PrefixTreeArraySearcher (Apache HBase - Prefix Tree 1.4.14 API)

java.lang.Object
- org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeCell
- - org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayScanner
  - - org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayReversibleScanner
    - - org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArraySearcher

所有已实现的接口:

Comparable<Cell>, Cell, CellScanner, CellSearcher, ReversibleCellScanner, SettableSequenceId
```
@InterfaceAudience.Private
public class PrefixTreeArraySearcher
extends PrefixTreeArrayReversibleScanner
implements CellSearcher
```
Searcher extends the capabilities of the Scanner + ReversibleScanner to add the ability to position itself on a requested Cell without scanning through cells before it. The PrefixTree is set up to be a Trie of rows, so finding a particular row is extremely cheap.
Once it finds the row, it does a binary search through the cells inside the row, which is not as fast as the trie search, but faster than iterating through every cell like existing block formats do. For this reason, this implementation is targeted towards schemas where rows are narrow enough to have several or many per block, and where you are generally looking for the entire row or the first cell. It will still be fast for wide rows or point queries, but could be improved upon.

字段概要
- 从类继承的字段 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayScanner
  afterLast, beforeFirst, blockMeta, currentCellIndex, currentRowNode, familyReader, mvccVersionDecoder, nubCellsRemain, qualifierReader, rowNodes, rowNodeStackIndex, tagsReader, timestampDecoder
- 从类继承的字段 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeCell
  absoluteValueOffset, block, DEFAULT_TYPE, familyBuffer, familyLength, familyOffset, includeMvccVersion, mvccVersion, qualifierBuffer, qualifierLength, qualifierOffset, rowBuffer, rowLength, tagsBuffer, tagsLength, tagsOffset, timestamp, type, TYPES, valueLength

构造器概要

构造器
构造器和说明
`PrefixTreeArraySearcher(PrefixTreeBlockMeta blockMeta, int rowTreeDepth, int rowBufferLength, int qualifierBufferLength, int tagsBufferLength)` construct

方法概要

方法
限定符和类型	方法和说明
`protected int`	`compareToCurrentToken(Cell key)` Compare only the bytes within the window of the current token
`protected boolean`	`currentPositionIsAfter(Cell cell)` internal methods
`boolean`	`equals(Object obj)` Object methods
`protected CellScannerPosition`	`fixRowFanMissForward(int fanInsertionPoint)`
`protected CellScannerPosition`	`fixRowFanMissReverse(int fanInsertionPoint)` complete seek when fan mismatch
`protected CellScannerPosition`	`fixRowTokenMissForward(int searcherIsAfterInputKey)`
`protected CellScannerPosition`	`fixRowTokenMissReverse(int searcherIsAfterInputKey)`
`protected void`	`followLastFansUntilExhausted()`
`void`	`positionAfterLastCell()` The content of the buffers doesn't matter here, only that afterLast=true and beforeFirst=false
`boolean`	`positionAt(Cell key)` CellSearcher methods
`CellScannerPosition`	`positionAtOrAfter(Cell key)` Identical workflow as positionAtOrBefore, but split them to avoid having ~10 extra if-statements.
`CellScannerPosition`	`positionAtOrBefore(Cell key)` Same as positionAt(..), but go to the extra effort of finding the previous key if there's no exact match.
`protected CellScannerPosition`	`positionAtQualifierTimestamp(Cell key, boolean beforeOnMiss)`
`protected boolean`	`rowMatchesAfterCurrentPosition(Cell key)` compare this.row to key.row but starting at the current rowLength
`boolean`	`seekForwardTo(Cell key)` Note: Added for backwards compatibility with `KeyValueScanner` Look for the key, but only look after the current position.
`CellScannerPosition`	`seekForwardToOrAfter(Cell key)` Same as seekForwardTo(..), but go to the extra effort of finding the next key if there's no exact match.
`CellScannerPosition`	`seekForwardToOrBefore(Cell key)` Same as seekForwardTo(..), but go to the extra effort of finding the next key if there's no exact match.

