Question

\((\) Sorting Words with a Treeset) Write a program that uses a String method split to tokenize a line of text input by the user and places each token in a TreeSet. Print the elements of the TreeSet. [Note: This should cause the elements to be printed in ascending sorted order.]

Short answer

Split the user input into tokens, add them to a TreeSet to sort, and print the TreeSet elements in ascending order.

Step-by-step solution

Use the split method

First, prompt the user for a line of text and store it in a variable. Use the String method split with a space (' ') as the delimiter to tokenize the given input and store the tokens in an array of strings. For example: String[] tokens = userInput.split(' ');

Create a TreeSet and add tokens

Create an instance of TreeSet. Then, iterate over the array of strings and add each token to the TreeSet. This will automatically sort the tokens in ascending order. For example: TreeSet treeSet = new TreeSet<>(); for(String token : tokens) { treeSet.add(token); }

Print the TreeSet elements

Iterate over the TreeSet using an enhanced for loop or a method like toString and print the elements. Each element will be printed in ascending order, which is the natural ordering of the TreeSet. For example: for(String token : treeSet) { System.out.println(token); }

Key concepts

String Tokenization

String tokenization is the process of splitting a string into a series of tokens, which can be thought of as pieces or units of the original string, often using a delimiter to indicate where one token stops and another starts. In Java, this can be easily accomplished with the split() method of the String class.

When users input a line of text that they wish to tokenize, such as 'The quick brown fox jumps over the lazy dog', and we want to split this sentence into individual words, we use a space (' ') as the delimiter. This would result in an array of tokens like ['The', 'quick', 'brown', 'fox', 'jumps', 'over', 'the', 'lazy', 'dog'].

Practical Application

Tokenization is especially useful for tasks such as word sorting, text analysis, and in cases where data needs to be split into usable components. It's a fundamental operation in text-processing programs and applications like those used for language parsing, search engines, or data processing.

Natural Ordering of Elements

In Java, the natural ordering of elements refers to the order in which Java sorts a collection of objects based on their intrinsic ordering. For example, String objects in Java are sorted lexicographically—that is, in a dictionary-like order—with uppercase letters considered to precede lowercase letters.

In the TreeSet example provided in the exercise, when we add strings to it, the TreeSet automatically arranges them according to their natural order, without the need for any additional coding to specify how they should be sorted. This is a feature of the Comparable interface, which String and other wrapper classes like Integer, Double implement.

Understanding the Hierarchy

This behavior is beneficial because it provides a consistent way to sort objects, simplifies coding, and minimizes errors. However, developers can also define custom ordering by implementing the Comparator interface if the natural order isn't suited to their needs.

Java Collections Framework

The Java Collections Framework is a set of classes and interfaces that implement commonly reusable collection data structures. Among these, the TreeSet class is a part of the Set interface and uses a tree for storage, ensuring that the elements are sorted in ascending order, according to their natural order, at all times.

TreeSet not only maintains a sorted order but also does not allow duplicate entries, thus every element in a TreeSet is unique. The benefits include easy traversal, lookups, and the assurance that the collection remains sorted, which can be particularly convenient when needing to display data in a sorted manner without additional work.

Part of a Larger System

It's important to understand that TreeSet is just one component of the Java Collections Framework, which includes various other collections like List, Queue, and Map, each serving different data manipulation needs. Familiarizing oneself with the Java Collections Framework is crucial for effective Java programming since these data structures form the backbone of many Java applications.