org.jscience.linguistics.search
Class ShiftOrClasses

java.lang.Object
  org.jscience.linguistics.search.StringSearch
      org.jscience.linguistics.search.ShiftOr
          org.jscience.linguistics.search.ShiftOrClasses

public class ShiftOrClasses
extends ShiftOr

An implementation of the Shift-Or algorithm that supports character classes. The following character classes are supported:

x	a character from the Alphabet Σ
?	a "don't care" symbol which matches all symbols
[characters]	a class of characters where ranges (a-z, 0-9) are allowed
^	the negation of a class(^a, ^[abc], ^[c-h])
\	escapes the next character (\ must be written as \\ in Java).

Examples:

• mpeg will obviously match mpeg, and not mpag
• mp?g will match mpeg, mp7g, mpog, but not mpg (see ShiftOrWildcards)
• mp^ag will match mpeg, mpog, mpcg, but not mpag
• mpe^ will only match mpe^
• mp\^ag ("mp\\^ag" in Java) will match mp^ag, but not mpeg
• mp[aeiou]g will match mpeg, mpug, but not mptg
• mp^[a-k]g will match mpog, mpzg, but not mpeg
• mp[u-a]g will match mpeg, too
• mp^?g will match mpeg
• mp^[]g will match mpeg, too (negation of the empty class == all characters)

 Preprocessing: O(2n + ∑) time
 

 Searching    : O(mn / log n) (worst case and average)
 

See Also:

ShiftOr

Nested Class Summary

Nested classes/interfaces inherited from class org.jscience.linguistics.search.StringSearch

StringSearch.Dispatch, StringSearch.ReflectionDispatch

Field Summary

Fields inherited from class org.jscience.linguistics.search.StringSearch

activeDispatch, useNative

Constructor Summary

ShiftOrClasses()
Constructor for ShiftOrClasses.

Method Summary

java.lang.Object	processBytes(byte[] pattern) Pre-processing of the pattern.
java.lang.Object	processChars(char[] pattern) Pre-processing of the pattern.

Methods inherited from class org.jscience.linguistics.search.ShiftOr

searchBytes, searchChars

Methods inherited from class org.jscience.linguistics.search.StringSearch

createCharIntMap, createCharIntMap, equals, hashCode, index, processString, searchBytes, searchBytes, searchBytes, searchBytes, searchBytes, searchChars, searchChars, searchChars, searchChars, searchChars, searchString, searchString, searchString, searchString, searchString, searchString, toString, toStringBuffer, usesNative, usesReflection

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ShiftOrClasses

public ShiftOrClasses()

Constructor for ShiftOrClasses. Note that it is not required to create multiple instances.

Method Detail

processBytes

public java.lang.Object processBytes(byte[] pattern)

Description copied from class: ShiftOr

Pre-processing of the pattern. The pattern may not exceed 31 bytes in length. If it does, only it's first 31 bytes are processed which might lead to unexpected results. Returns an int array.

Overrides:

processBytes in class ShiftOr

Parameters:

pattern - the byte array containing the pattern, may not be null

Returns:

an Object

See Also:

ShiftOr.processBytes(byte[])

processChars

public java.lang.Object processChars(char[] pattern)

Description copied from class: ShiftOr

Pre-processing of the pattern. The pattern may not exceed 31 characters in length. If it does, only it's first 31 characters are processed which might lead to unexpected results. Returns a CharIntMap.

Overrides:

processChars in class ShiftOr

Parameters:

pattern - the pattern

Returns:

an Object

See Also:

ShiftOr.processChars(char[])