public final class ReverseStringFilter extends TokenFilter
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.
AttributeSource.State
Modifier and Type | Field and Description |
---|---|
static char |
INFORMATION_SEPARATOR_MARKER
Example marker character: U+001F (INFORMATION SEPARATOR ONE)
|
private char |
marker |
private static char |
NOMARKER |
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)
|
private CharTermAttribute |
termAtt |
input
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
Constructor and Description |
---|
ReverseStringFilter(TokenStream in)
Create a new ReverseStringFilter that reverses all tokens in the
supplied
TokenStream . |
ReverseStringFilter(TokenStream in,
char marker)
Create a new ReverseStringFilter that reverses and marks all tokens in the
supplied
TokenStream . |
Modifier and Type | Method and Description |
---|---|
boolean |
incrementToken()
Consumers (i.e.,
IndexWriter ) use this method to advance the stream to
the next token. |
static void |
reverse(char[] buffer)
Reverses the given input buffer in-place
|
static void |
reverse(char[] buffer,
int len)
Partially reverses the given input buffer in-place from offset 0
up to the given length.
|
static void |
reverse(char[] buffer,
int start,
int len)
Partially reverses the given input buffer in-place from the given offset
up to the given length.
|
static java.lang.String |
reverse(java.lang.String input)
Reverses the given input string
|
close, end, reset
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
private final CharTermAttribute termAtt
private final char marker
private static final char NOMARKER
public static final char START_OF_HEADING_MARKER
public static final char INFORMATION_SEPARATOR_MARKER
public static final char PUA_EC00_MARKER
public static final char RTL_DIRECTION_MARKER
public ReverseStringFilter(TokenStream in)
TokenStream
.
The reversed tokens will not be marked.
in
- TokenStream
to filterpublic ReverseStringFilter(TokenStream in, char marker)
TokenStream
.
The reversed tokens will be prepended (marked) by the marker
character.
in
- TokenStream
to filtermarker
- A character used to mark reversed tokenspublic boolean incrementToken() throws java.io.IOException
TokenStream
IndexWriter
) use this method to advance the stream to
the next token. Implementing classes must implement this method and update
the appropriate AttributeImpl
s with the attributes of the next
token.
The producer must make no assumptions about the attributes after the method
has been returned: the caller may arbitrarily change it. If the producer
needs to preserve the state for subsequent calls, it can use
AttributeSource.captureState()
to create a copy of the current attribute state.
This method is called for every token of a document, so an efficient
implementation is crucial for good performance. To avoid calls to
AttributeSource.addAttribute(Class)
and AttributeSource.getAttribute(Class)
,
references to all AttributeImpl
s that this stream uses should be
retrieved during instantiation.
To ensure that filters and consumers know which attributes are available,
the attributes must be added during instantiation. Filters and consumers
are not required to check for availability of attributes in
TokenStream.incrementToken()
.
incrementToken
in class TokenStream
java.io.IOException
public static java.lang.String reverse(java.lang.String input)
input
- the string to reversepublic static void reverse(char[] buffer)
buffer
- the input char array to reversepublic static void reverse(char[] buffer, int len)
buffer
- the input char array to reverselen
- the length in the buffer up to where the
buffer should be reversedpublic static void reverse(char[] buffer, int start, int len)
buffer
- the input char array to reversestart
- the offset from where to reverse the bufferlen
- the length in the buffer up to where the
buffer should be reversed