org.opennms.netmgt.dnsresolver.netty

Class CaffeineDnsCache

java.lang.Object

org.opennms.netmgt.dnsresolver.netty.CaffeineDnsCache

All Implemented Interfaces:

io.netty.resolver.dns.DnsCache, ExtendedDnsCache

public class CaffeineDnsCache
extends Object
implements ExtendedDnsCache

DNS cache implementation largely copied from Netty's https://github.com/netty/netty/blob/netty-4.1.38.Final/resolver-dns/src/main/java/io/netty/resolver/dns/DefaultDnsCache.java but adapted slightly to work with our CaffeineCache.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	DEFAULT_MAX_SIZE
protected static int	DEFAULT_NEGATIVE_TTL_SECS
protected static int	MAX_SUPPORTED_TTL_SECS

Constructor Summary

Constructors

Constructor and Description
CaffeineDnsCache() Create a cache that respects the TTL returned by the DNS server and doesn't cache negative responses.
CaffeineDnsCache(int minTtl, int maxTtl, int negativeTtl, long maxSize) Create a cache.

Method Summary

Modifier and Type	Method and Description
ExtendedDnsCacheEntry	cache(String hostname, io.netty.handler.codec.dns.DnsPtrRecord ptrRecord, io.netty.channel.EventLoop loop) Positive caching for reverse lookups.
io.netty.resolver.dns.DnsCacheEntry	cache(String hostname, io.netty.handler.codec.dns.DnsRecord[] additionals, InetAddress address, long originalTtl, io.netty.channel.EventLoop loop) Positive caching for normal lookups.
io.netty.resolver.dns.DnsCacheEntry	cache(String hostname, io.netty.handler.codec.dns.DnsRecord[] additionals, Throwable cause, io.netty.channel.EventLoop loop) Negative caching for failures (or empty reverse lookups).
void	clear()
boolean	clear(String hostname)
List<? extends io.netty.resolver.dns.DnsCacheEntry>	get(String hostname, io.netty.handler.codec.dns.DnsRecord[] additionals)
long	getSize()
long	maxSize() Returns the maximum number of elements allows in the cache.
int	maxTtl() Returns the maximum TTL of the cached DNS resource records (in seconds).
int	minTtl() Returns the minimum TTL of the cached DNS resource records (in seconds).
int	negativeTtl() Returns the TTL of the cache for the failed DNS queries (in seconds).
void	registerMetrics(com.codahale.metrics.MetricRegistry metrics)
String	toString()
void	unregisterMetrics(com.codahale.metrics.MetricRegistry metrics)

Methods inherited from class java.lang.Object

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

Field Detail

MAX_SUPPORTED_TTL_SECS

protected static final int MAX_SUPPORTED_TTL_SECS

DEFAULT_NEGATIVE_TTL_SECS

protected static final int DEFAULT_NEGATIVE_TTL_SECS

DEFAULT_MAX_SIZE

protected static final int DEFAULT_MAX_SIZE

See Also:

Constant Field Values

Constructor Detail

CaffeineDnsCache

public CaffeineDnsCache()

Create a cache that respects the TTL returned by the DNS server and doesn't cache negative responses.

CaffeineDnsCache

public CaffeineDnsCache(int minTtl,
                        int maxTtl,
                        int negativeTtl,
                        long maxSize)

Create a cache.

Parameters:

minTtl - the minimum TTL

maxTtl - the maximum TTL

negativeTtl - the TTL for failed queries

Method Detail

minTtl

public int minTtl()

Returns the minimum TTL of the cached DNS resource records (in seconds).

See Also:

maxTtl()

maxTtl

public int maxTtl()

Returns the maximum TTL of the cached DNS resource records (in seconds).

See Also:

minTtl()

negativeTtl

public int negativeTtl()

Returns the TTL of the cache for the failed DNS queries (in seconds). The default value is 0, which disables the cache for negative results.

maxSize

public long maxSize()

Returns the maximum number of elements allows in the cache.

clear

public void clear()

Specified by:

clear in interface io.netty.resolver.dns.DnsCache

clear

public boolean clear(String hostname)

Specified by:

clear in interface io.netty.resolver.dns.DnsCache

get

public List<? extends io.netty.resolver.dns.DnsCacheEntry> get(String hostname,
                                                               io.netty.handler.codec.dns.DnsRecord[] additionals)

Specified by:

get in interface io.netty.resolver.dns.DnsCache

cache

public io.netty.resolver.dns.DnsCacheEntry cache(String hostname,
                                                 io.netty.handler.codec.dns.DnsRecord[] additionals,
                                                 InetAddress address,
                                                 long originalTtl,
                                                 io.netty.channel.EventLoop loop)

Positive caching for normal lookups.

Specified by:

cache in interface io.netty.resolver.dns.DnsCache

cache

public ExtendedDnsCacheEntry cache(String hostname,
                                   io.netty.handler.codec.dns.DnsPtrRecord ptrRecord,
                                   io.netty.channel.EventLoop loop)

Positive caching for reverse lookups.

Specified by:

cache in interface ExtendedDnsCache

cache

public io.netty.resolver.dns.DnsCacheEntry cache(String hostname,
                                                 io.netty.handler.codec.dns.DnsRecord[] additionals,
                                                 Throwable cause,
                                                 io.netty.channel.EventLoop loop)

Negative caching for failures (or empty reverse lookups).

Specified by:

cache in interface io.netty.resolver.dns.DnsCache

toString

public String toString()

Overrides:

toString in class Object

getSize

public long getSize()

registerMetrics

public void registerMetrics(com.codahale.metrics.MetricRegistry metrics)

unregisterMetrics

public void unregisterMetrics(com.codahale.metrics.MetricRegistry metrics)