Java tutorial
/* * Copyright 2011-2014 the original author or authors. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package de.jdellay.wallet; import java.io.BufferedInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.Reader; import java.math.BigDecimal; import java.math.BigInteger; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.Currency; import java.util.Iterator; import java.util.Locale; import java.util.Map; import java.util.TreeMap; import java.util.zip.GZIPInputStream; import javax.annotation.CheckForNull; import javax.annotation.Nonnull; import android.content.SharedPreferences; import android.preference.PreferenceManager; import org.json.JSONObject; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import android.content.ContentProvider; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.MatrixCursor; import android.net.Uri; import android.provider.BaseColumns; import android.text.format.DateUtils; import de.jdellay.wallet.util.GenericUtils; import de.jdellay.wallet.util.Io; /** * @author Andreas Schildbach */ public class ExchangeRatesProvider extends ContentProvider { public static class ExchangeRate { public ExchangeRate(@Nonnull final String currencyCode, @Nonnull final BigInteger rate, final String source) { this.currencyCode = currencyCode; this.rate = rate; this.source = source; } public final String currencyCode; public BigInteger rate; public final String source; @Override public String toString() { return getClass().getSimpleName() + '[' + currencyCode + ':' + GenericUtils.formatDebugValue(rate) + ']'; } } public static final String KEY_CURRENCY_CODE = "currency_code"; private static final String KEY_RATE = "rate"; private static final String KEY_SOURCE = "source"; private Configuration config; private String userAgent; @CheckForNull private Map<String, ExchangeRate> exchangeRates = null; private long lastUpdated = 0; private float ccnBtcConversion = -1; private static final URL BITCOINAVERAGE_URL; private static final String[] BITCOINAVERAGE_FIELDS = new String[] { "24h_avg", "last" }; private static final String BITCOINAVERAGE_SOURCE = "BitcoinAverage.com"; private static final String BLOCKCHAININFO_SOURCE = "blockchain.info"; private static final URL BLOCKCHAININFO_URL; private static final String[] BLOCKCHAININFO_FIELDS = new String[] { "15m" }; private static final URL CCNSWISSCEX_URL; // https://bitmarket.eu/api/ticker static { try { BITCOINAVERAGE_URL = new URL("https://api.bitcoinaverage.com/custom/abw"); BLOCKCHAININFO_URL = new URL("https://blockchain.info/ticker"); CCNSWISSCEX_URLL = new URL("http://cannacoin.cc/lastprice"); } catch (final MalformedURLException x) { throw new RuntimeException(x); // cannot happen } } private static final long UPDATE_FREQ_MS = 10 * DateUtils.MINUTE_IN_MILLIS; private static final Logger log = LoggerFactory.getLogger(ExchangeRatesProvider.class); @Override public boolean onCreate() { final Context context = getContext(); this.config = new Configuration(PreferenceManager.getDefaultSharedPreferences(context)); this.userAgent = WalletApplication .httpUserAgent(WalletApplication.packageInfoFromContext(context).versionName); final ExchangeRate cachedExchangeRate = config.getCachedExchangeRate(); if (cachedExchangeRate != null) { exchangeRates = new TreeMap<String, ExchangeRate>(); exchangeRates.put(cachedExchangeRate.currencyCode, cachedExchangeRate); } return true; } public static Uri contentUri(@Nonnull final String packageName) { return Uri.parse("content://" + packageName + '.' + "exchange_rates"); } @Override public Cursor query(final Uri uri, final String[] projection, final String selection, final String[] selectionArgs, final String sortOrder) { final long now = System.currentTimeMillis(); SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getContext()); int provider = Integer.parseInt(sp.getString(Configuration.PREFS_KEY_EXCHANGE_PROVIDER, "0")); boolean forceRefresh = sp.getBoolean(Configuration.PREFS_KEY_EXCHANGE_FORCE_REFRESH, false); if (forceRefresh) sp.edit().putBoolean(Configuration.PREFS_KEY_EXCHANGE_FORCE_REFRESH, false).commit(); if (lastUpdated == 0 || now - lastUpdated > UPDATE_FREQ_MS) { float newCcnBtcConversion = -1; if ((ccnBtcConversion == -1 && newCcnBtcConversion == -1) || forceRefresh) newCcnBtcConversion = requestCcnBtcConversion(provider); if (newCcnBtcConversion != -1) ccnBtcConversion = newCcnBtcConversion; if (CCNBtcConversion == -1) return null; Map<String, ExchangeRate> newExchangeRates = null; if (newExchangeRates == null) newExchangeRates = requestExchangeRates(BITCOINAVERAGE_URL, ccnBtcConversion, userAgent, BITCOINAVERAGE_SOURCE, BITCOINAVERAGE_FIELDS); if (newExchangeRates == null) newExchangeRates = requestExchangeRates(BLOCKCHAININFO_URL, ccnBtcConversion, userAgent, BLOCKCHAININFO_SOURCE, BLOCKCHAININFO_FIELDS); if (newExchangeRates != null) { String providerUrl; switch (provider) { case 0: providerUrl = "http://www.cryptsy.com"; break; case 1: providerUrl = "http://www.vircurex.com"; break; default: providerUrl = ""; break; } float mBTCRate = ccnBtcConversion * 1000; String strmBTCRate = String.format(Locale.US, "%.5f", mBTCRate).replace(',', '.'); newExchangeRates.put("mBTC", new ExchangeRate("mBTC", new BigDecimal(GenericUtils.toNanoCoins(strmBTCRate, 0)).toBigInteger(), providerUrl)); newExchangeRates.put("CCN", new ExchangeRate("CCN", BigInteger.valueOf(100000000), "priceofccn.com")); exchangeRates = newExchangeRates; lastUpdated = now; final ExchangeRate exchangeRateToCache = bestExchangeRate(config.getExchangeCurrencyCode()); if (exchangeRateToCache != null) config.setCachedExchangeRate(exchangeRateToCache); } } if (exchangeRates == null || ccnBtcConversion == -1) return null; final MatrixCursor cursor = new MatrixCursor( new String[] { BaseColumns._ID, KEY_CURRENCY_CODE, KEY_RATE, KEY_SOURCE }); if (selection == null) { for (final Map.Entry<String, ExchangeRate> entry : exchangeRates.entrySet()) { final ExchangeRate rate = entry.getValue(); cursor.newRow().add(rate.currencyCode.hashCode()).add(rate.currencyCode).add(rate.rate.longValue()) .add(rate.source); } } else if (selection.equals(KEY_CURRENCY_CODE)) { final ExchangeRate rate = bestExchangeRate(selectionArgs[0]); if (rate != null) cursor.newRow().add(rate.currencyCode.hashCode()).add(rate.currencyCode).add(rate.rate.longValue()) .add(rate.source); } return cursor; } private ExchangeRate bestExchangeRate(final String currencyCode) { ExchangeRate rate = currencyCode != null ? exchangeRates.get(currencyCode) : null; if (rate != null) return rate; final String defaultCode = defaultCurrencyCode(); rate = defaultCode != null ? exchangeRates.get(defaultCode) : null; if (rate != null) return rate; return exchangeRates.get(Constants.DEFAULT_EXCHANGE_CURRENCY); } private String defaultCurrencyCode() { try { return Currency.getInstance(Locale.getDefault()).getCurrencyCode(); } catch (final IllegalArgumentException x) { return null; } } public static ExchangeRate getExchangeRate(@Nonnull final Cursor cursor) { final String currencyCode = cursor .getString(cursor.getColumnIndexOrThrow(ExchangeRatesProvider.KEY_CURRENCY_CODE)); final BigInteger rate = BigInteger .valueOf(cursor.getLong(cursor.getColumnIndexOrThrow(ExchangeRatesProvider.KEY_RATE))); final String source = cursor.getString(cursor.getColumnIndexOrThrow(ExchangeRatesProvider.KEY_SOURCE)); return new ExchangeRate(currencyCode, rate, source); } @Override public Uri insert(final Uri uri, final ContentValues values) { throw new UnsupportedOperationException(); } @Override public int update(final Uri uri, final ContentValues values, final String selection, final String[] selectionArgs) { throw new UnsupportedOperationException(); } @Override public int delete(final Uri uri, final String selection, final String[] selectionArgs) { throw new UnsupportedOperationException(); } @Override public String getType(final Uri uri) { throw new UnsupportedOperationException(); } private static Map<String, ExchangeRate> requestExchangeRates(final URL url, float