On Fri, Sep 25, 2009 at 6:41 AM, Daniel Augustin Pavel < daniel.pa...@gmail.com> wrote:
> Hello, > > I've worked a bit on improving the perfomance of equals() and > hashCode() for the generated message clases. > Cool! Unfortunately, increasing the generated code size really is a big problem. Protobuf generated code is *huge*, and we're always looking for ways to reduce it. We made a conscious decision not to implement equals() and hashCode() in generated code because, in our experience, these methods are rarely actually desired outside of tests, so the benefit of reducing the generated code size outweighs the cost of these methods being slow. Can you tell us a bit about your use case? Again, in my experience, people who are comparing message objects by content outside of tests are almost always doing something they don't need to be (usually they actually want to compare by identity instead). But, I'm willing to be proven wrong. BTW, another way you could possibly speed up equals() and hashCode() is to serialize the objects and compare raw bytes. This can be done pretty easily in a wrapper class, without modifying the protobuf implementation. You could also implement your hash-caching trick in a wrapper class, which alone could probably make a huge difference for List.contains(). Or we could perhaps implement the hash caching in the official implementation, since it wouldn't require new generated code. > The above does not apply to LITE messages from what I can tell, they > just use the standard Object implementation of these methods (which I > find quite inappropiate for the kind of data protobuf objects are > supposed to represent). > The goal of "lite" messages is to shed features in order to reduce code size. equals() and hashCode() were two of the casualties. Since lite messages don't support reflection, our options were either to generate more code (bad -- lite users are exactly the users who don't want more code) or not implement them. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to protobuf@googlegroups.com To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/protobuf?hl=en -~----------~----~----~----~------~----~------~--~---
