org.apache.hadoop.hbase

Class CellComparator

java.lang.Object

org.apache.hadoop.hbase.CellComparator

All Implemented Interfaces:

Serializable, Comparator<Cell>

Direct Known Subclasses:

CellComparator.RowComparator

@InterfaceAudience.Private
 @InterfaceStability.Evolving
public class CellComparator
extends Object
implements Comparator<Cell>, Serializable

Compare two HBase cells. Do not use this method comparing -ROOT- or hbase:meta cells. Cells from these tables need a specialized comparator, one that takes account of the special formatting of the row where we have commas to delimit table from regionname, from row. See KeyValue for how it has a special comparator to do hbase:meta cells and yet another for -ROOT-.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CellComparator.RowComparator Counter part for the KeyValue.RowOnlyComparator

Constructor Summary

Constructors

Constructor and Description
CellComparator()

Method Summary

Modifier and Type	Method and Description
static boolean	areKeyLengthsEqual(Cell a, Cell b) lengths
static boolean	areRowLengthsEqual(Cell a, Cell b)
int	compare(Cell a, Cell b)
static int	compare(Cell a, Cell b, boolean ignoreSequenceid) Compare cells.
static int	compareColumns(Cell left, Cell right)
static int	compareCommonFamilyPrefix(Cell left, Cell right, int familyCommonPrefix)
static int	compareCommonQualifierPrefix(Cell left, Cell right, int qualCommonPrefix)
static int	compareCommonRowPrefix(Cell left, Cell right, int rowCommonPrefix)
static int	compareFamilies(Cell left, Cell right)
int	compareFlatKey(Cell left, Cell right)
static int	compareQualifiers(Cell left, Cell right)
static int	compareRows(byte[] left, int loffset, int llength, byte[] right, int roffset, int rlength) Do not use comparing rows from hbase:meta.
static int	compareRows(Cell left, Cell right) Do not use comparing rows from hbase:meta.
static int	compareTimestamps(Cell left, Cell right)
static int	compareWithoutRow(Cell leftCell, Cell rightCell)
static boolean	equals(Cell a, Cell b) equals
static boolean	equalsFamily(Cell a, Cell b)
static boolean	equalsIgnoreMvccVersion(Cell a, Cell b) special case for KeyValue.equals
static boolean	equalsQualifier(Cell a, Cell b)
static boolean	equalsRow(Cell a, Cell b)
static boolean	equalsTimestamp(Cell a, Cell b)
static boolean	equalsType(Cell a, Cell b)
static int	findCommonPrefixInFamilyPart(Cell left, Cell right, int familyCommonPrefix)
static int	findCommonPrefixInQualifierPart(Cell left, Cell right, int qualifierCommonPrefix)
static int	findCommonPrefixInRowPart(Cell left, Cell right, int rowCommonPrefix)
static Cell	getMidpoint(KeyValue.KVComparator comparator, Cell left, Cell right) Try to return a Cell that falls between left and right but that is shorter; i.e.
static int	hashCode(Cell cell) Returns a hash code that is always the same for two Cells having a matching equals(..) result.
static int	hashCodeIgnoreMvcc(Cell cell) Returns a hash code that is always the same for two Cells having a matching equals(..) result.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Detail

CellComparator

public CellComparator()

Method Detail

compare

public int compare(Cell a,
                   Cell b)

Specified by:

compare in interface Comparator<Cell>

compare

public static int compare(Cell a,
                          Cell b,
                          boolean ignoreSequenceid)

Compare cells. TODO: Replace with dynamic rather than static comparator so can change comparator implementation.

Parameters:

a -

b -

ignoreSequenceid - True if we are to compare the key portion only and ignore the sequenceid. Set to false to compare key and consider sequenceid.

Returns:

0 if equal, -1 if a < b, and +1 if a > b.

findCommonPrefixInRowPart

public static int findCommonPrefixInRowPart(Cell left,
                                            Cell right,
                                            int rowCommonPrefix)

findCommonPrefixInFamilyPart

public static int findCommonPrefixInFamilyPart(Cell left,
                                               Cell right,
                                               int familyCommonPrefix)

findCommonPrefixInQualifierPart

public static int findCommonPrefixInQualifierPart(Cell left,
                                                  Cell right,
                                                  int qualifierCommonPrefix)

equals

public static boolean equals(Cell a,
                             Cell b)

equals

equalsRow

public static boolean equalsRow(Cell a,
                                Cell b)

equalsFamily

public static boolean equalsFamily(Cell a,
                                   Cell b)

equalsQualifier

public static boolean equalsQualifier(Cell a,
                                      Cell b)

equalsTimestamp

public static boolean equalsTimestamp(Cell a,
                                      Cell b)

equalsType

public static boolean equalsType(Cell a,
                                 Cell b)

compareColumns

public static int compareColumns(Cell left,
                                 Cell right)

compareFamilies

public static int compareFamilies(Cell left,
                                  Cell right)

compareQualifiers

public static int compareQualifiers(Cell left,
                                    Cell right)

compareFlatKey

public int compareFlatKey(Cell left,
                          Cell right)

compareRows

public static int compareRows(Cell left,
                              Cell right)

Do not use comparing rows from hbase:meta. Meta table Cells have schema (table,startrow,hash) so can't be treated as plain byte arrays as this method does.

compareRows

public static int compareRows(byte[] left,
                              int loffset,
                              int llength,
                              byte[] right,
                              int roffset,
                              int rlength)

Do not use comparing rows from hbase:meta. Meta table Cells have schema (table,startrow,hash) so can't be treated as plain byte arrays as this method does.

compareWithoutRow

public static int compareWithoutRow(Cell leftCell,
                                    Cell rightCell)

compareTimestamps

public static int compareTimestamps(Cell left,
                                    Cell right)

hashCode

public static int hashCode(Cell cell)

Returns a hash code that is always the same for two Cells having a matching equals(..) result.

hashCodeIgnoreMvcc

public static int hashCodeIgnoreMvcc(Cell cell)

Returns a hash code that is always the same for two Cells having a matching equals(..) result. Note : Ignore mvcc while calculating the hashcode

Parameters:

cell -

Returns:

hashCode

areKeyLengthsEqual

public static boolean areKeyLengthsEqual(Cell a,
                                         Cell b)

lengths

areRowLengthsEqual

public static boolean areRowLengthsEqual(Cell a,
                                         Cell b)

compareCommonRowPrefix

public static int compareCommonRowPrefix(Cell left,
                                         Cell right,
                                         int rowCommonPrefix)

compareCommonFamilyPrefix

public static int compareCommonFamilyPrefix(Cell left,
                                            Cell right,
                                            int familyCommonPrefix)

compareCommonQualifierPrefix

public static int compareCommonQualifierPrefix(Cell left,
                                               Cell right,
                                               int qualCommonPrefix)

equalsIgnoreMvccVersion

public static boolean equalsIgnoreMvccVersion(Cell a,
                                              Cell b)

special case for KeyValue.equals

getMidpoint

public static Cell getMidpoint(KeyValue.KVComparator comparator,
                               Cell left,
                               Cell right)

Try to return a Cell that falls between left and right but that is shorter; i.e. takes up less space. This trick is used building HFile block index. Its an optimization. It does not always work. In this case we'll just return the right cell.

Parameters:

comparator - Comparator to use.

left -

right -

Returns:

A cell that sorts between left and right.