heron/api/src/java/org/apache/heron/streamlet/Builder.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;

import org.apache.heron.api.spout.IRichSpout;
import org.apache.heron.streamlet.impl.BuilderImpl;

/**
 * Builder is used to register all sources. Builder thus keeps track
 * of all the starting points of the computation DAG and uses this
 * information to build the topology
 */
public interface Builder {
  static Builder newBuilder() {
    return new BuilderImpl();
  }

  /**
   * All sources of the computation should register using addSource.
   * @param supplier The supplier function that is used to create the streamlet
   */
  <R> Streamlet<R> newSource(SerializableSupplier<R> supplier);

  /**
   * Creates a new Streamlet using the underlying generator
   * @param generator The generator that generates the tuples of the streamlet
   * @param <R>
   * @return
   */
  <R> Streamlet<R> newSource(Source<R> generator);

  /**
   * Creates a new Streamlet using the provided spout
   * @param spout The spout that emits the tuples of the streamlet
   * @param <R>
   * @return
   */
  <R> Streamlet<R> newSource(IRichSpout spout);
}