code: /*
   * Computoser is a music-composition algorithm and a website to present the results
   * Copyright (C) 2012-2014  Bozhidar Bozhanov
   *
   * Computoser 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.
   *
   * Computoser 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 Computoser.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package com.music;
  
  import java.util.Random;
  
  import com.music.model.PartType;
  import com.music.model.ToneType;
  import com.music.model.prefs.UserPreferences;
  import com.music.util.music.Chance;
  import com.music.util.music.NoteFactory;
  
  import jm.constants.Pitches;
  import jm.music.data.Note;
  import jm.music.data.Part;
  import jm.music.data.Phrase;
  import jm.music.data.Rest;
  import jm.music.data.Score;
  
  public class TimpaniPartGenerator implements ScoreManipulator {
  
      private Random random = new Random();
  
      @Override
      public void handleScore(Score score, ScoreContext ctx, UserPreferences prefs) {
          Part timpaniPart = ctx.getParts().get(PartType.TIMPANI);
          if (timpaniPart == null) {
              return;
          }
  
          Phrase phrase = new Phrase();
          for (int i = 0; i < ctx.getMeasures(); i++) {
              if (Chance.test(20)) {
                  phrase.add(getNote(ctx, ToneType.TONIC));
                  phrase.add(getNote(ctx, ToneType.MEDIANT));
                  if (Chance.test(20)) {
                      phrase.add(getNote(ctx, ToneType.TONIC));
                  } else {
                      phrase.addRest(new Rest(ctx.getNormalizedMeasureSize() / 4));
                  }
                  phrase.addRest(new Rest(ctx.getNormalizedMeasureSize() / 4));
              } else {
                  phrase.addRest(new Rest(ctx.getNormalizedMeasureSize()));
              }
          }
          phrase.setDynamic(100);
          timpaniPart.add(phrase);
      }
  
      private Note getNote(ScoreContext ctx, ToneType tone) {
          int pitch = Pitches.C3 + ctx.getScale().getDefinition()[tone.getDegree()];
          Note note = NoteFactory.createNote(pitch, ctx.getNormalizedMeasureSize() / 4);
          note.setDynamic(52 + random.nextInt(10));
          note.setDuration(1.2);
          return note;
      }
  
  }
  