uk.ac.starlink.ttools.filter
Class QuantCalc

java.lang.Object
  extended by uk.ac.starlink.ttools.filter.QuantCalc

public abstract class QuantCalc
extends Object

Object for accumulating values in order to calculate quantiles.

Since:
2 May 2006
Author:
Mark Taylor

Constructor Summary
protected QuantCalc(Class clazz)
          Constructor.
 
Method Summary
abstract  void acceptDatum(Object obj)
          Submits a datum for accumulation.
static QuantCalc createInstance(Class clazz, long nrow)
          Factory method to create a quantile accumulator for a given row count and value class.
abstract  Number getQuantile(double quant)
          Returns a quantile corresponding to a given point.
abstract  void ready()
          Call this method after all acceptDatum(java.lang.Object) calls have been made and before any call to getQuantile(double).
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

QuantCalc

protected QuantCalc(Class clazz)
Constructor.

Parameters:
clazz - class of data objects which will be submitted; must be assignable from Number class
Method Detail

acceptDatum

public abstract void acceptDatum(Object obj)
Submits a datum for accumulation.

Parameters:
obj - data object - must be instance of numeric class suitable for this accumulator

ready

public abstract void ready()
Call this method after all acceptDatum(java.lang.Object) calls have been made and before any call to getQuantile(double).


getQuantile

public abstract Number getQuantile(double quant)
Returns a quantile corresponding to a given point.

Parameters:
quant - quant value between 0 and 1, for instance 0.5 indicates median

createInstance

public static QuantCalc createInstance(Class clazz,
                                       long nrow)
                                throws IOException
Factory method to create a quantile accumulator for a given row count and value class.

Parameters:
nrow - row count; may be -1 to indicate that the row count is unknown
clazz - class of data objects which will be submitted; must be assignable from Number.class.
Throws:
IOException


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