added ensembly

src/Main.java

@@ -3,9 +3,12 @@
 import model.Purchase;
 import model.Purchases;
 import service.JackSparrowHelper;
+import service.JackSparrowHelperEnsemble;
 import service.JackSparrowHelperGreedy;
 import service.JackSparrowHelperWithSolver;
 
+import static java.util.Arrays.asList;
+
 /**
  * Created by SBT-Kovalev-DA on 24.02.2016.
  */
@@ -14,13 +17,17 @@ public static void main(String[] args) {
         JackSparrowHelper jackSparrowHelperOld = new JackSparrowHelperGreedy(new CSVCommodityParserImpl(";"));
         JackSparrowHelper jackSparrowHelper = new JackSparrowHelperWithSolver(new CSVCommodityParserImpl(";"), new GreedyBoundedKnapsackSolver());
 
+        JackSparrowHelper jackSparrowHelperEnsemble = new JackSparrowHelperEnsemble(asList(jackSparrowHelper, jackSparrowHelperOld));
+
         printSolution(jackSparrowHelperOld);
         System.out.println();
         printSolution(jackSparrowHelper);
+        System.out.println();
+        printSolution(jackSparrowHelperEnsemble);
     }
 
     private static void printSolution(JackSparrowHelper jackSparrowHelper) {
-        Purchases abr = jackSparrowHelper.helpJackSparrow("C:\\Users\\SBT-Kovalev-DA\\Downloads\\pirates\\sources.csv", 222);
+        Purchases abr = jackSparrowHelper.helpJackSparrow("C:\\Users\\SBT-Kovalev-DA\\Downloads\\pirates\\sources.csv", 353);
 
         System.out.println(abr.calculateAveragePrice() + "  REAL AVG: " + getAvg(abr));
         System.out.println("amount: " + getGallons(abr));

src/model/Purchase.java

@@ -1,6 +1,7 @@
 package model;
 
 public class Purchase {
+    public static final Purchase HEAVY = new Purchase("", Integer.MAX_VALUE, Double.MAX_VALUE);
     private final String sourceName;
     private final Integer numberOfGallons;
     private final Double priceOfGallon;

src/model/Purchases.java

@@ -2,6 +2,9 @@
 
 import java.util.Set;
 
+import static java.util.Collections.singleton;
+import static model.Purchase.HEAVY;
+
 public class Purchases {
     private final int requestedNumberOfGallons;
     private final Set<Purchase> purchases;
@@ -11,6 +14,10 @@ public Purchases(int requestedNumberOfGallons, Set<Purchase> purchases) {
         this.purchases = purchases;
     }
 
+    public static Purchases heavyEmpty(int requestedNumberOfGallons){
+        return new Purchases(requestedNumberOfGallons, singleton(HEAVY));
+    }
+
     public Double calculateAveragePrice() {
         double totalSum = 0;
         for (Purchase purchase : getPurchases()) {
@@ -25,6 +32,17 @@ public Integer getRequestedNumberOfGallons() {
         return requestedNumberOfGallons;
     }
 
+    public double getAvg() {
+        return getTotalPrice()/getGallons();
+    }
+
+    public  int getGallons( ) {
+        return purchases.stream().mapToInt(Purchase::getNumberOfGallons).sum();
+    }
+    public  double getTotalPrice( ) {
+        return purchases.stream().mapToDouble(Purchase::getTotalPrice).sum();
+    }
+
     public Set<Purchase> getPurchases() {
         return purchases;
     }

src/service/JackSparrowHelperEnsemble.java

@@ -0,0 +1,37 @@
+package service;
+
+import model.Purchases;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static java.util.Comparator.comparing;
+import static java.util.Comparator.comparingDouble;
+import static model.Purchases.heavyEmpty;
+
+/**
+ * Created by SBT-Kovalev-DA on 03.03.2016.
+ */
+public class JackSparrowHelperEnsemble implements JackSparrowHelper {
+    private final List<JackSparrowHelper> helpers;
+
+    public JackSparrowHelperEnsemble(List<JackSparrowHelper> helpers) {
+        this.helpers = helpers;
+    }
+
+    @Override
+    public Purchases helpJackSparrow(String pathToPrices, int numberOfGallons) {
+        List<Purchases> candidates = helpers.stream()
+                .map(h -> h.helpJackSparrow(pathToPrices, numberOfGallons))
+                .collect(Collectors.toList());
+        return candidates.stream()
+                .reduce(heavyEmpty(numberOfGallons), this::findBest);
+    }
+
+    private Purchases findBest(Purchases first, Purchases second) {
+        Comparator<Purchases> purchasesComparator = comparingDouble(Purchases::getTotalPrice)
+                .thenComparing(comparing(Purchases::getGallons).reversed());
+        return purchasesComparator.compare(first, second) <= 0 ? first : second;
+    }
+}