com.alibaba.dcm.internal

Class InetAddressCacheUtil

java.lang.Object

com.alibaba.dcm.internal.InetAddressCacheUtil

public class InetAddressCacheUtil
extends Object

Util class to manipulate dns cache InetAddress.Cache#cache in InetAddress.addressCache.

Caution:
Manipulation on InetAddress.addressCache MUST be guarded by InetAddress.addressCache to avoid multithreaded problem, you can see the implementation of InetAddress to confirm this (See Also lists key code of InetAddress related to this point).

Author:

Jerry Lee (oldratlee at gmail dot com)

See Also:

InetAddress, InetAddress.addressCache, InetAddress.CacheEntry, InetAddress.cacheInitIfNeeded(), InetAddress.cacheAddresses(String, InetAddress[], boolean)

Method Summary

Methods

Modifier and Type	Method and Description
static void	clearInetAddressCache()
static int	getDnsCachePolicy()
static int	getDnsNegativeCachePolicy()
static DnsCacheEntry	getInetAddressCache(String host)
static DnsCache	listInetAddressCache()
static void	removeInetAddressCache(String host)
static void	setDnsCachePolicy(int cacheSeconds) Set JVM DNS cache policy
static void	setDnsNegativeCachePolicy(int negativeCacheSeconds) Set JVM DNS negative cache policy
static void	setInetAddressCache(String host, String[] ips, long expiration) Need convert host to lowercase, see InetAddress.cacheAddresses(String, InetAddress[], boolean).

Methods inherited from class java.lang.Object

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

Method Detail

setInetAddressCache

public static void setInetAddressCache(String host,
                       String[] ips,
                       long expiration)
                                throws NoSuchMethodException,
                                       UnknownHostException,
                                       IllegalAccessException,
                                       InstantiationException,
                                       InvocationTargetException,
                                       ClassNotFoundException,
                                       NoSuchFieldException

Need convert host to lowercase, see InetAddress.cacheAddresses(String, InetAddress[], boolean).

Throws:

NoSuchMethodException

UnknownHostException

IllegalAccessException

InstantiationException

InvocationTargetException

ClassNotFoundException

NoSuchFieldException

removeInetAddressCache

public static void removeInetAddressCache(String host)
                                   throws NoSuchFieldException,
                                          IllegalAccessException

Throws:

NoSuchFieldException

IllegalAccessException

getInetAddressCache

@Nullable
public static DnsCacheEntry getInetAddressCache(String host)
                                         throws NoSuchFieldException,
                                                IllegalAccessException

Throws:

NoSuchFieldException

IllegalAccessException

listInetAddressCache

public static DnsCache listInetAddressCache()
                                     throws NoSuchFieldException,
                                            IllegalAccessException

Throws:

NoSuchFieldException

IllegalAccessException

clearInetAddressCache

public static void clearInetAddressCache()
                                  throws NoSuchFieldException,
                                         IllegalAccessException

Throws:

NoSuchFieldException

IllegalAccessException

setDnsCachePolicy

public static void setDnsCachePolicy(int cacheSeconds)
                              throws NoSuchFieldException,
                                     IllegalAccessException

Set JVM DNS cache policy

Parameters:

cacheSeconds - set default dns cache time. Special input case:

• -1 means never expired.(In effect, all negative value)
• 0 never cached.

Throws:

NoSuchFieldException

IllegalAccessException

See Also:

InetAddressCachePolicy, InetAddressCachePolicy.cachePolicy

getDnsCachePolicy

public static int getDnsCachePolicy()
                             throws NoSuchFieldException,
                                    IllegalAccessException

Throws:

NoSuchFieldException

IllegalAccessException

setDnsNegativeCachePolicy

public static void setDnsNegativeCachePolicy(int negativeCacheSeconds)
                                      throws NoSuchFieldException,
                                             IllegalAccessException

Set JVM DNS negative cache policy

Parameters:

negativeCacheSeconds - set default dns cache time. Special input case:

• -1 means never expired.(In effect, all negative value)
• 0 never cached.

Throws:

NoSuchFieldException

IllegalAccessException

See Also:

InetAddressCachePolicy, InetAddressCachePolicy.negativeCachePolicy

getDnsNegativeCachePolicy

public static int getDnsNegativeCachePolicy()
                                     throws NoSuchFieldException,
                                            IllegalAccessException

Throws:

NoSuchFieldException

IllegalAccessException