Add websocket bookTicker call

src/main/java/com/binance/api/client/BinanceApiWebSocketClient.java

@@ -1,10 +1,6 @@
 package com.binance.api.client;
 
-import com.binance.api.client.domain.event.AggTradeEvent;
-import com.binance.api.client.domain.event.AllMarketTickersEvent;
-import com.binance.api.client.domain.event.CandlestickEvent;
-import com.binance.api.client.domain.event.DepthEvent;
-import com.binance.api.client.domain.event.UserDataUpdateEvent;
+import com.binance.api.client.domain.event.*;
 import com.binance.api.client.domain.market.CandlestickInterval;
 
 import java.io.Closeable;
@@ -15,6 +11,15 @@
  */
 public interface BinanceApiWebSocketClient extends Closeable {
 
+    /**
+     * Open a new web socket to receive {@link BookTickerEvent bookTickerEvents} on a callback.
+     *
+     * @param symbols   market (one or coma-separated) symbol(s) to subscribe to
+     * @param callback  the callback to call on new events
+     * @return a {@link Closeable} that allows the underlying web socket to be closed.
+     */
+    Closeable onBookTicker(String symbols, BinanceApiCallback<BookTickerEvent> callback);
+
     /**
      * Open a new web socket to receive {@link DepthEvent depthEvents} on a callback.
      *

src/main/java/com/binance/api/client/domain/event/BookTickerEvent.java

@@ -0,0 +1,90 @@
+package com.binance.api.client.domain.event;
+
+import com.binance.api.client.constant.BinanceApiConstants;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+
+import java.math.BigDecimal;
+
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class BookTickerEvent {
+
+  @JsonProperty("u")
+  private long updateId;
+
+  @JsonProperty("s")
+  private String symbol;
+
+  @JsonProperty("b")
+  private String bestBidPrice;
+
+  @JsonProperty("B")
+  private String bestBidQuantity;
+
+  @JsonProperty("a")
+  private String bestAskPrice;
+
+  @JsonProperty("A")
+  private String bestAskQuantity;
+
+  public long getUpdateId() {
+    return updateId;
+  }
+
+  public void setUpdateId(long updateId) {
+    this.updateId = updateId;
+  }
+
+  public String getSymbol() {
+    return symbol;
+  }
+
+  public void setSymbol(String symbol) {
+    this.symbol = symbol;
+  }
+
+  public String getBestBidPrice() {
+    return bestBidPrice;
+  }
+
+  public void setBestBidPrice(String bestBidPrice) {
+    this.bestBidPrice = bestBidPrice;
+  }
+
+  public String getBestBidQuantity() {
+    return bestBidQuantity;
+  }
+
+  public void setBestBidQuantity(String bestBidQuantity) {
+    this.bestBidQuantity = bestBidQuantity;
+  }
+
+  public String getBestAskPrice() {
+    return bestAskPrice;
+  }
+
+  public void setBestAskPrice(String bestAskPrice) {
+    this.bestAskPrice = bestAskPrice;
+  }
+
+  public String getBestAskQuantity() {
+    return bestAskQuantity;
+  }
+
+  public void setBestAskQuantity(String bestAskQuantity) {
+    this.bestAskQuantity = bestAskQuantity;
+  }
+
+  @Override
+  public String toString() {
+    return new ToStringBuilder(this, BinanceApiConstants.TO_STRING_BUILDER_STYLE)
+        .append("updateId", updateId)
+        .append("symbol", symbol)
+        .append("bestBidPrice", bestBidPrice)
+        .append("bestBidQuantity", bestBidQuantity)
+        .append("bestAskPrice", bestAskPrice)
+        .append("bestAskQuantity", bestAskQuantity)
+        .toString();
+  }
+}

src/main/java/com/binance/api/client/impl/BinanceApiWebSocketClientImpl.java

@@ -4,11 +4,7 @@
 import com.binance.api.client.BinanceApiWebSocketClient;
 import com.binance.api.client.config.BinanceApiConfig;
 import com.binance.api.client.constant.BinanceApiConstants;
-import com.binance.api.client.domain.event.AggTradeEvent;
-import com.binance.api.client.domain.event.AllMarketTickersEvent;
-import com.binance.api.client.domain.event.CandlestickEvent;
-import com.binance.api.client.domain.event.DepthEvent;
-import com.binance.api.client.domain.event.UserDataUpdateEvent;
+import com.binance.api.client.domain.event.*;
 import com.binance.api.client.domain.market.CandlestickInterval;
 import com.fasterxml.jackson.core.type.TypeReference;
 
@@ -32,6 +28,15 @@ public BinanceApiWebSocketClientImpl(OkHttpClient client) {
         this.client = client;
     }
 
+    @Override
+    public Closeable onBookTicker(String symbols, BinanceApiCallback<BookTickerEvent> callback) {
+        final String channel = Arrays.stream(symbols.split(","))
+            .map(String::trim)
+            .map(s -> String.format("%s@bookTicker", s))
+            .collect(Collectors.joining("/"));
+        return createNewWebSocket(channel, new BinanceApiWebSocketListener<>(callback, BookTickerEvent.class));
+    }
+
     @Override
     public Closeable onDepthEvent(String symbols, BinanceApiCallback<DepthEvent> callback) {
         final String channel = Arrays.stream(symbols.split(","))

src/test/java/com/binance/api/examples/MarketDataStreamExample.java

@@ -19,6 +19,9 @@ public static void main(String[] args) throws InterruptedException, IOException
     // Listen for aggregated trade events for ETH/BTC
     client.onAggTradeEvent("ethbtc", response -> System.out.println(response));
 
+    // Listen for book ticker events for ETH/BTC
+    client.onBookTicker("ethbtc", response -> System.out.println(response));
+
     // Listen for changes in the order book in ETH/BTC
     client.onDepthEvent("ethbtc", response -> System.out.println(response));