get Child Double Value from XML Element via Node - Java XML

Java examples for XML:XML Element Child

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Description

get Child Double Value from XML Element via Node

Demo Code


import java.util.ArrayList;
import java.util.List;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class Main{
    public static double getChildDoubleValue(Element parent, String nodeName)
            throws XMLHelperException {
        return getNodeDoubleValue(getUniqueNode(parent, nodeName));
    }// ww  w.ja v a  2s .c o  m
    public static double getNodeDoubleValue(Node node)
            throws XMLHelperException {
        try {
            return Double.parseDouble(getNodeValue(node));
        } catch (NumberFormatException e) {
            throw new XMLHelperException("value of \"" + node.getNodeName()
                    + "\" must be a floating point");
        }
    }
    public static Node getUniqueNode(Element parent, String nodeName)
            throws XMLHelperException {
        NodeList childNodes = parent.getChildNodes();
        int length = childNodes.getLength();

        Node node = null;
        for (int i = 0; i < length; i++) {
            Node current = childNodes.item(i);
            if (current.getNodeName().equals(nodeName)) {
                if (node != null)
                    throw new XMLHelperException("\"" + nodeName
                            + "\" in \"" + parent.getNodeName()
                            + "\" must be unique");
                node = current;
            }
        }

        if (node == null)
            throw new XMLHelperException("\"" + nodeName
                    + "\" not found in \"" + parent.getNodeName() + "\"");
        return node;
    }
    public static String getNodeValue(Node node) throws XMLHelperException {
        NodeList childNodes = node.getChildNodes();
        if (childNodes.getLength() > 1)
            throw new XMLHelperException(
                    "can't read value - multiple child nodes");
        Node textNode = childNodes.item(0);
        if (textNode.getNodeType() != Node.TEXT_NODE)
            throw new XMLHelperException(
                    "can't read value - child node must be a text node");
        return textNode.getNodeValue().trim();
    }
}

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