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/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package org.dom4j;

import org.dom4j.io.SAXReader;
import org.dom4j.rule.Pattern;
import org.jaxen.VariableContext;
import org.xml.sax.InputSource;

import java.io.StringReader;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

/**
 * <p>
 * <code>DocumentHelper</code> is a collection of helper methods for using
 * DOM4J.
 * </p>
 *
 * @author <a href="mailto:jstrachan@apache.org">James Strachan </a>
 * @version $Revision: 1.26 $
 */
public final class DocumentHelper {
  private DocumentHelper() {
  }

  private static DocumentFactory getDocumentFactory() {
    return DocumentFactory.getInstance();
  }

  // Static helper methods

  public static Document createDocument() {
    return getDocumentFactory().createDocument();
  }

  public static Document createDocument(Element rootElement) {
    return getDocumentFactory().createDocument(rootElement);
  }

  public static Element createElement(QName qname) {
    return getDocumentFactory().createElement(qname);
  }

  public static Element createElement(String name) {
    return getDocumentFactory().createElement(name);
  }

  public static Attribute createAttribute(Element owner, QName qname,
                                          String value) {
    return getDocumentFactory().createAttribute(owner, qname, value);
  }

  public static Attribute createAttribute(Element owner, String name,
                                          String value) {
    return getDocumentFactory().createAttribute(owner, name, value);
  }

  public static CDATA createCDATA(String text) {
    return DocumentFactory.getInstance().createCDATA(text);
  }

  public static Comment createComment(String text) {
    return DocumentFactory.getInstance().createComment(text);
  }

  public static Text createText(String text) {
    return DocumentFactory.getInstance().createText(text);
  }

  public static Entity createEntity(String name, String text) {
    return DocumentFactory.getInstance().createEntity(name, text);
  }

  public static Namespace createNamespace(String prefix, String uri) {
    return DocumentFactory.getInstance().createNamespace(prefix, uri);
  }

  public static ProcessingInstruction createProcessingInstruction(String pi,
                                                                  String d) {
    return getDocumentFactory().createProcessingInstruction(pi, d);
  }

  public static ProcessingInstruction createProcessingInstruction(String pi,
                                                                  Map data) {
    return getDocumentFactory().createProcessingInstruction(pi, data);
  }

  public static QName createQName(String localName, Namespace namespace) {
    return getDocumentFactory().createQName(localName, namespace);
  }

  public static QName createQName(String localName) {
    return getDocumentFactory().createQName(localName);
  }

  /**
   * <p>
   * <code>createXPath</code> parses an XPath expression and creates a new
   * XPath <code>XPath</code> instance using the singleton {@link
   * DocumentFactory}.
   * </p>
   *
   * @param xpathExpression is the XPath expression to create
   * @return a new <code>XPath</code> instance
   * @throws InvalidXPathException if the XPath expression is invalid
   */
  public static XPath createXPath(String xpathExpression)
      throws InvalidXPathException {
    return getDocumentFactory().createXPath(xpathExpression);
  }

  /**
   * <p>
   * <code>createXPath</code> parses an XPath expression and creates a new
   * XPath <code>XPath</code> instance using the singleton {@link
   * DocumentFactory}.
   * </p>
   *
   * @param xpathExpression is the XPath expression to create
   * @param context         is the variable context to use when evaluating the XPath
   * @return a new <code>XPath</code> instance
   * @throws InvalidXPathException if the XPath expression is invalid
   */
  public static XPath createXPath(String xpathExpression,
                                  VariableContext context) throws InvalidXPathException {
    return getDocumentFactory().createXPath(xpathExpression, context);
  }

  /**
   * <p>
   * <code>createXPathFilter</code> parses a NodeFilter from the given XPath
   * filter expression using the singleton {@link DocumentFactory}. XPath
   * filter expressions occur within XPath expressions such as
   * <code>self::node()[ filterExpression ]</code>
   * </p>
   *
   * @param xpathFilterExpression is the XPath filter expression to create
   * @return a new <code>NodeFilter</code> instance
   */
  public static NodeFilter createXPathFilter(String xpathFilterExpression) {
    return getDocumentFactory().createXPathFilter(xpathFilterExpression);
  }

  /**
   * <p>
   * <code>createPattern</code> parses the given XPath expression to create
   * an XSLT style {@link Pattern}instance which can then be used in an XSLT
   * processing model.
   * </p>
   *
   * @param xpathPattern is the XPath pattern expression to create
   * @return a new <code>Pattern</code> instance
   */
  public static Pattern createPattern(String xpathPattern) {
    return getDocumentFactory().createPattern(xpathPattern);
  }

