Why Realm

GDG Android Seoul talk by by Leonardo Taehwan Kim
1. Introduction to Realm
https://realm.io/

2. Use case of Realm with Instagram tag API
https://github.com/TheFinestArtist/InstagRealm

Transcript

1. Realm The Finest Artist
2. Realm [Relm]
3. ۬ [ۨৄ]
4. Realm = Kingdom
5. Realm = Mobile Database
6. Realm Replacement for SQLite & Core Data Android, Android Wear, iOS, OS X, Watch OS Java, Kotlin, Objective-C, Swift
7. Why Realm?
8. Realm Very Fast ORM like models & queries RealmResults auto refresh More features… Open source Documentation in Korean
9. How Fast?
13. Gson vs Realm This test is to compare the speed of Gson and Realm with an extremely simple object model. The overall result of the test shows that Realm performs a little faster than Gson. However, it could show different results in other test conditions. Refer to the appendix for further information. Gson.toJson Gson.fromJson Realm.createObject copyToRealm Milisecond 0 300 600 900 1200
14. ORM like models & queries
15. Model public class User extends RealmObject { @PrimaryKey private String name; private int age; @Ignore private int sessionId; // + Standard getters & setters generated by your IDE }
16. Relation public class Email extends RealmObject { private String address; private boolean active; } // Many to One public class Contact extends RealmObject { private Email email; } // Many to Many public class Contact extends RealmObject { private RealmList<Email> emails; }
17. Write realm.beginTransaction(); User user = realm.createObject(User.class); // Create a new object user.setName("John"); user.setEmail("john@corporation.com"); realm.commitTransaction();
18. Write User user = new User("John"); user.setEmail("john@corporation.com"); realm.beginTransaction(); realm.copyToRealm(user); // Copy the object to Realm. realm.copyToRealmOrUpdate(user); realm.commitTransaction();
19. Query // Fluent interface RealmResults<User> result = realm.where(User.class) .sort("age"); .beginGroup() .equalTo("name", "John") .or() .equalTo("name", "Peter") .endGroup() .findAll(); for (User user : result) { // do something... }
20. Query Options // Conditions between(), greaterThan(), lessThan(), greaterThanOrEqualTo() & lessThanOrEqualTo() equalTo() & notEqualTo() contains(), beginsWith() & endsWith() isNull() & isNotNull() beginsWith() & endsWith() & contains() // Conditions Grouping beginGroup() & endGroup() & not() & or() // Sorting RealmResults<User> result = realm.where(User.class).findAll(); result.sort("age", RealmResults.SORT_ORDER_DESCENDING); // Querying findAll() & findFirst() & findAllSorted()
21. RealmResults Auto-refresh
22. RealmResults public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> { RealmResults<Post> realmResults; public RecyclerViewAdapter(Realm realm) { realmResults = realm.where(Post.class).findAll(); } @Override public int getItemCount() { return realmResults.size(); } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(layoutRes, parent, false); return new ViewHolder(view); } @Override public void onBindViewHolder(ViewHolder holder, int position) { Post post = realmResults.get(position); // do something... } }
23. RealmResults public class UserRecyclerAdapter extends RecyclerView.Adapter<ChatRecyclerAdapter.ViewHolder> { List<User> users; public ChatRecyclerAdapter() { /*...*/ } public void setUsers(List<User> users) { this.users = users; } @Override public int getItemCount() { return users == null ? 0 : users.size(); } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(layoutRes, parent, false); return new ViewHolder(view); } @Override public void onBindViewHolder(ViewHolder holder, int position) { User user = users.get(position); /*...*/ } }
24. More Features
25. More Features Encryption (AES-256) Multiple Databases In-Memory Realm Listeners Migration Realm Browser (Mac OS)
26. Realm Configuration RealmConfiguration config1 = new RealmConfiguration.Builder(context) .name("myrealm1.realm") .encryptionKey(getKey1()) .schemaVersion(1) .setModules(new MySchemaModule1()) .migration(new MyMigration1()) .build(); RealmConfiguration config2 = new RealmConfiguration.Builder(context) .name("myrealm2.realm") .encryptionKey(null) .inMemory() .schemaVersion(2) .setModules(new MySchemaModule2()) .migration(new MyMigration2()) .build();
27. Realm Listener private RealmChangeListener realmListener; @Override public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); realmListener = new RealmChangeListener() { @Override public void onChange() { // ... do something with the updates (UI, etc.) ... } }; realm.addChangeListener(realmListener); } @Override public void onDestroy() { super.onDestroy(); realm.removeChangeListener(realmListener); }
