steppattern.java

java1.6众多例子参考

    DTM dtm = xctxt.getDTM(context);
    int parent = dtm.getParent(context);

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

      for (int child = traverser.first(parent); DTM.NULL != child;
              child = traverser.next(parent, 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())
                    {
                      if ((pos + 1) != (int) pred.numWithSideEffects())
                      {
                        pass = false;
    
                        break;
                      }
                    }
                    else if (!pred.boolWithSideEffects())
                    {
                      pass = false;
    
                      break;
                    }
                  }
                  finally
                  {
                    pred.detach();
                  }
                }
                finally
                {
                  xctxt.popPredicatePos();
                }
              }
            }
            finally
            {
              xctxt.popSubContextList();
            }

            if (pass)
              pos++;

            if (!findLast && child == context)
            {
              return pos;
            }
          }
        }
        finally
        {
          xctxt.popCurrentNode();
        }
      }
    }
    catch (javax.xml.transform.TransformerException se)
    {

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

    return pos;
  }

  /**
   * Get the proximity position index of the current node based on this
   * node test.
   *
   *
   * @param xctxt XPath runtime context.
   *
   * @return the proximity position index of the current node based on the
   *         node test.
   */
  public int getProximityPosition(XPathContext xctxt)
  {
    return getProximityPosition(xctxt, xctxt.getPredicatePos(), false);
  }
  
  /**
   * Get the count of the nodes that match the test, which is the proximity
   * position of the last node that can pass this test in the sub context
   * selection.  In XSLT 1-based indexing, this count is the index of the last
   * node.
   *
   *
   * @param xctxt XPath runtime context.
   *
   * @return the count of the nodes that match the test.
   */
  public int getLastPos(XPathContext xctxt)
  {
    return getProximityPosition(xctxt, xctxt.getPredicatePos(), true);
  }

  /**
   * 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;
  }

  /**
   * 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;
  }

  /**
   * Get the string represenentation of this step for diagnostic purposes.
   *
   *
   * @return A string representation of this step, built by reverse-engineering 
   * the contained info.
   */
  public String toString()
  {

    StringBuffer buf = new StringBuffer();

    for (StepPattern pat = this; pat != null; pat = pat.m_relativePathPattern)
    {
      if (pat != this)
        buf.append("/");

      buf.append(Axis.getNames(pat.m_axis));
      buf.append("::");

      if (0x000005000 == pat.m_whatToShow)
      {
        buf.append("doc()");
      }
      else if (DTMFilter.SHOW_BYFUNCTION == pat.m_whatToShow)
      {
        buf.append("function()");
      }
      else if (DTMFilter.SHOW_ALL == pat.m_whatToShow)
      {
        buf.append("node()");
      }
      else if (DTMFilter.SHOW_TEXT == pat.m_whatToShow)
      {
        buf.append("text()");
      }
      else if (DTMFilter.SHOW_PROCESSING_INSTRUCTION == pat.m_whatToShow)
      {
        buf.append("processing-instruction(");

        if (null != pat.m_name)
        {
          buf.append(pat.m_name);
        }

        buf.append(")");
      }
      else if (DTMFilter.SHOW_COMMENT == pat.m_whatToShow)
      {
        buf.append("comment()");
      }
      else if (null != pat.m_name)
      {
        if (DTMFilter.SHOW_ATTRIBUTE == pat.m_whatToShow)
        {
          buf.append("@");
        }

        if (null != pat.m_namespace)
        {
          buf.append("{");
          buf.append(pat.m_namespace);
          buf.append("}");
        }

        buf.append(pat.m_name);
      }
      else if (DTMFilter.SHOW_ATTRIBUTE == pat.m_whatToShow)
      {
        buf.append("@");
      }
      else if ((DTMFilter.SHOW_DOCUMENT | DTMFilter.SHOW_DOCUMENT_FRAGMENT)
               == pat.m_whatToShow)
      {
        buf.append("doc-root()");
      }
      else
      {
        buf.append("?" + Integer.toHexString(pat.m_whatToShow));
      }

      if (null != pat.m_predicates)
      {
        for (int i = 0; i < pat.m_predicates.length; i++)
        {
          buf.append("[");
          buf.append(pat.m_predicates[i]);
          buf.append("]");
        }
      }
    }

    return buf.toString();
  }

  /** Set to true to send diagnostics about pattern matches to the consol. */
  private static final boolean DEBUG_MATCHES = false;

