From 9e064d395de4746f14106c1c296bc94696a6190e Mon Sep 17 00:00:00 2001
From: kiramt <k.mourao@dundee.ac.uk>
Date: Mon, 29 Jan 2018 12:00:35 +0000
Subject: [PATCH] JAL-2759 numColumns reset

---
 src/jalview/datamodel/HiddenColumns.java |   28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/jalview/datamodel/HiddenColumns.java b/src/jalview/datamodel/HiddenColumns.java
index 402ea25..9a8669f 100644
--- a/src/jalview/datamodel/HiddenColumns.java
+++ b/src/jalview/datamodel/HiddenColumns.java
@@ -66,6 +66,9 @@ public class HiddenColumns
 {
   private static final int HASH_MULTIPLIER = 31;
 
+  private static final int NUMCOLUMNS_RESET = -1; // value of numColumns if it
+                                                  // needs to be recalculated
+
   private static final ReentrantReadWriteLock LOCK = new ReentrantReadWriteLock();
 
   /*
@@ -212,7 +215,7 @@ public class HiddenColumns
               prevHiddenCount);
 
       // reset the number of columns so they will be recounted
-      numColumns = 0;
+      resetNumColumns();
 
     } finally
     {
@@ -303,7 +306,7 @@ public class HiddenColumns
         hideColumns(r[0], r[1]);
       }
       cursor = new HiddenColumnsCursor(hiddenColumns);
-      numColumns = 0;
+      resetNumColumns();
     } finally
     {
       LOCK.writeLock().unlock();
@@ -328,7 +331,7 @@ public class HiddenColumns
       }
       hiddenColumns.clear();
       cursor = new HiddenColumnsCursor(hiddenColumns);
-      numColumns = 0;
+      resetNumColumns();
 
     } finally
     {
@@ -372,7 +375,7 @@ public class HiddenColumns
 
             if (hiddenColumns.isEmpty())
             {
-              numColumns = 0;
+              resetNumColumns();
             }
             else
             {
@@ -438,7 +441,7 @@ public class HiddenColumns
     {
       LOCK.readLock().lock();
 
-      if (numColumns == 0)
+      if (numColumns == NUMCOLUMNS_RESET)
       {
         // numColumns is out of date, so recalculate
         int size = 0;
@@ -459,6 +462,17 @@ public class HiddenColumns
   }
 
   /**
+   * Reset numColumns so that it gets recalculated. Currently the code does not
+   * recalculate numColumns on hide/reveal as it requires a full sweep of the
+   * hidden columns collection / smarter updating. Placeholder here if later on
+   * a recalculation is added.
+   */
+  private void resetNumColumns()
+  {
+    numColumns = NUMCOLUMNS_RESET;
+  }
+
+  /**
    * Get the number of distinct hidden regions
    * 
    * @return number of regions
@@ -783,7 +797,7 @@ public class HiddenColumns
         hideColumns(firstSet, lastSet - 1);
       }
       cursor = new HiddenColumnsCursor(hiddenColumns);
-      numColumns = 0;
+      resetNumColumns();
     } finally
     {
       LOCK.writeLock().unlock();
@@ -867,7 +881,7 @@ public class HiddenColumns
 
         hiddenColumns.subList(startindex, endindex + 1).clear();
         cursor = new HiddenColumnsCursor(hiddenColumns);
-        numColumns = 0;
+        resetNumColumns();
       }
     } finally
     {
-- 
1.7.10.2