28. Realm Migration public class Migration implements RealmMigration { @Override public long execute(Realm realm, long version) { // Migrate from version 0 to version 1 if (version == 0) { Table personTable = realm.getTable(Person.class); long fistNameIndex = getIndexForProperty(personTable, "firstName"); long lastNameIndex = getIndexForProperty(personTable, "lastName"); long fullNameIndex = personTable.addColumn(ColumnType.STRING, "fullName"); personTable.removeColumn(getIndexForProperty(personTable, "firstName")); personTable.removeColumn(getIndexForProperty(personTable, "lastName")); version++; } return version; } } https://github.com/realm/realm-java/blob/master/examples/migrationExample
29. Realm Browser
30. Open Source
31. Documentation in Korean
32. Current Limitations RealmObject Only private field Only default getter & setter Static field & method are allowed Null Values Threads
33. Users
34. More Homepage: http://realm.io/ Facebook: http://fb.com/groups/realmkr Email: kr@realm.io
35. Use Case InstagRealm https://github.com/TheFinestArtist/InstagRealm
36. InstagRealm
37. Features Instagram Tag API ScrollView, ListView, RecyclerView, CardView Infinite Scroll (Paging), Swipe to Refresh Retrofit Gson EventBus Royal Fresco, Butterknife, RecyclerView-Animator, Logger
38. Flow Retrofit (Instagram Tag API) => Gson (Serialize) => Realm (Insert data) => EventBus => Update UI & Notify Adpater
39. RestAdapter private static Gson gson = new GsonBuilder() .setExclusionStrategies(new ExclusionStrategy() { @Override public boolean shouldSkipField(FieldAttributes f) { return f.getDeclaringClass().equals(RealmObject.class); } @Override public boolean shouldSkipClass(Class<?> clazz) { return false; } }) .create(); private static RestAdapter restAdapter = new RestAdapter.Builder() .setEndpoint(END_POINT) .setConverter(new GsonConverter(gson)) .setRequestInterceptor(requestInterceptor) .build(); private static InstagramService instagramService = restAdapter.create(InstagramService.class);
40. Instagram API public static void getTag(final Activity activity, final Class<? extends RoyalDatabase> clazz, String next) { instagramService.getTags("art", accessToken, next, new Callback<TagsCallback>() { @Override public void success(TagsCallback tagsCallback, Response response) { RoyalTransaction.save(clazz, tagsCallback.data); if (ScrollViewDatabase.class.equals(clazz)) EventBus.getDefault().post(new OnScrollViewUpdateEvent(tagsCallback.pagination.next_max_tag_id, tagsCallback.data)); if (ListViewDatabase.class.equals(clazz)) EventBus.getDefault().post(new OnListViewUpdateEvent(tagsCallback.pagination.next_max_tag_id)); if (RecyclerViewDatabase.class.equals(clazz)) EventBus.getDefault().post(new OnRecyclerViewUpdateEvent(tagsCallback.pagination.next_max_tag_id)); if (CardViewDatabase.class.equals(clazz)) EventBus.getDefault().post(new OnCardViewUpdateEvent(tagsCallback.pagination.next_max_tag_id)); } @Override public void failure(RetrofitError error) { SnackBar.alert(activity, "Please check your network status!"); } }); }
41. OnEvent int itemCount = 0; public void onEvent(OnRecyclerViewUpdateEvent event) { swipeRefreshLayout.setRefreshing(false); if (event.isFailed()) return; next = event.getNext(); if (itemCount < adapter.getItemCount()) adapter.notifyItemRangeInserted(itemCount, adapter.getItemCount() - itemCount); else adapter.notifyItemRangeRemoved(itemCount, itemCount - adapter.getItemCount()); itemCount = adapter.getItemCount(); }
42. RecyclerViewAdapter public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> { RealmResults<Post> realmResults; public RecyclerViewAdapter(Realm realm) { realmResults = realm.where(Post.class).findAll(); } @Override public int getItemCount() { return realmResults.size(); } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(layoutRes, parent, false); return new ViewHolder(view); } @Override public void onBindViewHolder(ViewHolder holder, int position) { Post post = realmResults.get(position); // do something... } }
43. ListViewAdapter public class ListViewAdapter extends RealmBaseAdapter<Post> implements ListAdapter { public ListViewAdapter(Context context, RealmResults<Post> realmResults) { super(context, realmResults, true); } static class ViewHolder { ViewHolder(View view) { /*...*/ } public void setPost(Post post) { /*...*/ } } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; /* ViewHolder Inflating */ Post post = realmResults.get(position); viewHolder.setPost(post); return convertView; } }
44. Use Case InstagRealm https://github.com/TheFinestArtist/InstagRealm
47. Thank You :)
48. Appendix Test Device: Galaxy S3 Test Model public class Contact { public String address; public String number; public boolean active; } 10000 times iteration per each test. 5 times test per each method Test Code: https://github.com/Test-Codes/Realm-Java-Benchmark