/// <param name="key">
/// the key is expected to be a Text object, whose prefix indicates
/// the type of aggregation to aggregate the values. In effect, data
/// driven computing is achieved. It is assumed that each aggregator's
/// getReport method emits appropriate output for the aggregator. This
/// may be further customiized.
/// </param>
/// <param name="values">the values to be aggregated</param>
/// <exception cref="System.IO.IOException"/>
public override void Reduce(Text key, IEnumerator <Text> values, OutputCollector <Text
, Text> output, Reporter reporter)
{
string keyStr = key.ToString();
int pos = keyStr.IndexOf(ValueAggregatorDescriptor.TypeSeparator);
string type = Sharpen.Runtime.Substring(keyStr, 0, pos);
keyStr = Sharpen.Runtime.Substring(keyStr, pos + ValueAggregatorDescriptor.TypeSeparator
.Length);
ValueAggregator aggregator = ValueAggregatorBaseDescriptor.GenerateValueAggregator
(type);
while (values.HasNext())
{
aggregator.AddNextValue(values.Next());
}
string val = aggregator.GetReport();
key = new Text(keyStr);
output.Collect(key, new Text(val));
}
/// <param name="key">
/// the key is expected to be a Text object, whose prefix indicates
/// the type of aggregation to aggregate the values. In effect, data
/// driven computing is achieved. It is assumed that each aggregator's
/// getReport method emits appropriate output for the aggregator. This
/// may be further customized.
/// </param>
/// <param name="values">the values to be aggregated</param>
/// <param name="context"></param>
/// <exception cref="System.IO.IOException"/>
/// <exception cref="System.Exception"/>
protected internal override void Reduce(Text key, IEnumerable <Text> values, Reducer.Context
context)
{
string keyStr = key.ToString();
int pos = keyStr.IndexOf(ValueAggregatorDescriptor.TypeSeparator);
string type = Sharpen.Runtime.Substring(keyStr, 0, pos);
keyStr = Sharpen.Runtime.Substring(keyStr, pos + ValueAggregatorDescriptor.TypeSeparator
.Length);
long uniqCount = context.GetConfiguration().GetLong(UniqValueCount.MaxNumUniqueValues
, long.MaxValue);
ValueAggregator aggregator = ValueAggregatorBaseDescriptor.GenerateValueAggregator
(type, uniqCount);
foreach (Text value in values)
{
aggregator.AddNextValue(value);
}
string val = aggregator.GetReport();
key = new Text(keyStr);
context.Write(key, new Text(val));
}
