From c2e66b24e48a699d9c7c3d4b31f119d28df70b07 Mon Sep 17 00:00:00 2001
From: Axel Uhl <axel.uhl@sap.com>
Date: Sun, 11 Aug 2019 14:54:55 -0600
Subject: [PATCH] performance improvement by re-using total points calculation
 for net points in comparator

Change-Id: I92a0fdf5270414d05465fbb3a6101e11dc736a3b
---
 .../sap/sailing/domain/leaderboard/Leaderboard.java    | 10 ++++++++++
 .../impl/AbstractSimpleLeaderboardImpl.java            |  9 ++++++++-
 .../impl/LeaderboardTotalRankComparator.java           |  6 ++++--
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/Leaderboard.java b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/Leaderboard.java
index 01b3ed75872..5e4366997d0 100644
--- a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/Leaderboard.java
+++ b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/Leaderboard.java
@@ -5,6 +5,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
+import java.util.function.Supplier;
 
 import com.sap.sailing.domain.base.Boat;
 import com.sap.sailing.domain.base.BoatClass;
@@ -539,6 +540,15 @@ public interface Leaderboard extends LeaderboardBase, HasRaceColumns {
     Double getNetPoints(Competitor competitor, RaceColumn raceColumn, TimePoint timePoint,
             Set<RaceColumn> discardedRaceColumns);
 
+    /**
+     * Same as {@link #getNetPoints(Competitor, RaceColumn, TimePoint, Set)}, only that a supplier for
+     * the total points for the {@code competitor} in column {@code raceColumn} at time point {@code timePoint}
+     * is provided. This helps if a caller also needs to determine the total points anyway, saving redundant
+     * calculations.
+     */
+    Double getNetPoints(Competitor competitor, RaceColumn raceColumn, TimePoint timePoint,
+            Set<RaceColumn> discardedRaceColumns, Supplier<Double> totalPointsProvider);
+
     TimePoint getNowMinusDelay();
     
     /**
diff --git a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/AbstractSimpleLeaderboardImpl.java b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/AbstractSimpleLeaderboardImpl.java
index 8185529a029..e1c2add400f 100644
--- a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/AbstractSimpleLeaderboardImpl.java
+++ b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/AbstractSimpleLeaderboardImpl.java
@@ -13,6 +13,7 @@ import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
@@ -466,11 +467,17 @@ public abstract class AbstractSimpleLeaderboardImpl extends AbstractLeaderboardW
     @Override
     public Double getNetPoints(Competitor competitor, RaceColumn raceColumn, TimePoint timePoint,
             Set<RaceColumn> discardedRaceColumns) {
+        return getNetPoints(competitor, raceColumn, timePoint, discardedRaceColumns, ()->getTotalPoints(competitor, raceColumn, timePoint));
+    }
+    
+    @Override
+    public Double getNetPoints(Competitor competitor, RaceColumn raceColumn, TimePoint timePoint,
+            Set<RaceColumn> discardedRaceColumns, Supplier<Double> totalPointsProvider) {
         Double result;
         if (isDiscarded(competitor, raceColumn, timePoint, discardedRaceColumns)) {
             result = 0.0;
         } else {
-            final Double totalPoints = getTotalPoints(competitor, raceColumn, timePoint);
+            final Double totalPoints = totalPointsProvider.get();
             if (totalPoints == null) {
                 result = null;
             } else {
diff --git a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/LeaderboardTotalRankComparator.java b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/LeaderboardTotalRankComparator.java
index 3b79eee114d..377cfbe0fd1 100644
--- a/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/LeaderboardTotalRankComparator.java
+++ b/java/com.sap.sailing.domain/src/com/sap/sailing/domain/leaderboard/impl/LeaderboardTotalRankComparator.java
@@ -94,8 +94,10 @@ public class LeaderboardTotalRankComparator implements Comparator<Competitor> {
             this.discardedRaceColumnsPerCompetitor.put(competitor, discardedRaceColumns);
             for (RaceColumn raceColumn : raceColumnsToConsider) {
                 Pair<Competitor, RaceColumn> key = new Util.Pair<Competitor, RaceColumn>(competitor, raceColumn);
-                netPointsCache.put(key, leaderboard.getNetPoints(competitor, raceColumn, timePoint, discardedRaceColumns));
-                totalPointsCache.put(key, leaderboard.getTotalPoints(competitor, raceColumn, timePoint));
+                final Double totalPoints = leaderboard.getTotalPoints(competitor, raceColumn, timePoint);
+                netPointsCache.put(key, leaderboard.getNetPoints(competitor, raceColumn, timePoint, discardedRaceColumns,
+                        /* total points provider */ ()->totalPoints));
+                totalPointsCache.put(key, totalPoints);
             }
         }
     }