Java Code Examples for org.apache.xpath.XPathContext#pushSubContextList()

/**
 * New Method to check whether the current node satisfies a position predicate
 *
 * @param xctxt The XPath runtime context.
 * @param predPos Which predicate we're evaluating of foo[1][2][3].
 * @param dtm The DTM of the current node.
 * @param context The currentNode.
 * @param pos The position being requested, i.e. the value returned by 
 *            m_predicates[predPos].execute(xctxt).
 *
 * @return true of the position of the context matches pos, false otherwise.
 */
private final boolean checkProximityPosition(XPathContext xctxt,
        int predPos, DTM dtm, int context, int pos)
{

  try
  {
    DTMAxisTraverser traverser =
      dtm.getAxisTraverser(Axis.PRECEDINGSIBLING);

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

        if (NodeTest.SCORE_NONE != super.execute(xctxt, child))
        {
          boolean pass = true;

          try
          {
            xctxt.pushSubContextList(this);

            for (int i = 0; i < predPos; i++)
            {
              xctxt.pushPredicatePos(i);
              try
              {
                XObject pred = m_predicates[i].execute(xctxt);
                
                try
                {
                  if (XObject.CLASS_NUMBER == pred.getType())
                  {
                    throw new Error("Why: Should never have been called");
                  }
                  else if (!pred.boolWithSideEffects())
                  {
                    pass = false;
  
                    break;
                  }
                }
                finally
                {
                  pred.detach();
                }
              }
              finally
              {
                xctxt.popPredicatePos();
              }
            }
          }
          finally
          {
            xctxt.popSubContextList();
          }

          if (pass)
            pos--;

          if (pos < 1)
            return false;
        }
      }
      finally
      {
        xctxt.popCurrentNode();
      }
    }
  }
  catch (javax.xml.transform.TransformerException se)
  {

    // TODO: should keep throw sax exception...
    throw new java.lang.RuntimeException(se.getMessage());
  }

  return (pos == 1);
}
 

/**
 * Execute the predicates on this step to determine if the current node 
 * should be filtered or accepted.
 *
 * @param xctxt The XPath runtime context.
 * @param dtm The DTM of the current node.
 * @param currentNode The current node context.
 *
 * @return true if the node should be accepted, false otherwise.
 *
 * @throws javax.xml.transform.TransformerException
 */
protected final boolean executePredicates(
        XPathContext xctxt, DTM dtm, int currentNode)
          throws javax.xml.transform.TransformerException
{

  boolean result = true;
  boolean positionAlreadySeen = false;
  int n = getPredicateCount();

  try
  {
    xctxt.pushSubContextList(this);

    for (int i = 0; i < n; i++)
    {
      xctxt.pushPredicatePos(i);

      try
      {
        XObject pred = m_predicates[i].execute(xctxt);

        try
        {
          if (XObject.CLASS_NUMBER == pred.getType())
          {
            int pos = (int) pred.num();

            if (positionAlreadySeen)
            {
              result = (pos == 1);

              break;
            }
            else
            {
              positionAlreadySeen = true;

              if (!checkProximityPosition(xctxt, i, dtm, currentNode, pos))
              {
                result = false;

                break;
              }
            }
          
          }
          else if (!pred.boolWithSideEffects())
          {
            result = false;

            break;
          }
        }
        finally
        {
          pred.detach();
        }
      }
      finally
      {
        xctxt.popPredicatePos();
      }
    }
  }
  finally
  {
    xctxt.popSubContextList();
  }

  return result;
}
 

/**
 * Process the predicates.
 *
 * @param context The current context node.
 * @param xctxt The XPath runtime context.
 *
 * @return the result of executing the predicate expressions.
 *
 * @throws javax.xml.transform.TransformerException
 */
boolean executePredicates(int context, XPathContext xctxt)
        throws javax.xml.transform.TransformerException
{
  
  int nPredicates = getPredicateCount();
  // System.out.println("nPredicates: "+nPredicates);
  if (nPredicates == 0)
    return true;

  PrefixResolver savedResolver = xctxt.getNamespaceContext();

  try
  {
    m_predicateIndex = 0;
    xctxt.pushSubContextList(this);
    xctxt.pushNamespaceContext(m_lpi.getPrefixResolver());
    xctxt.pushCurrentNode(context);

    for (int i = 0; i < nPredicates; i++)
    {
      // System.out.println("Executing predicate expression - waiting count: "+m_lpi.getWaitingCount());
      XObject pred = m_predicates[i].execute(xctxt);
      // System.out.println("\nBack from executing predicate expression - waiting count: "+m_lpi.getWaitingCount());
      // System.out.println("pred.getType(): "+pred.getType());
      if (XObject.CLASS_NUMBER == pred.getType())
      {
        if (DEBUG_PREDICATECOUNTING)
        {
          System.out.flush();
          System.out.println("\n===== start predicate count ========");
          System.out.println("m_predicateIndex: " + m_predicateIndex);
          // System.out.println("getProximityPosition(m_predicateIndex): "
          //                   + getProximityPosition(m_predicateIndex));
          System.out.println("pred.num(): " + pred.num());
        }

        int proxPos = this.getProximityPosition(m_predicateIndex);
        int predIndex = (int) pred.num();
        if (proxPos != predIndex)
        {
          if (DEBUG_PREDICATECOUNTING)
          {
            System.out.println("\nnode context: "+nodeToString(context));
            System.out.println("index predicate is false: "+proxPos);
            System.out.println("\n===== end predicate count ========");
          }
          return false;
        }
        else if (DEBUG_PREDICATECOUNTING)
        {
          System.out.println("\nnode context: "+nodeToString(context));
          System.out.println("index predicate is true: "+proxPos);
          System.out.println("\n===== end predicate count ========");
        }
        
        // If there is a proximity index that will not change during the 
        // course of itteration, then we know there can be no more true 
        // occurances of this predicate, so flag that we're done after 
        // this.
        //
        // bugzilla 14365
        // We can't set m_foundLast = true unless we're sure that -all-
        // remaining parameters are stable, or else last() fails. Fixed so
        // only sets m_foundLast if on the last predicate
        if(m_predicates[i].isStableNumber() && i == nPredicates - 1)
        {
          m_foundLast = true;
        }
      }
      else if (!pred.bool())
        return false;

      countProximityPosition(++m_predicateIndex);
    }
  }
  finally
  {
    xctxt.popCurrentNode();
    xctxt.popNamespaceContext();
    xctxt.popSubContextList();
    m_predicateIndex = -1;
  }

  return true;
}