Package org.apache.storm.utils

Class RotatingMap<K,V>

java.lang.Object

org.apache.storm.utils.RotatingMap<K,V>

public class RotatingMap<K,V>
extends Object

Expires keys that have not been updated in the configured number of seconds. The algorithm used will take between expirationSecs and expirationSecs * (1 + 1 / (numBuckets-1)) to actually expire the message.

get, put, remove, containsKey, and size take O(numBuckets) time to run.

The advantage of this design is that the expiration thread only locks the object for O(1) time, meaning the object is essentially always available for gets/puts.

Note: This class is not thread-safe since it does not protect against changes to buckets while it is being read

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	RotatingMap.ExpiredCallback<K,V>

Constructor Summary

Constructors

Constructor	Description
RotatingMap(int numBuckets)
RotatingMap(int numBuckets, RotatingMap.ExpiredCallback<K,V> callback)
RotatingMap(RotatingMap.ExpiredCallback<K,V> callback)

Method Summary

Modifier and Type	Method	Description
boolean	containsKey(K key)
V	get(K key)
void	put(K key, V value)
V	remove(K key)
Map<K,V>	rotate()
int	size()

Methods inherited from class java.lang.Object

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

Constructor Details

RotatingMap

public RotatingMap(int numBuckets,
 RotatingMap.ExpiredCallback<K,V> callback)

RotatingMap

public RotatingMap(RotatingMap.ExpiredCallback<K,V> callback)

RotatingMap

public RotatingMap(int numBuckets)

Method Details

rotate

public Map<K,V> rotate()

containsKey

public boolean containsKey(K key)

get

public V get(K key)

put

public void put(K key,
 V value)

remove

public V remove(K key)

size

public int size()