BlockReader (org.apache.lucene.codecs)

java.lang.Object
- BaseTermsEnum
- - org.apache.lucene.codecs.uniformsplit.BlockReader

Direct Known Subclasses:

IntersectBlockReader, STBlockReader
```
public class BlockReader
extends BaseTermsEnum
```
Seeks the block corresponding to a given term, read the block bytes, and scans the block terms.
Reads fully the block in blockReadBuffer. Then scans the block terms in memory. The details region is lazily decoded with termStatesReadBuffer which shares the same byte array with blockReadBuffer. See BlockWriter and BlockLine for the block format.

Field Summary

Fields
Modifier and Type	Field and Description
`protected BlockDecoder`	`blockDecoder`
`protected int`	`blockFirstLineStart` Offset of the start of the first line of the current block (just after the header), relative to the block start.
`protected BlockHeader`	`blockHeader` Current block header.
`protected IndexInput`	`blockInput` `IndexInput` on the `block file`.
`protected BlockLine`	`blockLine` Current block line.
`protected BlockLine.Serializer`	`blockLineReader`
`protected ByteArrayDataInput`	`blockReadBuffer` In-memory read buffer for the current block.
`protected long`	`blockStartFP` Current block start file pointer, absolute in the `block file`.
`protected IndexDictionary.Browser`	`dictionaryBrowser` Holds the `IndexDictionary.Browser` once loaded.
`protected java.util.function.Supplier<IndexDictionary.Browser>`	`dictionaryBrowserSupplier` `IndexDictionary.Browser` supplier for lazy loading.
`protected FieldMetadata`	`fieldMetadata`
`protected BytesRefBuilder`	`forcedTerm` Set when `seekExact(BytesRef, TermState)` is called.
`protected int`	`lineIndexInBlock` Current line index in the block.
`protected PostingsReaderBase`	`postingsReader`
`protected BytesRef`	`scratchBlockBytes`
`protected BlockTermState`	`scratchTermState`
`protected BlockTermState`	`termState` Current block line details.
`protected boolean`	`termStateForced` Whether the current `TermState` has been forced with a call to `seekExact(BytesRef, TermState)`.
`protected DeltaBaseTermStateSerializer`	`termStateSerializer`
`protected ByteArrayDataInput`	`termStatesReadBuffer` In-memory read buffer for the details region of the current block.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`BlockReader(java.util.function.Supplier<IndexDictionary.Browser> dictionaryBrowserSupplier, IndexInput blockInput, PostingsReaderBase postingsReader, FieldMetadata fieldMetadata, BlockDecoder blockDecoder)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`clearTermState()` Called by the primary `TermsEnum` methods to clear the previous `TermState`.
`protected int`	`compareToMiddleAndJump(BytesRef searchedTerm)` Compares the searched term to the middle term of the block.
`protected BytesRef`	`decodeBlockBytesIfNeeded(int numBlockBytes)`
`int`	`docFreq()`
`protected IndexDictionary.Browser`	`getOrCreateDictionaryBrowser()`
`ImpactsEnum`	`impacts(int flags)`
`protected void`	`initializeBlockReadLazily()`
`protected void`	`initializeHeader(BytesRef searchedTerm, long targetBlockStartFP)` Reads and sets `blockHeader`.
`protected boolean`	`isBeyondLastTerm(BytesRef searchedTerm, long blockStartFP)` Indicates whether the searched term is beyond the last term of the field.
`protected boolean`	`isCurrentTerm(BytesRef searchedTerm)`
`BytesRef`	`next()`
`protected BytesRef`	`nextTerm()` Moves to the next term line and reads it, it may be in the next block.
`long`	`ord()`
`PostingsEnum`	`postings(PostingsEnum reuse, int flags)`
`long`	`ramBytesUsed()`
`protected BlockHeader`	`readHeader()` Reads the block header.
`protected BlockLine`	`readLineInBlock()` Reads the current block line.
`protected BlockTermState`	`readTermState()` Reads the `BlockTermState` on the current line.
`protected BlockTermState`	`readTermStateIfNotRead()` Reads the `BlockTermState` if it is not already set.
`SeekStatus`	`seekCeil(BytesRef searchedTerm)`
`boolean`	`seekExact(BytesRef searchedTerm)`
`void`	`seekExact(BytesRef term, TermState state)` Positions this `BlockReader` without re-seeking the term dictionary.
`protected SeekStatus`	`seekInBlock(BytesRef searchedTerm)` Seeks to the provided term in this block.
`protected SeekStatus`	`seekInBlock(BytesRef searchedTerm, long blockStartFP)` Seeks to the provided term in the block starting at the provided file pointer.
`BytesRef`	`term()`
`TermState`	`termState()`
`long`	`totalTermFreq()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - blockInput
```
protected IndexInput blockInput
```
    IndexInput on the block file.
  - postingsReader
```
protected final PostingsReaderBase postingsReader
```
  - fieldMetadata
```
protected final FieldMetadata fieldMetadata
```
  - blockDecoder
```
protected final BlockDecoder blockDecoder
```
  - blockLineReader
```
protected BlockLine.Serializer blockLineReader
```
  - blockReadBuffer
```
protected ByteArrayDataInput blockReadBuffer
```
    In-memory read buffer for the current block.
  - termStatesReadBuffer
```
protected ByteArrayDataInput termStatesReadBuffer
```
    In-memory read buffer for the details region of the current block. It shares the same byte array as blockReadBuffer, with a different position.
  - termStateSerializer
```
protected DeltaBaseTermStateSerializer termStateSerializer
```
  - dictionaryBrowserSupplier
```
protected final java.util.function.Supplier<IndexDictionary.Browser> dictionaryBrowserSupplier
```
    IndexDictionary.Browser supplier for lazy loading.
  - dictionaryBrowser
```
protected IndexDictionary.Browser dictionaryBrowser
```
    Holds the IndexDictionary.Browser once loaded.
  - blockStartFP
```
protected long blockStartFP
```
    Current block start file pointer, absolute in the block file.
  - blockHeader
```
protected BlockHeader blockHeader
```
    Current block header.
  - blockLine
```
protected BlockLine blockLine
```
    Current block line.
  - termState
```
protected BlockTermState termState
```
    Current block line details.
  - blockFirstLineStart
```
protected int blockFirstLineStart
```
    Offset of the start of the first line of the current block (just after the header), relative to the block start.
  - lineIndexInBlock
```
protected int lineIndexInBlock
```
    Current line index in the block.
  - termStateForced
```
protected boolean termStateForced
```
    Whether the current TermState has been forced with a call to seekExact(BytesRef, TermState).
    
