Cell (Apache HBase 1.2.12 API)

```
@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface Cell
```
The unit of storage in HBase consisting of the following fields:
```
 1) row
 2) column family
 3) column qualifier
 4) timestamp
 5) type
 6) MVCC version
 7) value
 
```
Uniqueness is determined by the combination of row, column family, column qualifier, timestamp, and type.

The natural comparator will perform a bitwise comparison on row, column family, and column qualifier. Less intuitively, it will then treat the greater timestamp as the lesser value with the goal of sorting newer cells first.

This interface should not include methods that allocate new byte[]'s such as those used in client or debugging code. These users should use the methods found in the CellUtil class. Currently for to minimize the impact of existing applications moving between 0.94 and 0.96, we include the costly helper methods marked as deprecated.

Cell implements Comparable<Cell> which is only meaningful when comparing to other keys in the same table. It uses CellComparator which does not work on the -ROOT- and hbase:meta tables.

In the future, we may consider adding a boolean isOnHeap() method and a getValueBuffer() method that can be used to pass a value directly from an off-heap ByteBuffer to the network without copying into an on-heap byte[].

Historic note: the original Cell implementation (KeyValue) requires that all fields be encoded as consecutive bytes in the same byte[], whereas this interface allows fields to reside in separate byte[]'s.

Method Summary

Methods
Modifier and Type	Method and Description
`byte[]`	`getFamily()` Deprecated. as of 0.96, use `CellUtil.cloneFamily(Cell)`
`byte[]`	`getFamilyArray()` Contiguous bytes composed of legal HDFS filename characters which may start at any index in the containing array.
`byte`	`getFamilyLength()`
`int`	`getFamilyOffset()`
`long`	`getMvccVersion()` Deprecated. as of 1.0, use `getSequenceId()` Internal use only. A region-specific sequence ID given to each operation. It always exists for cells in the memstore but is not retained forever. It may survive several flushes, but generally becomes irrelevant after the cell's row is no longer involved in any operations that require strict consistency.
`byte[]`	`getQualifier()` Deprecated. as of 0.96, use `CellUtil.cloneQualifier(Cell)`
`byte[]`	`getQualifierArray()` Contiguous raw bytes that may start at any index in the containing array.
`int`	`getQualifierLength()`
`int`	`getQualifierOffset()`
`byte[]`	`getRow()` Deprecated. as of 0.96, use `CellUtil.getRowByte(Cell, int)`
`byte[]`	`getRowArray()` Contiguous raw bytes that may start at any index in the containing array.
`short`	`getRowLength()`
`int`	`getRowOffset()`
`long`	`getSequenceId()` A region-specific unique monotonically increasing sequence ID given to each Cell.
`byte[]`	`getTagsArray()`
`int`	`getTagsLength()`
`int`	`getTagsOffset()`
`long`	`getTimestamp()`
`byte`	`getTypeByte()`
`byte[]`	`getValue()` Deprecated. as of 0.96, use `CellUtil.cloneValue(Cell)`
`byte[]`	`getValueArray()` Contiguous raw bytes that may start at any index in the containing array.
`int`	`getValueLength()`
`int`	`getValueOffset()`

- Method Detail
  - getRowArray
```
byte[] getRowArray()
```
    Contiguous raw bytes that may start at any index in the containing array. Max length is Short.MAX_VALUE which is 32,767 bytes.
    
    Returns:
    The array containing the row bytes.
  - getRowOffset
```
int getRowOffset()
```
    Returns:
    Array index of first row byte
  - getRowLength
```
short getRowLength()
```
    Returns:
    Number of row bytes. Must be < rowArray.length - offset.
  - getFamilyArray
```
byte[] getFamilyArray()
```
    Contiguous bytes composed of legal HDFS filename characters which may start at any index in the containing array. Max length is Byte.MAX_VALUE, which is 127 bytes.
    
    Returns:
    the array containing the family bytes.
  - getFamilyOffset
```
int getFamilyOffset()
```
    Returns:
    Array index of first family byte
  - getFamilyLength
```
byte getFamilyLength()
```
    Returns:
    Number of family bytes. Must be < familyArray.length - offset.
  - getQualifierArray
```
byte[] getQualifierArray()
```
    Contiguous raw bytes that may start at any index in the containing array.
    
