CalendarDeserializer.java

package br.com.caelum.vraptor.serialization.gson.adapters;

import java.lang.reflect.Type;
import java.text.DateFormat;
import java.text.ParseException;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;

import br.com.caelum.vraptor.converter.ConversionError;
import br.com.caelum.vraptor.core.Localization;
import br.com.caelum.vraptor.ioc.Component;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;

@Component
public class CalendarDeserializer implements JsonDeserializer<Calendar> {

	private final Localization localization;

	public CalendarDeserializer(Localization localization) {
		this.localization = localization;
	}

	public Calendar deserialize(JsonElement json, Type typeOfT,	JsonDeserializationContext context) {

		Calendar calendar = new GregorianCalendar();

		try {
			if (json.isJsonPrimitive()) {
				String value = json.getAsString();

				Locale locale = localization.getLocale();
				if (locale == null)
					locale = Locale.getDefault();

				DateFormat format = DateFormat.getDateInstance(DateFormat.SHORT, locale);
				Date date = format.parse(value);
				calendar.setTime(date);
			} else {
				JsonObject value = json.getAsJsonObject();

				String timezone = value.get("timezone").getAsString();
				Long time = value.get("time").getAsLong();

				calendar.setTimeZone(TimeZone.getTimeZone(timezone));
				calendar.setTimeInMillis(time);
			}

			return calendar;
		}
		catch (JsonParseException e) {
			throw new ConversionError("Invalid Json format to convert Calendar: " + e.getMessage());
		}
		catch (ParseException e) {
			throw new ConversionError("Error to convert Calendar: " + e.getMessage());
		}
	}

}