DateDeserializer for Gson based on different SimpleDateFormats

CalendarGson.java

package org.dallasmakerspace.kiosk.data.calendar;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import org.dallasmakerspace.kiosk.gson.DateDeserializer;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Created by javier.romero on 3/1/14.
 */
public class CalendarGson {

    private static Gson sGson;

    public static Gson getGson() {
        if (sGson == null) {
            sGson = new GsonBuilder()

                    .registerTypeAdapter(Event.EventDateTime.class,
                            new DateDeserializer<Event.EventDateTime>(
                                    Event.EventDateTime.DATE_FORMAT, Event.EventDateTime.class))

                    .registerTypeAdapter(Event.StartEndDateTime.class,
                            new DateDeserializer<Event.StartEndDateTime>(
                                    Event.StartEndDateTime.DATE_FORMAT, Event.StartEndDateTime.class))

                    .registerTypeAdapter(Event.SimpleDate.class,
                            new DateDeserializer<Event.SimpleDate>(
                                    Event.SimpleDate.DATE_FORMAT, Event.SimpleDate.class))
                    .create();
        }

        return sGson;
    }

    private CalendarGson() {
    }
}

DateDeserializer.java

package org.dallasmakerspace.kiosk.gson;

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

import java.lang.reflect.Type;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Created by javier.romero on 3/1/14.
 */
public class DateDeserializer<T extends Date> implements JsonDeserializer<T> {

    private static final String TAG = DateDeserializer.class.getSimpleName();

    private final SimpleDateFormat mSimpleDateFormat;
    private final Class<T> mClazz;

    public DateDeserializer(SimpleDateFormat simpleDateFormat, Class<T> clazz) {
        mSimpleDateFormat = simpleDateFormat;
        mClazz = clazz;
    }

    @Override
    public T deserialize(JsonElement element, Type arg1, JsonDeserializationContext context) throws JsonParseException {
        String dateString = element.getAsString();
        try {
            T date = mClazz.newInstance();
            date.setTime(mSimpleDateFormat.parse(dateString).getTime());
            return date;
        } catch (InstantiationException e) {
            throw new JsonParseException(e.getMessage(), e);
        } catch (IllegalAccessException e) {
            throw new JsonParseException(e.getMessage(), e);
        } catch (ParseException e) {
            throw new JsonParseException(e.getMessage(), e);
        }
    }
}

Event.java

package org.dallasmakerspace.kiosk.data.calendar;

import com.google.gson.annotations.SerializedName;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Created by javier.romero on 3/1/14.
 */
public class Event {

    @SerializedName("id")
    private String mId;

    @SerializedName("status")
    private String mStatus;

    @SerializedName("htmlLink")
    private String mHtmlLink;

    @SerializedName("created")
    private EventDateTime mCreated;

    //@SerializedName("updated")
    private EventDateTime mUpdated;

    @SerializedName("summary")
    private String mSummary;

    @SerializedName("description")
    private String mDescription;

    @SerializedName("location")
    private String mLocation;

    @SerializedName("start")
    private ConditionalDateTime mStart;

    @SerializedName("end")
    private ConditionalDateTime mEnd;

    public String getId() {
        return mId;
    }

    public String getStatus() {
        return mStatus;
    }

    public String getHtmlLink() {
        return mHtmlLink;
    }

    public EventDateTime getCreated() {
        return mCreated;
    }

    public EventDateTime getUpdated() {
        return mUpdated;
    }

    public String getSummary() {
        return mSummary;
    }

    public String getDescription() {
        return mDescription;
    }

    public String getLocation() {
        return mLocation;
    }

    public ConditionalDateTime getStart() {
        return mStart;
    }

    public ConditionalDateTime getEnd() {
        return mEnd;
    }

    public boolean isAllDayEvent() {
        return mStart.isAllDayEvent() && mEnd.isAllDayEvent();
    }

    /**
     *
     */
    public static class ConditionalDateTime {
        @SerializedName("dateTime")
        private StartEndDateTime mDateTime;

        @SerializedName("date")
        private SimpleDate mDate;

        public SimpleDate getDate() {
            return mDate;
        }

        public StartEndDateTime getDateTime() {
            return mDateTime;
        }

        /**
         * If it is an all day event then only date is populated (not DateTime)
         * @return
         */
        public boolean isAllDayEvent() {
            return mDate != null;
        }
    }

    public static class EventDateTime extends Date {
        public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    }

    public static class StartEndDateTime extends Date {
        public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ");
    }

    public static class SimpleDate extends java.util.Date {
        public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
    }
}