/*
 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */

package com.sun.org.apache.xpath.internal.jaxp;

import java.util.Iterator;
import javax.xml.xpath.XPathException;
import javax.xml.xpath.XPathNodes;
import javax.xml.xpath.XPathEvaluationResult.XPathResultType;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * This class implements XPathNodes that represents a set of nodes selected by 
 * evaluating an expression.
 */
public class XPathNodesImpl implements XPathNodes {
    XPathResultType type;
    Class<Node> elementType;
    NodeList nodeList = null;

    public XPathNodesImpl(NodeList nodeList, XPathResultType type, Class<Node> elementType) {
        this.nodeList = nodeList;
        this.type = type;
        this.elementType = elementType;
    }
    
    @Override
    public Iterator<Node> iterator() {
        return new NodeSetIterator<>(elementType);
    }


    class NodeSetIterator<E> implements Iterator<E> {
        int currentIndex;
        Class<E> elementType;
        NodeSetIterator(Class<E> elementType) {
            this.elementType = elementType;
        }
        public boolean hasNext() {
            if (type != XPathResultType.NODE) {
                throw new UnsupportedOperationException("Incorrect type: result"
                        + "type requested: " + type + ", but assumed"
                        + "Node.");
            }
            if (nodeList != null) {
                return currentIndex < nodeList.getLength();
            }

            return false;
        }

        public E next() {
            if (nodeList != null && nodeList.getLength() > 0) {
                return elementType.cast(nodeList.item(currentIndex++));
            }
            return null;
        }
    }

    @Override
    public int size() {
        if (nodeList != null) {
            return nodeList.getLength();
        }
        return 0;
    }

    @Override
    public Node get(int index) throws XPathException {
        if (index <0 || index >= size()) {
            throw new IndexOutOfBoundsException("Index " + index + " is out of bounds");
        }
        if (nodeList != null) {
            return (Node)nodeList.item(index);
        }
        return null;
    }
}