ar.com.wolox.wolmo.networking.retrofit.serializer.LocalDateSerializer.java Source code

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Here is the source code for ar.com.wolox.wolmo.networking.retrofit.serializer.LocalDateSerializer.java

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/*
 * MIT License
 * <p>
 * Copyright (c) 2017 Wolox S.A
 * <p>
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 * and associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * <p>
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 * <p>
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
package ar.com.wolox.wolmo.networking.retrofit.serializer;

import android.support.annotation.NonNull;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonParser;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

import org.joda.time.LocalDate;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

import java.lang.reflect.Type;
import java.util.Locale;

/**
 * Transforms a serialized {@link JsonElement} representing a {@link java.util.Date} into
 * a {@link LocalDate} instance. It also works the other way around, serializing a {@link LocalDate}
 * into a {@link JsonElement}.
 * <p>
 * This class is useful for sending and receiving {@link java.util.Date} instances over the network.
 */
public class LocalDateSerializer implements JsonDeserializer<LocalDate>, JsonSerializer<LocalDate> {

    protected static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";
    protected static final Locale DEFAULT_LOCALE = Locale.ENGLISH;

    private DateTimeFormatter mDateTimeFormatter;

    /**
     * Transforms a {@link JsonElement} representing a {@link java.util.Date} into a
     * {@link LocalDate} class from the JodaTime library.
     * This is useful for receiving data over the network.
     *
     * @param element a {@link JsonElement} representing a {@link java.util.Date}
     *
     * @return returns an instance of {@link LocalDate} representing a {@link java.util.Date}
     */
    @Override
    public LocalDate deserialize(JsonElement element, Type type, JsonDeserializationContext context)
            throws JsonParseException {
        initFormatter();
        String date = element.toString();
        if (date.startsWith("\"") && date.endsWith("\"")) {
            date = date.substring(1, date.length() - 1);
        }
        return mDateTimeFormatter.parseLocalDate(date);
    }

    /**
     * Transforms and instance of {@link LocalDate} from the JodaTime library into a
     * {@link JsonElement}. This is useful for sending the data over the network.
     *
     * @param date an instance of {@link LocalDate} to be serialized into a {@link JsonElement}
     *
     * @return an instance of {@link JsonElement} representing a {@link LocalDate}
     */
    @Override
    public JsonElement serialize(LocalDate date, Type type, JsonSerializationContext context) {
        initFormatter();
        return new JsonParser().parse(mDateTimeFormatter.print(date));
    }

    /**
     * Instance the formatter if it's null.
     */
    private void initFormatter() {
        if (mDateTimeFormatter == null) {
            mDateTimeFormatter = DateTimeFormat.forPattern(getDateFormat()).withLocale(getLocale());
        }
    }

    /**
     * Override if needed.
     * This method returns the format of the Date that will be serialized/deserialized.
     * Usually, this should match the format that is being received from the API over the network.
     * <p>
     * The default return value is the constant {@link #DEFAULT_DATE_FORMAT}, available in this
     * class.
     *
     * @return returns the format of the serialized Date
     */
    @NonNull
    protected String getDateFormat() {
        return DEFAULT_DATE_FORMAT;
    }

    /**
     * Override if needed.
     * This method returns the locale used by JodaTime to serialize/deserialize the date.
     * Usually, this should match the format that is being received from the API over the network.
     * <p>
     * The default return value is the constant {@link #DEFAULT_LOCALE}, available in this class.
     *
     * @return returns the locale of the serialized Date
     */
    @NonNull
    protected Locale getLocale() {
        return DEFAULT_LOCALE;
    }
}