InetAddress should utilize networkaddress.cache.ttl for getLocalHost() too

[Deven You]

Hi Alan and Michael,

I add a java doc[1] for the new networkaddress.cache.localhost.ttl 
property. Please take a look when you have time.

Again, I don't know how to set 
cachePolicyPropFallback/negativeCachePolicyPropFallback. Any suggestion 
please tell me.

[1] http://cr.openjdk.java.net/~youdwei/ojdk-527/webrev.01/ 
<http://cr.openjdk.java.net/%7Eyoudwei/ojdk-527/webrev.01/>
Thanks a lot!

On 07/12/2012 02:59 PM, Deven You wrote:
> 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


-- 
Best Regards,

Deven

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