私が現在取り組んでいるプロジェクトでは、テキストファイルから単語を読み取り、それらを配列にロードします（最終的にはバイナリツリーになりますが、後で終了します）。単語と単語の頻度（最初は1）の両方を配列にロードする必要があるため、両方の変数をオブジェクトにパックしましたWordNode。単語を配列にロードすることはできますが、単語がすでに配列にあるかどうかを確認しようとすると、状況が崩れます。もしそうなら、頻度を1増やす必要があります。ただし、私のコードは単語をチェックせず、とにかくそれを追加するだけです（単語自体ではなく、変数への参照をチェックしていると思います）。以下は私のmainメソッドとWordNodeクラスです。
主な方法：
public class Driver {
/////////////// fields ///////////////
public static ArrayUnorderedList<WordNode> wordArray = new ArrayUnorderedList<WordNode>();
public static LinkedBinarySearchTree<WordNode> wordTree = new LinkedBinarySearchTree<WordNode>(); //tree to hold words
/////////////// methods ///////////////
public static void main(String[] args) throws Exception {
//ask for filename
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the name of the file to read from: ");
Reader file = new FileReader(reader.readLine());
//read file
Scanner input = new Scanner(file);
while(input.hasNext()) {
//get words from file
String word = input.next();
//remove non-word characters and convert to lowercase
word = word.replaceAll("\\W", "");
word = word.toLowerCase();
//create node
WordNode newWord = new WordNode(word);
//if word is already in array
if(wordArray.contains(newWord)) {
System.out.println("Word is already in array");
//increment frequency by 1
int index = wordArray.find(newWord);
wordArray.list[index].setFrequency(wordArray.list[index].getFrequency() + 1);
System.out.println(newWord.getWord() + newWord.getFrequency());
} else {
System.out.println("Word is not yet in array");
//add word to tree
System.out.println(newWord.getWord());
wordArray.addToRear(newWord);
}
}
//insert into tree
//perform traversals on tree
}
WordNodeクラス：
public class WordNode {
protected String word;
protected WordNode left, right;
protected int frequency;
/**
* Creates a new node with the specified data.
* @param obj the element that will become a part of the new node
*/
WordNode(String obj) {
word = obj;
left = null;
right = null;
frequency = 1;
}
/**
* Gets the word.
* @return the word
*/
public String getWord() {
return word;
}
/**
* Sets the word.
* @param word the word to set
*/
public void setWord(String word) {
this.word = word;
}
/**
* Gets the left.
* @return the left
*/
public WordNode getLeft() {
return left;
}
/**
* Sets the left.
* @param left the left to set
*/
public void setLeft(WordNode left) {
this.left = left;
}
/**
* Gets the right.
* @return the right
*/
public WordNode getRight() {
return right;
}
/**
* Sets the right.
* @param right the right to set
*/
public void setRight(WordNode right) {
this.right = right;
}
/**
* Gets the frequency.
* @return the frequency
*/
public int getFrequency() {
return frequency;
}
/**
* Sets the frequency.
* @param frequency the frequency to set
*/
public void setFrequency(int frequency) {
this.frequency = frequency;
}
}
ArrayListクラスのいくつかのメソッド：
/**
* Returns true if this list contains the specified element.
* @param target the element that the list is searched for
* @return true if the target is in the list, false if otherwise
*/
public boolean contains(T target) {
return (find(target) != NOT_FOUND);
}
/**
* Returns the array index of the specified element, or the
* constant NOT_FOUND if it is not found.
* @param target the element that the list will be searched for
* @return the integer index into the array containing the target element, or the NOT_FOUND constant
*/
public int find(T target) {
int scan = 0, result = NOT_FOUND;
boolean found = false;
if (!isEmpty()) {
while (!found && scan < rear) {
if (target.equals(list[scan])) {
found = true;
} else {
scan++;
}
}
}
if (found) {
result = scan;
}
return result;
}