JSR 107 is not complete, but Infinispan's primary API is as close as possible to JSR 107's javax.cache.Cache interface. The goal is once JSR 107 is complete, the org.infinispan.Cache interface would extend javax.cache.Cache. The key thing to note is that just like javax.cache.Cache, org.infinispan.Cache looks just like a java.util.concurrent.ConcurrentMap which would make migration between JSR 107 compliant data structures simple.
Manik Surtani, who is project lead on Infinispan, and Pete Muir are on the JSR 107 expert group.