Re: Which library implementation to use/work on?

[Mike Hearn <mike@plan99.net>]

I finally got there, w00t! It turned out to be easier to switch to the
"lite" versions of BouncyCastle and protobufs than to upgrade
classpath, so that's what I did, and now I have a spiffy CNI exposed
API that can be used from C++, which is what I was after. Thanks!

On Sun, Apr 8, 2012 at 3:18 PM, Mike Hearn <mike@plan99.net> wrote:
> Thanks, I got it to work eventually. That switch disables building of
> ecj so I had to first compile without it, then install, then adjust my
> path, then reconfigure/make/make install - bit confusing.
>
> I then encountered a couple of other issues. Firstly it seems there's
> something odd about the Google protocol buffers library that gcj does
> not like:
>
> com/google/protobuf/SingleFieldBuilder.java: In method
> 'com.google.protobuf.SingleFieldBuilder.mergeFrom(com.google.protobuf.GeneratedMessage)':
> com/google/protobuf/SingleFieldBuilder.java:192:0: error: class
> 'com.google.protobuf.GeneratedMessage' has no method named
> 'getDefaultInstanceForType' matching signature
> '()Lcom/google/protobuf/Message;'
>
> The code is some morass of generics so it's hard for me to figure out
> what the issue is here. The relevant code is:
>
> public class SingleFieldBuilder
>    <MType extends GeneratedMessage,
>     BType extends GeneratedMessage.Builder,
>     IType extends MessageOrBuilder>
>    implements GeneratedMessage.BuilderParent {
>
>  ....
>  private MType message;
>
>  public SingleFieldBuilder<MType, BType, IType> mergeFrom(
>      MType value) {
>    if (builder == null && message == message.getDefaultInstanceForType()) {
>      message = value;
>    } else {
>      getBuilder().mergeFrom(value);
>    }
>    onChanged();
>    return this;
>  }
> }
>
> Sure enough the GeneratedMessage class doesn't have
> getDefaultInstanceForType - it's implemented by subclasses.
>
> GeneratedMessage says this at the top:
>
>
> /**
>  * All generated protocol message classes extend this class.  This class
>  * implements most of the Message and Builder interfaces using Java reflection.
>  * Users can ignore this class and pretend that generated messages implement
>  * the Message interface directly.
>  *
>  * @author kenton@google.com Kenton Varda
>  */
>
> I suspect the reference to "implementing most of the interfaces using
> reflection" is key. I don't know what that means exactly, the class is
> very large and complicated:
>
> http://code.google.com/p/protobuf/source/browse/trunk/java/src/main/java/com/google/protobuf/GeneratedMessage.java
>
> I switched to the "lite" runtime which is simpler and the issue went away.
>
> The next problem is more stubs in classpath: specifically the elliptic
> curve related classes in java.security.spec. I'm already using
> BouncyCastle to implement the EC crypto - these classes are literally
> just data structures. They're probably quite trivial to do.
>
> I'll try copying the equivalent code from openjdk and see if that works.