Added a method to get the number of failed content lookups

src/kademlia/KadStatistician.java

@@ -61,6 +61,11 @@ public interface KadStatistician
      */
     public int numContentLookups();
 
+    /**
+     * @return How many content lookups have failed.
+     */
+    public int numFailedContentLookups();
+
     /**
      * @return The total time spent on content lookups.
      */

src/kademlia/Statistician.java

@@ -21,7 +21,7 @@ public class Statistician implements KadStatistician
     private long bootstrapTime;
 
     /* Content lookup operation timing & route length */
-    private int numContentLookups;
+    private int numContentLookups, numFailedContentLookups;
     private long totalContentLookupTime;
     private long totalRouteLength;
 
@@ -75,11 +75,18 @@ public class Statistician implements KadStatistician
 
     @Override
     public void addContentLookup(long time, int routeLength, boolean isSuccessful)
+    {
+        if (isSuccessful)
         {
             this.numContentLookups++;
             this.totalContentLookupTime += time;
             this.totalRouteLength += routeLength;
         }
+        else
+        {
+            this.numFailedContentLookups++;
+        }
+    }
 
     @Override
     public int numContentLookups()
@@ -87,6 +94,12 @@ public class Statistician implements KadStatistician
         return this.numContentLookups;
     }
 
+    @Override
+    public int numFailedContentLookups()
+    {
+        return this.numFailedContentLookups;
+    }
+
     @Override
     public long totalContentLookupTime()
     {