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 * reserved comment block

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/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file 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,

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package com.sun.org.apache.xalan.internal.xsltc.dom;

import 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;

/**

 * UnionIterator takes a set of NodeIterators and produces

 * a merged NodeSet in document order with duplicates removed

 * The individual iterators are supposed to generate nodes

 * in document order

 * @author Jacek Ambroziak

 * @author Santiago Pericas-Geertsen

 */

public final class UnionIterator extends MultiValuedNodeHeapIterator {

    /** wrapper for NodeIterators to support iterator

        comparison on the value of their next() method

    */

    final private DOM _dom;

    private final class LookAheadIterator

            extends MultiValuedNodeHeapIterator.HeapNode

    {

        public DTMAxisIterator iterator;

        public LookAheadIterator(DTMAxisIterator iterator) {

            super();

            this.iterator = iterator;

        }

        public int step() {

            _node = iterator.next();

            return _node;

        }

        public HeapNode cloneHeapNode() {

            LookAheadIterator clone = (LookAheadIterator) super.cloneHeapNode();

            clone.iterator = iterator.cloneIterator();

            return clone;

        }

        public void setMark() {

            super.setMark();

            iterator.setMark();

        }

        public void gotoMark() {

            super.gotoMark();

            iterator.gotoMark();

        }

        public boolean isLessThan(HeapNode heapNode) {

            LookAheadIterator comparand = (LookAheadIterator) heapNode;

            return _dom.lessThan(_node, heapNode._node);

        }

        public HeapNode setStartNode(int node) {

            iterator.setStartNode(node);

            return this;

        }

        public HeapNode reset() {

            iterator.reset();

            return this;

        }

    } // end of LookAheadIterator

    public UnionIterator(DOM dom) {

        _dom = dom;

    }

    public UnionIterator addIterator(DTMAxisIterator iterator) {

        addHeapNode(new LookAheadIterator(iterator));

        return this;

    }

}