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 * Licensed to the Apache Software Foundation (ASF) under one or more
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package com.sun.org.apache.xalan.internal.xsltc.dom;

import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase;

A step iterator is used to evaluate expressions like "BOOK/TITLE".
A better name for this iterator would have been ParentIterator since
both "BOOK" and "TITLE" are steps in XPath lingo. Step iterators are
constructed from two other iterators which we are going to refer to
as "outer" and "inner". Every node from the outer iterator (the one
for BOOK in our example) is used to initialize the inner iterator.
After this initialization, every node from the inner iterator is
returned (in essence, implementing a "nested loop").
Author:
Jacek Ambroziak, Santiago Pericas-Geertsen, Erwin Bolwidt , Morten Jorgensen/**
 * A step iterator is used to evaluate expressions like "BOOK/TITLE".
 * A better name for this iterator would have been ParentIterator since
 * both "BOOK" and "TITLE" are steps in XPath lingo. Step iterators are
 * constructed from two other iterators which we are going to refer to
 * as "outer" and "inner". Every node from the outer iterator (the one
 * for BOOK in our example) is used to initialize the inner iterator.
 * After this initialization, every node from the inner iterator is
 * returned (in essence, implementing a "nested loop").
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Erwin Bolwidt <ejb@klomp.org>
 * @author Morten Jorgensen
 */
public class StepIterator extends DTMAxisIteratorBase {

    
A reference to the "outer" iterator.
/**
     * A reference to the "outer" iterator.
     */
    protected DTMAxisIterator _source;

    
A reference to the "inner" iterator.
/**
     * A reference to the "inner" iterator.
     */
    protected DTMAxisIterator _iterator;

    
Temp variable to store a marked position.
/**
     * Temp variable to store a marked position.
     */
    private int _pos = -1;

    public StepIterator(DTMAxisIterator source, DTMAxisIterator iterator) {
        _source = source;
        _iterator = iterator;
// System.out.println("SI source = " + source + " this = " + this);
// System.out.println("SI iterator = " + iterator + " this = " + this);
    }


    public void setRestartable(boolean isRestartable) {
        _isRestartable = isRestartable;
        _source.setRestartable(isRestartable);
        _iterator.setRestartable(true);         // must be restartable
    }

    public DTMAxisIterator cloneIterator() {
        _isRestartable = false;
        try {
            final StepIterator clone = (StepIterator) super.clone();
            clone._source = _source.cloneIterator();
            clone._iterator = _iterator.cloneIterator();
            clone._iterator.setRestartable(true);       // must be restartable
            clone._isRestartable = false;
            return clone.reset();
        }
        catch (CloneNotSupportedException e) {
            BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
                                      e.toString());
            return null;
        }
    }

    public DTMAxisIterator setStartNode(int node) {
        if (_isRestartable) {
            // Set start node for left-hand iterator...
            _source.setStartNode(_startNode = node);

            // ... and get start node for right-hand iterator from left-hand,
            // with special case for //* path - see ParentLocationPath
            _iterator.setStartNode(_includeSelf ? _startNode : _source.next());
            return resetPosition();
        }
        return this;
    }

    public DTMAxisIterator reset() {
        _source.reset();
        // Special case for //* path - see ParentLocationPath
        _iterator.setStartNode(_includeSelf ? _startNode : _source.next());
        return resetPosition();
    }

    public int next() {
        for (int node;;) {
            // Try to get another node from the right-hand iterator
            if ((node = _iterator.next()) != END) {
                return returnNode(node);
            }
            // If not, get the next starting point from left-hand iterator...
            else if ((node = _source.next()) == END) {
                return END;
            }
            // ...and pass it on to the right-hand iterator
            else {
                _iterator.setStartNode(node);
            }
        }
    }

    public void setMark() {
        _source.setMark();
        _iterator.setMark();
        //_pos = _position;
    }

    public void gotoMark() {
        _source.gotoMark();
        _iterator.gotoMark();
        //_position = _pos;
    }
}