Realm object repository sample

NoteRepository.java

// The code using Java 8 Lambda
public class NoteRepository {

  public static Note createNote() {
    Note note = new Note();
    note.setId(new RandomString(6).nextString());
    return note;
  }

  public static void updateTitle(String noteId, String title) {
    Note note = findNote(noteId);
    if (note != null) {
      getRealm().executeTransaction(realm -> note.setTitle(title));
    }
  }

  public static Note findNote(String noteId) {
    return query().equalTo(Note.Column.ID, noteId).findFirst();
  }

  public static RealmResults<Note> search(String queryString) {
    return query().contains(Note.Column.TITLE, queryString)
        .or()
        .contains(Note.Column.TAGS, queryString)
        .findAllSorted(Note.Column.CATEGORY);
  }

  public static void deleteNote(String noteId) {
    Note note = findNote(noteId);
    if (note != null) {
      getRealm().executeTransaction(realm -> note.deleteFromRealm());
    }
  }
  
  // can be moved to Realm utility class, ex: RealmHelper.java
  private static RealmQuery<Note> query() {
    return getRealm().where(Note.class);
  }

  // can be moved to Realm utility class, or injected using DI
  private static Realm getRealm() {
    return Realm.getDefaultInstance();
  }
}