接口 org.apache.hadoop.mapred.lib.aggregate.ValueAggregator
的使用

使用ValueAggregator的程序包

程序包	说明
org.apache.hadoop.mapred.lib.aggregate	Classes for performing various counting and aggregations.

org.apache.hadoop.mapred.lib.aggregate中ValueAggregator的使用

实现ValueAggregator的org.apache.hadoop.mapred.lib.aggregate中的类

限定符和类型	类和说明
class	DoubleValueSum This class implements a value aggregator that sums up a sequence of double values.
class	LongValueMax This class implements a value aggregator that maintain the maximum of a sequence of long values.
class	LongValueMin This class implements a value aggregator that maintain the minimum of a sequence of long values.
class	LongValueSum This class implements a value aggregator that sums up a sequence of long values.
class	StringValueMax This class implements a value aggregator that maintain the biggest of a sequence of strings.
class	StringValueMin This class implements a value aggregator that maintain the smallest of a sequence of strings.
class	UniqValueCount This class implements a value aggregator that dedupes a sequence of objects.
class	ValueHistogram This class implements a value aggregator that computes the histogram of a sequence of strings.

返回ValueAggregator的org.apache.hadoop.mapred.lib.aggregate中的方法

限定符和类型	方法和说明
static ValueAggregator	ValueAggregatorBaseDescriptor.generateValueAggregator(String type)