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java.lang.Objectnet.sf.jagg.Aggregator
net.sf.jagg.AbstractVarianceAggregator
public abstract class AbstractVarianceAggregator
This abstract class represents variance-like aggregator calculations over numeric values.
Field Summary | |
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protected long |
myCount
A running count of items processed so far for the given property. |
protected DoubleDouble |
mySum
A running total of items processed so far for the given property. |
protected DoubleDouble |
myVarNumerator
A running total of the variance, before it is divided by the denominator in the variance calculation. |
Fields inherited from class net.sf.jagg.Aggregator |
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PROP_SELF |
Constructor Summary | |
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AbstractVarianceAggregator(java.lang.String property)
Constructs an VarianceAggregator that operates on the specified
property. |
Method Summary | |
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void |
init()
Initialize the sum and count to zero. |
void |
iterate(java.lang.Object value)
If the property is non-null, then count it and add the property value to the sum. |
void |
merge(Aggregator agg)
Merge the given Aggregator into this one. |
abstract DoubleDouble |
terminateDoubleDouble()
Return the result as a DoubleDouble . |
Methods inherited from class net.sf.jagg.Aggregator |
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equals, getAggregator, getAggregator, getProperty, getValueFromProperty, hashCode, isInUse, replicate, setInUse, setProperty, terminate, toString |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Field Detail |
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protected long myCount
protected DoubleDouble mySum
protected DoubleDouble myVarNumerator
Constructor Detail |
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public AbstractVarianceAggregator(java.lang.String property)
VarianceAggregator
that operates on the specified
property.
property
- Calculate the variance of this property's values.Method Detail |
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public void init()
init
in class Aggregator
public void iterate(java.lang.Object value)
iterate
in class Aggregator
value
- The value to aggregate.Aggregator.getValueFromProperty(java.lang.Object, java.lang.String)
public void merge(Aggregator agg)
Aggregator
into this one. Add the
respective sums and counts together. Update the variance numerator.
merge
in class Aggregator
agg
- The Aggregator
to merge into this one.public abstract DoubleDouble terminateDoubleDouble()
DoubleDouble
. This is used mainly
when other Aggregators
that use this result must maintain a
high precision.
terminateDoubleDouble
in class Aggregator
DoubleDouble
representing the result of the
aggregation.DoubleDouble
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