Merge branch 'feature/JAL-2759' into merge/JAL-2759_2104

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

diff --git a/src/jalview/datamodel/RangeElementsIterator.java b/src/jalview/datamodel/RangeElementsIterator.java
new file mode 100644 (file)
index 0000000..85272f2
--- /dev/null
+++ b/src/jalview/datamodel/RangeElementsIterator.java
@@ -0,0 +1,88 @@
+package jalview.datamodel;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+/**
+ * Iterator over each element in a set of ranges i.e. if ranges is {[3,6],
+ * [12,15]} it will iterate over {3,4,5,6,12,13,14,15}. Uses a local copy of the
+ * set of ranges.
+ * 
+ * @author kmourao
+ *
+ */
+public class RangeElementsIterator implements Iterator<Integer>
+{
+  private int last;
+
+  private int current;
+
+  private int next;
+
+  private Iterator<int[]> rangeIterator;
+
+  private int[] nextRange = null;
+
+  RangeElementsIterator(Iterator<int[]> it)
+  {
+    rangeIterator = it;
+    if (rangeIterator.hasNext())
+    {
+      nextRange = rangeIterator.next();
+      next = nextRange[0];
+      last = nextRange[1];
+    }
+  }
+
+  @Override
+  public boolean hasNext()
+  {
+    return rangeIterator.hasNext() || next <= last;
+  }
+
+  @Override
+  public Integer next()
+  {
+    if (!hasNext())
+    {
+      throw new NoSuchElementException();
+    }
+
+    current = next;
+
+    // recalculate next
+    next++;
+
+    // if there are more ranges need to check if next is in a range
+    checkNextRange();
+    return current;
+  }
+
+  /**
+   * Check how next position relates to next range, and update next position if
+   * necessary
+   */
+  private void checkNextRange()
+  {
+    if (nextRange != null && next > nextRange[1])
+    {
+      if (rangeIterator.hasNext())
+      {
+        nextRange = rangeIterator.next();
+        next = nextRange[0];
+        last = nextRange[1];
+      }
+      else
+      {
+        nextRange = null;
+      }
+
+    }
+  }
+
+  @Override
+  public void remove()
+  {
+    throw new UnsupportedOperationException();
+  }
+}