Question

Hi all I have an XML file in java which holds a 2d array of numbers it looks something like

<tableNumbers>
     <row id="0">
         <column id="0"> 4 </column>
         <column id="1"> 2 </column>
         <column id="2"> 5 </column>
         <column id="3"> 6 </column>
    </row>
    <row id="1">
         <column id="0"> 5 </column>
         <column id="1"> 10 </column>
         <column id="2"> 7 </column>
         <column id="3"> 9 </column>
    </row>
</tableNumbers>

Now every row in the table has the same number of colums and what I am trying to do is cycle through the xml and store the number from the XML file into an Integer array. (e.g. row 0 column 0 would be stored in numbers[0][0].

The code I currently have is:

public static Integer[][] getNumbers(File file, int noRows, int noColums){
        Integer[][] numbersArray = new Integer[noRows][noColumns];

        DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
        try {
            Document document = docBuilderFactory.newDocumentBuilder().parse(file);
            Element rootElement = document.getDocumentElement(); 

            NodeList rowList = rootElement.getElementsByTagName("row");
            if ((rowList != null)) 
                for (int i = 0; i < rowList.getLength(); i++) {
                    NodeList columnsList = rowList.item(i).getChildNodes();
                    if ((columnsList != null)) 
                        for (int j = 0; j < columnsList.getLength(); j++) {
                            Element number = (Element) columnsList.item(j); 
                            System.out.println("(" +i + "," + j + ") " + number.getNodeValue());
                            numbersArray[i][j] = number.getNodeValue();
                        }
                }

            return numbersArray;
        }
        catch (Exception c){}
        return null;
}

A few lines from the standard the output are:

(0,0) null
(0,1) null
(0,2) null
(0,3) null
(1,0) null
(1,1) null
(1,2) null
(1,3) null

The value which is returned from all the cells is null. I know the error is reading from the xml file. If anyone could show me where I am going wrong I would be most grateful

Answer 1

I would add the following:

Element number = (Element) columnsList.item(j);
if ("column".equals(number.getTagName())) }
    System.out.println("(" +i + "," + j + ") " + number.getTextContent());
}

Since you may have an empty element. Also, I’m using getTextContent() method from Node declaration.