com.lastcalc.parsers.currency.Currencies.java Source code

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Here is the source code for com.lastcalc.parsers.currency.Currencies.java

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/*******************************************************************************
 * LastCalc - The last calculator you'll ever need
 * Copyright (C) 2011, 2012 Uprizer Labs LLC
 * 
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Affero General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU Affero General Public License for more
 * details.
 ******************************************************************************/
package com.lastcalc.parsers.currency;

import java.io.InputStreamReader;
import java.net.URL;
import java.util.*;
import java.util.Map.Entry;
import java.util.logging.Logger;

import com.google.common.collect.*;

import org.jscience.economics.money.Currency;

import com.lastcalc.*;
import com.lastcalc.parsers.Parser;
import com.lastcalc.parsers.amounts.UnitParser;

public class Currencies {
    private static final Logger log = Logger.getLogger(Currencies.class.getName());

    public static long lastExchangeRateUpdateAttempt = 0;

    public static volatile Map<String, Currency> currenciesByCode;

    public static boolean shouldUpdate() {
        return System.currentTimeMillis() - lastExchangeRateUpdateAttempt > 60l * 60l * 1000l;
    }

    public static List<Parser> getParsers() {
        if (currenciesByCode == null) {
            updateExchangeRates();
        }
        final LinkedList<Parser> parsers = Lists.newLinkedList();
        if (currenciesByCode != null) {
            for (final Entry<String, Currency> e : currenciesByCode.entrySet()) {
                parsers.add(new UnitParser(e.getValue(), TokenList.createD(e.getKey())));
                parsers.add(new UnitParser(e.getValue(), TokenList.createD(e.getKey().toLowerCase())));
            }
            parsers.add(new UnitParser(currenciesByCode.get("USD"), TokenList.createD("$")));
            parsers.add(new UnitParser(currenciesByCode.get("EUR"), TokenList.createD("")));
            parsers.add(new UnitParser(currenciesByCode.get("JPY"), TokenList.createD("")));
            parsers.add(new UnitParser(currenciesByCode.get("GBP"), TokenList.createD("")));

            parsers.add(new CurrencyReverser());
        }

        return parsers;
    }

    public static void updateExchangeRates() {
        Currency.setReferenceCurrency(Currency.USD);
        try {
            final URL url = new URL(
                    "http://openexchangerates.org/api/latest.json?app_id=d1bd706a92774feca9c15d615ae85685");
            final Rates rates = Misc.gson.fromJson(new InputStreamReader(url.openStream()), Rates.class);
            if (!rates.base.equalsIgnoreCase("usd")) {
                log.warning("We assume base rate of USD, but it is " + rates.base);
            }
            final Map<String, Currency> currencies = Maps.newHashMap();
            for (final Entry<String, Double> e : rates.rates.entrySet()) {
                final Currency currency = new Currency(e.getKey());
                currency.setExchangeRate(1.0 / e.getValue());
                currencies.put(e.getKey(), currency);
            }

            currenciesByCode = currencies;
        } catch (final Exception e) {
            log.warning("Couldn't update currency conversion rates " + e);
            e.printStackTrace();
        }
        lastExchangeRateUpdateAttempt = System.currentTimeMillis();
    }

    public static class Rates {
        public String base;
        public Map<String, Double> rates;
    }
}