  /**
   * Get the match score of the given node.
   *
   * @param xctxt The XPath runtime context.
   * @param context The node to be tested.
   *
   * @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 double getMatchScore(XPathContext xctxt, int context)
          throws javax.xml.transform.TransformerException
  {

    xctxt.pushCurrentNode(context);
    xctxt.pushCurrentExpressionNode(context);

    try
    {
      XObject score = execute(xctxt);

      return score.num();
    }
    finally
    {
      xctxt.popCurrentNode();
      xctxt.popCurrentExpressionNode();
    }

    // return XPath.MATCH_SCORE_NONE;
  }

  /**
   * Set the axis that this step should follow. 
   *
   *
   * @param axis The Axis for this test, one of of Axes.ANCESTORORSELF, etc.
   */
  public void setAxis(int axis)
  {
    m_axis = axis;
  }

  /**
   * Get the axis that this step follows. 
   *
   *
   * @return The Axis for this test, one of of Axes.ANCESTORORSELF, etc.
   */
  public int getAxis()
  {
    return m_axis;
  }
  
  class PredOwner implements ExpressionOwner
  {
  	int m_index;
  	
  	PredOwner(int index)
  	{
  		m_index = index;
  	}
  	
    /**
     * @see ExpressionOwner#getExpression()
     */
    public Expression getExpression()
    {
      return m_predicates[m_index];
    }


    /**
     * @see ExpressionOwner#setExpression(Expression)
     */
    public void setExpression(Expression exp)
    {
    	exp.exprSetParent(StepPattern.this);
    	m_predicates[m_index] = exp;
    }
  }
  
  /**
   * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
   */
  public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
  {
  	 	if(visitor.visitMatchPattern(owner, this))
  	 	{
  	 		callSubtreeVisitors(visitor);
  	 	}
  }

  /**
   * Call the visitors on the subtree.  Factored out from callVisitors 
   * so it may be called by derived classes.
   */
  protected void callSubtreeVisitors(XPathVisitor visitor)
  {
    if (null != m_predicates)
    {
      int n = m_predicates.length;
      for (int i = 0; i < n; i++)
      {
        ExpressionOwner predOwner = new PredOwner(i);
        if (visitor.visitPredicate(predOwner, m_predicates[i]))
        {
          m_predicates[i].callVisitors(predOwner, visitor);
        }
      }
    }
    if (null != m_relativePathPattern)
    {
      m_relativePathPattern.callVisitors(this, visitor);
    }
  }


  /**
   * @see ExpressionOwner#getExpression()
   */
  public Expression getExpression()
  {
    return m_relativePathPattern;
  }

  /**
   * @see ExpressionOwner#setExpression(Expression)
   */
  public void setExpression(Expression exp)
  {
    exp.exprSetParent(this);
  	m_relativePathPattern = (StepPattern)exp;
  }
  
  /**
   * @see Expression#deepEquals(Expression)
   */
  public boolean deepEquals(Expression expr)
  {
  	if(!super.deepEquals(expr))
  		return false;
  		
  	StepPattern sp = (StepPattern)expr;
  	
    if (null != m_predicates)
    {
        int n = m_predicates.length;
        if ((null == sp.m_predicates) || (sp.m_predicates.length != n))
              return false;
        for (int i = 0; i < n; i++)
        {
          if (!m_predicates[i].deepEquals(sp.m_predicates[i]))
          	return false; 
        }
    }
    else if (null != sp.m_predicates)
    	return false;
  		
  	if(null != m_relativePathPattern)
  	{
  		if(!m_relativePathPattern.deepEquals(sp.m_relativePathPattern))
  			return false;
  	}
  	else if(sp.m_relativePathPattern != null)
  		return false;
  		
  	return true;
  }


}