/*
 * This file is part of ELKI:
 * Environment for Developing KDD-Applications Supported by Index-Structures
 *
 * Copyright (C) 2017
 * ELKI Development Team
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package de.lmu.ifi.dbs.elki.result;

import java.util.Collection;

import de.lmu.ifi.dbs.elki.database.ids.DBIDs;
import de.lmu.ifi.dbs.elki.database.relation.Relation;
/**
 * Wrapper for storing the current database sample.
 * 
 * @author Erich Schubert
 * @since 0.4.0
 * 
 * @apiviz.composedOf DBIDs
 */
public class SamplingResult implements Result {
  /**
   * The actual selection
   */
  DBIDs sample = null;

  /**
   * Constructor.
   * 
   * @param rel Relation
   */
  public SamplingResult(Relation<?> rel) {
    super();
    sample = rel.getDBIDs();
  }

  /**
   * @return the current sample
   */
  public DBIDs getSample() {
    return sample;
  }

  /**
   * Note: trigger a resultchanged event!
   * 
   * @param sample the new sample
   */
  public void setSample(DBIDs sample) {
    this.sample = sample;
  }

  @Override
  public String getLongName() {
    return "Sample";
  }

  @Override
  public String getShortName() {
    return "sample";
  }

  /**
   * Get the sampling result attached to a relation
   *
   * @param rel Relation
   * @return Sampling result.
   */
  public static SamplingResult getSamplingResult(final Relation<?> rel) {
    Collection<SamplingResult> selections = ResultUtil.filterResults(rel.getHierarchy(), rel, SamplingResult.class);
    if(selections.isEmpty()) {
      final SamplingResult newsam = new SamplingResult(rel);
      ResultUtil.addChildResult(rel, newsam);
      return newsam;
    }
    return selections.iterator().next();
  }
}