here is a small example :
@PersistenceCapable
public class Property implements Serializable{
@PrimaryKey
@Persistent
private String Key;
@Persistent(serialized = "true", defaultFetchGroup = "true")
private Object Value;
@Persistent
private Long Expiry;
private Property(String key, Object value, long expirationDeltaMillis){
this.Key = key;
this.Value = value;
if(expirationDeltaMillis > 0)
this.Expiry = new Date().getTime() + expirationDeltaMillis;
}
public static <T> T get(String key) {
Property property = WCMSHelper.getObjectById(Property.class, key);
if (property != null
&& (property.Expiry == null || property.Expiry >= new Date().getTime()))
return (T) property.Value;
else
return null;
}
public static void put(String key, Object value) {
Property.put(key, value, -1);
}
public static void put(String key, Object value,
long expirationDeltaMillis) {
Property property = new Property(key, value, expirationDeltaMillis);
*pmf*.makePersistent(property);
*cache*.put(property.Key, property);
}
}
2010/1/8 Prashant Gupta <nextprash...@gmail.com>
>
>
> 2010/1/8 Nicanor Cristian <nicanor.bab...@gmail.com>
>
>> On 01/08/2010 10:58 AM, Prashant Gupta wrote:
>>
>>
>>
>> 2010/1/8 nicanor.babula <nicanor.bab...@gmail.com>
>>
>>> Hi everyone.
>>>
>>> How memcache works on GAE? Let me explain:
>>> Do I get one memcache instance per app instance or there is one
>>> memcache instance for all instastances of my app?
>>>
>> one instance for all app instances.
>>
>> so if one app instance does:
>> memcacheService.put("loggedUser", userData1);
>>
>> and later another app instance does:
>> (UserData) memcacheService.get("loggedUser");
>> The latter instance will get the same data that the first instance put?
>>
> yeah.
>
>>
>> My app uses google accounts to handle users. I am thinking that it
>>> might be faster reading the current user data from the memcache
>>> instead of calling userService.getCurrentUser(). It would be a good
>>> approach?
>>
>> no! memcache data is not persistent, your memcache data could be removed
>> any time for any reason, like limited memory, cache age, etc. I suggest you
>> to go through docs.
>>
>> I don't want to use it for persistence. I use the datastore for
>> persistence.
>> Once a user logs in I want to write to the memcache the logged user data
>> in order to read it later (during one login session).
>>
> yes you can do this but memcache doesn't guarantee to keep the data for you
> when you come back to see it. so, you must use a persistent storage i.e.
> datasore, to make sure that you will get your data back next time. what you
> can do is to save your data to datastore and memcache both, next time if you
> do not find your data in memcache you can get it from datastore and save it
> to memcache again for next time !
>
>>
>>
>>
>>
>> Thanks,
>>> Cristian.
>>>
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>>>
>>>
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