    See Also:
    
    forcedTerm
  - forcedTerm
```
protected BytesRefBuilder forcedTerm
```
    Set when seekExact(BytesRef, TermState) is called.
    This optimizes the use-case when the caller calls first seekExact(BytesRef, TermState) and then postings(PostingsEnum, int). In this case we don't access the terms block file (we don't seek) but directly the postings file because we already have the TermState with the file pointers to the postings file.
  - scratchBlockBytes
```
protected BytesRef scratchBlockBytes
```
  - scratchTermState
```
protected final BlockTermState scratchTermState
```
- Constructor Detail
  - BlockReader
```
protected BlockReader(java.util.function.Supplier<IndexDictionary.Browser> dictionaryBrowserSupplier,
                      IndexInput blockInput,
                      PostingsReaderBase postingsReader,
                      FieldMetadata fieldMetadata,
                      BlockDecoder blockDecoder)
               throws java.io.IOException
```
    Parameters:
    
    dictionaryBrowserSupplier - to load the IndexDictionary.Browser lazily in seekCeil(BytesRef).
    
    blockDecoder - Optional block decoder, may be null if none. It can be used for decompression or decryption.
    
    Throws:
    
    java.io.IOException
- Method Detail
  - seekCeil
```
public SeekStatus seekCeil(BytesRef searchedTerm)
                    throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - seekExact
```
public boolean seekExact(BytesRef searchedTerm)
                  throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - isCurrentTerm
```
protected boolean isCurrentTerm(BytesRef searchedTerm)
```
  - isBeyondLastTerm
```
protected boolean isBeyondLastTerm(BytesRef searchedTerm,
                                   long blockStartFP)
```
    Indicates whether the searched term is beyond the last term of the field.
    
    Parameters:
    
    blockStartFP - The current block start file pointer.
  - seekInBlock
```
protected SeekStatus seekInBlock(BytesRef searchedTerm,
                                 long blockStartFP)
                          throws java.io.IOException
```
    Seeks to the provided term in the block starting at the provided file pointer. Does not exceed the block.
    
    Throws:
    
    java.io.IOException
  - seekInBlock
```
protected SeekStatus seekInBlock(BytesRef searchedTerm)
                          throws java.io.IOException
```
    Seeks to the provided term in this block.
    Does not exceed this block; org.apache.lucene.index.TermsEnum.SeekStatus#END is returned if it follows the block.
    Compares the line terms with the searchedTerm, taking advantage of the incremental encoding properties.
    Scans linearly the terms. Updates the current block line with the current term.
    
