extensions.java

来自「java jdk 1.4的源码」· Java 代码 · 共 442 行 · 第 1/2 页

    return ExsltSets.distinct(nl);
  }

  /**
   * Returns true if both node-sets contain the same set of nodes.
   *
   * @param nl1 NodeList for first node-set
   * @param nl2 NodeList for second node-set
   * @return true if nl1 and nl2 contain exactly the same set of nodes.
   */
  public static boolean hasSameNodes(NodeList nl1, NodeList nl2)
  {

    NodeSet ns1 = new NodeSet(nl1);
    NodeSet ns2 = new NodeSet(nl2);

    if (ns1.getLength() != ns2.getLength())
      return false;

    for (int i = 0; i < ns1.getLength(); i++)
    {
      Node n = ns1.elementAt(i);

      if (!ns2.contains(n))
        return false;
    }

    return true;
  }

  /**
   * Returns the result of evaluating the argument as a string containing
   * an XPath expression.  Used where the XPath expression is not known until
   * run-time.  The expression is evaluated as if the run-time value of the
   * argument appeared in place of the evaluate function call at compile time.
   *
   * @param myContext an <code>ExpressionContext</code> passed in by the
   *                  extension mechanism.  This must be an XPathContext.
   * @param xpathExtr The XPath expression to be evaluated.
   * @return the XObject resulting from evaluating the XPath
   *
   * @throws SAXNotSupportedException
   *
   * Note: The usage of this extension function in the xalan namespace 
   * is deprecated. Please use the same function in the EXSLT dynamic extension
   * (http://exslt.org/dynamic).
   */
  public static XObject evaluate(ExpressionContext myContext, String xpathExpr)
         throws SAXNotSupportedException
  {
    return ExsltDynamic.evaluate(myContext, xpathExpr);
  }

  /**
   * Returns a NodeSet containing one text node for each token in the first argument.
   * Delimiters are specified in the second argument.
   * Tokens are determined by a call to <code>StringTokenizer</code>.
   * If the first argument is an empty string or contains only delimiters, the result
   * will be an empty NodeSet.
   *
   * Contributed to XalanJ1 by <a href="mailto:[e-mail]">Benoit Cerrina</a>.
   * 
   * @param myContext an <code>ExpressionContext</code> passed in by the
   *                  extension mechanism.  This must be an XPathContext.
   * @param toTokenize The string to be split into text tokens.
   * @param delims The delimiters to use.
   * @return a NodeSet as described above.
   */
  public static NodeList tokenize(String toTokenize, String delims)
  {

    try
    {
      if (lDoc == null)
        lDoc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
    }
    catch(ParserConfigurationException pce)
    {
      throw new org.apache.xml.utils.WrappedRuntimeException(pce);
    }

    StringTokenizer lTokenizer = new StringTokenizer(toTokenize, delims);
    NodeSet resultSet = new NodeSet();

    while (lTokenizer.hasMoreTokens())
    {
      resultSet.addNode(lDoc.createTextNode(lTokenizer.nextToken()));
    }

    return resultSet;
  }

  /**
   * Returns a NodeSet containing one text node for each token in the first argument.
   * Delimiters are whitespace.  That is, the delimiters that are used are tab (&#x09),
   * linefeed (&#x0A), return (&#x0D), and space (&#x20).
   * Tokens are determined by a call to <code>StringTokenizer</code>.
   * If the first argument is an empty string or contains only delimiters, the result
   * will be an empty NodeSet.
   *
   * Contributed to XalanJ1 by <a href="mailto:[e-mail]">Benoit Cerrina</a>.
   * 
   * @param myContext an <code>ExpressionContext</code> passed in by the
   *                  extension mechanism.  This must be an XPathContext.
   * @param toTokenize The string to be split into text tokens.
   * @return a NodeSet as described above.
   */
  public static NodeList tokenize(String toTokenize)
  {
    return tokenize(toTokenize, " \t\n\r");
  }

