com.erudika.para.i18n.OXRCurrencyConverter.java Source code

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Here is the source code for com.erudika.para.i18n.OXRCurrencyConverter.java

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/*
 * Copyright 2013-2015 Erudika. http://erudika.com
 *
 * 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.
 *
 * For issues and patches go to: https://github.com/erudika
 */
package com.erudika.para.i18n;

import com.erudika.para.Para;
import com.erudika.para.core.ParaObjectUtils;
import com.erudika.para.persistence.DAO;
import com.erudika.para.core.Sysprop;
import com.erudika.para.utils.Config;
import com.erudika.para.utils.Utils;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectReader;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import org.slf4j.Logger;
import javax.inject.Inject;
import javax.inject.Singleton;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.slf4j.LoggerFactory;

/**
 * A converter that uses http://openexchangerates.org
 * @author Alex Bogdanovski [alex@erudika.com]
 */
@Singleton
public class OXRCurrencyConverter implements CurrencyConverter {

    private static final Logger logger = LoggerFactory.getLogger(OXRCurrencyConverter.class);
    private static final String FXRATES_KEY = "fxrates";
    private static final long REFRESH_AFTER = 24 * 60 * 60 * 1000; // 24 hours in ms
    private static final String SERVICE_URL = "http://openexchangerates.org/api/latest.json?app_id="
            .concat(Config.OPENX_API_KEY);

    private DAO dao;

    /**
     * Default constructor
     * @param dao dao
     */
    @Inject
    public OXRCurrencyConverter(DAO dao) {
        this.dao = dao;
    }

    @Override
    public Double convertCurrency(Number amount, String from, String to) {
        if (amount == null || StringUtils.isBlank(from) || StringUtils.isBlank(to)) {
            return 0.0;
        }
        Sysprop s = dao.read(FXRATES_KEY);
        if (s == null) {
            s = fetchFxRatesJSON();
        } else if ((Utils.timestamp() - s.getTimestamp()) > REFRESH_AFTER) {
            // lazy refresh fx rates
            Para.asyncExecute(new Runnable() {
                public void run() {
                    fetchFxRatesJSON();
                }
            });
        }

        double ratio = 1.0;

        if (s.hasProperty(from) && s.hasProperty(to)) {
            Double f = NumberUtils.toDouble(s.getProperty(from).toString(), 1.0);
            Double t = NumberUtils.toDouble(s.getProperty(to).toString(), 1.0);
            ratio = t / f;
        }
        return amount.doubleValue() * ratio;
    }

    @SuppressWarnings("unchecked")
    private Sysprop fetchFxRatesJSON() {
        Map<String, Object> map = new HashMap<String, Object>();
        Sysprop s = new Sysprop();
        ObjectReader reader = ParaObjectUtils.getJsonReader(Map.class);

        try {
            CloseableHttpClient http = HttpClients.createDefault();
            HttpGet httpGet = new HttpGet(SERVICE_URL);
            HttpResponse res = http.execute(httpGet);
            HttpEntity entity = res.getEntity();

            if (entity != null && Utils.isJsonType(entity.getContentType().getValue())) {
                JsonNode jsonNode = reader.readTree(entity.getContent());
                if (jsonNode != null) {
                    JsonNode rates = jsonNode.get("rates");
                    if (rates != null) {
                        map = reader.treeToValue(rates, Map.class);
                        s.setId(FXRATES_KEY);
                        s.setProperties(map);
                        //                  s.addProperty("fetched", Utils.formatDate("dd MM yyyy HH:mm", Locale.UK));
                        dao.create(s);
                    }
                }
                EntityUtils.consume(entity);
            }
            logger.debug("Fetched rates from OpenExchange for {}.", new Date().toString());
        } catch (Exception e) {
            logger.error("TimerTask failed: {}", e);
        }
        return s;
    }

}