Integrate initial set of ExchangeRateProviders

Add support for a few exchanges to demonstrate and test the pricenode
aggregate rates.

The chose exchanges were selected because they each provide a varied
list of fiat and altcoins, with a substantial overlap between them. This
 provides a robust initial set of datapoints and scenarios for aggregate
  rates.

pricenode/src/main/java/bisq/price/spot/ExchangeRateProvider.java

@@ -19,9 +19,24 @@
 
 import bisq.price.PriceProvider;
 
+import bisq.core.locale.CurrencyUtil;
+import bisq.core.locale.TradeCurrency;
+
+import org.knowm.xchange.Exchange;
+import org.knowm.xchange.ExchangeFactory;
+import org.knowm.xchange.currency.Currency;
+import org.knowm.xchange.currency.CurrencyPair;
+import org.knowm.xchange.dto.marketdata.Ticker;
+import org.knowm.xchange.exceptions.CurrencyPairNotValidException;
+import org.knowm.xchange.service.marketdata.MarketDataService;
+
 import java.time.Duration;
 
+import java.util.Date;
+import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 /**
  * Abstract base class for providers of bitcoin {@link ExchangeRate} data. Implementations
@@ -60,4 +75,82 @@ protected void onRefresh() {
             .filter(e -> "USD".equals(e.getCurrency()) || "LTC".equals(e.getCurrency()))
             .forEach(e -> log.info("BTC/{}: {}", e.getCurrency(), e.getPrice()));
     }
+
+    /**
+     * @param exchangeClass Class of the {@link Exchange} for which the rates should be polled
+     * @return Exchange rates for Bisq-supported fiat currencies and altcoins in the specified {@link Exchange}
+     *
+     * @see CurrencyUtil#getAllSortedFiatCurrencies()
+     * @see CurrencyUtil#getAllSortedCryptoCurrencies()
+     */
+    protected Set<ExchangeRate> doGet(Class<? extends Exchange> exchangeClass) {
+        Set<ExchangeRate> result = new HashSet<ExchangeRate>();
+
+        // Initialize XChange objects
+        Exchange exchange = ExchangeFactory.INSTANCE.createExchange(exchangeClass.getName());
+        MarketDataService marketDataService = exchange.getMarketDataService();
+
+        // Retrieve all currency pairs supported by the exchange
+        List<CurrencyPair> currencyPairs = exchange.getExchangeSymbols();
+
+        Set<String> supportedCryptoCurrencies = CurrencyUtil.getAllSortedCryptoCurrencies().stream()
+                .map(TradeCurrency::getCode)
+                .collect(Collectors.toSet());
+
+        Set<String> supportedFiatCurrencies = CurrencyUtil.getAllSortedFiatCurrencies().stream()
+                .map(TradeCurrency::getCode)
+                .collect(Collectors.toSet());
+
+        // Filter the supported fiat currencies (currency pair format is BTC-FIAT)
+        currencyPairs.stream()
+                .filter(cp -> cp.base.equals(Currency.BTC))
+                .filter(cp -> supportedFiatCurrencies.contains(cp.counter.getCurrencyCode()))
+                .forEach(cp -> {
+                    try {
+                        Ticker t = marketDataService.getTicker(new CurrencyPair(cp.base, cp.counter));
+
+                        result.add(new ExchangeRate(
+                                cp.counter.getCurrencyCode(),
+                                t.getLast(),
+                                // Some exchanges do not provide timestamps
+                                t.getTimestamp() == null ? new Date() : t.getTimestamp(),
+                                this.getName()
+                        ));
+                    } catch (CurrencyPairNotValidException cpnve) {
+                        // Some exchanges support certain currency pairs for other services but not for spot markets
+                        // In that case, trying to retrieve the market ticker for that pair may fail with this specific type of exception
+                        log.info("Currency pair " + cp + " not supported in Spot Markets: " + cpnve.getMessage());
+                    } catch (Exception e) {
+                        // Catch any other type of generic exception (IO, network level, rate limit reached, etc)
+                        log.info("Exception encountered while retrieving rate for currency pair " + cp + ": " + e.getMessage());
+                    }
+                });
+
+        // Filter the supported altcoins (currency pair format is ALT-BTC)
+        currencyPairs.stream()
+                .filter(cp -> cp.counter.equals(Currency.BTC))
+                .filter(cp -> supportedCryptoCurrencies.contains(cp.base.getCurrencyCode()))
+                .forEach(cp -> {
+                    try {
+                        Ticker t = marketDataService.getTicker(new CurrencyPair(cp.base, cp.counter));
+
+                        result.add(new ExchangeRate(
+                                cp.base.getCurrencyCode(),
+                                t.getLast(),
+                                // Some exchanges do not provide timestamps
+                                t.getTimestamp() == null ? new Date() : t.getTimestamp(),
+                                this.getName()
+                        ));
+                    } catch (CurrencyPairNotValidException cpnve) {
+                        // Some exchanges support certain currency pairs for other services but not for spot markets
+                        // In that case, trying to retrieve the market ticker for that pair may fail with this specific type of exception
+                        log.info("Currency pair " + cp + " not supported in Spot Markets: " + cpnve.getMessage());
+                    } catch (Exception e) {
+                        // Catch any other type of generic exception (IO, network level, rate limit reached, etc)
+                        log.info("Exception encountered while retrieving rate for currency pair " + cp + ": " + e.getMessage());
+                    }
+                });
+
+        return result;
+    }
 }

