http://xml.apache.org/xalan-j/: Serializer to write out XML, HTML etc. as a stream of characters from an input DOM or from input SAX events. (The Apache Software Foundation) 
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 * Licensed to the Apache Software Foundation (ASF) under one
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 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: PredicatedNodeTest.java 468655 2006-10-28 07:12:06Z minchau $
 */
package org.apache.xpath.axes;

import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xpath.Expression;
import org.apache.xpath.ExpressionOwner;
import org.apache.xpath.XPathContext;
import org.apache.xpath.XPathVisitor;
import org.apache.xpath.compiler.Compiler;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.patterns.NodeTest;

public abstract class PredicatedNodeTest extends NodeTest implements SubContextList
{
    static final long serialVersionUID = -6193530757296377351L;

  
Construct an AxesWalker using a LocPathIterator.

Params:
  • locPathIterator – non-null reference to the parent iterator.
/**
   * Construct an AxesWalker using a LocPathIterator.
   *
   * @param locPathIterator non-null reference to the parent iterator.
   */
  PredicatedNodeTest(LocPathIterator locPathIterator)
  {
    m_lpi = locPathIterator;
  }
  
  
Construct an AxesWalker.  The location path iterator will have to be set
before use.

/**
   * Construct an AxesWalker.  The location path iterator will have to be set
   * before use.
   */
  PredicatedNodeTest()
  {
  }
  
  
Read the object from a serialization stream.

Params:
  • stream – Input stream to read from
Throws:
/**
   * Read the object from a serialization stream.
   *
   * @param stream Input stream to read from
   *
   * @throws java.io.IOException
   * @throws javax.xml.transform.TransformerException
   */
  private void readObject(java.io.ObjectInputStream stream)
          throws java.io.IOException, javax.xml.transform.TransformerException
  {
    try
    {
      stream.defaultReadObject();
      m_predicateIndex = -1;
      resetProximityPositions();
    }
    catch (ClassNotFoundException cnfe)
    {
      throw new javax.xml.transform.TransformerException(cnfe);
    }
  }
  
  
Get a cloned PrdicatedNodeTest.

Throws:
Returns:A new PredicatedNodeTest that can be used without mutating this one.
/**
   * Get a cloned PrdicatedNodeTest.
   *
   * @return A new PredicatedNodeTest that can be used without mutating this one.
   *
   * @throws CloneNotSupportedException
   */
  public Object clone() throws CloneNotSupportedException
  {
    // Do not access the location path itterator during this operation!
    
    PredicatedNodeTest clone = (PredicatedNodeTest) super.clone();

    if ((null != this.m_proximityPositions)
            && (this.m_proximityPositions == clone.m_proximityPositions))
    {
      clone.m_proximityPositions = new int[this.m_proximityPositions.length];

      System.arraycopy(this.m_proximityPositions, 0,
                       clone.m_proximityPositions, 0,
                       this.m_proximityPositions.length);
    }
    
    if(clone.m_lpi == this)
      clone.m_lpi = (LocPathIterator)clone;

    return clone;
  }
  
  // Only for clones for findLastPos.  See bug4638.
  protected int m_predCount = -1;

  
Get the number of predicates that this walker has.

Returns:the number of predicates that this walker has.
/**
   * Get the number of predicates that this walker has.
   *
   * @return the number of predicates that this walker has.
   */
  public int getPredicateCount()
  {
    if(-1 == m_predCount)
      return (null == m_predicates) ? 0 : m_predicates.length;
    else
      return m_predCount;
  }

  
Set the number of predicates that this walker has.  This does more 
that one would think, as it creates a new predicate array of the 
size of the count argument, and copies count predicates into the new 
one from the old, and then reassigns the predicates value.  All this 
to keep from having to have a predicate count value.

Params:
  • count – The number of predicates, which must be equal or less 
              than the existing count.
/**
   * Set the number of predicates that this walker has.  This does more 
   * that one would think, as it creates a new predicate array of the 
   * size of the count argument, and copies count predicates into the new 
   * one from the old, and then reassigns the predicates value.  All this 
   * to keep from having to have a predicate count value.
   *
   * @param count The number of predicates, which must be equal or less 
   *               than the existing count.
   */
  public void setPredicateCount(int count)
  {
    if(count > 0)
    {
      Expression[] newPredicates = new Expression[count];
      for (int i = 0; i < count; i++) 
      {
        newPredicates[i] = m_predicates[i];
      }
      m_predicates = newPredicates;
    }
    else
      m_predicates = null;
    
  }

  
Init predicate info.

