| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.gearpump.streaming.dsl.scalaapi.functions |
| |
| import org.apache.gearpump.streaming.dsl.api.functions.{FilterFunction, MapFunction} |
| import org.apache.gearpump.streaming.dsl.javaapi.functions.{FlatMapFunction => JFlatMapFunction} |
| |
| import scala.collection.JavaConverters._ |
| |
| object FlatMapFunction { |
| |
| def apply[T, R](fn: JFlatMapFunction[T, R]): FlatMapFunction[T, R] = { |
| new FlatMapFunction[T, R] { |
| |
| override def setup(): Unit = { |
| fn.setup() |
| } |
| |
| override def apply(t: T): TraversableOnce[R] = { |
| fn.apply(t).asScala |
| } |
| |
| |
| override def teardown(): Unit = { |
| fn.teardown() |
| } |
| } |
| } |
| |
| def apply[T, R](fn: T => TraversableOnce[R]): FlatMapFunction[T, R] = { |
| new FlatMapFunction[T, R] { |
| override def apply(t: T): TraversableOnce[R] = { |
| fn(t) |
| } |
| } |
| } |
| |
| def apply[T, R](fn: MapFunction[T, R]): FlatMapFunction[T, R] = { |
| new FlatMapFunction[T, R] { |
| |
| override def setup(): Unit = { |
| fn.setup() |
| } |
| |
| override def apply(t: T): TraversableOnce[R] = { |
| Option(fn(t)) |
| } |
| |
| override def teardown(): Unit = { |
| fn.teardown() |
| } |
| } |
| } |
| |
| def apply[T, R](fn: FilterFunction[T]): FlatMapFunction[T, T] = { |
| new FlatMapFunction[T, T] { |
| |
| override def setup(): Unit = { |
| fn.setup() |
| } |
| |
| override def apply(t: T): TraversableOnce[T] = { |
| if (fn(t)) { |
| Option(t) |
| } else { |
| None |
| } |
| } |
| |
| override def teardown(): Unit = { |
| fn.teardown() |
| } |
| } |
| } |
| } |
| |
| /** |
| * Transforms one input into zero or more outputs of possibly different types. |
| * This Scala version of FlatMapFunction returns a TraversableOnce. |
| * |
| * @param T Input value type |
| * @param R Output value type |
| */ |
| abstract class FlatMapFunction[T, R] extends SerializableFunction { |
| |
| def apply(t: T): TraversableOnce[R] |
| |
| } |