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The "ProtocolBuffers" page has been changed by SteveLoughran: http://wiki.apache.org/hadoop/ProtocolBuffers?action=diff&rev1=2&rev2=3 Comment: I can't believe we have two binary protocols in the ASF, WS-* and avro yet Hadoop now depends on something external. * Excellent support for forward versioning, in which a remote service can support older versions of a client. * Workable support for backward versioning, in which a remote service can support newer versions of a client. This requires more careful programming in the service code. - It's closest equivalent formats are [[http://thrift.apache.org/|Apache Thrift]]. + It's closest equivalent formats are [[http://thrift.apache.org/|Apache Thrift]] and the -in Apache incubation- [[http://incubator.apache.org/etch/|Etch]] protocol The protocol is significantly different from the Web Services WS-* stack, that has been criticised by [[SteveLoughran|Steve Loughran]] and Edmund Smith in [[http://www.hpl.hp.com/techreports/2005/HPL-2005-83.pdf|Rethinking the Java SOAP Stack]] and [[http://steve.vinoski.net/pdf/IEEE-RPC_Under_Fire.pdf|RPC under fire]] in that the WS-* language for describing data XML-Schema, is not completely mappable to the Object-Oriented model of today's languages, yet the WS-* stacks attempt to seamlessly do so, even across languages. Loughran and Smith regard such an O/X mapping to be as insolvable as a perfect O/R Mapping, and hence doomed. Instead SOAP stacks should embrace the XML nature of documents and use mechanisms such as !XPath to directly work with the XML content. No widely used SOAP stack does this, as WS-* developers appear to prefer to write implementation-first code in which the datatypes are written in their native language, the interface specification reverse-engineered from this and then everyone hopes that this specification will be convertable into usable datatypes in other languages, and stable across protocol versions.