ccnBtcConversion, final String userAgent, final String source, final String... fields) { final long start = System.currentTimeMillis(); HttpURLConnection connection = null; Reader reader = null; try { connection = (HttpURLConnection) url.openConnection(); connection.setInstanceFollowRedirects(false); connection.setConnectTimeout(Constants.HTTP_TIMEOUT_MS); connection.setReadTimeout(Constants.HTTP_TIMEOUT_MS); connection.addRequestProperty("User-Agent", userAgent); connection.addRequestProperty("Accept-Encoding", "gzip"); connection.connect(); final int responseCode = connection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { final String contentEncoding = connection.getContentEncoding(); InputStream is = new BufferedInputStream(connection.getInputStream(), 1024); if ("gzip".equalsIgnoreCase(contentEncoding)) is = new GZIPInputStream(is); reader = new InputStreamReader(is, Constants.UTF_8); final StringBuilder content = new StringBuilder(); final long length = Io.copy(reader, content); final Map<String, ExchangeRate> rates = new TreeMap<String, ExchangeRate>(); final JSONObject head = new JSONObject(content.toString()); for (final Iterator<String> i = head.keys(); i.hasNext();) { final String currencyCode = i.next(); if (!"timestamp".equals(currencyCode)) { final JSONObject o = head.getJSONObject(currencyCode); for (final String field : fields) { final String rate = o.optString(field, null); if (rate != null) { try { BigDecimal btcRate = new BigDecimal(GenericUtils.toNanoCoins(rate, 0)); BigInteger ccnRate = btcRate.multiply(BigDecimal.valueOf(ccnBtcConversion)) .toBigInteger(); if (ccnRate.signum() > 0) { rates.put(currencyCode, new ExchangeRate(currencyCode, ccnRate, source)); break; } } catch (final ArithmeticException x) { log.warn("problem fetching {} exchange rate from {} ({}): {}", currencyCode, url, contentEncoding, x.getMessage()); } } } } } log.info("fetched exchange rates from {} ({}), {} chars, took {} ms", url, contentEncoding, length, System.currentTimeMillis() - start); return rates; } else { log.warn("http status {} when fetching {}", responseCode, url); } } catch (final Exception x) { log.warn("problem fetching exchange rates from " + url, x); } finally { if (reader != null) { try { reader.close(); } catch (final IOException x) { // swallow } } if (connection != null) connection.disconnect(); } return null; } private static float requestCcnBtcConversion(int provider) { HttpURLConnection connection = null; Reader reader = null; URL providerUrl; switch (provider) { case 0: providerUrl = CCNPOOL_URL; break; case 1: providerUrl = VIRCUREX_URL; break; default: providerUrl = CCNPOOL_URL; break; } try { connection = (HttpURLConnection) providerUrl.openConnection(); connection.setConnectTimeout(Constants.HTTP_TIMEOUT_MS); connection.setReadTimeout(Constants.HTTP_TIMEOUT_MS); connection.connect(); final int responseCode = connection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { reader = new InputStreamReader(new BufferedInputStream(connection.getInputStream(), 1024), Constants.UTF_8); final StringBuilder content = new StringBuilder(); Io.copy(reader, content); try { float rate; switch (provider) { case 0: /*rate = Float.parseFloat( json.getJSONObject("return") .getJSONObject("markets") .getJSONObject("CCN") .getString("lasttradeprice"));*/ //For later use. rate = Float.parseFloat(content.toString()); break; case 1: final JSONObject json = new JSONObject(content.toString()); rate = Float.parseFloat(json.getString("value")); break; default: return -1; } return rate; } catch (NumberFormatException e) { log.debug("Couldn't get the current exchnage rate from provider " + String.valueOf(provider)); return -1; } } else { log.debug("http status " + responseCode + " when fetching " + providerUrl); } } catch (final Exception x) { log.debug("problem reading exchange rates", x); } finally { if (reader != null) { try { reader.close(); } catch (final IOException x) { // swallow } } if (connection != null) connection.disconnect(); } return -1; } }