Params:
  • compiler – The Compiler object that has information about this 
                walker in the op map.
  • opPos – The op code position of this location step.
Throws:
/**
   * Init predicate info.
   *
   * @param compiler The Compiler object that has information about this 
   *                 walker in the op map.
   * @param opPos The op code position of this location step.
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected void initPredicateInfo(Compiler compiler, int opPos)
          throws javax.xml.transform.TransformerException
  {

    int pos = compiler.getFirstPredicateOpPos(opPos);

    if(pos > 0)
    {
      m_predicates = compiler.getCompiledPredicates(pos);
      if(null != m_predicates)
      {
      	for(int i = 0; i < m_predicates.length; i++)
      	{
      		m_predicates[i].exprSetParent(this);
      	}
      }
    }
  }

  
Get a predicate expression at the given index.

Params:
  • index – Index of the predicate.
Returns:A predicate expression.
/**
   * Get a predicate expression at the given index.
   *
   *
   * @param index Index of the predicate.
   *
   * @return A predicate expression.
   */
  public Expression getPredicate(int index)
  {
    return m_predicates[index];
  }
  
  
Get the current sub-context position.

Returns:The node position of this walker in the sub-context node list.
/**
   * Get the current sub-context position.
   *
   * @return The node position of this walker in the sub-context node list.
   */
  public int getProximityPosition()
  {

    // System.out.println("getProximityPosition - m_predicateIndex: "+m_predicateIndex);
    return getProximityPosition(m_predicateIndex);
  }

  
Get the current sub-context position.

Params:
  • xctxt – The XPath runtime context.
Returns:The node position of this walker in the sub-context node list.
/**
   * Get the current sub-context position.
   *
   * @param xctxt The XPath runtime context.
   *
   * @return The node position of this walker in the sub-context node list.
   */
  public int getProximityPosition(XPathContext xctxt)
  {
    return getProximityPosition();
  }
  
  
Get the index of the last node that can be itterated to.

Params:
  • xctxt – XPath runtime context.
Returns:the index of the last node that can be itterated to.
/**
   * Get the index of the last node that can be itterated to.
   *
   *
   * @param xctxt XPath runtime context.
   *
   * @return the index of the last node that can be itterated to.
   */
  public abstract int getLastPos(XPathContext xctxt);

  
Get the current sub-context position.

Params:
  • predicateIndex – The index of the predicate where the proximity 
                      should be taken from.
Returns:The node position of this walker in the sub-context node list.
/**
   * Get the current sub-context position.
   *
   * @param predicateIndex The index of the predicate where the proximity 
   *                       should be taken from.
   *
   * @return The node position of this walker in the sub-context node list.
   */
  protected int getProximityPosition(int predicateIndex)
  {
    return (predicateIndex >= 0) ? m_proximityPositions[predicateIndex] : 0;
  }

  
Reset the proximity positions counts.

/**
   * Reset the proximity positions counts.
   */
  public void resetProximityPositions()
  {
    int nPredicates = getPredicateCount();
    if (nPredicates > 0)
    {
      if (null == m_proximityPositions)
        m_proximityPositions = new int[nPredicates];

      for (int i = 0; i < nPredicates; i++)
      {
        try
        {
          initProximityPosition(i);
        }
        catch(Exception e)
        {
          // TODO: Fix this...
          throw new org.apache.xml.utils.WrappedRuntimeException(e);
        }
      }
    }
  }

  
Init the proximity position to zero for a forward axes.

Params:
  • i – The index into the m_proximityPositions array.
Throws:
/**
   * Init the proximity position to zero for a forward axes.
   *
   * @param i The index into the m_proximityPositions array.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public void initProximityPosition(int i) throws javax.xml.transform.TransformerException
  {
    m_proximityPositions[i] = 0;
  }

  
Count forward one proximity position.

