OwaGate Code

/*-----------------------------------------------------------------------------
    Xml.java
    Copyright (C) 2007 Donald Griffin

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

-----------------------------------------------------------------------------*/
package owagate.util;

import java.io.InputStream;
import java.util.regex.*;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.commons.httpclient.HttpMethodBase;

import org.w3c.dom.Document;
import org.w3c.dom.Node;

/**
 This class contains XML helper methods.
 */
public final class Xml
{
    /**
     Descends from the given parent looking for the first node to match path.
     @param parent The DOM parent from which to start.
     @param path The set of regular expressions for each level of the descent.
     @return The child node at the end of the path or null if no match.
     */
    public static Node getChild (Node parent, Pattern[] path)
    {
        Node c = parent;
        int i;

        for (i = 0; c != null && i < path.length; ++i)
            for (c = c.getFirstChild(); c != null; c = c.getNextSibling())
            {
                String nn = c.getNodeName();
                Matcher m = path[i].matcher(nn);

                if (m != null && m.matches())
                    break;
            }

        return (i == path.length) ? c : null;
    }

    /**
     Reads an XML Document from the given InputStream.
     */
    public static Document readDocument (InputStream input)
    {
        try
        {
            DocumentBuilder builder = mDocFactory.newDocumentBuilder();

            return builder.parse(input);
        }
        catch (Exception ex)
        {
            throw Ex.failed("Failed to read XML document", ex);
        }
    }

    /**
     Reads an XML Document from the given HttpMethodBase's response stream.
     */
    public static Document readResponseDocument (HttpMethodBase method)
    {
        try
        {
            return readDocument(method.getResponseBodyAsStream());
        }
        catch (Exception ex)
        {
            throw Ex.failed("Failed to read XML document", ex);
        }
    }

    private final static DocumentBuilderFactory mDocFactory = DocumentBuilderFactory.newInstance();
}