Hi Alan and Michael,
Thanks very much for your kind suggestions.
I agree that local host shouldn't follow the default caching mechanism
because the IP may change frequently. And I also think making the cache
time configurable is a better solution.
I am willing to make these changes including adding the local host
caching mechanism into the java doc.
I have gone through the related code for InetAddress.java and
InetAddressCachePolicy.java. And I think we could add a new security
property networkaddress.cache.localhost.ttl to achieve the goal.
As far as I know, to add networkaddress.cache.localhost.ttl I need
change jdk/src/share/lib/security/java.security*(include java.security,
java.security-solaris, java.security-macosx and java.security-windows).
Please correct me if I have any misunderstanding.
Here I have one question need your help:
the static block in InetAddressCachePolicy.java will first try to
get cachePolicyProp/negativeCachePolicyProp from System properties. If
one of the cache values is null then the value of
cachePolicyPropFallback/negativeCachePolicyProp would be got from System
properties.
I don't know where we declare these fallback properties so I have no
idea where I can do the same thing for networkaddress.cache.localhost.ttl.
Please take a look.
Thanks a lot!
On 07/11/2012 06:55 PM, Michael McMahon wrote:
On 11/07/12 08:00, Alan Bateman wrote:
On 05/07/2012 07:10, Deven You wrote:
Hi All,
I noticed that InetAddress.getLocalHost() uses cache to improve the
performance. However the default implementation is caching local
host within 5 seconds.
From the spec, networkaddress.cache.ttl should be used to control
the cache behaviour and I think it is a better solution.
For example, if the networkaddress.cache.ttl is set to -1 which
means always cache the local host then we can avoid unnecessary
operations on getAddressesFromNameService to improve the performance.
I have made a patch for this solution, so anyone would like to take
a look?
[1] http://cr.openjdk.java.net/~littlee/OJDK-527/webrev.00/
<http://cr.openjdk.java.net/%7Elittlee/OJDK-527/webrev.00/>
Thanks a lot!
--
Best Regards,
Deven
I'm not sure about this one as I suspect it will cause problems in
DHCP or any environments where the host addresses changes, say moving
to a different wireless network or waking up a machine after hibernation.
-Alan
That's true. We updated the spec for the caching behavior a while
back, and probably should have included this exception
for the local host. I agree that we shouldn't change the behavior.
Perhaps, the 5 seconds could be configurable itself,
but I think it should be kept separate from the main caching behavior.
- Michael.
--
Best Regards,
Deven
