src/main/java/net/pterodactylus/rhynodge/mergers/ComicMerger.java

   1 /*
   2  * rhynodge - ComicMerger.java - Copyright © 2013–2021 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.rhynodge.mergers;
  19
  20 import java.util.ArrayList;
  21 import java.util.HashSet;
  22 import java.util.List;
  23 import java.util.Set;
  24 import javax.annotation.Nonnull;
  25
  26 import net.pterodactylus.rhynodge.Merger;
  27 import net.pterodactylus.rhynodge.State;
  28 import net.pterodactylus.rhynodge.states.ComicState;
  29 import net.pterodactylus.rhynodge.states.ComicState.Comic;
  30
  31 import static com.google.common.base.Preconditions.checkArgument;
  32
  33 /**
  34  * {@link Merger} implementation that merger two {@link ComicState}s.
  35  *
  36  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  37  */
  38 public class ComicMerger implements Merger {
  39
  40         @Nonnull
  41         @Override
  42         public State mergeStates(@Nonnull State previousState, @Nonnull State currentState) {
  43                 checkArgument(previousState instanceof ComicState, "previous state must be a comic state");
  44                 checkArgument(currentState instanceof ComicState, "current state must be a comic state");
  45
  46                 ComicState previousComicState = (ComicState) previousState;
  47                 ComicState currentComicState = (ComicState) currentState;
  48
  49                 List<Comic> allComics = new ArrayList<>(previousComicState.comics());
  50                 Set<Comic> newComics = new HashSet<>();
  51
  52                 for (Comic comic : currentComicState) {
  53                         if (!allComics.contains(comic)) {
  54                                 allComics.add(comic);
  55                                 newComics.add(comic);
  56                         }
  57                 }
  58
  59                 return new ComicState(allComics, newComics);
  60         }
  61
  62 }