Bitap

java.lang.Object
- org.crosswire.common.diff.Bitap

All Implemented Interfaces:

Locator
```
public class Bitap
extends Object
implements Locator
```
An implementation of the Bitap algorithm for finding a "fuzzy" location of a match. Based on the LGPL Diff_Match_Patch v1.5 javascript of Neil Fraser, Copyright (C) 2006
http://neil.fraser.name/software/diff_match_patch/

Author:

DM Smith

See Also:
The GNU Lesser General Public License for details.

Field Summary

Fields
Modifier and Type	Field and Description
`private Map<Character,Integer>`	`alphabet` Alphabet is the compiled representation of the pattern.
`private static float`	`balance`
`private static float`	`BALANCE` Tweak the relative importance (0.0 = accuracy, 1.0 = proximity)
`private int`	`loc` The location in text to focus the search.
`private static int`	`MAXBITS` The maximum number of bits in an int.
`private static int`	`maxLength`
`private static int`	`MAXLENGTH`
`private static int`	`minLength`
`private static int`	`MINLENGTH` The min and max cutoffs used when computing text lengths.
`private String`	`pattern` The pattern to find in the text.
`private int`	`scoreTextLength` The length of the string constrained between MINLENGHT and MAXLENGTH
`private String`	`text` The text to search.
`private static float`	`threshold`
`private static float`	`THRESHOLD` At what point is no match declared (0.0 = perfection, 1.0 = very loose)

Constructor Summary

Constructors
Constructor and Description

Bitap(String text, String pattern, int loc)
Locate the best instance of 'pattern' in 'text' near 'loc'.

Constructors
Constructor and Description
`Bitap(String text, String pattern, int loc)` Locate the best instance of 'pattern' in 'text' near 'loc'.

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`alphabet()`
`private double`	`bitapScore(int e, int x)` Compute and return the score for a match with e errors and x location.
`protected Map<Character,Integer>`	`getAlphabet()`
`int`	`locate()` Locate the best match of a pattern in text near a supplied location.
`int`	`maxPatternLength()` The maximum length a pattern can be.
`static void`	`setBalance(float newBalance)`
`static void`	`setMaxLength(int newMaxLength)`
`static void`	`setMinLength(int newMinLength)`
`static void`	`setThreshold(float newThreshold)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - MAXBITS
```
private static final int MAXBITS
```
    The maximum number of bits in an int. Change this to 64 if long is used by alphabet.
    
    See Also:
    Constant Field Values
  - BALANCE
```
private static final float BALANCE
```
    Tweak the relative importance (0.0 = accuracy, 1.0 = proximity)
    
    See Also:
    Constant Field Values
  - balance
```
private static float balance
```
  - THRESHOLD
```
private static final float THRESHOLD
```
    At what point is no match declared (0.0 = perfection, 1.0 = very loose)
    
    See Also:
    Constant Field Values
  - threshold
```
private static float threshold
```
  - MINLENGTH
```
private static final int MINLENGTH
```
    The min and max cutoffs used when computing text lengths.
    
    See Also:
    Constant Field Values
  - minLength
```
private static int minLength
```
  - MAXLENGTH
```
private static final int MAXLENGTH
```
    See Also:
    Constant Field Values
  - maxLength
```
private static int maxLength
```
  - text
```
private String text
```
    The text to search.
  - pattern
```
private String pattern
```
    The pattern to find in the text.
  - loc
```
private int loc
```
    The location in text to focus the search.
  - scoreTextLength
```
private int scoreTextLength
```
    The length of the string constrained between MINLENGHT and MAXLENGTH
  - alphabet
```
private Map<Character,Integer> alphabet
```
    Alphabet is the compiled representation of the pattern.
- Constructor Detail
  - Bitap
```
public Bitap(String text,
     String pattern,
     int loc)
```
    Locate the best instance of 'pattern' in 'text' near 'loc'.
    
    Parameters:
    text - The text to search
    pattern - The pattern to search for
    loc - The location to search around
- Method Detail
  - maxPatternLength
```
public int maxPatternLength()
```
    Description copied from interface: Locator
    
    The maximum length a pattern can be.
    
    Specified by:
    
    maxPatternLength in interface Locator
    
    Returns:
    maximum pattern length.
  - locate
```
public int locate()
```
    Description copied from interface: Locator
    
    Locate the best match of a pattern in text near a supplied location.
    
    Specified by:
    
    locate in interface Locator
    
    Returns:
    Best match index or -1, if no match found
  - getAlphabet
```
protected Map<Character,Integer> getAlphabet()
```
  - bitapScore
```
private double bitapScore(int e,
                int x)
```
    Compute and return the score for a match with e errors and x location.
    
    Parameters:
    e - Number of errors in match
    x - Location of match
    
    Returns:
    Overall score for match
  - alphabet
```
protected void alphabet()
```
  - setBalance
```
public static void setBalance(float newBalance)
```
  - setThreshold
```
public static void setThreshold(float newThreshold)
```
  - setMinLength
```
public static void setMinLength(int newMinLength)
```
  - setMaxLength
```
public static void setMaxLength(int newMaxLength)
```

Class Bitap

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MAXBITS

BALANCE

balance

THRESHOLD

threshold

MINLENGTH

minLength

MAXLENGTH

maxLength

text

pattern

loc

scoreTextLength

alphabet

Constructor Detail

Bitap

Method Detail

maxPatternLength

locate

getAlphabet

bitapScore

alphabet

setBalance

setThreshold

setMinLength

setMaxLength