net.nikr.eve.jeveasset.io.local.update.Update.java Source code

Introduction

Here is the source code for net.nikr.eve.jeveasset.io.local.update.Update.java

Source

/*
 * Copyright 2009-2016 Contributors (see credits.txt)
 *
 * This file is part of jEveAssets.
 *
 * jEveAssets is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * jEveAssets 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with jEveAssets; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */
package net.nikr.eve.jeveasset.io.local.update;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import net.nikr.eve.jeveasset.io.local.update.updates.Update1To2;
import net.nikr.eve.jeveasset.io.shared.AbstractXmlReader;
import net.nikr.eve.jeveasset.io.shared.AttributeGetters;
import net.nikr.eve.jeveasset.io.shared.FileLock;
import net.nikr.eve.jeveasset.io.shared.XmlException;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.XPath;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.dom4j.tree.DefaultAttribute;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Node;

/**
 *
 * @author Candle
 */
public class Update extends AbstractXmlReader {
    private static final Logger LOG = LoggerFactory.getLogger(Update.class);

    int getVersion(final String filename) throws XmlException, IOException {
        org.w3c.dom.Element element = getDocumentElement(filename, true);
        if (element.getNodeName().equals("settings")) {
            if (AttributeGetters.haveAttribute((Node) element, "version")) {
                return AttributeGetters.getInt((Node) element, "version");
            } else {
                return 1;
            }
        } else {
            throw new XmlException("Wrong root element name.");
        }
    }

    void setVersion(final File xml, final int newVersion) throws DocumentException {
        SAXReader xmlReader = new SAXReader();
        Document doc = xmlReader.read(xml);

        XPath xpathSelector = DocumentHelper.createXPath("/settings");
        List<?> results = xpathSelector.selectNodes(doc);
        for (Iterator<?> iter = results.iterator(); iter.hasNext();) {
            Element element = (Element) iter.next();
            Attribute attr = element.attribute("version");
            if (attr == null) {
                element.add(new DefaultAttribute("version", String.valueOf(newVersion)));
            } else {
                attr.setText(String.valueOf(newVersion));
            }
        }

        try {
            FileOutputStream fos = new FileOutputStream(xml);
            OutputFormat outformat = OutputFormat.createPrettyPrint();
            outformat.setEncoding("UTF-16");
            XMLWriter writer = new XMLWriter(fos, outformat);
            writer.write(doc);
            writer.flush();
        } catch (IOException ioe) {
            LOG.error("Failed to update the serttings.xml version number", ioe);
            throw new RuntimeException(ioe);
        }
    }

    /**
     * TODO When more updates are added convert this to a graph-based
     * search for a suitable list of updates and then perform the updates
     * in the correct order. - Candle 2010-09-19
     * @param requiredVersion current version
     * @param path settings path
     * @throws net.nikr.eve.jeveasset.io.shared.XmlException on any error
     */
    public void performUpdates(final int requiredVersion, final String path) throws XmlException {
        File xml = new File(path);
        if (!xml.exists()) {
            LOG.info("No settings.xml file found - nothing to update");
            return;
        }
        try {
            int currentVersion = getVersion(path); //Got Its own lock...
            lock(path);
            if (requiredVersion > currentVersion) {
                LOG.info("settings.xml are out of date, updating.");
                Update1To2 update = new Update1To2();
                update.performUpdate(path);
                setVersion(new File(path), requiredVersion);
            } else {
                LOG.info("settings.xml are up to date.");
            }
        } catch (XmlException ex) {
            LOG.warn("Failed to update settings", ex);
            throw new XmlException(ex);
        } catch (IOException ex) {
            LOG.warn("Failed to update settings", ex);
            throw new XmlException(ex);
        } catch (DocumentException ex) {
            LOG.warn("Failed to update settings", ex);
            throw new XmlException(ex);
        } finally {
            unlock(path);
        }
    }
}