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UnionChildIterator.javaAPI DocJava SE 5 API4660Fri Aug 26 14:56:06 BST 2005com.sun.org.apache.xpath.internal.axes

UnionChildIterator

public class UnionChildIterator extends ChildTestIterator
This class defines a simplified type of union iterator that only tests along the child axes. If the conditions are right, it is much faster than using a UnionPathIterator.

Fields Summary
private PredicatedNodeTest[]
m_nodeTests
Even though these may hold full LocPathIterators, this array does not have to be cloned, since only the node test and predicate portion are used, and these only need static information. However, also note that index predicates can not be used!
Constructors Summary
public UnionChildIterator()
Constructor for UnionChildIterator


        
   
  
    super(null);
Methods Summary
public shortacceptNode(int n)
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 .

    XPathContext xctxt = getXPathContext();
    try
    {
      xctxt.pushCurrentNode(n);
      for (int i = 0; i < m_nodeTests.length; i++)
      {
        PredicatedNodeTest pnt = m_nodeTests[i];
        XObject score = pnt.execute(xctxt, n);
        if (score != NodeTest.SCORE_NONE)
        {
          // Note that we are assuming there are no positional predicates!
          if (pnt.getPredicateCount() > 0)
          {
            if (pnt.executePredicates(n, xctxt))
              return DTMIterator.FILTER_ACCEPT;
          }
          else
            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;
public voidaddNodeTest(com.sun.org.apache.xpath.internal.axes.PredicatedNodeTest test)
Add a node test to the union list.

param
test reference to a NodeTest, which will be added directly to the list of node tests (in other words, it will not be cloned). The parent of this test will be set to this object.


    // Increase array size by only 1 at a time.  Fix this
    // if it looks to be a problem.
    if (null == m_nodeTests)
    {
      m_nodeTests = new PredicatedNodeTest[1];
      m_nodeTests[0] = test;
    }
    else
    {
      PredicatedNodeTest[] tests = m_nodeTests;
      int len = m_nodeTests.length;

      m_nodeTests = new PredicatedNodeTest[len + 1];

      System.arraycopy(tests, 0, m_nodeTests, 0, len);

      m_nodeTests[len] = test;
    }
    test.exprSetParent(this);
public voidfixupVariables(java.util.Vector vars, int globalsSize)
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).

    super.fixupVariables(vars, globalsSize);
    if (m_nodeTests != null) {
      for (int i = 0; i < m_nodeTests.length; i++) {
        m_nodeTests[i].fixupVariables(vars, globalsSize);
      }
    }