  /**
   * Return a Node of basic debugging information from the 
   * EnvironmentCheck utility about the Java environment.
   *
   * <p>Simply calls the {@link org.apache.xalan.xslt.EnvironmentCheck}
   * utility to grab info about the Java environment and CLASSPATH, 
   * etc., and then returns the resulting Node.  Stylesheets can 
   * then maniuplate this data or simply xsl:copy-of the Node.  Note 
   * that we first attempt to load the more advanced 
   * org.apache.env.Which utility by reflection; only if that fails 
   * to we still use the internal version.  Which is available from 
   * <a href="http://xml.apache.org/commons/">http://xml.apache.org/commons/</a>.</p>
   *
   * <p>We throw a WrappedRuntimeException in the unlikely case 
   * that reading information from the environment throws us an 
   * exception. (Is this really the best thing to do?)</p>
   *
   * @param myContext an <code>ExpressionContext</code> passed in by the
   *                  extension mechanism.  This must be an XPathContext.
   * @return a Node as described above.
   */
  public static Node checkEnvironment(ExpressionContext myContext)
  {

    Document factoryDocument;
    try
    {
      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      DocumentBuilder db = dbf.newDocumentBuilder();
      factoryDocument = db.newDocument();
    }
    catch(ParserConfigurationException pce)
    {
      throw new org.apache.xml.utils.WrappedRuntimeException(pce);
    }

    Node resultNode = null;
    try
    {
      // First use reflection to try to load Which, which is a 
      //  better version of EnvironmentCheck
      resultNode = checkEnvironmentUsingWhich(myContext, factoryDocument);

      if (null != resultNode)
        return resultNode;

      // If reflection failed, fallback to our internal EnvironmentCheck
      EnvironmentCheck envChecker = new EnvironmentCheck();
      Hashtable h = envChecker.getEnvironmentHash();
      resultNode = factoryDocument.createElement("checkEnvironmentExtension");
      envChecker.appendEnvironmentReport(resultNode, factoryDocument, h);
      envChecker = null;
    }
    catch(Exception e)
    {
      throw new org.apache.xml.utils.WrappedRuntimeException(e);
    }

    return resultNode;
  }

  /**
   * Private worker method to attempt to use org.apache.env.Which.
   *
   * @param myContext an <code>ExpressionContext</code> passed in by the
   *                  extension mechanism.  This must be an XPathContext.
   * @param factoryDocument providing createElement services, etc.
   * @return a Node with environment info; null if any error
   */
  private static Node checkEnvironmentUsingWhich(ExpressionContext myContext, 
        Document factoryDocument)
  {
    final String WHICH_CLASSNAME = "org.apache.env.Which";
    final String WHICH_METHODNAME = "which";
    final Class WHICH_METHOD_ARGS[] = { java.util.Hashtable.class,
                                        java.lang.String.class,
                                        java.lang.String.class };
    try
    {
      // Use reflection to try to find xml-commons utility 'Which'
      // Classloader note: if anyone really cares, we could try to 
      //    use the context classloader instead
      Class clazz = Class.forName(WHICH_CLASSNAME);
      if (null == clazz)
        return null;

      // Fully qualify names since this is the only method they're used in
      java.lang.reflect.Method method = clazz.getMethod(WHICH_METHODNAME, WHICH_METHOD_ARGS);
      Hashtable report = new Hashtable();

      // Call the method with our Hashtable, common options, and ignore return value
      Object[] methodArgs = { report, "XmlCommons;Xalan;Xerces;Crimson;Ant", "" };
      Object returnValue = method.invoke(null, methodArgs);

      // Create a parent to hold the report and append hash to it
      Node resultNode = factoryDocument.createElement("checkEnvironmentExtension");
      org.apache.xml.utils.Hashtree2Node.appendHashToNode(report, "whichReport", 
            resultNode, factoryDocument);

      return resultNode;
    }
    catch (Throwable t)
    {
      // Simply return null; no need to report error
      return null;
    }
  }
}