com.google.gwt.dev.util.editdistance

Class CharIndex.Masked

java.lang.Object

com.google.gwt.dev.util.editdistance.CharIndex

com.google.gwt.dev.util.editdistance.CharIndex.Masked

Enclosing class:

CharIndex

public static class CharIndex.Masked
extends CharIndex

An index based on a simple mask: index(c) = (c & MASK). This allows for a very fast index function for many languages outside of the ASCII spectrum. Most languages fit in a single 8-bit Unicode slice. Even languages that cross slices for special characters (such as extended Latin) often have no collisions under simple masking.

Nested Class Summary

Nested classes/interfaces inherited from class com.google.gwt.dev.util.editdistance.CharIndex

CharIndex.FullHash, CharIndex.Masked, CharIndex.Straight

Method Summary

Methods

Modifier and Type	Method and Description
int	lookup(char c) Returns the index (mapping result) for a given character.
int[]	map(CharSequence s, int[] mapped) Performs lookups on an entire sequence of characters.
int	nullElement() Returns an index that is not used for any character in the alphabet.
int	size() Returns the maximum index result that can be returned by the lookup function (including the nullElement result if applicable).

Methods inherited from class com.google.gwt.dev.util.editdistance.CharIndex

getInstance

Methods inherited from class java.lang.Object

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

Method Detail

lookup

public int lookup(char c)

Description copied from class: CharIndex

Returns the index (mapping result) for a given character. If the character is present in the alphabet, then a unique index is returned; other characters may be mapped to unique values, *or* may be mapped to a shared nullElement value.

Specified by:

lookup in class CharIndex

Parameters:

c - character for which an index is sought

Returns:

an integer index for the character

map

public int[] map(CharSequence s,
        int[] mapped)

Description copied from class: CharIndex

Performs lookups on an entire sequence of characters. This allows an entire string to be mapped with fewer method invocations, and possibly with some added internal efficiencies.

Specified by:

map in class CharIndex

Parameters:

s - character sequence to be indexed

mapped - array for storing results

Returns:

an array of indices for the character sequence, either the mapped parameter or a larger newly-allocated array if required

nullElement

public int nullElement()

Description copied from class: CharIndex

Returns an index that is not used for any character in the alphabet. This index *may* be returned for characters not in the alphabet.

Specified by:

nullElement in class CharIndex

Returns:

an index not used for a valid character

size

public int size()

Description copied from class: CharIndex

Returns the maximum index result that can be returned by the lookup function (including the nullElement result if applicable). No negative values are ever returned from lookup.

Specified by:

size in class CharIndex

Returns:

maximum index returned from any lookup