Package org.apache.cassandra.dht

Class Token

java.lang.Object
org.apache.cassandra.dht.Token
All Implemented Interfaces:
Serializable, Comparable<Token>, RingPosition<Token>
Direct Known Subclasses:
ByteOrderedPartitioner.BytesToken, LocalPartitioner.LocalToken, Murmur3Partitioner.LongToken, OrderPreservingPartitioner.StringToken, RandomPartitioner.BigIntegerToken
public abstract class Token extends Object implements RingPosition<Token>, Serializable
See Also:

  • Field Details

  • Constructor Details

    • Token

      public Token()

  • Method Details

    • getPartitioner

      public abstract IPartitioner getPartitioner()
      Specified by:
      getPartitioner in interface RingPosition<Token>

    • getHeapSize

      public abstract long getHeapSize()

    • getTokenValue

      public abstract Object getTokenValue()

    • getLongValue

      public long getLongValue()
      This method exists so that callers can access the primitive long value for this Token, if one exits. It is especially useful when the auto-boxing induced by a call to getTokenValue() would be unacceptable for reasons of performance.
      Returns:
      the primitive long value of this token, if one exists
      Throws:
      UnsupportedOperationException - if this Token is not backed by a primitive long value

    • asComparableBytes

      public abstract ByteSource asComparableBytes(ByteComparable.Version version)
      Produce a weakly prefix-free byte-comparable representation of the token, i.e. such a sequence of bytes that any pair x, y of valid tokens of this type and any bytes b1, b2 between 0x10 and 0xEF, (+ stands for concatenation) compare(x, y) == compareLexicographicallyUnsigned(asByteComparable(x)+b1, asByteComparable(y)+b2) (i.e. the values compare like the original type, and an added 0x10-0xEF byte at the end does not change that) and: asByteComparable(x)+b1 is not a prefix of asByteComparable(y) (weakly prefix free) (i.e. a valid representation of a value may be a prefix of another valid representation of a value only if the following byte in the latter is smaller than 0x10 or larger than 0xEF). These properties are trivially true if the encoding compares correctly and is prefix free, but also permits a little more freedom that enables somewhat more efficient encoding of arbitrary-length byte-comparable blobs.

    • size

      public abstract double size(Token next)
      Returns a measure for the token space covered between this token and next. Used by the token allocation algorithm (see CASSANDRA-7032).

    • nextValidToken

      public abstract Token nextValidToken()
      Returns the next possible token in the token space, one that compares greater than this and such that there is no other token that sits between this token and it in the token order. This is not possible for all token types, esp. for comparison-based tokens such as the LocalPartioner used for classic secondary indexes. Used to avoid clashes between nodes in separate datacentres trying to use the same token via the token allocation algorithm, as well as in constructing token ranges for sstables.

    • getToken

      public Token getToken()
      Specified by:
      getToken in interface RingPosition<Token>

    • minValue

      public Token minValue()
      Specified by:
      minValue in interface RingPosition<Token>

    • isMinimum

      public boolean isMinimum()
      Specified by:
      isMinimum in interface RingPosition<Token>

    • minKeyBound

      public Token.KeyBound minKeyBound()

    • maxKeyBound

      public Token.KeyBound maxKeyBound()