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BasicTestIterator.javaAPI DocJava SE 5 API5980Fri Aug 26 14:56:06 BST 2005com.sun.org.apache.xpath.internal.axes

BasicTestIterator

public abstract class BasicTestIterator extends LocPathIterator
Base for iterators that handle predicates. Does the basic next node logic, so all the derived iterator has to do is get the next node.

Fields Summary
Constructors Summary
protected BasicTestIterator()
Create a LocPathIterator object.

param
nscontext The namespace context for this iterator, should be OK if null.
protected BasicTestIterator(PrefixResolver nscontext)
Create a LocPathIterator object.

param
nscontext The namespace context for this iterator, should be OK if null.


    super(nscontext);
protected BasicTestIterator(Compiler compiler, int opPos, int analysis)
Create a LocPathIterator object, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.

param
compiler The Compiler which is creating this expression.
param
opPos The position of this iterator in the opcode list from the compiler.
throws
javax.xml.transform.TransformerException

    super(compiler, opPos, analysis, false);
    
    int firstStepPos = compiler.getFirstChildPos(opPos);
    int whatToShow = compiler.getWhatToShow(firstStepPos);

    if ((0 == (whatToShow
               & (DTMFilter.SHOW_ATTRIBUTE 
               | DTMFilter.SHOW_NAMESPACE 
               | DTMFilter.SHOW_ELEMENT
               | DTMFilter.SHOW_PROCESSING_INSTRUCTION))) 
               || (whatToShow == DTMFilter.SHOW_ALL))
      initNodeTest(whatToShow);
    else
    {
      initNodeTest(whatToShow, compiler.getStepNS(firstStepPos),
                              compiler.getStepLocalName(firstStepPos));
    }
    initPredicateInfo(compiler, firstStepPos);
protected BasicTestIterator(Compiler compiler, int opPos, int analysis, boolean shouldLoadWalkers)
Create a LocPathIterator object, including creation of step walkers from the opcode list, and call back into the Compiler to create predicate expressions.

param
compiler The Compiler which is creating this expression.
param
opPos The position of this iterator in the opcode list from the compiler.
param
shouldLoadWalkers True if walkers should be loaded, or false if this is a derived iterator and it doesn't wish to load child walkers.
throws
javax.xml.transform.TransformerException

    super(compiler, opPos, analysis, shouldLoadWalkers);
Methods Summary
public com.sun.org.apache.xml.internal.dtm.DTMIteratorcloneWithReset()
Get a cloned Iterator that is reset to the beginning of the query.

return
A cloned NodeIterator set of the start of the query.
throws
CloneNotSupportedException


    ChildTestIterator clone = (ChildTestIterator) super.cloneWithReset();

    clone.resetProximityPositions();

    return clone;
protected abstract intgetNextNode()
Get the next node via getNextXXX. Bottlenecked for derived class override.

return
The next node on the axis, or DTM.NULL.

public intnextNode()
Returns the next node in the set and advances the position of the
iterator in the set. After a NodeIterator is created, the first call
to nextNode() returns the first node in the set.
return
The next Node in the set being iterated over, or
null if there are no more members in that set.
      
  	if(m_foundLast)
  	{
  		m_lastFetched = DTM.NULL;
  		return DTM.NULL;
  	}
  		
    if(DTM.NULL == m_lastFetched)
    {
      resetProximityPositions();
    }

    int next;
    
    com.sun.org.apache.xpath.internal.VariableStack vars;
    int savedStart;
    if (-1 != m_stackFrame)
    {
      vars = m_execContext.getVarStack();

      // These three statements need to be combined into one operation.
      savedStart = vars.getStackFrame();

      vars.setStackFrame(m_stackFrame);
    }
    else
    {
      // Yuck.  Just to shut up the compiler!
      vars = null;
      savedStart = 0;
    }
    
    try
    {
      do
      {
        next = getNextNode();
  
        if (DTM.NULL != next)
        {
          if(DTMIterator.FILTER_ACCEPT == acceptNode(next))
            break;
          else
            continue;
        }
        else
          break;
      }
      while (next != DTM.NULL);
  
      if (DTM.NULL != next)
      {
      	m_pos++;
        return next;
      }
      else
      {
        m_foundLast = true;
  
        return DTM.NULL;
      }
    }
    finally
    {
      if (-1 != m_stackFrame)
      {
        // These two statements need to be combined into one operation.
        vars.setStackFrame(savedStart);
      }
    }