org.minidns.cache

Class LruCache

java.lang.Object

org.minidns.DnsCache

org.minidns.cache.LruCache

Direct Known Subclasses:

ExtendedLruCache

public class LruCache
extends DnsCache

LRU based DNSCache backed by a LinkedHashMap.

Field Summary

Fields

Modifier and Type	Field and Description
protected LinkedHashMap<DnsMessage,DnsMessage>	backend The backend cache.
protected int	capacity The internal capacity of the backend cache.
protected long	expireCount Internal expire count (subset of misses that was caused by expire).
protected long	hitCount Internal hit count.
protected long	maxTTL The upper bound of the ttl.
protected long	missCount Internal miss count.

Fields inherited from class org.minidns.DnsCache

DEFAULT_CACHE_SIZE

Constructor Summary

Constructors

Constructor and Description
LruCache()
LruCache(int capacity) Create a new LRUCache with given capacity.
LruCache(int capacity, long maxTTL) Create a new LRUCache with given capacity and upper bound ttl.

Method Summary

Modifier and Type	Method and Description
void	clear() Clear all entries in this cache.
long	getExpireCount() The number of expires (cache hits that have had a ttl to low to be retrieved).
long	getHitCount() The cache hit count (all sucessful calls to get).
long	getMissCount() Get the miss count of this cache which is the number of fruitless get calls since this cache was last resetted.
protected DnsMessage	getNormalized(DnsMessage q)
void	offer(DnsMessage query, DnsMessage reply, DnsName knownAuthoritativeZone)
protected void	putNormalized(DnsMessage q, DnsMessage message)
String	toString()

Methods inherited from class org.minidns.DnsCache

get, put

Methods inherited from class java.lang.Object

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

Field Detail

missCount

protected long missCount

Internal miss count.

expireCount

protected long expireCount

Internal expire count (subset of misses that was caused by expire).

hitCount

protected long hitCount

Internal hit count.

capacity

protected int capacity

The internal capacity of the backend cache.

maxTTL

protected long maxTTL

The upper bound of the ttl. All longer TTLs will be capped by this ttl.

backend

protected LinkedHashMap<DnsMessage,DnsMessage> backend

The backend cache.

Constructor Detail

LruCache

public LruCache(int capacity,
                long maxTTL)

Create a new LRUCache with given capacity and upper bound ttl.

Parameters:

capacity - The internal capacity.

maxTTL - The upper bound for any ttl.

LruCache

public LruCache(int capacity)

Create a new LRUCache with given capacity.

Parameters:

capacity - The capacity of this cache.

LruCache

public LruCache()

Method Detail

putNormalized

protected void putNormalized(DnsMessage q,
                             DnsMessage message)

Specified by:

putNormalized in class DnsCache

getNormalized

protected DnsMessage getNormalized(DnsMessage q)

Specified by:

getNormalized in class DnsCache

clear

public void clear()

Clear all entries in this cache.

getMissCount

public long getMissCount()

Get the miss count of this cache which is the number of fruitless get calls since this cache was last resetted.

Returns:

The number of cache misses.

getExpireCount

public long getExpireCount()

The number of expires (cache hits that have had a ttl to low to be retrieved).

Returns:

The expire count.

getHitCount

public long getHitCount()

The cache hit count (all sucessful calls to get).

Returns:

The hit count.

toString

public String toString()

Overrides:

toString in class Object

offer

public void offer(DnsMessage query,
                  DnsMessage reply,
                  DnsName knownAuthoritativeZone)

Specified by:

offer in class DnsCache