Say "hi" to Moshi (Droidcon London 2021)

JSON serialization is an everyday task for Android developers, but it's still not a trivial one. Long used solutions such as Gson have serious pain points, especially when using them with Kotlin. Could Moshi be our saviour when it comes to dealing with JSON on Android? We'll look at how to use it, what problems it solves, and how nicely it plays with our favourite JVM language.

More resources and info: https://zsmb.co/talks/say-hi-to-moshi/

Transcript

1. Say “hi” to zsmb.co zsmb13 Márton Braun Moshi
2. @zsmb13
3. Serialization @zsmb13
4. JSON Serialization @zsmb13
5. JSON Serialization on the JVM @zsmb13
6. @zsmb13
7. @zsmb13
8. @zsmb13
9. @zsmb13
10. Gson github.com/google/gson @zsmb13
11. Gson 101 @zsmb13
12. Gson 101 val burger: Burger = Gson().fromJson("{...}", Burger::class.java) @zsmb13
13. Gson 101 val burger: Burger = Gson().fromJson("{...}", Burger::class.java) val json: String = Gson().toJson(Burger()) @zsmb13
14. Gson 101 val burger: Burger = Gson().fromJson("{...}", Burger::class.java) val json: String = Gson().toJson(Burger()) @zsmb13
15. Gson 101 val burger: Burger = Gson().fromJson("{...}", Burger::class.java) val json: String = Gson().toJson(Burger()) @zsmb13
16. Gson 101 val gson = Gson() val burger: Burger = Gson().fromJson("{...}", Burger::class.java) val json: String = Gson().toJson(Burger()) @zsmb13
17. Gson 101 val gson = Gson() val burger: Burger = gson.fromJson("{...}", Burger::class.java) val json: String = gson.toJson(Burger()) @zsmb13
18. Gson val gson = Gson() val burger: Burger = gson.fromJson("{...}", Burger::class.java) val json: String = gson.toJson(Burger()) 101 @zsmb13
19. Gson val gson = Gson() : built-in types @zsmb13
20. Gson val gson = Gson() gson.toJson(Date()) : built-in types @zsmb13 "Oct 29, 2021 : : PM" 04 08 9
21. Gson val gson = Gson() gson.toJson(Date()) "Oct 29, 2021 : : PM" : built-in types @zsmb13 04 20 9
22. Gson val gson = Gson() gson.toJson(Date()) "Oct 29, 2021 : : PM" : built-in types @zsmb13 04 24 9 gson.toJson(Calendar.getInstance()) , 21 04 24 {"year":2021,"month":9,"dayOfMonth":29,"hourOfDay": "minute": ,"second": }
23. Gson val gson = Gson() gson.toJson(Date()) "Oct 29, 2021 : : PM" gson.toJson(Calendar.getInstance()) {"year":2021,"month":9,"dayOfMonth":29,"hourOfDay": "minute": ,"second": } : built-in types @zsmb13 , 21 04 37 04 37 9
24. Gson val gson = Gson() gson.toJson(Date()) "Oct 29, 2021 : : PM" gson.toJson(Calendar.getInstance()) {"year":2021,"month":9,"dayOfMonth":29,"hourOfDay": "minute": ,"second": } : built-in types @zsmb13 21 04 40 9 , 04 40 gson.toJson(Random())
25. Gson val gson = Gson() gson.toJson(Date()) "Oct 29, 2021 : : PM" gson.toJson(Calendar.getInstance()) {"year":2021,"month":9,"dayOfMonth":29,"hourOfDay": "minute": ,"second": } : built-in types @zsmb13 21 04 55 9 , 04 55 gson.toJson(Random()) {"seed":{"value":137564286790437},"nextNextGaussian":0.0, "haveNextNextGaussian":false}
26. Gson: field naming val gson = Gson() @zsmb13
27. Gson: field naming val gson = GsonBuilder() .create() @zsmb13
28. val gson = GsonBuilder() .setFieldNamingPolicy( FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .create() Gson: field naming @zsmb13
29. val gson = GsonBuilder() .setFieldNamingPolicy( FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .create() Gson: field naming data class Burger( val name: String, val totalCost: Int, val salesPrice: Int ) @zsmb13
30. val gson = GsonBuilder() .setFieldNamingPolicy( FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .create() Gson: field naming data class Burger( val name: String, val totalCost: Int, val salesPrice: Int ) gson.toJson(Burger("Classic", 10, 13)) @zsmb13
31. val gson = GsonBuilder() .setFieldNamingPolicy( FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .create() Gson: field naming data class Burger( val name: String, val totalCost: Int, val salesPrice: Int ) gson.toJson(Burger("Classic", 10, 13)) {"name":"Classic","total_cost":10,"sales_price":13} @zsmb13
32. GsonBuilder() .setFieldNamingPolicy( FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES) .create() Gson: field naming gson.toJson(Burger("Classic", 10, 13)) {"name":"Classic","total_cost":10,"sales_price":13} val gson = data class Burger( val name: String, val totalCost: Int, val salesPrice: Int ) @zsmb13
33. @SerializedName("name") @SerializedName("total_cost") @SerializedName("sales_price") Gson() Gson: field naming gson.toJson(Burger("Classic", 10, 13)) {"name":"Classic","total_cost":10,"sales_price":13} data class Burger( val gson = val name: String, val totalCost: Int, ) val salesPrice: Int @zsmb13
34. Gson: missing data Gson() val gson = @zsmb13
35. data class Burger( val name: String, val price: Int ) Gson: missing data Gson() val gson = @zsmb13
36. data class Burger( val name: String, val price: Int ) Gson: missing data val burger = gson.fromJson("{\"name\": \"Cheeseburger\"}", Burger::class.java) Gson() val gson = @zsmb13
