Merge pull request alteryx#100 from JoshRosen/spark-902

Remove redundant Java Function call() definitions

This should fix [SPARK-902](https://spark-project.atlassian.net/browse/SPARK-902), an issue where some Java API Function classes could cause AbstractMethodErrors when user code is compiled using the Eclipse compiler.

Thanks to @MartinWeindel for diagnosing this problem.

(This PR subsumes alteryx#30).

(cherry picked from commit 9dfcf53)
Signed-off-by: Reynold Xin <rxin@apache.org>

core/src/main/scala/org/apache/spark/api/java/function/DoubleFlatMapFunction.java

@@ -18,20 +18,14 @@
 package org.apache.spark.api.java.function;
 
 
-import scala.runtime.AbstractFunction1;
-
 import java.io.Serializable;
 
 /**
  * A function that returns zero or more records of type Double from each input record.
  */
 // DoubleFlatMapFunction does not extend FlatMapFunction because flatMap is
 // overloaded for both FlatMapFunction and DoubleFlatMapFunction.
-public abstract class DoubleFlatMapFunction<T> extends AbstractFunction1<T, Iterable<Double>>
+public abstract class DoubleFlatMapFunction<T> extends WrappedFunction1<T, Iterable<Double>>
   implements Serializable {
-
-  public abstract Iterable<Double> call(T t);
-
-  @Override
-  public final Iterable<Double> apply(T t) { return call(t); }
+    // Intentionally left blank
 }

core/src/main/scala/org/apache/spark/api/java/function/DoubleFunction.java

@@ -18,8 +18,6 @@
 package org.apache.spark.api.java.function;
 
 
-import scala.runtime.AbstractFunction1;
-
 import java.io.Serializable;
 
 /**
@@ -29,6 +27,5 @@
 // are overloaded for both Function and DoubleFunction.
 public abstract class DoubleFunction<T> extends WrappedFunction1<T, Double>
   implements Serializable {
-
-  public abstract Double call(T t) throws Exception;
+    // Intentionally left blank
 }

core/src/main/scala/org/apache/spark/api/java/function/FlatMapFunction.scala

@@ -21,8 +21,5 @@ package org.apache.spark.api.java.function
  * A function that returns zero or more output records from each input record.
  */
 abstract class FlatMapFunction[T, R] extends Function[T, java.lang.Iterable[R]] {
-  @throws(classOf[Exception])
-  def call(x: T) : java.lang.Iterable[R]
-
   def elementType() : ClassManifest[R] = ClassManifest.Any.asInstanceOf[ClassManifest[R]]
 }

core/src/main/scala/org/apache/spark/api/java/function/FlatMapFunction2.scala

@@ -21,8 +21,5 @@ package org.apache.spark.api.java.function
  * A function that takes two inputs and returns zero or more output records.
  */
 abstract class FlatMapFunction2[A, B, C] extends Function2[A, B, java.lang.Iterable[C]] {
-  @throws(classOf[Exception])
-  def call(a: A, b:B) : java.lang.Iterable[C]
-
   def elementType() : ClassManifest[C] = ClassManifest.Any.asInstanceOf[ClassManifest[C]]
 }

core/src/main/scala/org/apache/spark/api/java/function/Function.java

@@ -19,7 +19,6 @@
 
 import scala.reflect.ClassManifest;
 import scala.reflect.ClassManifest$;
-import scala.runtime.AbstractFunction1;
 
 import java.io.Serializable;
 
@@ -30,8 +29,6 @@
  * when mapping RDDs of other types.
  */
 public abstract class Function<T, R> extends WrappedFunction1<T, R> implements Serializable {
-  public abstract R call(T t) throws Exception;
-
   public ClassManifest<R> returnType() {
     return (ClassManifest<R>) ClassManifest$.MODULE$.fromClass(Object.class);
   }

core/src/main/scala/org/apache/spark/api/java/function/Function2.java

@@ -19,7 +19,6 @@
 
 import scala.reflect.ClassManifest;
 import scala.reflect.ClassManifest$;
-import scala.runtime.AbstractFunction2;
 
 import java.io.Serializable;
 
@@ -29,8 +28,6 @@
 public abstract class Function2<T1, T2, R> extends WrappedFunction2<T1, T2, R>
   implements Serializable {
 
-  public abstract R call(T1 t1, T2 t2) throws Exception;
-
   public ClassManifest<R> returnType() {
     return (ClassManifest<R>) ClassManifest$.MODULE$.fromClass(Object.class);
   }

core/src/main/scala/org/apache/spark/api/java/function/PairFlatMapFunction.java

@@ -20,7 +20,6 @@
 import scala.Tuple2;
 import scala.reflect.ClassManifest;
 import scala.reflect.ClassManifest$;
-import scala.runtime.AbstractFunction1;
 
 import java.io.Serializable;
 
@@ -34,8 +33,6 @@ public abstract class PairFlatMapFunction<T, K, V>
   extends WrappedFunction1<T, Iterable<Tuple2<K, V>>>
   implements Serializable {
 
-  public abstract Iterable<Tuple2<K, V>> call(T t) throws Exception;
-
   public ClassManifest<K> keyType() {
     return (ClassManifest<K>) ClassManifest$.MODULE$.fromClass(Object.class);
   }

core/src/main/scala/org/apache/spark/api/java/function/PairFunction.java

@@ -20,7 +20,6 @@
 import scala.Tuple2;
 import scala.reflect.ClassManifest;
 import scala.reflect.ClassManifest$;
-import scala.runtime.AbstractFunction1;
 
 import java.io.Serializable;
 
@@ -29,12 +28,9 @@
  */
 // PairFunction does not extend Function because some UDF functions, like map,
 // are overloaded for both Function and PairFunction.
-public abstract class PairFunction<T, K, V>
-  extends WrappedFunction1<T, Tuple2<K, V>>
+public abstract class PairFunction<T, K, V> extends WrappedFunction1<T, Tuple2<K, V>>
   implements Serializable {
 
-  public abstract Tuple2<K, V> call(T t) throws Exception;
-
   public ClassManifest<K> keyType() {
     return (ClassManifest<K>) ClassManifest$.MODULE$.fromClass(Object.class);
   }