Battle of Immutables

AutoValue vs Lombok

DroidconUK 2016 Lightning Talk

Transcript

1. Battle Of Immutables AutoValue vs Lombok Evelina Vrabie - Consumer Team Carlo Marinangeli - Restaurant Team DELIVEROO
2. Why, What & How
3. Why • Write • less • useless • boilerplate • code
4. What Annotation processors help you remove boilerplate. • no more getters • no more setters • no more hashCode(), equals(), toString() • no more builders
5. How • How they generate code • Features offered • How much code to write • Number of methods generated
6. How AutoValue is a standard compile-time annotation processor.
7. How Lombok is not a standard annotation processor. Modifies the Abstract Syntax Tree, allowing to generate new methods or inject new code.
 
 It does not generate new classes.
9. Features Code generation • getters (and setters) • equals, hashCode • toString • builder Extensions • Parcelable • Json serialization • more...
10. public class Card { private final String number; private final String expiryDate; private final int cvc; private final String nameOnCard; private Card(Builder builder) {} public String getNumber() {} public String getExpiryDate() {} public int getCvc() {} public String getNameOnCard() {} @Override public boolean equals(Object o) {} @Override public int hashCode() {} @Override public String toString() {} public static Builder builder() {} public Builder copy() {} public static final class Builder { private String number; private String expiryDate; private int cvc; private String nameOnCard; public Builder number(String val) {} public Builder expiryDate(String val) {} public Builder cvc(int val) {} public Builder nameOnCard(String val) {} public Card build() {} } } Some code How we used to write
11. @AutoValue public abstract class Card { public abstract String number(); public abstract String expiryDate(); public abstract int cvc(); public abstract String nameOnCard(); public abstract Builder copyBuilder(); public static Builder builder() {...} @AutoValue.Builder public abstract static class Builder { public abstract Builder number(String number); public abstract Builder expiryDate(String expiryDate); public abstract Builder cvc(int cvc); public abstract Builder nameOnCard(String nameOnCard); public abstract Card build(); } } @lombok.Value() @lombok.Builder(toBuilder = true) public class Card { private final String number; private final String expiryDate; private final int cvc; private final String nameOnCard; } Some code How we write now
12. The cost Method reference count • How many methods does the generated code have? • How does the pojo compare to AutoValue and to Lombok?
13. The cost Method reference count • dx • dexdump • dex-method-counts • dex-method-list
14. The cost Method reference count • ./gradlew compileDebugSources • cd app/build/intermediates/classes/debug • dx --dex --output=output.dex com/deliveroo/.../ Order.class • dexdump -f output.dex • look for `method_ids_size`
16. The cost dexdump Processing 'output.dex'... Opened 'output.dex', DEX version '035' DEX file header: magic : 'dex\n035\0' checksum : 60d6b095 signature : c81d...e4a5 file_size : 1420 header_size : 112 link_size : 0 link_off : 0 (0x000000) string_ids_size : 34 string_ids_off : 112 (0x000070) type_ids_size : 10type_ids_off : 248 (0x0000f8) proto_ids_size : 11 proto_ids_off : 288 (0x000120) field_ids_size : 1 field_ids_off : 420 (0x0001a4) method_ids_size : 13 method_ids_off : 428 (0x0001ac) class_defs_size : 1 class_defs_off : 532 (0x000214) data_size : 856 data_off : 564 (0x000234)
17. The cost dex-method-counts Processing output.dex Read in 13 method IDs. <root>: 13 com: 6 deliveroo: 6 battleofimmutables: 6 model: 6 java: 7 lang: 7 Overall method count: 13
