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eXist-db NoSQL Database Core
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/*
 * eXist-db Open Source Native XML Database
 * Copyright (C) 2001 The eXist-db Authors
 *
 * [email protected]
 * http://www.exist-db.org
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package org.exist.indexing;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.exist.dom.persistent.AttrImpl;
import org.exist.dom.persistent.ElementImpl;
import org.exist.dom.persistent.IStoredNode;
import org.exist.dom.persistent.TextImpl;
import org.exist.storage.DBBroker;
import org.exist.storage.NodePath;
import org.exist.storage.dom.INodeIterator;
import org.exist.storage.txn.Txn;
import org.w3c.dom.Node;

import java.io.IOException;

/**
 * Various utility methods to be used by Index implementations.
 */
public class IndexUtils {

    protected static final Logger LOG = LogManager.getLogger(IndexUtils.class);

    public static void scanNode(DBBroker broker, Txn transaction, IStoredNode node, StreamListener listener) {
        try(final INodeIterator iterator = broker.getNodeIterator(node)) {
            iterator.next();
            final NodePath path = node.getPath();
            scanNode(transaction, iterator, node, listener, path);
        } catch(final IOException ioe) {
            LOG.warn("Unable to close iterator", ioe);
        }
    }

    private static void scanNode(Txn transaction, INodeIterator iterator,
            IStoredNode node, StreamListener listener, NodePath currentPath) {
        switch (node.getNodeType()) {
        case Node.ELEMENT_NODE:
            if (listener != null) {
                listener.startElement(transaction, (ElementImpl) node, currentPath);
            }
            if (node.hasChildNodes() || node.hasAttributes()) {
                final int childCount = node.getChildCount();
                for (int i = 0; i < childCount; i++) {
                    final IStoredNode child = iterator.next();
                    if (child.getNodeType() == Node.ELEMENT_NODE) {
                        currentPath.addComponent(child.getQName());
                    }
                    scanNode(transaction, iterator, child, listener, currentPath);
                    if (child.getNodeType() == Node.ELEMENT_NODE) {
                        currentPath.removeLastComponent();
                    }
                }
            }
            if (listener != null) {
                listener.endElement(transaction, (ElementImpl) node, currentPath);
            }
            break;
        case Node.TEXT_NODE :
            if (listener != null) {
                listener.characters(transaction, (TextImpl) node, currentPath);
            }
            break;
        case Node.ATTRIBUTE_NODE :
            if (listener != null) {
                listener.attribute(transaction, (AttrImpl) node, currentPath);
            }
            break;
        }
    }
}