Interface ITimeSyncedIterator

src/query/expression/ITimeSyncedIterator.java:22–89

An interface for expressions or queries that operate across time series and require point-by-point timestamp synchronization. @since 2.3

 * @since 2.3
 */
public interface ITimeSyncedIterator {

  /** @return true if any of the series in the set has another value */
  public boolean hasNext();
  
  /**
   * @param timestamp The timestamp to fastforward to
   * @return The data point array for the given timestamp. Implementations
   * may throw an exception if the timestamp is invliad or they may return an
   * empty array.
   */
  public ExpressionDataPoint[] next(final long timestamp);
  
  /** 
   * Determines whether the individual series in the {@link values} array has 
   * another value. This may be used for non-synchronous iteration.
   * @param index The index of the series in the values array to check for
   * @return True if the series has another value, false if not
   */
  public boolean hasNext(final int index);
  
  /**
   * Fetches the next value for an individual series in the {@link values} array.
   * @param index The index of the series in the values array to advance
   */
  public void next(final int index);  
  
  /**
   * @return the next timestamp available in this set.
   */
  public long nextTimestamp();
  
  /** @return the number of series in this set */
  public int size();
  
  /** @return an array of the emitters populated during iteration */
  public ExpressionDataPoint[] values();

  /** @param index the index to null. Nulls the given object so we don't use it
   * in timestamps.
   */
  public void nullIterator(final int index);
  
  /** @return the index in the ExpressionIterator */
  public int getIndex();
  
  /** @param index the index in the ExpressionIterator */
  public void setIndex(final int index);
  
  /** @return the ID of this set given by the user */
  public String getId();

  /** @return a set of unique tag key UIDs from the filter list. If no filters
   * were defined then the set may be empty.  */
  public ByteSet getQueryTagKs();

  /** @param policy A fill policy for the iterator. Iterators should implement a default */
  public void setFillPolicy(final NumericFillPolicy policy);