public abstract class SegmentingTokenizerBase extends Tokenizer
BreakIterator and
allows subclasses to decompose these sentences into words.
This can be used by subclasses that need sentence context for tokenization purposes, such as CJK segmenters.
Additionally it can be used by subclasses that want to mark sentence boundaries (with a custom attribute, extra token, position increment, etc) for downstream processing.
AttributeSource.State| Modifier and Type | Field and Description |
|---|---|
protected char[] |
buffer |
protected static int |
BUFFERMAX |
protected int |
offset
accumulated offset of previous buffers for this reader, for offsetAtt
|
DEFAULT_TOKEN_ATTRIBUTE_FACTORY| Constructor and Description |
|---|
SegmentingTokenizerBase(AttributeFactory factory,
BreakIterator iterator)
Construct a new SegmenterBase, also supplying the AttributeFactory
|
SegmentingTokenizerBase(BreakIterator iterator)
Construct a new SegmenterBase, using
the provided BreakIterator for sentence segmentation.
|
| Modifier and Type | Method and Description |
|---|---|
void |
end()
This method is called by the consumer after the last token has been
consumed, after
TokenStream.incrementToken() returned false
(using the new TokenStream API). |
boolean |
incrementToken()
Consumers (i.e.,
IndexWriter) use this method to advance the stream to
the next token. |
protected abstract boolean |
incrementWord()
Returns true if another word is available
|
protected boolean |
isSafeEnd(char ch)
For sentence tokenization, these are the unambiguous break positions.
|
void |
reset()
This method is called by a consumer before it begins consumption using
TokenStream.incrementToken(). |
protected abstract void |
setNextSentence(int sentenceStart,
int sentenceEnd)
Provides the next input sentence for analysis
|
close, correctOffset, setReaderaddAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toStringprotected static final int BUFFERMAX
protected final char[] buffer
protected int offset
public SegmentingTokenizerBase(BreakIterator iterator)
Note that you should never share BreakIterators across different TokenStreams, instead a newly created or cloned one should always be provided to this constructor.
public SegmentingTokenizerBase(AttributeFactory factory, BreakIterator iterator)
public final boolean incrementToken() throws IOException
TokenStreamIndexWriter) use this method to advance the stream to
the next token. Implementing classes must implement this method and update
the appropriate AttributeImpls 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 AttributeImpls 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 TokenStreamIOExceptionpublic void reset() throws IOException
TokenStreamTokenStream.incrementToken().
Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.
If you override this method, always call super.reset(), otherwise
some internal state will not be correctly reset (e.g., Tokenizer will
throw IllegalStateException on further usage).
reset in class TokenizerIOExceptionpublic final void end() throws IOException
TokenStreamTokenStream.incrementToken() returned false
(using the new TokenStream API). Streams implementing the old API
should upgrade to use this feature.
This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but a WhitespaceTokenizer was used.
Additionally any skipped positions (such as those removed by a stopfilter) can be applied to the position increment, or any adjustment of other attributes where the end-of-stream value may be important.
If you override this method, always call super.end().
end in class TokenStreamIOException - If an I/O error occursprotected boolean isSafeEnd(char ch)
protected abstract void setNextSentence(int sentenceStart, int sentenceEnd)
protected abstract boolean incrementWord()