  /**
   * <p>
   * <code>selectNodes</code> performs the given XPath expression on the
   * {@link List}of {@link Node}instances appending all the results together
   * into a single list.
   * </p>
   *
   * @param xpathFilterExpression is the XPath filter expression to evaluate
   * @param nodes                 is the list of nodes on which to evalute the XPath
   * @return the results of all the XPath evaluations as a single list
   */
  public static List<? extends Node> selectNodes(String xpathFilterExpression, List<? extends Node> nodes) {
    XPath xpath = createXPath(xpathFilterExpression);

    return xpath.selectNodes(nodes);
  }

  /**
   * <p>
   * <code>selectNodes</code> performs the given XPath expression on the
   * {@link List}of {@link Node}instances appending all the results together
   * into a single list.
   * </p>
   *
   * @param xpathFilterExpression is the XPath filter expression to evaluate
   * @param node                  is the Node on which to evalute the XPath
   * @return the results of all the XPath evaluations as a single list
   */
  public static List<? extends Node> selectNodes(String xpathFilterExpression, Node node) {
    XPath xpath = createXPath(xpathFilterExpression);

    return xpath.selectNodes(node);
  }

  /**
   * <p>
   * <code>sort</code> sorts the given List of Nodes using an XPath
   * expression as a {@link java.util.Comparator}.
   * </p>
   *
   * @param list            is the list of Nodes to sort
   * @param xpathExpression is the XPath expression used for comparison
   */
  public static void sort(List<? extends Node> list, String xpathExpression) {
    XPath xpath = createXPath(xpathExpression);
    xpath.sort(list);
  }

  /**
   * <p>
   * <code>sort</code> sorts the given List of Nodes using an XPath
   * expression as a {@link java.util.Comparator}and optionally removing
   * duplicates.
   * </p>
   *
   * @param list       is the list of Nodes to sort
   * @param expression is the XPath expression used for comparison
   * @param distinct   if true then duplicate values (using the sortXPath for
   *                   comparisions) will be removed from the List
   */
  public static void sort(List<? extends Node> list, String expression, boolean distinct) {
    XPath xpath = createXPath(expression);
    xpath.sort(list, distinct);
  }

  /**
   * <p>
   * <code>parseText</code> parses the given text as an XML document and
   * returns the newly created Document.
   * </p>
   *
   * @param text the XML text to be parsed
   * @return a newly parsed Document
   * @throws DocumentException if the document could not be parsed
   */
  public static Document parseText(String text) throws DocumentException {
    Document result = null;

    SAXReader reader = new SAXReader();
    String encoding = getEncoding(text);

    InputSource source = new InputSource(new StringReader(text));
    source.setEncoding(encoding);

    result = reader.read(source);

    // if the XML parser doesn't provide a way to retrieve the encoding,
    // specify it manually
    if (result.getXMLEncoding() == null) {
      result.setXMLEncoding(encoding);
    }

    return result;
  }

  private static String getEncoding(String text) {
    String result = null;

    String xml = text.trim();

    if (xml.startsWith("<?xml")) {
      int end = xml.indexOf("?>");
      String sub = xml.substring(0, end);
      StringTokenizer tokens = new StringTokenizer(sub, " =\"\'");

      while (tokens.hasMoreTokens()) {
        String token = tokens.nextToken();

        if ("encoding".equals(token)) {
          if (tokens.hasMoreTokens()) {
            result = tokens.nextToken();
          }

          break;
        }
      }
    }

    return result;
  }

  /**
   * <p>
   * makeElement
   * </p>
   * a helper method which navigates from the given Document or Element node
   * to some Element using the path expression, creating any necessary
   * elements along the way. For example the path <code>a/b/c</code> would
   * get the first child &lt;a&gt; element, which would be created if it did
   * not exist, then the next child &lt;b&gt; and so on until finally a
   * &lt;c&gt; element is returned.
   *
   * @param source is the Element or Document to start navigating from
   * @param path   is a simple path expression, seperated by '/' which denotes
   *               the path from the source to the resulting element such as
   *               a/b/c
   * @return the first Element on the given path which either already existed
   *         on the path or were created by this method.
   */
  public static Element makeElement(Branch source, String path) {
    StringTokenizer tokens = new StringTokenizer(path, "/");
    Element parent;

    if (source instanceof Document) {
      Document document = (Document) source;
      parent = document.getRootElement();

      // lets throw a NoSuchElementException
      // if we are given an empty path
      String name = tokens.nextToken();

      if (parent == null) {
        parent = document.addElement(name);
      }
    } else {
      parent = (Element) source;
    }

    Element element = null;

    while (tokens.hasMoreTokens()) {
      String name = tokens.nextToken();

      if (name.indexOf(':') > 0) {
        element = parent.element(parent.getQName(name));
      } else {
        element = parent.element(name);
      }

      if (element == null) {
        element = parent.addElement(name);
      }

      parent = element;
    }

    return element;
  }
}

/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 * 
 * 2. Redistributions 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.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived
 * from this Software without prior written permission of MetaStuff, Ltd. For
 * written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may
 * "DOM4J" appear in their names without prior written permission of MetaStuff,
 * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://dom4j.sourceforge.net
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
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