dr. Rudolf Flesch as a tool for estimating how difficult a document is to read and comprehend. The index does not consider the meaning of words, only their lengths and the lengths of sentences, in order to assign a readability index to the document. The higher the readability index, the easier a document is to comprehend. Flesch readability indexes are often translated into the educational level that is usually necessary to understand a document, as shown in the table below:

The Flesch readability index for a document is calculated using the total number of sentences, words, and syllables in the document:

The purpose of the index is to enable authors to assess the difficulty of their writing and, subsequently, to guide them in revising the text to match its intended audience. For example, the following sentence has a Flesch index of 28.4, corresponding to a college graduate reading level.

The above index was invented by Flesch as a simple tool to estimate the legibility of a document without linguistic analysis.

It is possible to set up Microsoft Word so that it will calculate and display the Flesch readability index for a file. For this assignment, however, you will write a collection of Java classes that will read a file, calculate its readability index, and determine its corresponding reading level. To keep things relatively simple, we will make the following assumptions:

• A word is any sequence of characters delineated by whitespace.
• The number of syllables in a word is the number of groups of adjacent vowels (aeiouy) in the word. For example, "Creighton" has two syllables, while "University" has five syllables. However, if 'e' is the last letter in a word and is preceded by a non-vowel, then it does not count as a syllable. For example, "life" has only one syllable, while "alumnae" has three syllables. Each word has at least one syllable, even if the previous rules give a count of 0.
• The only punctuation marks we will consider are period, colon, semi-colon, question mark, and exclamation point.

The Word Class

Define a class named Word that represents a single word of text. Your class should have the following constructor and methods:

public Word(String word); // constructs a Word object representing the // specified word public String toString(); // returns the String value represented by // this Word object public int numChars(); // returns the number of characters in the // word, not counting punctuation (.:;?!) public int numSyllables(); // returns the number of syllables in the // word, using the rules described above public boolean endsWithPunctuation();// returns true if the words ends with // a punctuation mark (.:;?!)

The Document Class

Define a class named Document that is intended to represent a text document. Your class should have the following constructor and methods:

public Document(String filename); // constructs a Document object representing the // specified file public String fileName(); // returns the name of the file associated // with this Document object public int numWords(); // returns the number of words in the // document, using the above definition public int numSyllables(); // returns the number of syllables in the // document, using the above definition public int numSentences(); // returns the number of sentences in the // document, using the above definition public double fleschIndex(); // returns the Flesch Index for the text // in the document public String gradeLevel(); // returns the reading level, e.g., // "6th grader", for the document

You should create a few simple text files to test your Document class. Create the files in any text editor, such as NotePad, and save them in your BlueJ project folder. You can then create Document objects by specifying the file names in constructor calls.

Once you are sure that your class works correctly, you can execute it on larger documents, such as the following: