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 (最終的にはバイナリ ツリーですが、後で完成します) にロードします。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 object 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、単語が既に配列にあるかどうかを確認しようとすると、うまくいきません。そうであれば、頻度を 1 増やす必要がありequals()ます。変数参照ではなく単語が比較されるように、既定のメソッドをオーバーライドする新しいメソッドを作成しました。ただし、現在エラーが発生していますException in thread "main" java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [LWordNode;。なぜこれが出てくるのですか？WordNodeオブジェクトだけが に渡されていると思いましたequals()。
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.getFrequency() + ") " + newWord.getWord());
} else {
System.out.println("Word is not yet in array");
//add word to tree
System.out.println("(" + newWord.getFrequency() + ") " + 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;
}
/**
* Method to check for string equivalence.
* @return true if words are the same
*/
public boolean equals(Object obj) {
WordNode tempWord = (WordNode)obj;
return(tempWord.getWord().equals(this.word));
}
/**
* 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;
}