gestionecassa.XmlPreferencesHandler.java Source code

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Here is the source code for gestionecassa.XmlPreferencesHandler.java

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/*
 * XmlPreferencesHandler.java
 * 
 * Copyright (C) 2009 Nicola Roberto Vigan
 * 
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package gestionecassa;

import java.io.FileWriter;
import java.io.IOException;
import java.lang.reflect.Field;
import org.apache.log4j.Logger;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

/**
 * Class that manages loading and saving preferences to file
 * @param <DataType> Type of preferences to manage
 * @author ben
 */
public class XmlPreferencesHandler<DataType extends Preferences> {

    /**
     * reference to the logger used for error reporting
     */
    Logger logger;

    /**
     * Constructor
     * @param logger reference to the used logger
     */
    public XmlPreferencesHandler(Logger logger) {
        this.logger = logger;
    }

    /**
     * Saves options to a file given by the option type
     * @param preferences 
     * @throws IOException
     */
    public void savePrefs(DataType preferences) throws IOException {

        Document document = DocumentHelper.createDocument();
        Element root = document.addElement("config");
        root.addAttribute("version", preferences.getVersion());
        root.addAttribute("application", preferences.getApplication());

        for (Field field : preferences.getClass().getFields()) {
            try {
                root.addElement(field.getName()).addText(field.get(preferences) + "");
            } catch (IllegalArgumentException ex) {
                logger.warn("campo sbagliato", ex);
            } catch (IllegalAccessException ex) {
                logger.warn("campo sbagliato", ex);
            }
        }

        // lets write to a file
        OutputFormat format = OutputFormat.createPrettyPrint();
        XMLWriter writer = new XMLWriter(new FileWriter(preferences.getFileName()), format);
        writer.write(document);
        writer.close();
    }

    /**
     * Loads options from a file
     * @param preferences
     * @throws IOException
     * @throws DocumentException
     */
    public void loadPrefs(DataType preferences) throws IOException, DocumentException {

        SAXReader reader = new SAXReader();
        Document document = reader.read(preferences.getFileName());

        Element nodoRoot = document.getRootElement();
        if (!nodoRoot.attributeValue("version").equals(preferences.getVersion())) {
            throw new IOException("Wrong file version!");
        } else if (!nodoRoot.attributeValue("application").equals(preferences.getApplication())) {
            throw new IOException("This config file is for another client");
        }

        for (Field field : preferences.getClass().getFields()) {
            Element node = nodoRoot.element(field.getName());
            try {
                if (node != null) {
                    assignField(preferences, field, node.getTextTrim());
                } else {
                    System.out.println(
                            "errore campo: " + field.getName() + "\nThis config file does not contain right info");
                    assignField(preferences, field, "");
                }
            } catch (IllegalArgumentException ex) {
                logger.warn("campo sbagliato", ex);
            } catch (IllegalAccessException ex) {
                logger.warn("campo sbagliato", ex);
            }
        }
    }

    private void assignField(DataType preferences, Field field, String nodeText)
            throws IllegalArgumentException, IllegalAccessException {

        if (field.getType().equals(Boolean.TYPE)) {
            if (nodeText.toLowerCase().equals("true")) {
                nodeText = "true";
            }
            field.setBoolean(preferences, Boolean.valueOf(nodeText));
        } else if (field.getType().equals(Integer.TYPE)) {
            if (nodeText.equals("")) {
                nodeText = "0";
            }
            field.setInt(preferences, Integer.valueOf(nodeText));
        } else if (field.getType().isInstance(Boolean.valueOf("true"))) {
            if (nodeText.toLowerCase().equals("true")) {
                nodeText = "true";
            }
            field.set(preferences, Boolean.valueOf(nodeText));
        } else if (field.getType().isInstance(Integer.valueOf("0"))) {
            if (nodeText.equals("")) {
                nodeText = "0";
            }
            field.set(preferences, Integer.valueOf(nodeText));
        } else {
            field.set(preferences, nodeText);
        }
    }

}