37. data class Burger( val name: String, val price: Int ) Gson: missing data val burger = gson.fromJson("{\"name\": \"Cheeseburger\"}", Burger::class.java) Burger(name=Cheeseburger, price=0) Gson() val gson = @zsmb13
38. data class Burger( val name: String, val description: String ) val gson = Gson() Gson: missing data val burger = gson.fromJson("{\"name\": \"Cheeseburger\"}", Burger::class.java) @zsmb13
39. data class Burger( val name: String, val description: String ) val gson = Gson() Gson: missing data val burger = gson.fromJson("{\"name\": \"Cheeseburger\"}", Burger::class.java) Burger(name=Cheeseburger, description=null) @zsmb13
40. data class Burger( val name: String, val description: String = "One of our best burgers!" ) val gson = Gson() Gson: missing data val burger = gson.fromJson("{\"name\": \"Cheeseburger\"}", Burger::class.java) @zsmb13
41. data class Burger( val name: String, val description: String = "One of our best burgers!" ) val gson = Gson() Gson: missing data val burger = gson.fromJson("{\"name\": \"Cheeseburger\"}", Burger::class.java) Burger(name=Cheeseburger, description=null) @zsmb13
42. val gson = Gson() Gson: malformed data @zsmb13
43. val gson = Gson() Gson: malformed data data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) @zsmb13
44. val gson = Gson() Gson: malformed data data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" @zsmb13
45. val gson = Gson() Gson: malformed data data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" @zsmb13
46. val gson = Gson() Gson: malformed data data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" val restaurant = gson.fromJson(json, Restaurant::class.java) @zsmb13
47. Gson: malformed data val gson = Gson() data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" val restaurant = gson.fromJson(json, Restaurant::class.java) Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "crocodile" @zsmb13
48. val gson = Gson() Gson: malformed data data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" val restaurant = gson.fromJson(json, Restaurant::class.java) Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "crocodile" @zsmb13
49. val gson = Gson() Gson: malformed data data class Burger(val name: String, val price: Int) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "" } ] }""" val restaurant = gson.fromJson(json, Restaurant::class.java) Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "" @zsmb13
51. Say “hi” to zsmb.co zsmb13 Márton Braun Moshi
52. Moshi github.com/square/moshi @zsmb13
53. Okio github.com/square/okio Retrofit github.com/square/retrofit Moshi github.com/square/moshi OkHttp github.com/square/okhttp @zsmb13
54. Moshi github.com/square/moshi @zsmb13
55. Moshi 101 @zsmb13
56. Moshi 101 def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" @zsmb13
57. public JavaBurger(String name, int price) { this.name = name; this.price = price; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } Moshi 101 } public class JavaBurger { private String name; private int price; @zsmb13
58. // ... public JavaBurger(String name, int price) { this.name = name; this.price = price; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } Moshi 101 } public class JavaBurger { private String name; private int price; @zsmb13
59. // ... public JavaBurger(String name, int price) { this.name = name; this.price = price; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } Moshi 101 val moshi = Moshi.Builder().build() } public class JavaBurger { private String name; private int price; @zsmb13
60. // ... public JavaBurger(String name, int price) { this.name = name; this.price = price; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } Moshi 101 val moshi = Moshi.Builder().build() val json = moshi.toJson(JavaBurger("Classic", 10)) } public class JavaBurger { private String name; private int price; @zsmb13
61. // ... Moshi 101 val moshi = Moshi.Builder().build() val json = moshi.toJson(JavaBurger("Classic", 10)) } public class JavaBurger { private String name; private int price; @zsmb13
62. // ... Moshi 101 val moshi = Moshi.Builder().build() val json = moshi.toJson(JavaBurger("Classic", 10)) } public class JavaBurger { private String name; private int price; val burgerAdapter: JsonAdapter<JavaBurger> = moshi.adapter(JavaBurger::class.java) @zsmb13
63. // ... Moshi 101 val moshi = Moshi.Builder().build() } public class JavaBurger { private String name; private int price; val burgerAdapter: JsonAdapter<JavaBurger> = moshi.adapter(JavaBurger::class.java) val json = burgerAdapter.toJson(JavaBurger("Classic", 10)) @zsmb13
64. // ... Moshi 101 val moshi = Moshi.Builder().build() } public class JavaBurger { private String name; private int price; val burgerAdapter: JsonAdapter<JavaBurger> = moshi.adapter(JavaBurger::class.java) val json = burgerAdapter.toJson(JavaBurger("Classic", 10)) {"name":"Classic","price":10} @zsmb13
