org.apache.cassandra.dht
Interface IPartitioner<T extends Token>
- All Known Implementing Classes:
- CollatingOrderPreservingPartitioner, OrderPreservingPartitioner, RandomPartitioner
public interface IPartitioner<T extends Token>
decorateKey
java.lang.String decorateKey(java.lang.String key)
- Transform key to on-disk format s.t. keys are stored in node comparison order.
This lets bootstrap rip out parts of the sstable sequentially instead of doing random seeks.
- Parameters:
key
- the raw, client-facing key
- Returns:
- decorated on-disk version of key
undecorateKey
java.lang.String undecorateKey(java.lang.String decoratedKey)
getDecoratedKeyComparator
java.util.Comparator<java.lang.String> getDecoratedKeyComparator()
getReverseDecoratedKeyComparator
java.util.Comparator<java.lang.String> getReverseDecoratedKeyComparator()
midpoint
T midpoint(T left,
T right)
- Calculate a Token representing the approximate "middle" of the given
range.
The Tokens must have been generated by previous calls to midpoint,
or be equal to this.getMinimumToken(). The range may not wrap unless it
involves this.getMinimumToken().
- Returns:
- The approximate midpoint between left and right.
getMinimumToken
T getMinimumToken()
- Returns:
- The minimum possible Token in the range that is being partitioned.
getToken
T getToken(java.lang.String key)
- Returns:
- a Token that can be used to route a given key
getDefaultToken
T getDefaultToken()
- Returns:
- the default Token to represent this node if none was saved.
Uses the one given in the InitialToken configuration directive,
or picks one automatically if that was not given.
getTokenFactory
Token.TokenFactory getTokenFactory()
preservesOrder
boolean preservesOrder()
- Returns:
- True if the implementing class preserves key order in the Tokens
it generates.
Copyright © 2009 The Apache Software Foundation