test

app/src/main/java/model/Cell.java

@@ -42,5 +42,7 @@ public interface Cell {
      */
     Property<Color> getColorProperty();
 
+    Iterator<Cell> iterator();
+
 
 }

app/src/main/java/model/ColoredCellIterator.java

+package model;
+
+import javafx.scene.paint.Color;
+
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+
+public class ColoredCellIterator implements Iterator<Cell> {
+    private Color color;
+    private Set<Cell> visitedCells;
+    private Set<Cell> pendingCells ;
+
+    public ColoredCellIterator(Cell startCell){
+        this.color = startCell.getColor();
+        this.visitedCells = new HashSet<>();
+        this.pendingCells = new HashSet<>();
+        pendingCells.add(startCell);
+    }
+
+    @Override
+    public Cell next() {
+        for(Cell cell : pendingCells){
+            if(cell.getColor() == pendingCells.stream().findFirst().get().getColor()&& hasNext()&& !visitedCells.contains(cell)  ){
+                for (int i=0;i<cell.getNeighbours().size()-1;i++){
+                    if(visitedCells.contains(cell.getNeighbours().get(i)) ||
+                                cell.getNeighbours().get(i).getColor()!= pendingCells.stream().findFirst().get().getColor()){
+                        visitedCells.add(cell);
+                        return cell;
+                    }
+                    else {
+                        pendingCells.add(cell.getNeighbours().get(i));
+                    }
+                visitedCells.add(cell);
+                return cell;
+                }
+            visitedCells.add(cell);
+            return cell;
+            }
+        }
+        return new SquareCell();
+    }
+
+    @Override
+    public boolean hasNext() {
+        if (pendingCells.isEmpty()){
+            return false;
+        }
+        else {
+            return true;
+        }
+    }
+}

app/src/main/java/model/GrayCell.java

@@ -3,6 +3,7 @@ package model;
 import javafx.beans.property.Property;
 import javafx.scene.paint.Color;
 
+import java.util.Iterator;
 import java.util.List;
 
 public class GrayCell extends AbstractCell{
@@ -34,4 +35,7 @@ public class GrayCell extends AbstractCell{
     public void setColor(Color color){
 
     }
+    public Iterator<Cell> iterator(){
+        return null;
+    }
 }

app/src/main/java/model/SquareCell.java

@@ -38,4 +38,8 @@ public class SquareCell extends AbstractCell {
             this.neighbours.set(i,cells.get(i));
         }
     }
+
+    public Iterator<Cell> iterator(){
+        return new ColoredCellIterator(new SquareCell());
+    }
 }
\ No newline at end of file

app/src/main/java/util/SetUtil.java

 package util;
 
+import model.Cell;
+
+import java.util.HashSet;
 import java.util.NoSuchElementException;
 import java.util.Set;
 
@@ -7,4 +10,5 @@ public class SetUtil {
     public static <T> T anyElement(Set<T> elements){
         return elements.stream().findAny().orElseThrow(NoSuchElementException::new);
     }
+
 }