Java XPathContext类代码示例

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * The dyn:evaluate function evaluates a string as an XPath expression and returns
 * the resulting value, which might be a boolean, number, string, node set, result
 * tree fragment or external object. The sole argument is the string to be evaluated.
 * <p>
 * If the expression string passed as the second argument is an invalid XPath
 * expression (including an empty string), this function returns an empty node set.
 * <p>
 * You should only use this function if the expression must be constructed dynamically,
 * otherwise it is much more efficient to use the expression literally.
 *
 * @param myContext The ExpressionContext passed by the extension processor
 * @param xpathExpr The XPath expression string
 *
 * @return The evaluation result
 */
public static XObject evaluate(ExpressionContext myContext, String xpathExpr)
  throws SAXNotSupportedException
{
  if (myContext instanceof XPathContext.XPathExpressionContext)
  {
    XPathContext xctxt = null;
    try
    {
      xctxt = ((XPathContext.XPathExpressionContext) myContext).getXPathContext();
      XPath dynamicXPath = new XPath(xpathExpr, xctxt.getSAXLocator(),
                                     xctxt.getNamespaceContext(),
                                     XPath.SELECT);

      return dynamicXPath.execute(xctxt, myContext.getContextNode(),
                                  xctxt.getNamespaceContext());
    }
    catch (TransformerException e)
    {
      return new XNodeSet(xctxt.getDTMManager());
    }
  }
  else
    throw new SAXNotSupportedException(XSLMessages.createMessage(XSLTErrorResources.ER_INVALID_CONTEXT_PASSED, new Object[]{myContext })); //"Invalid context passed to evaluate "
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the first argument expression that is expected to return a
 * number.  If the argument is null, then get the number value from the
 * current context node.
 *
 * @param xctxt Runtime XPath context.
 *
 * @return The number value of the first argument, or the number value of the
 *         current context node if the first argument is null.
 *
 * @throws javax.xml.transform.TransformerException if an error occurs while
 *                                   executing the argument expression.
 */
protected double getArg0AsNumber(XPathContext xctxt)
        throws javax.xml.transform.TransformerException
{

  if(null == m_arg0)
  {
    int currentNode = xctxt.getCurrentNode();
    if(DTM.NULL == currentNode)
      return 0;
    else
    {
      DTM dtm = xctxt.getDTM(currentNode);
      XMLString str = dtm.getStringValue(currentNode);
      return str.toDouble();
    }

  }
  else
    return m_arg0.execute(xctxt).num();
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Cast result object to a result tree fragment.
 *
 * @param support XPath context to use for the conversion
 *
 * @return the objec as a result tree fragment.
 */
public int rtf(XPathContext support)
{

  int result = rtf();

  if (DTM.NULL == result)
  {
    DTM frag = support.createDocumentFragment();

    // %OPT%
    frag.appendTextChild(str());

    result = frag.getDocument();
  }

  return result;
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the function.  The function must return
 * a valid object.
 * @param xctxt The current execution context.
 * @return A valid XObject.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{

  DTMIterator nodes = m_arg0.asIterator(xctxt, xctxt.getCurrentNode());
  double sum = 0.0;
  int pos;

  while (DTM.NULL != (pos = nodes.nextNode()))
  {
    DTM dtm = nodes.getDTM(pos);
    XMLString s = dtm.getStringValue(pos);

    if (null != s)
      sum += s.toDouble();
  }
  nodes.detach();

  return new XNumber(sum);
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Initialize the context values for this expression
 * after it is cloned.
 *
 * @param context The XPath runtime context for this
 * transformation.
 */
public void setRoot(int context, Object environment)
{

  m_context = context;

  XPathContext xctxt = (XPathContext)environment;
  m_execContext = xctxt;
  m_cdtm = xctxt.getDTM(context);

  m_currentContextNode = context; // only if top level?