18. The cost dex-method-list com.deliveroo.battleofimmutables.model.pojo.Card <init>(Card$Builder) com.deliveroo.battleofimmutables.model.pojo.Card <init>(Card$Builder, Card$1) com.deliveroo.battleofimmutables.model.pojo.Card builder() → Card$Builder com.deliveroo.battleofimmutables.model.pojo.Card builder(Card) → Card$Builder com.deliveroo.battleofimmutables.model.pojo.Card equals(Object) → boolean com.deliveroo.battleofimmutables.model.pojo.Card getCvc() → int com.deliveroo.battleofimmutables.model.pojo.Card getExpiryDate() → String com.deliveroo.battleofimmutables.model.pojo.Card getNameOnCard() → String com.deliveroo.battleofimmutables.model.pojo.Card getNumber() → String com.deliveroo.battleofimmutables.model.pojo.Card hashCode() → int com.deliveroo.battleofimmutables.model.pojo.Card toString() → String com.deliveroo.battleofimmutables.model.pojo.Card$Builder <init>(Card$1) com.deliveroo.battleofimmutables.model.pojo.Card$Builder access$000(Card$Builder) → String com.deliveroo.battleofimmutables.model.pojo.Card$Builder access$002(Card$Builder, String) → String
19. The cost Method count Pojo AutoValue Lombok 1 field 6 (+7) = 13 7 (+4) = 11 7 (+5) = 12 4 fields 24 (+12) = 36 22 (+14) = 36 10 (+10) = 20 15 fields 158 (+18) = 176 188 (+26) = 220 101 (+12) = 113
20. The cost access$ ??? 11: getfield #4 // Field number:Ljava/lang/String; 14: invokestatic #28 // Method com/deliveroo/battleofimmutables/ model/pojo/Card$Builder.access$002:(Lcom/deliveroo/battleofimmutables/ model/pojo/Card$Builder;Ljava/lang/String;)Ljava/lang/String;
21. Handwritten code Pojo AutoValue Lombok 15 fields 307 50 19 AutoValue gives 85% less lines Lombok gives 94% less lines
23. The benefits • The generated code is tested • The generated code is smaller • Forward-compatible code • Human-readable generated code* • Helps prevent null references • Helps eliminate coding mistakes • Easier assertions in tests *with a plugin, for Lombok
24. AutoValue Extensions • Copy methods • Json serialization • Parcelable
25. AutoValue + Gson apt 'com.ryanharter.auto.value:auto-value-gson:0.4.2' provided 'com.ryanharter.auto.value:auto-value-gson:0.4.2' @GsonTypeAdapterFactory public abstract class OrderGsonAdapterFactory implements TypeAdapterFactory { public static OrderGsonAdapterFactory create() { return new AutoValueGson_OrderGsonAdapterFactory(); } } // auto-value-gson extension public static TypeAdapter<Order> typeAdapter(Gson gson) { return new GsonTypeAdapter(gson); }
26. AutoValue + Parcelable apt 'com.ryanharter.auto.value:auto-value-parcel:0.2.5' @AutoValue public abstract class Order implements Parcelable { }
27. AutoValue + ‘with’ apt 'com.gabrielittner.auto.value:auto-value-with:1.0.0' // auto-value-with extension public abstract Order withStatus(String status);
28. AutoValue + more • http://jakewharton.com/auto-value-extensions- ny-android-meetup/ • http://ryanharter.com/blog/2016/05/16/ autovalue-extensions/
30. Features in Lombok • @Getter • @Setter • @EqualsAndHashCode • @ToString • @[No|Required|All]ArgsConstructor • @Value => @Getter, @EqualsAndHashCode, @ToString, @AllArgsConstructor • @Data => @Value @Setter • @Synchronized
31. Features in Lombok • @Getter(lazy=true) • @Builders - @Builder(toBuilder = true) • @Singular • @FieldDefault(makeFinal=true, level=PRIVATE) • @Wither • @Cleanup • @NonNull
32. Other generators • Immutables • Google Protobuf + Wire • Apache Thrift
33. Links • https://github.com/mihaip/dex-method-counts • https://projectlombok.org/features/ • https://immutables.github.io • https://github.com/google/auto/blob/master/value/userguide/index.md • https://github.com/JakeWharton/dex-method-list • https://github.com/square/wire • https://github.com/Microsoft/thrifty • https://github.com/mg6maciej/hrisey • https://github.com/evelyne24/BattleOfImmutables
34. Thank you @inryaa @carlonzo yes, we are hiring…
35. Q&A • Does it work with Jack toolchain? • Not from what we’ve tried… • ...but it works with Retrolambda • Can AutoValue/Lombok implement interfaces? • Yes • … with default methods? • Yes
36. Pitfalls • AutoValue & Json deserialization: watch out for @Nullable annotations • AutoValue & Parcelable: watch out for non-parcelable fields • Lombok: all fields are nullable - must add @NonNull annotations • Immutability: watch out for collections (make a defensive copy in the builder)