pricenode/src/main/java/bisq/price/spot/providers/Binance.java

@@ -0,0 +1,46 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq 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.
+ *
+ * Bisq 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.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.price.spot.providers;
+
+import bisq.price.spot.ExchangeRate;
+import bisq.price.spot.ExchangeRateProvider;
+
+import org.knowm.xchange.binance.BinanceExchange;
+
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import java.time.Duration;
+
+import java.util.Set;
+
+@Component
+@Order(5)
+public class Binance extends ExchangeRateProvider {
+
+    public Binance() {
+        super("BINANCE", "binance", Duration.ofMinutes(1));
+    }
+
+    @Override
+    public Set<ExchangeRate> doGet() {
+        // Supported fiat: EUR, NGN, RUB, TRY, ZAR
+        // Supported alts: BEAM, DASH, DCR, DOGE, ETC, ETH, LTC, NAV, PIVX, XMR, XZC, ZEC, ZEN
+        return doGet(BinanceExchange.class);
+    }
+}

pricenode/src/main/java/bisq/price/spot/providers/Bitfinex.java

@@ -0,0 +1,46 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq 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.
+ *
+ * Bisq 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.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.price.spot.providers;
+
+import bisq.price.spot.ExchangeRate;
+import bisq.price.spot.ExchangeRateProvider;
+
+import org.knowm.xchange.bitfinex.BitfinexExchange;
+
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import java.time.Duration;
+
+import java.util.Set;
+
+@Component
+@Order(6)
+public class Bitfinex extends ExchangeRateProvider {
+
+    public Bitfinex() {
+        super("BITFINEX", "bitfinex", Duration.ofMinutes(1));
+    }
+
+    @Override
+    public Set<ExchangeRate> doGet() {
+        // Supported fiat: EUR, GBP, JPY, USD
+        // Supported alts: DAI, ETC, ETH, LTC, XMR, ZEC
+        return doGet(BitfinexExchange.class);
+    }
+}

pricenode/src/main/java/bisq/price/spot/providers/Kraken.java

@@ -0,0 +1,46 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq 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.
+ *
+ * Bisq 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.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.price.spot.providers;
+
+import bisq.price.spot.ExchangeRate;
+import bisq.price.spot.ExchangeRateProvider;
+
+import org.knowm.xchange.kraken.KrakenExchange;
+
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import java.time.Duration;
+
+import java.util.Set;
+
+@Component
+@Order(7)
+public class Kraken extends ExchangeRateProvider {
+
+    public Kraken() {
+        super("KRAKEN", "kraken", Duration.ofMinutes(1));
+    }
+
+    @Override
+    public Set<ExchangeRate> doGet() {
+        // Supported fiat: AUD, CAD, CHF, EUR, GBP, JPY, USD
+        // Supported alts: DASH, DOGE, ETC, ETH, LTC, XMR, ZEC
+        return doGet(KrakenExchange.class);
+    }
+}

pricenode/src/main/java/bisq/price/spot/providers/Poloniex.java

@@ -19,76 +19,28 @@
 
 import bisq.price.spot.ExchangeRate;
 import bisq.price.spot.ExchangeRateProvider;
-import bisq.price.util.Altcoins;
 
-import org.knowm.xchange.currency.Currency;
-import org.knowm.xchange.currency.CurrencyPair;
-import org.knowm.xchange.poloniex.dto.marketdata.PoloniexMarketData;
-import org.knowm.xchange.poloniex.dto.marketdata.PoloniexTicker;
+import org.knowm.xchange.poloniex.PoloniexExchange;
 
-import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.annotation.Order;
-import org.springframework.http.RequestEntity;
 import org.springframework.stereotype.Component;
-import org.springframework.web.client.RestTemplate;
-import org.springframework.web.util.UriComponentsBuilder;
 
 import java.time.Duration;
 
-import java.util.Date;
-import java.util.Map;
 import java.util.Set;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 @Component
 @Order(4)
-class Poloniex extends ExchangeRateProvider {
-
-    private final RestTemplate restTemplate = new RestTemplate();
+public class Poloniex extends ExchangeRateProvider {
 
     public Poloniex() {
         super("POLO", "poloniex", Duration.ofMinutes(1));
     }
 
     @Override
     public Set<ExchangeRate> doGet() {
-        Date timestamp = new Date(); // Poloniex tickers don't include their own timestamp
-
-        return getTickers()
-            .filter(t -> t.getCurrencyPair().base.equals(Currency.BTC))
-            .filter(t -> Altcoins.ALL_SUPPORTED.contains(t.getCurrencyPair().counter.getCurrencyCode()))
-            .map(t ->
-                new ExchangeRate(
-                    t.getCurrencyPair().counter.getCurrencyCode(),
-                    t.getPoloniexMarketData().getLast(),
-                    timestamp,
-                    this.getName()
-                )
-            )
-            .collect(Collectors.toSet());
-    }
-
-    private Stream<PoloniexTicker> getTickers() {
-
-        return getTickersKeyedByCurrencyPair().entrySet().stream()
-            .map(e -> {
-                String pair = e.getKey();
-                PoloniexMarketData data = e.getValue();
-                String[] symbols = pair.split("_"); // e.g. BTC_USD => [BTC, USD]
-                return new PoloniexTicker(data, new CurrencyPair(symbols[0], symbols[1]));
-            });
-    }
-
-    private Map<String, PoloniexMarketData> getTickersKeyedByCurrencyPair() {
-        return restTemplate.exchange(
-            RequestEntity
-                .get(UriComponentsBuilder
-                    .fromUriString("https://poloniex.com/public?command=returnTicker").build()
-                    .toUri())
-                .build(),
-            new ParameterizedTypeReference<Map<String, PoloniexMarketData>>() {
-            }
-        ).getBody();
+        // Supported fiat: -
+        // Supported alts: DASH, DCR, DOGE, ETC, ETH, GRIN, LTC, XMR, ZEC
+        return doGet(PoloniexExchange.class);
     }
 }