| /* |
| * 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.akkastream.module |
| |
| import akka.stream.impl.StreamLayout.{AtomicModule, Module} |
| import akka.stream.impl.{SinkModule, SourceModule} |
| import akka.stream.{Attributes, MaterializationContext, SinkShape, SourceShape} |
| import org.reactivestreams.{Publisher, Subscriber} |
| |
| /** |
| * [[DummyModule]] is a set of special module to help construct a RunnableGraph, |
| * so that all ports are closed. |
| * |
| * In runtime, [[DummyModule]] should be ignored during materialization. |
| * |
| * For example, if you have a [[BridgeModule]] which only accept the input |
| * message from out of band channel, then you can use DummySource to fake |
| * a Message Source Like this. |
| * |
| * [[DummySource]] -> [[BridgeModule]] -> Sink |
| * /| |
| * / |
| * out of band input message [[Publisher]] |
| * |
| * After materialization, [[DummySource]] will be removed. |
| |
| * [[BridgeModule]] -> Sink |
| * /| |
| * / |
| * [[akka.stream.impl.PublisherSource]] |
| * |
| * |
| */ |
| trait DummyModule extends AtomicModule |
| |
| |
| /** |
| * |
| * [[DummySource]]-> [[BridgeModule]] -> Sink |
| * /| |
| * / |
| * out of band input message Source |
| * |
| * @param attributes Attributes |
| * @param shape SourceShape[Out] |
| * @tparam Out Output |
| */ |
| class DummySource[Out](val attributes: Attributes, shape: SourceShape[Out]) |
| extends SourceModule[Out, Unit](shape) with DummyModule { |
| |
| override def create(context: MaterializationContext): (Publisher[Out], Unit) = { |
| throw new UnsupportedOperationException() |
| } |
| |
| override protected def newInstance(shape: SourceShape[Out]): SourceModule[Out, Unit] = { |
| new DummySource[Out](attributes, shape) |
| } |
| |
| override def withAttributes(attr: Attributes): Module = { |
| new DummySource(attr, amendShape(attr)) |
| } |
| } |
| |
| |
| /** |
| * |
| * Source-> [[BridgeModule]] -> [[DummySink]] |
| * \ |
| * \ |
| * \| |
| * out of band output message [[Subscriber]] |
| * |
| * @param attributes Attributes |
| * @param shape SinkShape[IN] |
| */ |
| class DummySink[IN](val attributes: Attributes, shape: SinkShape[IN]) |
| extends SinkModule[IN, Unit](shape) with DummyModule { |
| override def create(context: MaterializationContext): (Subscriber[IN], Unit) = { |
| throw new UnsupportedOperationException() |
| } |
| |
| override protected def newInstance(shape: SinkShape[IN]): SinkModule[IN, Unit] = { |
| new DummySink[IN](attributes, shape) |
| } |
| |
| override def withAttributes(attr: Attributes): Module = { |
| new DummySink[IN](attr, amendShape(attr)) |
| } |
| } |