Class DataPointsIterator

src/core/DataPointsIterator.java:18–138

Default iterator for simple implementations of DataPoints.

/** Default iterator for simple implementations of {@link DataPoints}. */
final class DataPointsIterator implements SeekableView, DataPoint {

  /** Instance to iterate on. */
  private final DataPoints dp;

  /** Where are we in the iteration. */
  private short index = -1;

  /**
   * Ctor.
   * @param dp The data points to iterate on.
   */
  DataPointsIterator(final DataPoints dp) {
    this.dp = dp;
  }

  // ------------------ //
  // Iterator interface //
  // ------------------ //

  public boolean hasNext() {
    return index < dp.size() - 1;
  }

  public DataPoint next() {
    if (hasNext()) {
      index++;
      return this;
    }
    throw new NoSuchElementException("no more elements in " + this);
  }

  public void remove() {
    throw new UnsupportedOperationException();
  }

  // ---------------------- //
  // SeekableView interface //
  // ---------------------- //

  public void seek(final long timestamp) {
    if ((timestamp & 0xFFFFFFFF00000000L) != 0) {  // negative or not 32 bits
      throw new IllegalArgumentException("invalid timestamp: " + timestamp);
    }
    // Do a binary search to find the timestamp given or the one right before.
    short lo = 0;
    short hi = (short) dp.size();

    while (lo <= hi) {
      index = (short) ((lo + hi) >>> 1);
      long cmp = dp.timestamp(index) - timestamp;

      if (cmp < 0) {
        lo = (short) (index + 1);
      } else if (cmp > 0) {
        hi = (short) (index - 1);
      } else {
        index--;  // 'index' is exactly on the timestamp wanted.