Package org.apache.lucene.misc.search

Class DocValuesStats<T>

java.lang.Object

org.apache.lucene.misc.search.DocValuesStats<T>

Direct Known Subclasses:

DocValuesStats.NumericDocValuesStats, DocValuesStats.SortedDocValuesStats, DocValuesStats.SortedNumericDocValuesStats, DocValuesStats.SortedSetDocValuesStats

public abstract class DocValuesStats<T>
extends Object

Holds statistics for a DocValues field.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	DocValuesStats.DoubleDocValuesStats	Holds DocValues statistics for a numeric field storing double values.
static final class	DocValuesStats.LongDocValuesStats	Holds DocValues statistics for a numeric field storing long values.
static class	DocValuesStats.NumericDocValuesStats<T extends Number>	Holds statistics for a numeric DocValues field.
static class	DocValuesStats.SortedDocValuesStats	Holds statistics for a sorted DocValues field.
static final class	DocValuesStats.SortedDoubleDocValuesStats	Holds DocValues statistics for a sorted-numeric field storing double values.
static final class	DocValuesStats.SortedLongDocValuesStats	Holds DocValues statistics for a sorted-numeric field storing long values.
static class	DocValuesStats.SortedNumericDocValuesStats<T extends Number>	Holds statistics for a sorted-numeric DocValues field.
static class	DocValuesStats.SortedSetDocValuesStats	Holds statistics for a sorted-set DocValues field.

Field Summary

Fields

Modifier and Type	Field	Description
protected int	count
protected final String	field
protected T	max
protected T	min
protected int	missing

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DocValuesStats(String field, T initialMin, T initialMax)

Method Summary

Modifier and Type	Method	Description
final int	count()	The number of documents which have a value of the field.
protected abstract void	doAccumulate(int count)	Called after accumulate(int) was processed and verified that the document has a value for the field.
final String	field()	The field for which these stats were computed.
protected abstract boolean	hasValue(int doc)	Returns whether the given document has a value for the requested DocValues field.
protected abstract boolean	init(LeafReaderContext context)	Initializes this object with the given reader context.
final T	max()	The maximum value of the field.
protected void	merge(DocValuesStats<T> other)	Merges the statistics from other into this instance.
final T	min()	The minimum value of the field.
final int	missing()	The number of documents which do not have a value of the field.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

missing

protected int missing

count

protected int count

field

protected final String field

min

protected T min

max

protected T max

Constructor Details

DocValuesStats

protected DocValuesStats(String field,
 T initialMin,
 T initialMax)

Method Details

doAccumulate

protected abstract void doAccumulate(int count)
                              throws IOException

Called after accumulate(int) was processed and verified that the document has a value for the field. Implementations should update the statistics based on the value of the current document.

Parameters:

count - the updated number of documents with value for this field.

Throws:

IOException

init

protected abstract boolean init(LeafReaderContext context)
                         throws IOException

Initializes this object with the given reader context. Returns whether stats can be computed for this segment (i.e. it does have the requested DocValues field).

Throws:

IOException

hasValue

protected abstract boolean hasValue(int doc)
                             throws IOException

Returns whether the given document has a value for the requested DocValues field.

Throws:

IOException

merge

protected void merge(DocValuesStats<T> other)

Merges the statistics from other into this instance. After the call, this instance reflects the combined statistics of both segments as if they had been collected together. Subclasses that track additional statistics (e.g. mean, variance, sum) must override this method, call super.merge(other), and combine their own fields accordingly.

Parameters:

other - the stats instance to merge into this one; must be of the same concrete type

field

public final String field()

The field for which these stats were computed.

count

public final int count()

The number of documents which have a value of the field.

missing

public final int missing()

The number of documents which do not have a value of the field.

min

public final T min()

The minimum value of the field. Undefined when count() is zero.

max

public final T max()

The maximum value of the field. Undefined when count() is zero.