/*
 * 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.samoa.learners;

import java.io.Serializable;
import java.util.Set;

import org.apache.samoa.core.Processor;
import org.apache.samoa.instances.Instances;
import org.apache.samoa.topology.Stream;
import org.apache.samoa.topology.TopologyBuilder;

/**
 * A Learner instance learns a model, and it can be either a classifier or a regressor. Initializing a Learner should
 * initialize a {@link Processor}, connect the Learner with the input stream, and initialize the result stream so that other processors
 * can subscribe to the results of this learner.
 */

public interface Learner extends Serializable {

  /**
   * Inits the Learner object.
   * 
   * @param topologyBuilder
   *          the topology builder
   * @param dataset
   *          the dataset
   * @param parallelism
   *          the parallelism
   */
  public void init(TopologyBuilder topologyBuilder, Instances dataset, int parallelism);

  /**
   * Gets the input processing item.
   * 
   * @return the input processing item
   */
  public Processor getInputProcessor();

  /**
   * Gets the result streams
   * 
   * @return the set of result streams
   */
  public Set<Stream> getResultStreams();
}