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 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *
 * -Redistribution in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 *
 * Neither the name of Oracle nor the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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 */

package jnlp.sample.servlet;

import javax.xml.parsers.*;
import java.util.ArrayList;
import java.util.List;
import org.xml.sax.*;
import org.w3c.dom.*;

/** Contains handy methods for looking up information
 *  stored in XMLNodes.
 */
public class XMLParsing {

    public static XMLNode convert(Node n) {
        if (n == null) {
            return null;
        } else if (n instanceof Text) {
            Text tn = (Text)n;
            return new XMLNode(tn.getNodeValue());
        } else if (n instanceof Element) {
            Element en = (Element)n;

            XMLAttribute xmlatts = null;
            NamedNodeMap attributes = en.getAttributes();
            for(int i = attributes.getLength() - 1; i >= 0; i--) {
                Attr ar = (Attr)attributes.item(i);
                xmlatts = new XMLAttribute(ar.getName(), ar.getValue(), xmlatts);
            }

            // Convert childern
            XMLNode thisNode = new XMLNode(en.getNodeName(), xmlatts, null, null);;
            XMLNode last = null;
            Node nn = en.getFirstChild();
            while(nn != null) {
                if (thisNode.getNested() == null) {
                    last = convert(nn);
                    thisNode.setNested(last);
                } else {
                    XMLNode nnode = convert(nn);
                    last.setNext(nnode);
                    last = nnode;
                }
                last.setParent(thisNode);
                nn = nn.getNextSibling();
            }

            return thisNode;
        }
        return null;
    }

    /** Returns true if the path exists in the document, otherwise false */
    static public boolean isElementPath(XMLNode root, String path) {
        return findElementPath(root, path) != null;
    }


    /** Returns a string describing the current location in the DOM */
    static public String getPathString(XMLNode e) {
        return (e == null || !(e.isElement())) ? "" : getPathString(e.getParent()) + "<" + e.getName() + ">";
    }


    /** Like getElementContents(...) but with a defaultValue of null */
    static public String getElementContent(XMLNode root, String path) {
        return getElementContent(root, path, null);
    }

    /** Like getElementContents(...) but with a defaultValue of null */
    static public String[] getMultiElementContent(XMLNode root, String path) {
        final List list = new ArrayList();
        visitElements(root, path, new ElementVisitor() {
                    public void visitElement(XMLNode n) {
                        String value = getElementContent(n, "");
                        if (value != null) list.add(value);
                    }
                });
        if (list.size() == 0) return null;
        return (String[])list.toArray(new String[list.size()]);
    }

    /** Returns the value of the last element tag in the path, e.g.,  <..><tag>value</tag>. The DOM is assumes
     *  to be normalized. If no value is found, the defaultvalue is returned
     */
    static public String getElementContent(XMLNode root, String path, String defaultvalue) {
        XMLNode e = findElementPath(root, path);
        if (e == null) return defaultvalue;
        XMLNode n = e.getNested();
        if (n != null && !n.isElement()) return n.getName();
        return defaultvalue;
    }

    /** Parses a path string of the form <tag1><tag2><tag3> and returns the specific Element
     *  node for that tag, or null if it does not exist. If multiple elements exists with same
     *  path the first is returned
     */
    static public XMLNode findElementPath(XMLNode elem, String path) {
        // End condition. Root null -> path does not exist
        if (elem == null) return null;
        // End condition. String empty, return current root
        if (path == null || path.length() == 0) return elem;

        // Strip of first tag
        int idx = path.indexOf('>');
        String head = path.substring(1, idx);
        String tail = path.substring(idx + 1);
        return findElementPath(findChildElement(elem, head), tail);
    }

    /** Returns an child element with the current tag name or null. */
    static public XMLNode findChildElement(XMLNode elem, String tag) {
        XMLNode n = elem.getNested();
        while(n != null) {
            if (n.isElement() && n.getName().equals(tag)) return n;
            n = n.getNext();
        }
        return null;
    }

    /** Iterator class */
    public abstract static class ElementVisitor {
        abstract public void visitElement(XMLNode e);
    }

    /** Visits all elements which matches the <path>. The iteration is only
     *  done on the last elment in the path.
     */
    static public void visitElements(XMLNode root, String path, ElementVisitor ev) {
        // Get last element in path
        int idx = path.lastIndexOf('<');
        String head = path.substring(0, idx);
        String tag  = path.substring(idx + 1, path.length() - 1);

        XMLNode elem = findElementPath(root, head);
        if (elem == null) return;

        // Iterate through all child nodes
        XMLNode n = elem.getNested();
        while(n != null) {
            if (n.isElement() && n.getName().equals(tag)) {
                ev.visitElement(n);
            }
            n = n.getNext();
        }
    }

    static public void visitChildrenElements(XMLNode elem, ElementVisitor ev) {
        // Iterate through all child nodes
        XMLNode n = elem.getNested();
        while(n != null) {
            if (n.isElement()) ev.visitElement(n);
            n = n.getNext();
        }
    }
}