  // Yech, shouldn't have to do this.  -sb
  if(null == m_prefixResolver)
      m_prefixResolver = xctxt.getNamespaceContext();

  m_lastFetched = DTM.NULL;
  m_foundLast = false;
  m_pos = 0;
  m_length = -1;

  if (m_isTopLevel)
    this.m_stackFrame = xctxt.getVarStack().getStackFrame();

  // reset();
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Get the position in the current context node list.
 *
 * @param xctxt non-null reference to XPath runtime context.
 *
 * @return The number of nodes in the list.
 *
 * @throws javax.xml.transform.TransformerException
 */
public int getCountOfContextNodeList(XPathContext xctxt)
        throws javax.xml.transform.TransformerException
{

  // assert(null != m_contextNodeList, "m_contextNodeList must be non-null");
  // If we're in a predicate, then this will return non-null.
  SubContextList iter = m_isTopLevel ? null : xctxt.getSubContextList();

  // System.out.println("iter: "+iter);
  if (null != iter)
    return iter.getLastPos(xctxt);

  DTMIterator cnl = xctxt.getContextNodeList();
  int count;
  if(null != cnl)
  {
    count = cnl.getLength();
    // System.out.println("count: "+count);
  }
  else
    count = 0;
  return count;
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the function.  The function must return
 * a valid object.
 * @param xctxt The current execution context.
 * @return A valid XObject.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{

  int which = getArg0AsNode(xctxt);

  if (DTM.NULL != which)
  {
    // Note that this is a different value than in previous releases
    // of Xalan. It's sensitive to the exact encoding of the node
    // handle anyway, so fighting to maintain backward compatability
    // really didn't make sense; it may change again as we continue
    // to experiment with balancing document and node numbers within
    // that value.
    return new XString("N" + Integer.toHexString(which).toUpperCase());
  }
  else
    return XString.EMPTYSTRING;
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the function.  The function must return
 * a valid object.
 * @param xctxt The current execution context.
 * @return A valid XObject.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{

  int context = getArg0AsNode(xctxt);
  XObject val;

  if (DTM.NULL != context)
  {
    DTM dtm = xctxt.getDTM(context);
    String qname = dtm.getNodeNameX(context);
    val = (null == qname) ? XString.EMPTYSTRING : new XString(qname);
  }
  else
  {
    val = XString.EMPTYSTRING;
  }

  return val;
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the function.  The function must return
 * a valid object.
 * @param xctxt The current execution context.
 * @return A valid XObject.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{

  StringBuffer sb = new StringBuffer();

  // Compiler says we must have at least two arguments.
  sb.append(m_arg0.execute(xctxt).str());
  sb.append(m_arg1.execute(xctxt).str());

  if (null != m_arg2)
    sb.append(m_arg2.execute(xctxt).str());

  if (null != m_args)
  {
    for (int i = 0; i < m_args.length; i++)
    {
      sb.append(m_args[i].execute(xctxt).str());
    }
  }

  return new XString(sb.toString());
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute an expression in the XPath runtime context, and return the
 * result of the expression.
 *
 *
 * @param xctxt The XPath runtime context.
 *
 * @return The result of the expression in the form of a <code>XObject</code>.
 *
 * @throws javax.xml.transform.TransformerException if a runtime exception
 *         occurs.
 */
public void executeCharsToContentHandler(XPathContext xctxt,
                                            ContentHandler handler)
  throws javax.xml.transform.TransformerException,
         org.xml.sax.SAXException
{
  if(Arg0IsNodesetExpr())
  {
    int node = getArg0AsNode(xctxt);
    if(DTM.NULL != node)
    {
      DTM dtm = xctxt.getDTM(node);
      dtm.dispatchCharactersEvents(node, handler, true);
    }
  }
  else
  {
    XObject obj = execute(xctxt);
    obj.dispatchCharactersEvents(handler);
  }
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the first argument expression that is expected to return a
 * string.  If the argument is null, then get the string value from the
 * current context node.
 *
 * @param xctxt Runtime XPath context.
 *
 * @return The string value of the first argument, or the string value of the
 *         current context node if the first argument is null.
 *
 * @throws javax.xml.transform.TransformerException if an error occurs while
 *                                   executing the argument expression.
 */
protected XMLString getArg0AsString(XPathContext xctxt)
        throws javax.xml.transform.TransformerException
{
  if(null == m_arg0)
  {
    int currentNode = xctxt.getCurrentNode();
    if(DTM.NULL == currentNode)
      return XString.EMPTYSTRING;
    else
    {
      DTM dtm = xctxt.getDTM(currentNode);
      return dtm.getStringValue(currentNode);
    }

