JAL-2759 First pass instantiate hiddenColumns collection in constructor

[jalview.git] / src / jalview / datamodel / HiddenColumnsCursor.java

diff --git a/src/jalview/datamodel/HiddenColumnsCursor.java b/src/jalview/datamodel/HiddenColumnsCursor.java
index 0fef622..a875f87 100644 (file)
--- a/src/jalview/datamodel/HiddenColumnsCursor.java
+++ b/src/jalview/datamodel/HiddenColumnsCursor.java
@@ -20,6 +20,7 @@
  */
 package jalview.datamodel;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -28,7 +29,7 @@ public class HiddenColumnsCursor
   // absolute position of first hidden column
   private int firstColumn;
 
-  private List<int[]> hiddenColumns;
+  private List<int[]> hiddenColumns = new ArrayList<>();
 
   // AtomicReference to hold the current region index and hidden column count
   // Could be done with synchronisation but benchmarking shows this way is 2x
@@ -70,7 +71,7 @@ public class HiddenColumnsCursor
           int hiddencount)
   {
     hiddenColumns = hiddenCols;
-    if ((hiddenCols != null) && (!hiddenCols.isEmpty()))
+    if (!hiddenCols.isEmpty())
     {
       firstColumn = hiddenColumns.get(0)[0];
       HiddenCursorPosition oldpos = cursorPos.get();
@@ -93,7 +94,7 @@ public class HiddenColumnsCursor
   protected void updateForDeletedRegion(List<int[]> hiddenCols)
   {
 
-    if ((hiddenCols != null) && (!hiddenCols.isEmpty()))
+    if (!hiddenCols.isEmpty())
     {
       // if there is a region to the right of the current region,
       // nothing changes; otherwise
@@ -130,7 +131,7 @@ public class HiddenColumnsCursor
    */
   protected HiddenCursorPosition findRegionForColumn(int column)
   {
-    if (hiddenColumns == null)
+    if (hiddenColumns.isEmpty())
     {
       return null;
     }
@@ -202,7 +203,7 @@ public class HiddenColumnsCursor
    */
   protected HiddenCursorPosition findRegionForVisColumn(int column)
   {
-    if (hiddenColumns == null)
+    if (hiddenColumns.isEmpty())
     {
       return null;
     }