Hi,
Following up on this question, is there a way to list (not multi-fetch,
just list) the existing counters in a bucket?
Regards,
Guido.
On 24/01/14 22:01, Dave Rusek wrote:
Guido,
I’m sorry, there are not currently any docs available. Rest assured
they are a work in progress. In the meantime, please feel free to
check-out the current pre-release [1]. The pre-release covers the low
level API we have built on top of the PB interface. There is a start
to a friendlier API in the develop branch of riak-java-client [2].
If you would like to get started with the low level API to begin
getting a feel for Riak datatypes, I have included a few snippets that
will hopefully help. The counters (and the data structures in general)
are implemented as two separate operations: Fetch and Update. Updating
a counter that does not exist will create it and initialize it to the
given value. Fetching a counter that has not had a value stored will
return an empty value.
While the low level API does not have convenience methods for
getAndIncrement and the like, they can all be easily accomplished
given fetch and update. It would clearly be easy for us to provide
methods for these typical access patterns and in fact, it is something
we are planning on doing.
RiakCluster cluster = …
BinaryValue bucket = …
BinaryValue key = …
BinaryValue type = ...
fetch():
DtFetchOperation get =
new DtFetchOperation.Builder(bucket, key)
.withBucketType(type)
.build();
DtFetchOperation.Response response = cluster.execute(get).get();
long value;
CrdtElement element = response.getCrdtElement();
if (crdtElement.isCounter()) {
value = element.getCounter().getValue();
} else {
...
}
update():
DtUpdateOperation update =
new DtUpdateOperation.Builder(bucket, key)
.withBucketType(type)
.withReturnBody(true)
.withOp(new CounterOp(1)) // increment by 1
.build();
DtUpdateOperation.Response response = cluster.execute(update).get();
long value;
CrdtElement element = response.getCrdtElement();
if (crdtElement.isCounter()) {
value = element.getCounter().getValue();
} else {
...
}
getAndIncrement();
long value = fetch();
update(1);
incrementAndGet():
long value = update(1); // make sure withReturnBody == true
[1] https://github.com/basho/riak-java-client
[2]https://github.com/basho/riak-java-client/tree/develop/src/main/java/com/basho/riak/client/operations
--
Dave Rusek
Basho Technologies
@davidjrusek
On January 24, 2014 at 8:41:07 AM, Guido Medina
([email protected] <mailto://[email protected]>) wrote:
Hi,
Is there any small doc that could explain its usage a little bit:
From the Java perspective it would be nice if it point out its
counter part methods with Atomic Integer like:
* How to create it? Does incrementing a counter will just create it
with zero as initial value and then increment it? What if you
need to know its value and then increment it before it is
created? (getAndIncrement)
* get()
* getAndIncrement()
* incrementAndGet()
Regards,
Guido.
_______________________________________________
riak-users mailing list
[email protected]
http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
_______________________________________________
riak-users mailing list
[email protected]
http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