    Throws:
    
    java.io.IOException
  - compareToMiddleAndJump
```
protected int compareToMiddleAndJump(BytesRef searchedTerm)
                              throws java.io.IOException
```
    Compares the searched term to the middle term of the block. If the searched term is lexicographically equal or after the middle term then jumps to the second half of the block directly.
    
    Returns:
    
    The comparison between the searched term and the middle term.
    
    Throws:
    
    java.io.IOException
  - readLineInBlock
```
protected BlockLine readLineInBlock()
                             throws java.io.IOException
```
    Reads the current block line. Sets blockLine and increments lineIndexInBlock.
    
    Returns:
    
    The BlockLine; or null if there no more line in the block.
    
    Throws:
    
    java.io.IOException
  - seekExact
```
public void seekExact(BytesRef term,
                      TermState state)
```
    Positions this BlockReader without re-seeking the term dictionary.
    The block containing the term is not read by this method. It will be read lazily only if needed, for example if next() is called. Calling postings(PostingsEnum, int) after this method does require the block to be read.
  - next
```
public BytesRef next()
              throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - nextTerm
```
protected BytesRef nextTerm()
                     throws java.io.IOException
```
    Moves to the next term line and reads it, it may be in the next block. The term details are not read yet. They will be read only when needed with readTermStateIfNotRead().
    
    Returns:
    
    The read term bytes; or null if there is no more term for the field.
    
    Throws:
    
    java.io.IOException
  - initializeHeader
```
protected void initializeHeader(BytesRef searchedTerm,
                                long targetBlockStartFP)
                         throws java.io.IOException
```
    Reads and sets blockHeader. Sets null if there is no block for the field anymore.
    
    Parameters:
    
    searchedTerm - The searched term; or null if none.
    
    targetBlockStartFP - The file pointer of the block to read.
    
    Throws:
    
    java.io.IOException
  - initializeBlockReadLazily
```
protected void initializeBlockReadLazily()
```
  - readHeader
```
protected BlockHeader readHeader()
                          throws java.io.IOException
```
    Reads the block header. Sets blockHeader.
    
    Returns:
    
    The block header; or null if there is no block for the field anymore.
    
    Throws:
    
    java.io.IOException
  - decodeBlockBytesIfNeeded
```
protected BytesRef decodeBlockBytesIfNeeded(int numBlockBytes)
                                     throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - readTermStateIfNotRead
```
protected BlockTermState readTermStateIfNotRead()
                                         throws java.io.IOException
```
    Reads the BlockTermState if it is not already set. Sets termState.
    
    Throws:
    
    java.io.IOException
  - readTermState
```
protected BlockTermState readTermState()
                                throws java.io.IOException
```
    Reads the BlockTermState on the current line. Sets termState.
    Overriding method may return null if there is no BlockTermState (in this case the extending class must support a null termState).
    
    Returns:
    
    The BlockTermState; or null if none.
    
    Throws:
    
    java.io.IOException
  - term
```
public BytesRef term()
```
  - ord
```
public long ord()
```
  - docFreq
```
public int docFreq()
            throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - totalTermFreq
```
public long totalTermFreq()
                   throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - termState
```
public TermState termState()
                    throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - postings
```
public PostingsEnum postings(PostingsEnum reuse,
                             int flags)
                      throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - impacts
```
public ImpactsEnum impacts(int flags)
                    throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - ramBytesUsed
```
public long ramBytesUsed()
```
  - getOrCreateDictionaryBrowser
```
protected IndexDictionary.Browser getOrCreateDictionaryBrowser()
```
  - clearTermState
```
protected void clearTermState()
```
    Called by the primary TermsEnum methods to clear the previous TermState.

Class BlockReader

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

blockInput

postingsReader

fieldMetadata

blockDecoder

blockLineReader

blockReadBuffer

termStatesReadBuffer

termStateSerializer

dictionaryBrowserSupplier

dictionaryBrowser

blockStartFP

blockHeader

blockLine

termState

blockFirstLineStart

lineIndexInBlock

termStateForced

forcedTerm

scratchBlockBytes

scratchTermState

Constructor Detail

BlockReader

Method Detail

seekCeil

seekExact

isCurrentTerm

isBeyondLastTerm

seekInBlock

seekInBlock

compareToMiddleAndJump

readLineInBlock

seekExact

next

nextTerm

initializeHeader

initializeBlockReadLazily

readHeader

decodeBlockBytesIfNeeded

readTermStateIfNotRead

readTermState

term

ord

docFreq

totalTermFreq

termState

postings

impacts

ramBytesUsed

getOrCreateDictionaryBrowser

clearTermState