I don't like limiting the operations at the top level. Here is an
alternative:
zk.multiOp(List<Operation> operations)
Where we have a polymorphic operation:
public class Operation {
private static String path;
public static class Check {
public Check(String path, int version) {
}
}
public static class Create {
public Create(String path, byte[] data) {
}
}
public static class Update {
public Update(String path, byte[] date, int version) {
}
}
public static class Delete {
public Delete(String path, int version) {
}
}
}
On Tue, Dec 21, 2010 at 5:44 PM, Jared Cantwell <[email protected]>wrote:
> I think this is the interface Ted eluded to, but I wanted to throw it out
> there more concretely:
>
> zoo_multi_test_and_set(List<string> znodesToTest, List<int>
> versions, List<string> znodesToModify, List<OperationType>
> typeOfModifications, List<byte[]> data）
>
> You can still keep it a subset by requiring that creations explicitly set
> the test version to -1. This type of interface would really open up the
> capability of multi_test_and_set(). I have no idea how much more
> complicated it would be to implement, but I can imagine each operation type
> having Test() and Commit() operations. I think that by limiting it to only
> updates from the start we may do work that will need reversed to make this
> extension on the interface functional.
>
> ~Jared
>
> On Tue, Dec 21, 2010 at 4:48 PM, Ted Dunning <[email protected]>
> wrote:
>
> > On Tue, Dec 21, 2010 at 1:30 PM, Henry Robinson <[email protected]>
> > wrote:
> >
> > > This is a more complicated requirement, and not something that can be
> > done
> > > right now with Zookeeper even in a single operation on a single znode.
> > The
> > > only conditional operations are updates.
> >
> >
> > Actually, creates and deletes are conditional also. Creates are
> > conditional
> > on the file
> > not existing previously and deletes can accept a version number.
> >
> >
> > > Designing an API to support three
> > > different kinds of operation would also be more complicated, and the
> > > implementation would be trickier.
> > >
> >
> > This is definitely true. Conceptually it is the same thing, but
> > practically
> > building a usable API is
> > a bit tricky. Using a builder style would work, though. For example:
> >
> > Zookeeper zk = ...;
> >
> >
> > zk.transaction()
> > .create("/foobar")
> > .update("/pig", data, version)
> > .delete("/dog"", otherVersion)
> > .commit()
> >
> > Another option would be to pass a list of operations which can be one of
> > Create, Update or delete.
> >
>
