Package com.atlassian.jira.search.utils

Class NumericUtils

java.lang.Object

com.atlassian.jira.search.utils.NumericUtils

@Internal
public class NumericUtils
extends Object

Utility class providing methods for numeric encoding and decoding, specifically porting functionality from Lucene 3.3.0's NumericUtils that was subsequently removed. This class primarily deals with prefix coding of long and double values into character arrays or strings, allowing for efficient storage and retrieval, particularly in Lucene indexes. Copied from lucene-extras

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BUF_SIZE_LONG	Expert: The maximum term length (used for char[] buffer size) for encoding long values.
static final char	SHIFT_START_LONG	Expert: Longs are stored at lower precision by shifting off lower bits.

Constructor Summary

Constructors

Constructor	Description
NumericUtils()

Method Summary

Modifier and Type	Method	Description
static String	doubleToPrefixCoded(double val)	Convenience method: this just returns: longToPrefixCoded(doubleToSortableLong(val))
static String	longToPrefixCoded(long val)	This is a convenience method, that returns prefix coded bits of a long without reducing the precision.
static String	longToPrefixCoded(long val, int shift)	Expert: Returns prefix coded bits after reducing the precision by shift bits.
static int	longToPrefixCoded(long val, int shift, char[] buffer)	Expert: Returns prefix coded bits after reducing the precision by shift bits.
static long	prefixCodedToLong(String prefixCoded)	Returns a long from prefixCoded characters.

Methods inherited from class java.lang.Object

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

Field Details

SHIFT_START_LONG

public static final char SHIFT_START_LONG

Expert: Longs are stored at lower precision by shifting off lower bits. The shift count is stored as SHIFT_START_LONG+shift in the first character

See Also:

• Constant Field Values

BUF_SIZE_LONG

public static final int BUF_SIZE_LONG

Expert: The maximum term length (used for char[] buffer size) for encoding long values.

See Also:

• longToPrefixCoded(long, int, char[])
• Constant Field Values

Constructor Details

NumericUtils

public NumericUtils()

Method Details

longToPrefixCoded

public static int longToPrefixCoded(long val,
 int shift,
 char[] buffer)

Expert: Returns prefix coded bits after reducing the precision by shift bits. This is method is used by NumericTokenStream.

Parameters:

val - the numeric value

shift - how many bits to strip from the right

buffer - that will contain the encoded chars, must be at least of BUF_SIZE_LONG length

Returns:

number of chars written to buffer

longToPrefixCoded

public static String longToPrefixCoded(long val,
 int shift)

Expert: Returns prefix coded bits after reducing the precision by shift bits. This is method is used by LongRangeBuilder.

Parameters:

val - the numeric value

shift - how many bits to strip from the right

longToPrefixCoded

public static String longToPrefixCoded(long val)

This is a convenience method, that returns prefix coded bits of a long without reducing the precision. It can be used to store the full precision value as a stored field in index.

To decode, use prefixCodedToLong(java.lang.String).

prefixCodedToLong

public static long prefixCodedToLong(String prefixCoded)

Returns a long from prefixCoded characters. Rightmost bits will be zero for lower precision codes. This method can be used to decode e.g. a stored field.

Throws:

NumberFormatException - if the supplied string is not correctly prefix encoded.

See Also:

• longToPrefixCoded(long)

doubleToPrefixCoded

public static String doubleToPrefixCoded(double val)

Convenience method: this just returns: longToPrefixCoded(doubleToSortableLong(val))