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 com.matthewmitchell.peercoin_android_wallet; import java.io.BufferedInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.Reader; import java.math.BigInteger; import java.math.BigDecimal; 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 org.json.JSONException; import org.json.JSONObject; import org.json.JSONArray; 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.preference.PreferenceManager; import android.provider.BaseColumns; import android.text.format.DateUtils; import com.matthewmitchell.peercoin_android_wallet.util.GenericUtils; import com.matthewmitchell.peercoin_android_wallet.util.Io; import com.matthewmitchell.peercoinj.core.Utils; /** * @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 final 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"; public static final String QUERY_PARAM_Q = "q"; private Configuration config; private String userAgent; @CheckForNull private Map<String, ExchangeRate> exchangeRates = null; private long lastUpdated = 0; private static final URL BTCE_URL; private static final String BTCE_SOURCE = "btc-e.com"; // https://bitmarket.eu/api/ticker static { try { BTCE_URL = new URL("https://btc-e.com/api/2/ppc_usd/ticker"); } 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(); if (lastUpdated == 0 || now - lastUpdated > UPDATE_FREQ_MS) { Map<String, ExchangeRate> newExchangeRates = null; if (newExchangeRates == null) newExchangeRates = requestExchangeRates(userAgent); if (newExchangeRates != null) { exchangeRates = newExchangeRates; lastUpdated = now; final ExchangeRate exchangeRateToCache = bestExchangeRate(config.getExchangeCurrencyCode()); if (exchangeRateToCache != null) config.setCachedExchangeRate(exchangeRateToCache); } } if (exchangeRates == null) 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(QUERY_PARAM_Q)) { final String selectionArg = selectionArgs[0].toLowerCase(Locale.US); for (final Map.Entry<String, ExchangeRate> entry : exchangeRates.entrySet()) { final ExchangeRate rate = entry.getValue(); final String currencyCode = rate.currencyCode; final String currencySymbol = GenericUtils.currencySymbol(currencyCode); if (currencyCode.toLowerCase(Locale.US).contains(selectionArg) || currencySymbol.toLowerCase(Locale.US).contains(selectionArg)) cursor.newRow().add(currencyCode.hashCode()).add(currencyCode).add(rate.rate.longValue()) .add(rate.source); } } else if (selection.equals(KEY_CURRENCY_CODE)) { final String selectionArg = selectionArgs[0]; final ExchangeRate rate = bestExchangeRate(selectionArg); 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 String getURLResult(URL url, final String userAgent) { 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.connect(); final int responseCode = connection.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { InputStream is = new BufferedInputStream(connection.getInputStream(), 1024); reader = new InputStreamReader(is, Constants.UTF_8); final StringBuilder content = new StringBuilder(); Io.copy(reader, content); return content.toString(); } else { log.warn("http status {} when fetching exchange rates from {}", responseCode, BTCE_URL); } } catch (final Exception x) { log.warn("problem fetching exchange rates from " + BTCE_URL, x); } finally { if (reader != null) { try { reader.close(); } catch (final IOException x) { // swallow } } if (connection != null) connection.disconnect(); } return null; } private static Map<String, ExchangeRate> requestExchangeRates(final String userAgent) { final Map<String, ExchangeRate> rates = new TreeMap<String, ExchangeRate>(); String usdPriceResult = getURLResult(BTCE_URL, userAgent); if (usdPriceResult == null) return null; BigInteger usdPrice; try { JSONObject jsonResult = new JSONObject(usdPriceResult); usdPrice = GenericUtils.parseCoin(jsonResult.getJSONObject("ticker").getString("last"), 0); } catch (JSONException e) { return null; } rates.put("USD", new ExchangeRate("USD", usdPrice, BTCE_SOURCE)); // Now for USD conversions URL yahoo; try { yahoo = new URL(Uri.parse("https://query.yahooapis.com/v1/public/yql").buildUpon().appendQueryParameter( "q", "select * from yahoo.finance.xchange where pair=\"usdeur, usdgbp, usdcny, usdjpy, usdsgd, usdhkd, usdcad, usdnzd, usdaud, usdclp, usddkk, usdsek, usdisk, usdchf, usdbrl, usdrub, usdpln, usdthb, usdkrw, usdtwd\"") .appendQueryParameter("format", "json") .appendQueryParameter("env", "store://datatables.org/alltableswithkeys").build().toString()); } catch (final MalformedURLException e) { return rates; } String yahooRes = getURLResult(yahoo, userAgent); if (yahooRes != null) { try { JSONObject head = new JSONObject(yahooRes); JSONArray convs = head.getJSONObject("query").getJSONObject("results").getJSONArray("rate"); for (int x = 0; x < convs.length(); x++) { JSONObject conv = convs.getJSONObject(x); String currency = conv.getString("id").substring(3); String priceString = conv.getString("Rate"); BigInteger price = (new BigDecimal(GenericUtils.parseCoin(priceString, 0).multiply(usdPrice))) .movePointLeft(6).toBigInteger(); rates.put(currency, new ExchangeRate(currency, price, BTCE_SOURCE)); } } catch (Exception e) { log.warn("Got error reading yahoo exchange rates: {}", e); } } return rates; } }