Initialization bugs with empty DeltaDiffCursor fixed

1 files changed, 16 insertions, 3 deletions

diff --git a/subprojects/store/src/main/java/tools/refinery/store/map/internal/DeltaDiffCursor.java b/subprojects/store/src/main/java/tools/refinery/store/map/internal/DeltaDiffCursor.java
index 49ea1f67..8ddca8ec 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/map/internal/DeltaDiffCursor.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/map/internal/DeltaDiffCursor.java
@@ -11,6 +11,7 @@ public class DeltaDiffCursor<K, V> implements DiffCursor<K, V> {
         final List<MapDelta<K, V>[]> backwardTransactions;
         final List<MapDelta<K, V>[]> forwardTransactions;
 
+        boolean started;
         /**
          * Denotes the direction of traversal. False means backwards, true means
          * forward.
@@ -35,6 +36,7 @@ public class DeltaDiffCursor<K, V> implements DiffCursor<K, V> {
                         direction = true;
                         listIndex = -1;
                 }
+                started = false;
         }
 
         protected MapDelta<K, V> getCurrentDelta() {
@@ -65,7 +67,10 @@ public class DeltaDiffCursor<K, V> implements DiffCursor<K, V> {
 
         @Override
         public boolean move() {
-                if (isTerminated()) {
+                if(!started) {
+                        started = true;
+                        return !isTerminated();
+                } else if (isTerminated()) {
                         return false;
                 } else {
                         if (this.direction) {
@@ -119,11 +124,19 @@ public class DeltaDiffCursor<K, V> implements DiffCursor<K, V> {
 
         @Override
         public V getFromValue() {
-                return getCurrentDelta().getOldValue();
+                if(this.direction) {
+                        return getCurrentDelta().getOldValue();
+                } else {
+                        return getCurrentDelta().getNewValue();
+                }
         }
 
         @Override
         public V getToValue() {
-                return getCurrentDelta().getNewValue();
+                if(this.direction) {
+                        return getCurrentDelta().getNewValue();
+                } else {
+                        return getCurrentDelta().getOldValue();
+                }
         }
 }