Expanding the Converter class in order to be able to use it with Price instances

src/main/java/de/bitsharesmunich/graphenej/Converter.java

@@ -1,12 +1,14 @@
 package de.bitsharesmunich.graphenej;
 
 import java.math.BigDecimal;
+import java.math.MathContext;
 
+import com.google.common.primitives.UnsignedLong;
 import de.bitsharesmunich.graphenej.errors.IncompleteAssetError;
 import de.bitsharesmunich.graphenej.models.BucketObject;
 
 /**
- * Converter class used to translate the market information contained in a BucketObject instance.
+ * Generic converter class used to translate the market information contained in a BucketObject and/or Price instances.
  *
  * Created by nelson on 12/23/16.
  */
@@ -24,6 +26,18 @@ public class Converter {
     private Asset quote;
     private BucketObject bucket;
 
+    /**
+     * Constructor meant to be used trying to perform a conversion and in possession of a Price object.
+     */
+    public Converter(){}
+
+    /**
+     * Constructor meant to be used when trying to perform a conversion and in possession of
+     * a BucketObject, typically resulting from a 'get_market_history' API call.
+     * @param base
+     * @param quote
+     * @param bucket
+     */
     public Converter(Asset base, Asset quote, BucketObject bucket){
         this.base = base;
         this.quote = quote;
@@ -109,4 +123,37 @@ public class Converter {
         long convertedBaseValue = (long) (assetAmountValue * conversionRate * precisionFactor);
         return convertedBaseValue;
     }
+
+    /**
+     * Method used to obtain the conversion rate between two assets given in a Price instance as recovered by the
+     * 'get_limit_orders' API call.
+     *
+     * The same rules that apply for the {@link #getConversionRate(int bucketAttribute, int direction) getConversionRate}
+     * are valid for the 'direction' argument.
+     *
+     * @param price: The Price object instance
+     * @param direction: The direction from which to perform the conversion, can be only one of BASE_TO_QUOTE or
+     *                 QUOTE_TO_BASE.
+     * @return: A double representing the exchange rate.
+     */
+    public double getConversionRate(Price price, int direction){
+        Asset base = price.base.getAsset();
+        Asset quote = price.quote.getAsset();
+        if(base.getPrecision() == -1 || quote.getPrecision() == -1){
+            throw new IncompleteAssetError("The given asset instance must provide precision information");
+        }
+        double conversionRate = 0;
+        double precisionFactor = 0.0;
+        MathContext mathContext = new MathContext(Math.max(base.getPrecision(), quote.getPrecision()));
+        BigDecimal baseValue = BigDecimal.valueOf(price.base.getAmount().longValue());
+        BigDecimal quoteValue = BigDecimal.valueOf(price.quote.getAmount().doubleValue());
+        if(direction == BASE_TO_QUOTE){
+            conversionRate = quoteValue.divide(baseValue, mathContext).doubleValue();
+            precisionFactor = Math.pow(10, base.getPrecision()) / Math.pow(10, quote.getPrecision());
+        }else{
+            conversionRate = baseValue.divide(quoteValue, mathContext).doubleValue();
+            precisionFactor = Math.pow(10, quote.getPrecision()) / Math.pow(10, base.getPrecision());
+        }
+        return conversionRate * precisionFactor;
+    }
 }