JAL-2850 MapList.isToForwardStrand added

[jalview.git] / src / jalview / util / MapList.java

diff --git a/src/jalview/util/MapList.java b/src/jalview/util/MapList.java
index 3ce0bb3..c944345 100644 (file)
--- a/src/jalview/util/MapList.java
+++ b/src/jalview/util/MapList.java
@@ -77,8 +77,8 @@ public class MapList
    */
   public MapList()
   {
-    fromShifts = new ArrayList<int[]>();
-    toShifts = new ArrayList<int[]>();
+    fromShifts = new ArrayList<>();
+    toShifts = new ArrayList<>();
   }
 
   /**
@@ -347,7 +347,7 @@ public class MapList
     }
 
     boolean changed = false;
-    List<int[]> merged = new ArrayList<int[]>();
+    List<int[]> merged = new ArrayList<>();
     int[] lastRange = ranges.get(0);
     int lastDirection = lastRange[1] >= lastRange[0] ? 1 : -1;
     lastRange = new int[] { lastRange[0], lastRange[1] };
@@ -803,7 +803,7 @@ public class MapList
     {
       return null;
     }
-    List<int[]> ranges = new ArrayList<int[]>();
+    List<int[]> ranges = new ArrayList<>();
     if (fs <= fe)
     {
       intv = fs;
@@ -1094,8 +1094,33 @@ public class MapList
    */
   public boolean isFromForwardStrand()
   {
+    return isForwardStrand(getFromRanges());
+  }
+
+  /**
+   * Returns true if mapping is to forward strand, false if to reverse strand.
+   * Result is just based on the first 'to' range that is not a single position.
+   * Default is true unless proven to be false. Behaviour is not well defined if
+   * the mapping has a mixture of forward and reverse ranges.
+   * 
+   * @return
+   */
+  public boolean isToForwardStrand()
+  {
+    return isForwardStrand(getToRanges());
+  }
+
+  /**
+   * A helper method that returns true unless at least one range has start > end.
+   * Behaviour is undefined for a mixture of forward and reverse ranges.
+   * 
+   * @param ranges
+   * @return
+   */
+  private boolean isForwardStrand(List<int[]> ranges)
+  {
     boolean forwardStrand = true;
-    for (int[] range : getFromRanges())
+    for (int[] range : ranges)
     {
       if (range[1] > range[0])
       {