heron/api/src/java/org/apache/heron/streamlet/StreamletBase.java

/**
 * 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.heron.streamlet;

/**
 * A Streamlet is a (potentially unbounded) ordered collection of tuples.
 * The StreamletBase class contains basic information of a Streamlet
 * such as name and partition count without the connection functions
 * such as map() and filter().
 */
public interface StreamletBase<R> {

  /**
   * Sets the name of the BaseStreamlet.
   * @param sName The name given by the user for this BaseStreamlet
   * @return Returns back the Streamlet with changed name
   */
  StreamletBase<R> setName(String sName);

  /**
   * Gets the name of the Streamlet.
   * @return Returns the name of the Streamlet
   */
  String getName();

  /**
   * Sets the number of partitions of the streamlet
   * @param numPartitions The user assigned number of partitions
   * @return Returns back the Streamlet with changed number of partitions
   */
  StreamletBase<R> setNumPartitions(int numPartitions);

  /**
   * Gets the number of partitions of this Streamlet.
   * @return the number of partitions of this Streamlet
   */
  int getNumPartitions();

  // This is the main interface that every Streamlet implementation should implement
  // The main tasks are generally to make sure that appropriate names/partitions are
  // computed and add a spout/bolt to the TopologyBuilder
  // void build(TopologyBuilder bldr, Set<String> stageNames);
}