/*
 * 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._
import akka.stream.impl.StreamLayout.{AtomicModule, Module}


/**
 *
 * Group the T value groupBy function
 *
 * @param groupBy T => Group
 * @param attributes Attributes
 * @tparam T type
 * @tparam Group type
 */
case class GroupByModule[T, Group](groupBy: T => Group,
    attributes: Attributes = Attributes.name("groupByModule"))
  extends AtomicModule {
  val inPort = Inlet[T]("GroupByModule.in")
  val outPort = Outlet[T]("GroupByModule.out")
  override val shape = new FlowShape(inPort, outPort)

  override def replaceShape(s: Shape): Module = if (s != shape) {
    throw new UnsupportedOperationException("cannot replace the shape of a FlowModule")
  } else {
    this
  }

  override def carbonCopy: Module = newInstance

  protected def newInstance: GroupByModule[T, Group] =
    new GroupByModule[T, Group](groupBy, attributes)

  override def withAttributes(attributes: Attributes): GroupByModule[T, Group] = {
    new GroupByModule[T, Group](groupBy, attributes)
  }
}