name.martingeisse.admin.application.converter.DateTimeConverter.java Source code

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Here is the source code for name.martingeisse.admin.application.converter.DateTimeConverter.java

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/**
 * Copyright (c) 2011 Martin Geisse
 *
 * This file is distributed under the terms of the MIT license.
 */

package name.martingeisse.admin.application.converter;

import java.util.Locale;

import name.martingeisse.wicket.application.MyWicketSession;

import org.apache.wicket.util.convert.ConversionException;
import org.apache.wicket.util.convert.IConverter;
import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

/**
 * Converts Joda {@link DateTime} objects.
 */
public class DateTimeConverter implements IConverter<DateTime> {

    /* (non-Javadoc)
     * @see org.apache.wicket.util.convert.IConverter#convertToObject(java.lang.String, java.util.Locale)
     */
    @Override
    public DateTime convertToObject(String value, Locale locale) {
        try {
            DateTimeFormatter formatter = getFormatter(locale);
            return formatter.parseDateTime(value);
        } catch (Exception e) {
            throw new ConversionException(e);
        }
    }

    /* (non-Javadoc)
     * @see org.apache.wicket.util.convert.IConverter#convertToString(java.lang.Object, java.util.Locale)
     */
    @Override
    public String convertToString(DateTime value, Locale locale) {
        try {
            DateTimeFormatter formatter = getFormatter(locale);
            return formatter.print(value);
        } catch (Exception e) {
            throw new ConversionException(e);
        }
    }

    /**
     * Obtains the formatter to use for the specified locale and current Wicket session.
     */
    private static DateTimeFormatter getFormatter(Locale locale) {
        return DateTimeFormat.mediumDateTime().withLocale(locale).withZone(getTimeZone());
    }

    /**
     * Obtains the time zone to use for conversion. This is taken from the current
     * Wicket session. There is no fallback to avoid hiding errors.
     */
    private static DateTimeZone getTimeZone() {
        MyWicketSession session = MyWicketSession.get();
        if (session == null) {
            throw new IllegalStateException("no session -- cannot determine time zone for conversion");
        }
        DateTimeZone timeZone = session.getTimeZone();
        if (timeZone == null) {
            throw new IllegalStateException("session time zone is null");
        }
        return timeZone;
    }

}