从类继承的方法 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayReversibleScanner
descendToLastRowFromCurrentPosition, isDirectlyAfterNub, positionAtLastCell, positionAtLastRow, previous, previousRow

从类继承的方法 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayScanner
advance, appendCurrentTokenToRowBuffer, appendToRowBuffer, areBuffersBigEnough, current, discardCurrentRowNode, followCurrentFan, followFan, followFirstFan, followLastFan, followNextFan, followPreviousFan, getBlockMeta, getMaxRowTreeStackNodes, getQualifierBufferLength, getRowBufferLength, getTagBufferLength, getTreeBytes, hashCode, hasOccurrences, initFirstNode, initOnBlock, isAfterLast, isBeforeFirst, isBranch, isFirstCellInRow, isLastCellInRow, isLeaf, isNub, isOutOfBounds, markAfterLast, markBeforeFirst, nextRow, nextRowInternal, popFromRowBuffer, populateFamily, populateFirstNonRowFields, populateLastNonRowFields, populateMvccVersion, populateNonRowFields, populateNonRowFieldsAndCompareTo, populatePreviousNonRowFields, populateQualifier, populateTag, populateTimestamp, populateType, populateValueOffsets, positionAtFirstCell, reInitFirstNode, releaseBlockReference, resetToBeforeFirstEntry, toString

从类继承的方法 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeCell
compareTo, getFamily, getFamilyArray, getFamilyLength, getFamilyOffset, getKeyValueString, getMvccVersion, getQualifier, getQualifierArray, getQualifierLength, getQualifierOffset, getRow, getRowArray, getRowLength, getRowOffset, getSequenceId, getTagsArray, getTagsLength, getTagsOffset, getTimestamp, getTypeByte, getValue, getValueArray, getValueLength, getValueOffset, setSequenceId

从类继承的方法 java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

从接口继承的方法 org.apache.hadoop.hbase.codec.prefixtree.scanner.CellSearcher
resetToBeforeFirstEntry

从接口继承的方法 org.apache.hadoop.hbase.codec.prefixtree.scanner.ReversibleCellScanner
previous, previousRow

从接口继承的方法 org.apache.hadoop.hbase.CellScanner
advance, current

- 构造器详细资料
  - PrefixTreeArraySearcher
```
public PrefixTreeArraySearcher(PrefixTreeBlockMeta blockMeta,
                       int rowTreeDepth,
                       int rowBufferLength,
                       int qualifierBufferLength,
                       int tagsBufferLength)
```
    construct
- 方法详细资料
  - positionAt
```
public boolean positionAt(Cell key)
```
    CellSearcher methods
    
    指定者:
    
    positionAt 在接口中 CellSearcher
    
    参数:
    key - position the CellScanner exactly on this key
    
    返回:
    true if the cell existed and getCurrentCell() holds a valid cell
  - positionAtOrBefore
```
public CellScannerPosition positionAtOrBefore(Cell key)
```
    从接口复制的说明: CellSearcher
    
    Same as positionAt(..), but go to the extra effort of finding the previous key if there's no exact match.
    
    指定者:
    
    positionAtOrBefore 在接口中 CellSearcher
    
    参数:
    key - position the CellScanner on this key or the closest cell before
    
    返回:
    AT if exact match
    BEFORE if on last cell before key
    BEFORE_FIRST if key was before the first cell in this scanner's scope
  - positionAtOrAfter
```
public CellScannerPosition positionAtOrAfter(Cell key)
```
    Identical workflow as positionAtOrBefore, but split them to avoid having ~10 extra if-statements. Priority on readability and debugability.
    
    指定者:
    
    positionAtOrAfter 在接口中 CellSearcher
    
    参数:
    key - position the CellScanner on this key or the closest cell after
    
    返回:
    AT if exact match
    AFTER if on first cell after key
    AFTER_LAST if key was after the last cell in this scanner's scope
  - seekForwardTo
```
public boolean seekForwardTo(Cell key)
```
    从接口复制的说明: CellSearcher
    
    Note: Added for backwards compatibility with KeyValueScanner
    Look for the key, but only look after the current position. Probably not needed for an efficient tree implementation, but is important for implementations without random access such as unencoded KeyValue blocks.
    
