-
- class BoundedVisRegionIterator implements Iterator<int[]>
- {
- private int start; // start position to iterate from
-
- private int end; // end position to iterate to
-
- // current region in visColumns
- private int[] currentRegion;
-
- // current index in visColumns
- private int currentPosition = 0;
-
- private List<int[]> vcontigs = null;
-
- /**
- * Construct an iterator over visibleColumn regions bounded at
- * [lowerBound,upperBound]
- *
- * @param lowerBound
- * lower bound to iterate from
- * @param upperBound
- * upper bound to iterate to
- * @param useCopyCols
- * whether to make a local copy for iteration (set to true if
- * calling from outwith the HiddenColumns class)
- */
- BoundedVisRegionIterator(int lowerBound, int upperBound,
- boolean useCopy)
- {
- try
- {
- start = lowerBound;
- end = upperBound;
-
- if (useCopy)
- {
- // assume that if useCopy is false the calling code has locked
- // hiddenColumns
- LOCK.readLock().lock();
- }
-
- int visStart = start;
-
- if (hiddenColumns != null)
- {
- vcontigs = new ArrayList<>(hiddenColumns.size() + 1);
-
- // navigate to start, keeping count of hidden columns
- int i = 0;
- int[] region = null;
- while ((i < hiddenColumns.size())
- && (hiddenColumns.get(i)[0] <= start))
- {
- i++;
- }
- // if there was a hidden region before (i>=1), and it ended after
- // start
- // and before end, adjust visStart to be just after that region
- if (i > 0)
- {
- region = hiddenColumns.get(i - 1);
- if ((region[1] > start) && (region[1] < end))
- {
- visStart = region[1] + 1;
- }
- else if (region[1] >= end)
- {
- // previous hidden region covers whole range [start,end]
- // early exit - vcontigs is empty
- return;
- }
- }
-
- // iterate from start to end, adding start positions of each
- // hidden region. Positions are visible columns count, not absolute
- while (i < hiddenColumns.size()
- && (hiddenColumns.get(i)[0] < end))
- {
- region = hiddenColumns.get(i);
- int[] prevVisibleRegion = new int[] { visStart, region[0] - 1 };
- vcontigs.add(prevVisibleRegion);
- visStart = region[1] + 1;
- i++;
- }
- // add on a final visible region if needed
- if (visStart <= end)
- {
- int[] lastRegion = new int[] { visStart, end };
- vcontigs.add(lastRegion);
- }
- }
- else
- {
- vcontigs = new ArrayList<>();
- int[] lastRegion = new int[] { start, end };
- vcontigs.add(lastRegion);
- }
- } finally
- {
- if (useCopy)
- {
- LOCK.readLock().unlock();
- }
- }
- }
-
- @Override
- public boolean hasNext()
- {
- return (currentPosition < vcontigs.size());
- }
-
- @Override
- public int[] next()
- {
- currentRegion = vcontigs.get(currentPosition);
- currentPosition++;
- return currentRegion;
- }
- }