Major Description
When trying to import a Scala UDAF using registerJavaFunction, I get this error:
In [1]: sqlContext.registerJavaFunction('geo_mean', 'com.foo.bar.GeometricMean') --------------------------------------------------------------------------- Py4JJavaError Traceback (most recent call last) <ipython-input-1-1f793218436f> in <module>() ----> 1 sqlContext.registerJavaFunction('geo_mean', 'com.foo.bar.GeometricMean') /home/kfb/src/projects/spark/python/pyspark/sql/context.pyc in registerJavaFunction(self, name, javaClassName, returnType) 227 if returnType is not None: 228 jdt = self.sparkSession._jsparkSession.parseDataType(returnType.json()) --> 229 self.sparkSession._jsparkSession.udf().registerJava(name, javaClassName, jdt) 230 231 # TODO(andrew): delete this once we refactor things to take in SparkSession /home/kfb/src/projects/spark/python/lib/py4j-0.10.4-src.zip/py4j/java_gateway.py in __call__(self, *args) 1131 answer = self.gateway_client.send_command(command) 1132 return_value = get_return_value( -> 1133 answer, self.gateway_client, self.target_id, self.name) 1134 1135 for temp_arg in temp_args: /home/kfb/src/projects/spark/python/pyspark/sql/utils.pyc in deco(*a, **kw) 61 def deco(*a, **kw): 62 try: ---> 63 return f(*a, **kw) 64 except py4j.protocol.Py4JJavaError as e: 65 s = e.java_exception.toString() /home/kfb/src/projects/spark/python/lib/py4j-0.10.4-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name) 317 raise Py4JJavaError( 318 "An error occurred while calling {0}{1}{2}.\n". --> 319 format(target_id, ".", name), value) 320 else: 321 raise Py4JError( Py4JJavaError: An error occurred while calling o28.registerJava. : java.io.IOException: UDF class com.foo.bar.GeometricMean doesn't implement any UDF interface at org.apache.spark.sql.UDFRegistration.registerJava(UDFRegistration.scala:438) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244) at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357) at py4j.Gateway.invoke(Gateway.java:280) at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132) at py4j.commands.CallCommand.execute(CallCommand.java:79) at py4j.GatewayConnection.run(GatewayConnection.java:214) at java.lang.Thread.run(Thread.java:745)
According to SPARK-10915, UDAFs in Python aren't happening anytime soon. Without this, there's no way to get Scala UDAFs into Python Spark SQL whatsoever. Fixing that would be a huge help so that we can keep aggregations in the JVM and using DataFrames. Otherwise, all our code has to drop to to RDDs and live in Python.
