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package org.openjdk.btrace.core.aggregation;

/**
 * An element of aggregated data stored in an {@link Aggregation}.
 *
 * <p>Concrete implementations of this interface will implement different aggregating functions.
 *
 * <p>
 *
 * @author Christian Glencross
 */
public interface AggregationValue {

  /**
   * Adds a data item to the aggregated value.
   *
   * @param data the data value
   */
  void add(long data);

  /** Removes all data items previously added. */
  void clear();

  /**
   * @return the aggregated value of all data items added since the aggregation was created or last
   *     cleared. The aggregation function is determined by the concrete implementation of the
   *     interface.
   */
  long getValue();

  /**
   * @return an object representation of the aggregated value. For most implementations this may be
   *     equivalent to <code>Integer.valueOf( getValue() )</code>. More complex aggregations such
   *     may return objects representing histograms, etc.
   */
  Object getData();
}
