Class TokenStreamFromTermVector
- java.lang.Object
-
- org.apache.lucene.util.AttributeSource
-
- org.apache.lucene.analysis.TokenStream
-
- org.apache.lucene.search.highlight.TokenStreamFromTermVector
-
- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public final class TokenStreamFromTermVector extends TokenStream
TokenStream created from a term vector field. The term vector requires positions and/or offsets (either). If you want payloads add PayloadAttributeImpl (as you would normally) but don't assume the attribute is already added just because you know the term vector has payloads, since the first call to incrementToken() will observe if you asked for them and if not then won't get them. This TokenStream supports an efficientreset()
, so there's no need to wrap with a caching impl.The implementation will create an array of tokens indexed by token position. As long as there aren't massive jumps in positions, this is fine. And it assumes there aren't large numbers of tokens at the same position, since it adds them to a linked-list per position in O(N^2) complexity. When there aren't positions in the term vector, it divides the startOffset by 8 to use as a temporary substitute. In that case, tokens with the same startOffset will occupy the same final position; otherwise tokens become adjacent.
-
-
Nested Class Summary
Nested Classes Modifier and Type Class Description private static class
TokenStreamFromTermVector.TokenLL
-
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
-
-
Field Summary
Fields Modifier and Type Field Description private TokenStreamFromTermVector.TokenLL
firstToken
private TokenStreamFromTermVector.TokenLL
incrementToken
private boolean
initialized
private int
maxStartOffset
private OffsetAttribute
offsetAttribute
private PayloadAttribute
payloadAttribute
private BytesRefArray
payloadsBytesRefArray
private PositionIncrementAttribute
positionIncrementAttribute
private BytesRefBuilder
spareBytesRefBuilder
private CharTermAttribute
termAttribute
private CharsRefBuilder
termCharsBuilder
private Terms
vector
-
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
-
-
Constructor Summary
Constructors Constructor Description TokenStreamFromTermVector(Terms vector, int maxStartOffset)
Constructor.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Terms
getTermVectorTerms()
boolean
incrementToken()
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.private void
init()
private TokenStreamFromTermVector.TokenLL[]
initTokensArray()
void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.-
Methods inherited from class org.apache.lucene.analysis.TokenStream
close, end
-
Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
-
-
-
-
Field Detail
-
vector
private final Terms vector
-
termAttribute
private final CharTermAttribute termAttribute
-
positionIncrementAttribute
private final PositionIncrementAttribute positionIncrementAttribute
-
maxStartOffset
private final int maxStartOffset
-
offsetAttribute
private OffsetAttribute offsetAttribute
-
payloadAttribute
private PayloadAttribute payloadAttribute
-
termCharsBuilder
private CharsRefBuilder termCharsBuilder
-
payloadsBytesRefArray
private BytesRefArray payloadsBytesRefArray
-
spareBytesRefBuilder
private BytesRefBuilder spareBytesRefBuilder
-
firstToken
private TokenStreamFromTermVector.TokenLL firstToken
-
incrementToken
private TokenStreamFromTermVector.TokenLL incrementToken
-
initialized
private boolean initialized
-
-
Constructor Detail
-
TokenStreamFromTermVector
public TokenStreamFromTermVector(Terms vector, int maxStartOffset) throws java.io.IOException
Constructor. The uninversion doesn't happen here; it's delayed till the first call toincrementToken
.- Parameters:
vector
- Terms that contains the data for creating the TokenStream. Must have positions and/or offsets.maxStartOffset
- if a token's start offset exceeds this then the token is not added. -1 disables the limit.- Throws:
java.io.IOException
-
-
Method Detail
-
getTermVectorTerms
public Terms getTermVectorTerms()
-
reset
public void reset() throws java.io.IOException
Description copied from class:TokenStream
This method is called by a consumer before it begins consumption usingTokenStream.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 throwIllegalStateException
on further usage).- Overrides:
reset
in classTokenStream
- Throws:
java.io.IOException
-
init
private void init() throws java.io.IOException
- Throws:
java.io.IOException
-
initTokensArray
private TokenStreamFromTermVector.TokenLL[] initTokensArray() throws java.io.IOException
- Throws:
java.io.IOException
-
incrementToken
public boolean incrementToken() throws java.io.IOException
Description copied from class:TokenStream
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriateAttributeImpl
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)
andAttributeSource.getAttribute(Class)
, references to allAttributeImpl
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()
.- Specified by:
incrementToken
in classTokenStream
- Returns:
- false for end of stream; true otherwise
- Throws:
java.io.IOException
-
-