## org.apache.cassandra.dht
Class LocalPartitioner

    java.lang.Object
      org.apache.cassandra.dht.LocalPartitioner

All Implemented Interfaces:
  IPartitioner<LocalToken>

    public class LocalPartitioner

extends java.lang.Object
implements IPartitioner<LocalToken>

Constructor Summary
`LocalPartitioner(AbstractType comparator)`

Method Summary
`DecoratedKey<LocalToken>` `convertFromDiskFormat(java.nio.ByteBuffer key)`
`DecoratedKey<LocalToken>` `decorateKey(java.nio.ByteBuffer key)` Transform key to object representation of the on-disk format.
`java.util.Map<Token,java.lang.Float>` `describeOwnership(java.util.List<Token> sortedTokens)` Calculate the deltas between tokens in the ring in order to compare relative sizes.
`LocalToken` `getMinimumToken()`
`LocalToken` `getRandomToken()`
`LocalToken` `getToken(java.nio.ByteBuffer key)`
`Token.TokenFactory` `getTokenFactory()`
`Token` `midpoint(Token left, Token right)` Calculate a Token representing the approximate "middle" of the given range.
`boolean` `preservesOrder()`

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

Constructor Detail

### LocalPartitioner

    public LocalPartitioner(AbstractType comparator)

Method Detail

### convertFromDiskFormat

    public DecoratedKey<LocalToken> convertFromDiskFormat(java.nio.ByteBuffer key)

  Specified by:
    `convertFromDiskFormat` in interface `IPartitioner<LocalToken>`
  Parameters:
    `key` - On disk representation
  Returns:
    DecoratedKey object

### decorateKey

    public DecoratedKey<LocalToken> decorateKey(java.nio.ByteBuffer key)

  Description copied from interface: `IPartitioner`
  Transform key to object representation of the on-disk format.

  Specified by:
    `decorateKey` in interface `IPartitioner<LocalToken>`
  Parameters:
    `key` - the raw, client-facing key
  Returns:
    decorated version of key

### midpoint

    public Token midpoint(Token left,
                          Token right)

  Description copied from interface: `IPartitioner`
  Calculate a Token representing the approximate "middle" of the given range.

  Specified by:
    `midpoint` in interface `IPartitioner<LocalToken>`
  Returns:
    The approximate midpoint between left and right.

### getMinimumToken

    public LocalToken getMinimumToken()

  Specified by:
    `getMinimumToken` in interface `IPartitioner<LocalToken>`
  Returns:
    The minimum possible Token in the range that is being partitioned.

### getToken

    public LocalToken getToken(java.nio.ByteBuffer key)

  Specified by:
    `getToken` in interface `IPartitioner<LocalToken>`
  Returns:
    a Token that can be used to route a given key (This is NOT a method to create a Token from its string representation; for that, use TokenFactory.fromString.)

### getRandomToken

    public LocalToken getRandomToken()

  Specified by:
    `getRandomToken` in interface `IPartitioner<LocalToken>`
  Returns:
    a randomly generated token

### getTokenFactory

    public Token.TokenFactory getTokenFactory()

  Specified by:
    `getTokenFactory` in interface `IPartitioner<LocalToken>`

### preservesOrder

    public boolean preservesOrder()

  Specified by:
    `preservesOrder` in interface `IPartitioner<LocalToken>`
  Returns:
    True if the implementing class preserves key order in the Tokens it generates.

### describeOwnership

    public java.util.Map<Token,java.lang.Float> describeOwnership(java.util.List<Token> sortedTokens)

  Description copied from interface: `IPartitioner`
  Calculate the deltas between tokens in the ring in order to compare relative sizes.

  Specified by:
    `describeOwnership` in interface `IPartitioner<LocalToken>`
  Parameters:
    `sortedTokens` - a sorted List of Tokens
  Returns:
    the mapping from 'token' to 'percentage of the ring owned by that token'.

Copyright © 2012 The Apache Software Foundation