/// <summary>
/// Aggregate the results of the parallel aggregations.
/// </summary>
/// <param name="results">
/// Results to aggregate.
/// </param>
/// <returns>
/// The aggregation of the parallel aggregation results.
/// </returns>
public virtual object AggregateResults(ICollection results)
{
IParallelAwareAggregator aggregator = (IParallelAwareAggregator)m_aggregator;
IDictionary dictionaryResult = new HashDictionary();
foreach (IDictionary dictPart in results)
{
// partial aggregation results are maps with distinct values
// as keys and partial aggregation results as values
foreach (DictionaryEntry entry in dictPart)
{
object distinct = entry.Key;
object result = entry.Value;
// collect all the aggregation results per group
ICollection group = (ICollection)dictionaryResult[distinct];
if (group == null)
{
dictionaryResult.Add(distinct, group = new ArrayList());
}
CollectionUtils.Add(group, result);
}
}
IDictionary newResult = new HashDictionary(dictionaryResult);
if (dictionaryResult.Count == 0)
{
// we need to call "AggregateResults" on the underlying
// aggregator to fulfill our contract, even though any result
// will be discarded
aggregator.AggregateResults(NullImplementation.GetCollection());
}
else
{
IFilter filter = m_filter;
foreach (DictionaryEntry entry in dictionaryResult)
{
ICollection group = (ICollection)entry.Value;
object result = aggregator.AggregateResults(group);
if (filter == null || filter.Evaluate(result))
{
newResult[entry.Key] = result;
}
else
{
newResult.Remove(entry.Key);
}
}
}
return(newResult);
}
/// <summary>
/// Construct a PriorityAggregator.
/// </summary>
/// <param name="aggregator">
/// The <see cref="IParallelAwareAggregator"/> wrapped by this
/// PriorityAggregator.
/// </param>
public PriorityAggregator(IParallelAwareAggregator aggregator)
{
m_aggregator = aggregator;
}
/// <summary>
/// Construct a Parallel aggregator based on a specified
/// <b>IValueExtractor</b> and underlying
/// <b>IParallelAwareAggregator</b>.
/// </summary>
/// <param name="extractor">
/// An <b>IValueExtractor</b> object; may not be <c>null</c>.
/// </param>
/// <param name="aggregator">
/// An <b>IEntryAggregator</b> object; may not be <c>null</c>.
/// </param>
/// <param name="filter">
/// An <b>IFilter</b> object.
/// </param>
protected internal Parallel(IValueExtractor extractor, IParallelAwareAggregator aggregator, IFilter filter)
: base(extractor, aggregator, filter)
{
}