    Returns:
    The array containing the qualifier bytes.
  - getQualifierOffset
```
int getQualifierOffset()
```
    Returns:
    Array index of first qualifier byte
  - getQualifierLength
```
int getQualifierLength()
```
    Returns:
    Number of qualifier bytes. Must be < qualifierArray.length - offset.
  - getTimestamp
```
long getTimestamp()
```
    Returns:
    Long value representing time at which this cell was "Put" into the row. Typically represents the time of insertion, but can be any value from 0 to Long.MAX_VALUE.
  - getTypeByte
```
byte getTypeByte()
```
    Returns:
    The byte representation of the KeyValue.TYPE of this cell: one of Put, Delete, etc
  - getMvccVersion
```
@Deprecated
long getMvccVersion()
```
    Deprecated. as of 1.0, use getSequenceId() Internal use only. A region-specific sequence ID given to each operation. It always exists for cells in the memstore but is not retained forever. It may survive several flushes, but generally becomes irrelevant after the cell's row is no longer involved in any operations that require strict consistency.
    
    Returns:
    mvccVersion (always >= 0 if exists), or 0 if it no longer exists
  - getSequenceId
```
long getSequenceId()
```
    A region-specific unique monotonically increasing sequence ID given to each Cell. It always exists for cells in the memstore but is not retained forever. It will be kept for HConstants.KEEP_SEQID_PERIOD days, but generally becomes irrelevant after the cell's row is no longer involved in any operations that require strict consistency.
    
    Returns:
    seqId (always > 0 if exists), or 0 if it no longer exists
  - getValueArray
```
byte[] getValueArray()
```
    Contiguous raw bytes that may start at any index in the containing array. Max length is Integer.MAX_VALUE which is 2,147,483,647 bytes.
    
    Returns:
    The array containing the value bytes.
  - getValueOffset
```
int getValueOffset()
```
    Returns:
    Array index of first value byte
  - getValueLength
```
int getValueLength()
```
    Returns:
    Number of value bytes. Must be < valueArray.length - offset.
  - getTagsArray
```
byte[] getTagsArray()
```
    Returns:
    the tags byte array
  - getTagsOffset
```
int getTagsOffset()
```
    Returns:
    the first offset where the tags start in the Cell
  - getTagsLength
```
int getTagsLength()
```
    Returns:
    the total length of the tags in the Cell.
  - getValue
```
@Deprecated
byte[] getValue()
```
    Deprecated. as of 0.96, use CellUtil.cloneValue(Cell)
    
    WARNING do not use, expensive. This gets an arraycopy of the cell's value. Added to ease transition from 0.94 -> 0.96.
  - getFamily
```
@Deprecated
byte[] getFamily()
```
    Deprecated. as of 0.96, use CellUtil.cloneFamily(Cell)
    
    WARNING do not use, expensive. This gets an arraycopy of the cell's family. Added to ease transition from 0.94 -> 0.96.
  - getQualifier
```
@Deprecated
byte[] getQualifier()
```
    Deprecated. as of 0.96, use CellUtil.cloneQualifier(Cell)
    
    WARNING do not use, expensive. This gets an arraycopy of the cell's qualifier. Added to ease transition from 0.94 -> 0.96.
  - getRow
```
@Deprecated
byte[] getRow()
```
    Deprecated. as of 0.96, use CellUtil.getRowByte(Cell, int)
    
    WARNING do not use, expensive. this gets an arraycopy of the cell's row. Added to ease transition from 0.94 -> 0.96.

Interface Cell

Method Summary

Method Detail

getRowArray

getRowOffset

getRowLength

getFamilyArray

getFamilyOffset

getFamilyLength

getQualifierArray

getQualifierOffset

getQualifierLength

getTimestamp

getTypeByte

getMvccVersion

getSequenceId

getValueArray

getValueOffset

getValueLength

getTagsArray

getTagsOffset

getTagsLength

getValue

getFamily

getQualifier

getRow