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POarrayOutOfBounds exception java
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copied!<p>I want to parse a text file and build a tree from it according to the rules i specified in the addToTree method. However, im getting this error: </p> <pre><code>Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at ie.gmit.TreeTest.addToTree(TreeTest.java:27) at ie.gmit.TreeTest.parse(TreeTest.java:20) at ie.gmit.TreeTest.main(TreeTest.java:77) </code></pre> <p>addChar1 and addChar2 are nodes that I created from the passing in the word in the parse method</p> <p>here is the code:</p> <pre><code>public class TreeTest { public void parse(File f) throws Exception { Node root = new Node('+'); //create a root node BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(f))); String line; while((line = br.readLine())!=null){ String[] words = line.toLowerCase().split(" "); for(int i = 0; i < words.length; i++){ addToTree(words[i], root); } } } public void addToTree(String s, Node root){ char[] characters = s.toCharArray(); Node addChar1 = new Node(characters[0]); Node addChar2 = new Node(characters[1]); Node fullWord = new Node(s); //get the child nodes of the root Node[] rootChildren = root.children(); //get the child nodes of the first node (addChar1) Node[] addChar1Children = addChar1.children(); //get each child of the root for(int i=0; i<rootChildren.length; i++){ Node rootChild = rootChildren[i]; //see if the addChar1 already exists in the tree //if it doesn't if(!rootChild.equals(addChar1)){ //add the addChar1 as a child of the root root.addChild(addChar1); //add the addChar2 as a child of the addChar1 also addChar1.addChild(addChar2); //insert the whole word as the child of the addChar2 addChar2.addChild(fullWord); } //if the addChar1 exists in the tree already else{ // get each child of the addChar1 for(int j=0; j<addChar1Children.length; j++){ Node addChar1Child = addChar1Children[i]; //see if the addChar2 already exists in the tree //if it doesn't if(!addChar1Child.equals(addChar2)){ //add the addChar2 as the child if the addChar1 addChar1.addChild(addChar2); //add the actual word addChar2.addChild(fullWord); } //if the addChar2 exists the the tree already else{ //insert the whole word as the child of the FOUND NODE addChar1Child.addChild(fullWord); } }//end of second for loop } }//end of the first for loop }//end of addToTree public static void main(String[] args) throws Exception { TreeTest test = new TreeTest(); File f = new File("textFile.txt"); test.parse(f); } </code></pre> <p>}</p> <p>Anyone would help ? all that the file contains:</p> <p>"website which allows its users to add modify or delete its content via web browser usually"</p> <p>the Node class:</p> <pre><code> public class Node<E> { private Node parent; private String fullWord; private char character; // value inside a node private boolean word; // put a true flag if the node is a word eg 'a' private List<Node> children = new ArrayList<Node>(); //creates a list of array list objects //** constructors **/ public Node(){ } public Node(String fullWord){ this.fullWord = fullWord; } public Node(Node parent){ this.parent = parent; } public Node(char character){ this.character = character; } public Node(boolean word){ this.word = word; } public Node(Node parent, char character){ this(parent); this.character = character; } public Node(Node parent, char character, boolean word){ this(parent); this.character = character; this.word = word; } //** methods **/ public boolean isRoot(){ return this.parent == null; } public boolean hasChildren(){ return this.children.size() > 0; } public void addChild(Node child){ child.setParent(this); children.add(child); } public Node getParent(){ return this.parent; } public void setParent(Node parent){ this.parent = parent; } public Node[] children(){ return (Node[]) children.toArray(new Node [children.size()]); } public char getItem() { return character; } </code></pre> <p>}</p>

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