Params:
  • i – The index into the m_proximityPositions array, where the increment 
         will occur.
/**
   * Count forward one proximity position.
   *
   * @param i The index into the m_proximityPositions array, where the increment 
   *          will occur.
   */
  protected void countProximityPosition(int i)
  {
  	// Note that in the case of a UnionChildIterator, this may be a 
  	// static object and so m_proximityPositions may indeed be null!
  	int[] pp = m_proximityPositions;
    if ((null != pp) && (i < pp.length))
      pp[i]++;
  }

  
Tells if this is a reverse axes.

Returns:false, unless a derived class overrides.
/**
   * Tells if this is a reverse axes.
   *
   * @return false, unless a derived class overrides.
   */
  public boolean isReverseAxes()
  {
    return false;
  }

  
Get which predicate is executing.

Returns:The current predicate index, or -1 if no predicate is executing.
/**
   * Get which predicate is executing.
   *
   * @return The current predicate index, or -1 if no predicate is executing.
   */
  public int getPredicateIndex()
  {
    return m_predicateIndex;
  }

  
Process the predicates.

Params:
  • context – The current context node.
  • xctxt – The XPath runtime context.
Throws:
Returns:the result of executing the predicate expressions.
/**
   * 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;
  }
  
  
This function is used to fixup variables from QNames to stack frame 
indexes at stylesheet build time.

Params:
  • vars – List of QNames that correspond to variables.  This list 
should be searched backwards for the first qualified name that 
corresponds to the variable reference qname.  The position of the 
QName in the vector from the start of the vector will be its position 
in the stack frame (but variables above the globalsTop value will need 
to be offset to the current stack frame).
/**
   * This function is used to fixup variables from QNames to stack frame 
   * indexes at stylesheet build time.
   * @param vars List of QNames that correspond to variables.  This list 
   * should be searched backwards for the first qualified name that 
   * corresponds to the variable reference qname.  The position of the 
   * QName in the vector from the start of the vector will be its position 
   * in the stack frame (but variables above the globalsTop value will need 
   * to be offset to the current stack frame).
   */
  public void fixupVariables(java.util.Vector vars, int globalsSize)
  {
    super.fixupVariables(vars, globalsSize);

    int nPredicates = getPredicateCount();

    for (int i = 0; i < nPredicates; i++)
    {
      m_predicates[i].fixupVariables(vars, globalsSize);
    }
  }

  
  
Diagnostics.

Params:
  • n – Node to give diagnostic information about, or null.
Returns:Informative string about the argument.
/**
   * Diagnostics.
   *
   * @param n Node to give diagnostic information about, or null.
   *
   * @return Informative string about the argument.
   */
  protected String nodeToString(int n)
  {
    if(DTM.NULL != n)
    {
      DTM dtm = m_lpi.getXPathContext().getDTM(n);
      return dtm.getNodeName(n) + "{" + (n+1) + "}";
    }
    else
    {
      return "null";
    }
  }
  
  //=============== NodeFilter Implementation ===============

  
 Test whether a specified node is visible in the logical view of a
TreeWalker or NodeIterator. This function will be called by the
implementation of TreeWalker and NodeIterator; it is not intended to
be called directly from user code.

Params:
  • n –  The node to check to see if it passes the filter or not.
Returns: a constant to determine whether the node is accepted,
  rejected, or skipped, as defined  above .
/**
   *  Test whether a specified node is visible in the logical view of a
   * TreeWalker or NodeIterator. This function will be called by the
   * implementation of TreeWalker and NodeIterator; it is not intended to
   * be called directly from user code.
   * @param n  The node to check to see if it passes the filter or not.
   * @return  a constant to determine whether the node is accepted,
   *   rejected, or skipped, as defined  above .
   */
  public short acceptNode(int n)
  {

    XPathContext xctxt = m_lpi.getXPathContext();

    try
    {
      xctxt.pushCurrentNode(n);

      XObject score = execute(xctxt, n);

      // System.out.println("\n::acceptNode - score: "+score.num()+"::");
      if (score != NodeTest.SCORE_NONE)
      {
        if (getPredicateCount() > 0)
        {
          countProximityPosition(0);

          if (!executePredicates(n, xctxt))
            return DTMIterator.FILTER_SKIP;
        }

        return DTMIterator.FILTER_ACCEPT;
      }
    }
    catch (javax.xml.transform.TransformerException se)
    {

      // TODO: Fix this.
      throw new RuntimeException(se.getMessage());
    }
    finally
    {
      xctxt.popCurrentNode();
    }

    return DTMIterator.FILTER_SKIP;
  }

  
  
Get the owning location path iterator.

