Java XPath Create getXPathExprFromNode(Node node)

Description

Generates an XPath expression that will return only the given node as its result.

License

Apache License

Parameter

Parameter	Description
node	the node to generate an XPath expression for. This node must be an element node, a text node, a document node, or a processing instruction node.

Return

an XPath expression that will return only the given node as its result.

Declaration

public static String getXPathExprFromNode(Node node) throws IllegalArgumentException

Method Source Code


//package com.java2s;
/*/*from  www  .  j a  v a 2  s  . c  om*/
 * The Apache Software License, Version 1.1
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 * reserved.
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 * modification, are permitted provided that the following conditions
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 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * This software consists of voluntary contributions made by many
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 * originally based on software copyright (c) 2000, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
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import java.util.Vector;
import org.w3c.dom.*;

public class Main {
    /**
     * Generates an XPath expression that will return only the given node as its
     * result. This method only works for element, text, document and PI nodes.
     *
     * @param node the node to generate an XPath expression for. This node must
     * be an element node, a text node, a document node, or a processing
     * instruction node.
     * @return an XPath expression that will return only the given node as its
     * result.
     * @exception IllegalArgumentException if the given node is not an element,
     * text, document or PI node.
     */
    public static String getXPathExprFromNode(Node node) throws IllegalArgumentException {
        short nodeType = getNodeType(node);

        switch (nodeType) {
        case Node.ELEMENT_NODE:
        case Node.TEXT_NODE:
        case Node.PROCESSING_INSTRUCTION_NODE:
            return getXPathFromVector(getVectorPathFromNode(node));

        case Node.DOCUMENT_NODE:
            return "/";

        default:
            throw new IllegalArgumentException("Only works for element, text, " + "document, and PI nodes.");
        }
    }

    private static short getNodeType(Node node) {
        return (node != null ? node.getNodeType() : -1);
    }

    private static String getXPathFromVector(Vector path) {
        StringBuffer strBuf = new StringBuffer();
        int length = path.size();

        for (int i = 0; i < length; i++) {
            Node tempNode = (Node) path.elementAt(i);
            short nodeType = getNodeType(tempNode);
            String targetValue = getValue(tempNode, nodeType);
            int position = 1;

            tempNode = getPreviousTypedNode(tempNode, nodeType);

            while (tempNode != null) {
                if (nodeType == Node.ELEMENT_NODE) {
                    if (getValue(tempNode, nodeType).equals(targetValue)) {
                        position++;
                    }
                } else {
                    position++;
                }

                tempNode = getPreviousTypedNode(tempNode, nodeType);
            }

            boolean hasMatchingSiblings = (position > 1);

            if (!hasMatchingSiblings) {
                tempNode = (Node) path.elementAt(i);
                tempNode = getNextTypedNode(tempNode, nodeType);

                while (!hasMatchingSiblings && tempNode != null) {
                    if (nodeType == Node.ELEMENT_NODE) {
                        if (getValue(tempNode, nodeType).equals(targetValue)) {
                            hasMatchingSiblings = true;
                        } else {
                            tempNode = getNextTypedNode(tempNode, nodeType);
                        }
                    } else {
                        hasMatchingSiblings = true;
                    }
                }
            }

            String step;

            switch (nodeType) {
            case Node.TEXT_NODE:
                step = "text()";
                break;
            case Node.PROCESSING_INSTRUCTION_NODE:
                step = "processing-instruction()";
                break;
            default:
                step = targetValue;
                break;
            }

            if (step != null && step.length() > 0) {
                strBuf.append('/' + step);
            }

            if (hasMatchingSiblings) {
                strBuf.append("[" + position + "]");
            }
        }

        return strBuf.toString();
    }

    private static Vector getVectorPathFromNode(Node node) {
        Vector path = new Vector();

        while (node != null) {
            path.insertElementAt(node, 0);
            node = node.getParentNode();
        }

        return path;
    }

    private static String getValue(Node node, short nodeType) {
        switch (nodeType) {
        case Node.ELEMENT_NODE:
            return ((Element) node).getTagName();

        case Node.TEXT_NODE:
            return ((Text) node).getData();

        case Node.PROCESSING_INSTRUCTION_NODE:
            return ((ProcessingInstruction) node).getData();

        default:
            return "";
        }
    }

    private static Node getPreviousTypedNode(Node node, short nodeType) {
        node = node.getPreviousSibling();

        while (node != null && node.getNodeType() != nodeType) {
            node = node.getPreviousSibling();
        }

        return node;
    }

    private static Node getNextTypedNode(Node node, short nodeType) {
        node = node.getNextSibling();

        while (node != null && node.getNodeType() != nodeType) {
            node = node.getNextSibling();
        }

        return node;
    }
}

Java XPath Create getXPathExprFromNode(Node node)

Description

License

Parameter

Return

Declaration

Method Source Code

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