X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fdatamodel%2Ffeatures%2FRangeComparator.java;fp=src%2Fjalview%2Fdatamodel%2Ffeatures%2FRangeComparator.java;h=26ffee1846edcec88888e4751fbdb0bede7f65d7;hb=2dd39c36211f947fda099c550e711ef5905efefd;hp=0000000000000000000000000000000000000000;hpb=4dd40d33a5becefd51c31a426f2501b21029f82c;p=jalview.git

diff --git a/src/jalview/datamodel/features/RangeComparator.java b/src/jalview/datamodel/features/RangeComparator.java
new file mode 100644
index 0000000..26ffee1
--- /dev/null
+++ b/src/jalview/datamodel/features/RangeComparator.java
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+package jalview.datamodel.features;
+
+import jalview.datamodel.ContiguousI;
+
+import java.util.Comparator;
+
+/**
+ * A comparator that orders ranges by either start position or end position
+ * ascending. If the position matches, ordering is resolved by end position (or
+ * start position).
+ * 
+ * @author gmcarstairs
+ *
+ */
+public class RangeComparator implements Comparator<ContiguousI>
+{
+  public static final Comparator<ContiguousI> BY_START_POSITION = new RangeComparator(
+          true);
+
+  public static final Comparator<ContiguousI> BY_END_POSITION = new RangeComparator(
+          false);
+
+  boolean byStart;
+
+  /**
+   * Constructor
+   * 
+   * @param byStartPosition
+   *          if true, order based on start position, if false by end position
+   */
+  RangeComparator(boolean byStartPosition)
+  {
+    byStart = byStartPosition;
+  }
+
+  @Override
+  public int compare(ContiguousI o1, ContiguousI o2)
+  {
+    int len1 = o1.getEnd() - o1.getBegin();
+    int len2 = o2.getEnd() - o2.getBegin();
+
+    if (byStart)
+    {
+      return compare(o1.getBegin(), o2.getBegin(), len1, len2);
+    }
+    else
+    {
+      return compare(o1.getEnd(), o2.getEnd(), len1, len2);
+    }
+  }
+
+  /**
+   * Compares two ranges for ordering
+   * 
+   * @param pos1
+   *          first range positional ordering criterion
+   * @param pos2
+   *          second range positional ordering criterion
+   * @param len1
+   *          first range length ordering criterion
+   * @param len2
+   *          second range length ordering criterion
+   * @return
+   */
+  public int compare(long pos1, long pos2, int len1, int len2)
+  {
+    int order = Long.compare(pos1, pos2);
+    if (order == 0)
+    {
+      /*
+       * if tied on position order, longer length sorts to left
+       * i.e. the negation of normal ordering by length
+       */
+      order = -Integer.compare(len1, len2);
+    }
+    return order;
+  }
+}