implement loop route specification

core/src/main/java/ru/trader/analysis/LoopRouteSpecification.java

@@ -0,0 +1,62 @@
+package ru.trader.analysis;
+
+import ru.trader.analysis.graph.Edge;
+import ru.trader.analysis.graph.Traversal;
+
+import java.util.Optional;
+
+public class LoopRouteSpecification<T> implements RouteSpecification<T> {
+    private final boolean unique;
+
+    public LoopRouteSpecification(boolean unique) {
+        this.unique = unique;
+    }
+
+    private Traversal<T> getStart(Traversal<T> entry){
+        Traversal<T> res = null;
+        Traversal<T> last = entry;
+        Optional<Traversal<T>> head = entry.getHead();
+        while (head.isPresent()) {
+            Traversal<T> e = head.get();
+            res = last;
+            last = e;
+            head = e.getHead();
+        }
+        return res;
+    }
+
+    @Override
+    public boolean specified(Edge<T> edge, Traversal<T> entry) {
+        return check(edge, entry, false);
+    }
+
+    @Override
+    public boolean updateSpecified(Edge<T> edge, Traversal<T> entry) {
+        return check(edge, entry, true);
+    }
+
+    private boolean check(Edge<T> edge, Traversal<T> entry, boolean update) {
+        Optional<Traversal<T>> head = entry.getHead();
+        if (!head.isPresent() || head.get().getEdge() == null) return false;
+        Traversal<T> start = getStart(head.get());
+        boolean found = edge.isConnect(start.getTarget().getEntry());
+        if (found && unique){
+            found = !start.isSkipped();
+            if (update){
+                start.setSkipped(true);
+                setSkip(entry);
+            }
+        }
+        return found;
+    }
+
+    private void setSkip(Traversal<T> entry) {
+        Traversal<T> curr = entry;
+        Optional<Traversal<T>> head = entry.getHead();
+        while (head.isPresent()) {
+            curr.setSkipped(true);
+            curr = head.get();
+            head = curr.getHead();
+        }
+    }
+}

core/src/main/java/ru/trader/analysis/RouteSearcher.java

@@ -89,6 +89,10 @@ public class RouteSearcher {
         return collector.get();
     }
 
+    public List<Route> getLoops(Vendor source, Collection<Vendor> vendors, int count){
+        return search(source, source, vendors, count, new LoopRouteSpecification<Vendor>(true));
+    }
+
     private class RouteCollector {
         private List<Route> routes = new ArrayList<>();
 

core/src/main/java/ru/trader/core/MarketAnalyzer.java

@@ -202,6 +202,10 @@ public class MarketAnalyzer {
         return top;
     }
 
+    public Collection<Route> getLoops(Vendor vendor, int limit){
+        return searcher.getLoops(vendor, getVendors(), limit);
+    }
+
     public Collection<Route> getRoutes(Place from){
         return searcher.getRoutes(getVendors(from), getVendors());
     }