    指定者:
    
    seekForwardTo 在接口中 CellSearcher
    
    参数:
    key - position the CellScanner exactly on this key
    
    返回:
    true if getCurrent() holds a valid cell
  - seekForwardToOrBefore
```
public CellScannerPosition seekForwardToOrBefore(Cell key)
```
    从接口复制的说明: CellSearcher
    
    Same as seekForwardTo(..), but go to the extra effort of finding the next key if there's no exact match.
    
    指定者:
    
    seekForwardToOrBefore 在接口中 CellSearcher
    
    返回:
    AT if exact match
    AFTER if on first cell after key
    AFTER_LAST if key was after the last cell in this scanner's scope
  - seekForwardToOrAfter
```
public CellScannerPosition seekForwardToOrAfter(Cell key)
```
    从接口复制的说明: CellSearcher
    
    Same as seekForwardTo(..), but go to the extra effort of finding the next key if there's no exact match.
    
    指定者:
    
    seekForwardToOrAfter 在接口中 CellSearcher
    
    返回:
    AT if exact match
    AFTER if on first cell after key
    AFTER_LAST if key was after the last cell in this scanner's scope
  - positionAfterLastCell
```
public void positionAfterLastCell()
```
    The content of the buffers doesn't matter here, only that afterLast=true and beforeFirst=false
    
    指定者:
    
    positionAfterLastCell 在接口中 CellSearcher
  - equals
```
public boolean equals(Object obj)
```
    Object methods
    
    覆盖:
    
    equals 在类中 PrefixTreeArrayReversibleScanner
  - currentPositionIsAfter
```
protected boolean currentPositionIsAfter(Cell cell)
```
    internal methods
  - positionAtQualifierTimestamp
```
protected CellScannerPosition positionAtQualifierTimestamp(Cell key,
                                               boolean beforeOnMiss)
```
  - rowMatchesAfterCurrentPosition
```
protected boolean rowMatchesAfterCurrentPosition(Cell key)
```
    compare this.row to key.row but starting at the current rowLength
    
    参数:
    key - Cell being searched for
    
    返回:
    true if row buffer contents match key.row
  - compareToCurrentToken
```
protected int compareToCurrentToken(Cell key)
```
    Compare only the bytes within the window of the current token
    
    参数:
    key -
    
    返回:
    return -1 if key is lessThan (before) this, 0 if equal, and 1 if key is after
  - followLastFansUntilExhausted
```
protected void followLastFansUntilExhausted()
```
  - fixRowTokenMissReverse
```
protected CellScannerPosition fixRowTokenMissReverse(int searcherIsAfterInputKey)
```
    参数:
    searcherIsAfterInputKey - <0: input key is before the searcher's position
    >0: input key is after the searcher's position
  - fixRowTokenMissForward
```
protected CellScannerPosition fixRowTokenMissForward(int searcherIsAfterInputKey)
```
    参数:
    searcherIsAfterInputKey - <0: input key is before the searcher's position
    >0: input key is after the searcher's position
  - fixRowFanMissReverse
```
protected CellScannerPosition fixRowFanMissReverse(int fanInsertionPoint)
```
    complete seek when fan mismatch
  - fixRowFanMissForward
```
protected CellScannerPosition fixRowFanMissForward(int fanInsertionPoint)
```

类 PrefixTreeArraySearcher

字段概要

从类继承的字段 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayScanner

从类继承的字段 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeCell

构造器概要

方法概要

从类继承的方法 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayReversibleScanner

从类继承的方法 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArrayScanner

从类继承的方法 org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeCell

从类继承的方法 java.lang.Object

从接口继承的方法 org.apache.hadoop.hbase.codec.prefixtree.scanner.CellSearcher

从接口继承的方法 org.apache.hadoop.hbase.codec.prefixtree.scanner.ReversibleCellScanner

从接口继承的方法 org.apache.hadoop.hbase.CellScanner

构造器详细资料

PrefixTreeArraySearcher

方法详细资料

positionAt

positionAtOrBefore

positionAtOrAfter

seekForwardTo

seekForwardToOrBefore

seekForwardToOrAfter

positionAfterLastCell

equals

currentPositionIsAfter

positionAtQualifierTimestamp

rowMatchesAfterCurrentPosition

compareToCurrentToken

followLastFansUntilExhausted

fixRowTokenMissReverse

fixRowTokenMissForward

fixRowFanMissReverse

fixRowFanMissForward