Class FSTDictionary
java.lang.Object
org.apache.lucene.codecs.uniformsplit.FSTDictionary
- All Implemented Interfaces:
IndexDictionary
Immutable stateless
FST-based index dictionary kept in memory.
Use IndexDictionary.Builder to build the IndexDictionary.
Create a stateful IndexDictionary.Browser to seek a term in this IndexDictionary and get its corresponding block file pointer to the terms block file.
Its greatest advantage is to be very compact in memory thanks to both the compaction of the
FST as a byte array, and the incremental encoding of the leaves block pointer values,
which are long integers in increasing order, with PositiveIntOutputs.
With a compact dictionary in memory we can increase the number of blocks. This allows us to
reduce the average block size, which means faster scan inside a block.
- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected classStatefulFSTDictionary.Browserto seek a term in thisFSTDictionaryand get its corresponding block file pointer in the block file.static classProvides statefulFSTDictionary.Browserto seek in theFSTDictionary.static classBuilds an immutableFSTDictionary. -
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionbrowser()Creates a newIndexDictionary.Browser.protected static FSTDictionaryread(DataInput input, BlockDecoder blockDecoder, boolean isFSTOnHeap) Reads aFSTDictionaryfrom the provided input.voidwrite(DataOutput output, BlockEncoder blockEncoder) Writes this dictionary to the provided output.
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Field Details
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fst
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Constructor Details
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FSTDictionary
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Method Details
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write
Description copied from interface:IndexDictionaryWrites this dictionary to the provided output.- Specified by:
writein interfaceIndexDictionary- Parameters:
blockEncoder- TheBlockEncoderfor specific encoding of this index dictionary; or null if none.- Throws:
IOException
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read
protected static FSTDictionary read(DataInput input, BlockDecoder blockDecoder, boolean isFSTOnHeap) throws IOException Reads aFSTDictionaryfrom the provided input.- Parameters:
blockDecoder- TheBlockDecoderto use for specific decoding; or null if none.- Throws:
IOException
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browser
Description copied from interface:IndexDictionaryCreates a newIndexDictionary.Browser.- Specified by:
browserin interfaceIndexDictionary
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