Added method for cross instrument creation.

juxeii · Nov 8, 2017 · 2af1662 · 2af1662
1 parent 267f70a
commit 2af1662
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diff --git a/src/main/java/com/jforex/programming/instrument/InstrumentFactory.java b/src/main/java/com/jforex/programming/instrument/InstrumentFactory.java
@@ -14,9 +14,12 @@
 
 import com.dukascopy.api.ICurrency;
 import com.dukascopy.api.Instrument;
+import com.jforex.programming.currency.CurrencyFactory;
 import com.jforex.programming.math.MathUtil;
 import com.jforex.programming.misc.StreamUtil;
 
+import io.reactivex.Maybe;
+
 public final class InstrumentFactory {
 
     private InstrumentFactory() {
@@ -90,4 +93,21 @@ public static final Set<Instrument> combineWithAnchorCurrency(final ICurrency an
             .flatMap(StreamUtil::optionalToStream)
             .collect(toSet());
     }
+
+    public static final Maybe<Instrument> maybeCrossInstrument(final Instrument firstInstrument,
+                                                               final Instrument secondInstrument) {
+        checkNotNull(firstInstrument);
+        checkNotNull(secondInstrument);
+
+        return Maybe
+            .just(CurrencyFactory.fromInstruments(firstInstrument, secondInstrument))
+            .filter(currencies -> currencies.size() == 3)
+            .map(InstrumentFactory::combineCurrencies)
+            .map(instruments -> {
+                instruments.remove(firstInstrument);
+                instruments.remove(secondInstrument);
+                return instruments;
+            })
+            .map(instruments -> instruments.iterator().next());
+    }
 }
diff --git a/src/test/java/com/jforex/programming/instrument/test/InstrumentFactoryTest.java b/src/test/java/com/jforex/programming/instrument/test/InstrumentFactoryTest.java
@@ -2,6 +2,7 @@
 
 import static com.jforex.programming.instrument.InstrumentFactory.combineCurrencies;
 import static com.jforex.programming.instrument.InstrumentFactory.combineWithAnchorCurrency;
+import static com.jforex.programming.instrument.InstrumentFactory.maybeCrossInstrument;
 import static com.jforex.programming.instrument.InstrumentFactory.maybeFromCurrencies;
 import static com.jforex.programming.instrument.InstrumentFactory.maybeFromName;
 import static org.hamcrest.Matchers.equalTo;
@@ -157,4 +158,23 @@ public void testCombineAllWithAnchorCurrencyReturnsCorrectInstruments() {
 
         assertAnchorCurrencySet(partnerCurrencies, instrumentsForAnchorCurrencyTests);
     }
+
+    @Test
+    public void testMaybeCrossInstrumentIsEmptyWhenInstrumentsFormNoCrossInstrument() {
+        maybeCrossInstrument(instrumentEURUSD, instrumentEURUSD)
+            .test()
+            .assertNoValues();
+
+        maybeCrossInstrument(instrumentEURUSD, instrumentGBPJPY)
+            .test()
+            .assertNoValues();
+    }
+
+    @Test
+    public void testMaybeCrossInstrumentIsCorrect() {
+        assertThat(maybeCrossInstrument(instrumentEURUSD, instrumentGBPUSD).blockingGet(), equalTo(instrumentEURGBP));
+        assertThat(maybeCrossInstrument(instrumentEURUSD, instrumentUSDJPY).blockingGet(), equalTo(instrumentEURJPY));
+        assertThat(maybeCrossInstrument(instrumentUSDJPY, instrumentGBPUSD).blockingGet(), equalTo(instrumentGBPJPY));
+        assertThat(maybeCrossInstrument(instrumentGBPAUD, instrumentAUDJPY).blockingGet(), equalTo(instrumentGBPJPY));
+    }
 }