org.apache.lucene.analysis.reverse
Class ReverseStringFilter

java.lang.Object
  extended by org.apache.lucene.util.AttributeSource
      extended by org.apache.lucene.analysis.TokenStream
          extended by org.apache.lucene.analysis.TokenFilter
              extended by org.apache.lucene.analysis.reverse.ReverseStringFilter
All Implemented Interfaces:
Closeable

public final class ReverseStringFilter
extends org.apache.lucene.analysis.TokenFilter

Reverse token string, for example "country" => "yrtnuoc".

If marker is supplied, then tokens will be also prepended by that character. For example, with a marker of \u0001, "country" => "\u0001yrtnuoc". This is useful when implementing efficient leading wildcards search.


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
org.apache.lucene.util.AttributeSource.AttributeFactory, org.apache.lucene.util.AttributeSource.State
 
Field Summary
static char INFORMATION_SEPARATOR_MARKER
          Example marker character: U+001F (INFORMATION SEPARATOR ONE)
static char PUA_EC00_MARKER
          Example marker character: U+EC00 (PRIVATE USE AREA: EC00)
static char RTL_DIRECTION_MARKER
          Example marker character: U+200F (RIGHT-TO-LEFT MARK)
static char START_OF_HEADING_MARKER
          Example marker character: U+0001 (START OF HEADING)
 
Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
 
Constructor Summary
ReverseStringFilter(org.apache.lucene.analysis.TokenStream in)
          Create a new ReverseStringFilter that reverses all tokens in the supplied TokenStream.
ReverseStringFilter(org.apache.lucene.analysis.TokenStream in, char marker)
          Create a new ReverseStringFilter that reverses and marks all tokens in the supplied TokenStream.
 
Method Summary
 boolean incrementToken()
           
static void reverse(char[] buffer)
           
static void reverse(char[] buffer, int len)
           
static void reverse(char[] buffer, int start, int len)
           
static String reverse(String input)
           
 
Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end, reset
 
Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, restoreState, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

START_OF_HEADING_MARKER

public static final char START_OF_HEADING_MARKER
Example marker character: U+0001 (START OF HEADING)

See Also:
Constant Field Values

INFORMATION_SEPARATOR_MARKER

public static final char INFORMATION_SEPARATOR_MARKER
Example marker character: U+001F (INFORMATION SEPARATOR ONE)

See Also:
Constant Field Values

PUA_EC00_MARKER

public static final char PUA_EC00_MARKER
Example marker character: U+EC00 (PRIVATE USE AREA: EC00)

See Also:
Constant Field Values

RTL_DIRECTION_MARKER

public static final char RTL_DIRECTION_MARKER
Example marker character: U+200F (RIGHT-TO-LEFT MARK)

See Also:
Constant Field Values
Constructor Detail

ReverseStringFilter

public ReverseStringFilter(org.apache.lucene.analysis.TokenStream in)
Create a new ReverseStringFilter that reverses all tokens in the supplied TokenStream.

The reversed tokens will not be marked.

Parameters:
in - TokenStream to filter

ReverseStringFilter

public ReverseStringFilter(org.apache.lucene.analysis.TokenStream in,
                           char marker)
Create a new ReverseStringFilter that reverses and marks all tokens in the supplied TokenStream.

The reversed tokens will be prepended (marked) by the marker character.

Parameters:
in - TokenStream to filter
marker - A character used to mark reversed tokens
Method Detail

incrementToken

public boolean incrementToken()
                       throws IOException
Specified by:
incrementToken in class org.apache.lucene.analysis.TokenStream
Throws:
IOException

reverse

public static String reverse(String input)

reverse

public static void reverse(char[] buffer)

reverse

public static void reverse(char[] buffer,
                           int len)

reverse

public static void reverse(char[] buffer,
                           int start,
                           int len)


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