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java.lang.Objectnet.sf.jagg.Aggregation
public class Aggregation
The Aggregation
class performs the actual aggregation
operations. It contains a Builder
class that, following the
Builder Pattern, builds a Aggregation
object that can be used
for the actual aggregation calculations.
Nested Class Summary | |
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static class |
Aggregation.Builder
This Builder class follows the "Builder" pattern to create
an Aggregation object. |
Method Summary | ||
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|
groupBy(java.util.List<T> values)
Perform one or more aggregate operations on a List<T> . |
|
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groupByComparable(java.util.List<T> values)
Perform one or more aggregate operations on a List<T> . |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Method Detail |
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public <T extends java.lang.Comparable<? super T>> java.util.List<AggregateValue<T>> groupByComparable(java.util.List<T> values)
List<T>
.
T
should have a "natural ordering", that is, it must be
Comparable
, and compareTo
defines the
properties with which to "group by" with its consideration of different
properties to determine order. This sorts a copy of the list of values,
based how the objects' compareTo
method compares them.
T
- The object type to aggregate, which must be
Comparable
.values
- The List<T>
of objects to aggregate.
List<AggregateValue<T>>
.public <T> java.util.List<AggregateValue<T>> groupBy(java.util.List<T> values)
List<T>
.
T
does not need to be Comparable
. This
operates on a copy of the list of values, either sorted based on the
"group by" properties (if any), or grouped into equivalence classes using
multiset discrimination.
T
- The object type to aggregate.values
- The List<T>
of objects to aggregate.
List<AggregateValue<T>>
.
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