GsonAwareParser.java

/**
 * Copyright 2012 the original author or authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.googlecode.phisix.api.parser;

import java.io.Reader;
import java.lang.reflect.Type;
import java.text.ParseException;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

import org.apache.commons.lang3.time.DateParser;
import org.apache.commons.lang3.time.FastDateFormat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonNull;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.reflect.TypeToken;
import com.googlecode.phisix.api.model.Stock;
import com.googlecode.phisix.api.model.Stocks;

/**
 * {@link Parser} that delegates to a {@link JsonParser}.
 * 
 * @author Edge Dalmacio
 * 
 */
public class GsonAwareParser implements Parser<Reader, Stocks> {

    private static final Logger LOGGER = LoggerFactory.getLogger(GsonAwareParser.class);
    private static final TimeZone ASIA_MANILA = TimeZone.getTimeZone("Asia/Manila");
    private static final DateParser dateParser = FastDateFormat.getInstance("MM/dd/yyyy hh:mm a", ASIA_MANILA);
    private final Gson gson;
    
    public GsonAwareParser() {
        Type type = new TypeToken<Stock>() {}.getType();
        gson = new GsonBuilder()
            .registerTypeAdapter(type, new PhisixDeserializer())
            .create();
    }

    @Override
    public Stocks parse(Reader source) {
        Stocks stocks = new Stocks();
        
        JsonElement parse = JsonParser.parseReader(source);
        if (JsonNull.INSTANCE.equals(parse)) {
            return stocks;
        }
        JsonArray jsonArray = parse.getAsJsonArray();
        Type type = new TypeToken<Stock>() {}.getType();
        
//      boolean isFirst = true;
        for (JsonElement jsonElement : jsonArray) {
//          if (isFirst) {
//              isFirst = !isFirst;
//              stocks.setAsOf(parseAsOfDate(jsonElement.getAsJsonObject()));
//              continue;
//          }
            Stock stock = gson.fromJson(jsonElement, type);
            if (stock != null) {
                stocks.getStocks().add(stock);
            }
        }
        if (stocks.getAsOf() == null) {
            Calendar calendar = Calendar.getInstance(ASIA_MANILA);
            calendar.set(Calendar.HOUR_OF_DAY, 0);
            calendar.set(Calendar.MINUTE, 0);
            calendar.set(Calendar.SECOND, 0);
            calendar.set(Calendar.MILLISECOND, 0);
            stocks.setAsOf(calendar);
        }
        
        return stocks;
    }
    
    protected Calendar parseAsOfDate(JsonObject jsonObject) {
        String asOfDate = jsonObject.get("securityAlias").getAsString();
        Calendar calendar = null;
        try {
            Date date = dateParser.parse(asOfDate);
            calendar = Calendar.getInstance(ASIA_MANILA);
            calendar.setTime(date);
        } catch (ParseException e) {
            if (LOGGER.isWarnEnabled()) {
                LOGGER.warn(e.getMessage(), e);
            }
        }
        return calendar;
    }

}