Returns:the owning location path iterator, which should not be null.
/**
   * Get the owning location path iterator.
   *
   * @return the owning location path iterator, which should not be null.
   */
  public LocPathIterator getLocPathIterator()
  {
    return m_lpi;
  }

  
Set the location path iterator owner for this walker.  Besides 
initialization, this function is called during cloning operations.

Params:
  • li – non-null reference to the owning location path iterator.
/**
   * Set the location path iterator owner for this walker.  Besides 
   * initialization, this function is called during cloning operations.
   *
   * @param li non-null reference to the owning location path iterator.
   */
  public void setLocPathIterator(LocPathIterator li)
  {
    m_lpi = li;
    if(this != li)
      li.exprSetParent(this);
  }
  
  
Tell if this expression or it's subexpressions can traverse outside 
the current subtree.

Returns:true if traversal outside the context node's subtree can occur.
/**
   * Tell if this expression or it's subexpressions can traverse outside 
   * the current subtree.
   * 
   * @return true if traversal outside the context node's subtree can occur.
   */
   public boolean canTraverseOutsideSubtree()
   {
    int n = getPredicateCount();
    for (int i = 0; i < n; i++) 
    {
      if(getPredicate(i).canTraverseOutsideSubtree())
        return true;
    }
    return false;
   }
   
	
This will traverse the heararchy, calling the visitor for 
each member.  If the called visitor method returns 
false, the subtree should not be called.

Params:
  • visitor – The visitor whose appropriate method will be called.
/**
	 * This will traverse the heararchy, calling the visitor for 
	 * each member.  If the called visitor method returns 
	 * false, the subtree should not be called.
	 * 
	 * @param visitor The visitor whose appropriate method will be called.
	 */
	public void callPredicateVisitors(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);
	      }
	
	    }
	  }
	} 
	
    
See Also:
  • deepEquals.deepEquals(Expression)
/**
     * @see Expression#deepEquals(Expression)
     */
    public boolean deepEquals(Expression expr)
    {
      if (!super.deepEquals(expr))
            return false;

      PredicatedNodeTest pnt = (PredicatedNodeTest) expr;
      if (null != m_predicates)
      {

        int n = m_predicates.length;
        if ((null == pnt.m_predicates) || (pnt.m_predicates.length != n))
              return false;
        for (int i = 0; i < n; i++)
        {
          if (!m_predicates[i].deepEquals(pnt.m_predicates[i]))
          	return false; 
        }
      }
      else if (null != pnt.m_predicates)
              return false; 
              
      return true; 
    }
    
  
This is true if nextNode returns null. 
/** This is true if nextNode returns null. */
  transient protected boolean m_foundLast = false;
    
  
The owning location path iterator.
 @serial 
/** The owning location path iterator.
   *  @serial */
  protected LocPathIterator m_lpi;
  
  
Which predicate we are executing.

/**
   * Which predicate we are executing.
   */
  transient int m_predicateIndex = -1;
  
  
The list of predicate expressions. Is static and does not need 
 to be deep cloned.
 @serial 

/** The list of predicate expressions. Is static and does not need 
   *  to be deep cloned.
   *  @serial 
   */
  private Expression[] m_predicates;

  
An array of counts that correspond to the number
of predicates the step contains.

/**
   * An array of counts that correspond to the number
   * of predicates the step contains.
   */
  transient protected int[] m_proximityPositions;

  
If true, diagnostic messages about predicate execution will be posted.  
/** If true, diagnostic messages about predicate execution will be posted.  */
  static final boolean DEBUG_PREDICATECOUNTING = false;
  
  class PredOwner implements ExpressionOwner
  {
  	int m_index;
  	
  	PredOwner(int index)
  	{
  		m_index = index;
  	}
  	
    
See Also:
  • getExpression.getExpression()
/**
     * @see ExpressionOwner#getExpression()
     */
    public Expression getExpression()
    {
      return m_predicates[m_index];
    }


    
See Also:
  • setExpression.setExpression(Expression)
/**
     * @see ExpressionOwner#setExpression(Expression)
     */
    public void setExpression(Expression exp)
    {
    	exp.exprSetParent(PredicatedNodeTest.this);
    	m_predicates[m_index] = exp;
    }
  }
    
}