  }
  else
    return m_arg0.execute(xctxt).xstr();
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
   * Execute the function.  The function must return
   * a valid object.
   * @param xctxt The current execution context.
   * @return A valid XObject.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
  {

//    DTMIterator nl = m_arg0.asIterator(xctxt, xctxt.getCurrentNode());

//    // We should probably make a function on the iterator for this,
//    // as a given implementation could optimize.
//    int i = 0;
//
//    while (DTM.NULL != nl.nextNode())
//    {
//      i++;
//    }
//    nl.detach();
        DTMIterator nl = m_arg0.asIterator(xctxt, xctxt.getCurrentNode());
        int i = nl.getLength();
        nl.detach();

    return new XNumber((double) i);
  }
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the function.  The function must return
 * a valid object.
 * @param xctxt The current execution context.
 * @return A valid XObject.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{

  SubContextList subContextList = xctxt.getCurrentNodeList();
  int currentNode = DTM.NULL;

  if (null != subContextList) {
      if (subContextList instanceof PredicatedNodeTest) {
          LocPathIterator iter = ((PredicatedNodeTest)subContextList)
                                                        .getLocPathIterator();
          currentNode = iter.getCurrentContextNode();
       } else if(subContextList instanceof StepPattern) {
         throw new RuntimeException(XSLMessages.createMessage(
            XSLTErrorResources.ER_PROCESSOR_ERROR,null));
       }
  } else {
      // not predicate => ContextNode == CurrentNode
      currentNode = xctxt.getContextNode();
  }
  return new XNodeSet(currentNode, xctxt.getDTMManager());
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Execute the match pattern step relative to another step.
 *
 *
 * @param xctxt The XPath runtime context.
 * @param dtm The DTM of the current node.
 * @param currentNode The current node context.
 *
 * @return {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NODETEST},
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NONE},
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NSWILD},
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_QNAME}, or
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_OTHER}.
 *
 * @throws javax.xml.transform.TransformerException
 */
protected final XObject executeRelativePathPattern(
        XPathContext xctxt, DTM dtm, int currentNode)
          throws javax.xml.transform.TransformerException
{

  XObject score = NodeTest.SCORE_NONE;
  int context = currentNode;
  DTMAxisTraverser traverser;

  traverser = dtm.getAxisTraverser(m_axis);

  for (int relative = traverser.first(context); DTM.NULL != relative;
          relative = traverser.next(context, relative))
  {
    try
    {
      xctxt.pushCurrentNode(relative);

      score = execute(xctxt);

      if (score != NodeTest.SCORE_NONE)
        break;
    }
    finally
    {
      xctxt.popCurrentNode();
    }
  }

  return score;
}
 

import com.sun.org.apache.xpath.internal.XPathContext; //导入依赖的package包/类
/**
 * Test a node to see if it matches the given node test.
 *
 * @param xctxt XPath runtime context.
 *
 * @return {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NODETEST},
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NONE},
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NSWILD},
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_QNAME}, or
 *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_OTHER}.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt, int context)
        throws javax.xml.transform.TransformerException
{

  DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
  XNumber score = SCORE_NONE;

  if (null != nl)
  {
    int n;

    while (DTM.NULL != (n = nl.nextNode()))
    {
      score = (n == context) ? SCORE_OTHER : SCORE_NONE;

      if (score == SCORE_OTHER)
      {
        context = n;

        break;
      }
    }

    // nl.detach();
  }
  nl.detach();

  return score;
}