65. // ... Moshi 101 val moshi = Moshi.Builder().build() } public class JavaBurger { private String name; private int price; val burgerAdapter: JsonAdapter<JavaBurger> = moshi.adapter(JavaBurger::class.java) val json = burgerAdapter.toJson(JavaBurger("Classic", 10)) {"name":"Classic","price":10} val burger = burgerAdapter.fromJson(json) @zsmb13
66. Burger::class.java) // ... val moshi = Moshi.Builder().build() } public Java { private String ; private int ; Java val json = burgerAdapter.toJson(JavaBurger("Classic", 10)) {"name":"Classic","price":10} val burger = burgerAdapter.fromJson(json) Burger class val burgerAdapter: JsonAdapter< Burger> = moshi.adapter(Java name price @zsmb13 Moshi 101
67. Burger::class.java) val moshi = Moshi.Builder().build() (val : String, val : Int) val burgerAdapter: JsonAdapter<Burger> = moshi.adapter( Burger class name price @zsmb13 Moshi ft. Kotlin
68. Burger::class.java) val moshi = Moshi.Builder().build() (val : String, val : Int) val burgerAdapter: JsonAdapter<Burger> = moshi.adapter( Burger class name price Moshi ft. Kotlin Exception in thread "main" java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.example.Burger. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from the moshi-kotlin- codegen artifact. @zsmb13
69. Moshi ft. Kotlin val moshi = Moshi.Builder().build() val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) Exception in thread "main" java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.example.Burger. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from the moshi-kotlin- codegen artifact. @zsmb13
70. Moshi ft. Kotlin val moshi = Moshi.Builder().build() val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) Exception in thread "main" java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.example.Burger. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from the moshi-kotlin- codegen artifact. @zsmb13
71. val moshi = Moshi.Builder().build() val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) Moshi ft. Kotlin Exception in thread "main" java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.example.Burger. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from the moshi-kotlin- codegen artifact. @zsmb13
72. val moshi = Moshi.Builder().build() val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" @zsmb13 Moshi: reflection
73. val moshi = Moshi.Builder().build() Moshi: reflection val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-kotlin:$moshi_version" @zsmb13
74. val moshi = Moshi.Builder() Moshi: reflection val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) .build() @zsmb13
75. Moshi: reflection .add(KotlinJsonAdapterFactory()) val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) .build() val moshi = Moshi.Builder() @zsmb13
76. Moshi: reflection .add(KotlinJsonAdapterFactory()) val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) val json = burgerAdapter.toJson(Burger("Classic", 10)) .build() val moshi = Moshi.Builder() @zsmb13
77. Moshi: reflection .add(KotlinJsonAdapterFactory()) val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) val json = burgerAdapter.toJson(Burger("Classic", 10)) .build() val moshi = Moshi.Builder() @zsmb13 {"name":"Classic","price":10}
78. Moshi: reflection .add(KotlinJsonAdapterFactory()) val burgerAdapter: JsonAdapter<Burger> = moshi.adapter(Burger::class.java) class Burger(val name: String, val price: Int) val json = burgerAdapter.toJson(Burger("Classic", 10)) .build() val moshi = Moshi.Builder() @zsmb13 {"name":"Classic","price":10} val burger = burgerAdapter.fromJson(json)
79. Moshi: reflection def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-kotlin:$moshi_version" @zsmb13
80. Moshi: reflection def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-kotlin:$moshi_version" Exception in thread "main" java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.example.Burger. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from the moshi-kotlin- codegen artifact. @zsmb13
81. implementation moshi-kotlin:$moshi_version" "com.squareup.moshi: def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" Moshi: reflection Exception in thread "main" java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.example.Burger. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from the artifact. moshi-kotlin- @zsmb13 codegen
82. def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" kapt moshi-kotlin-codegen:$moshi_version" "com.squareup.moshi: @zsmb13 Moshi: codegen
83. Moshi: codegen def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" @zsmb13
84. dependencies { } Moshi: codegen apply plugin: 'kotlin' apply plugin: 'kotlin-kapt' def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" @zsmb13
85. Moshi: codegen class Burger(val name: String, val price: Int) @zsmb13
86. @JsonClass(generateAdapter = true) class Burger(val name: String, val price: Int) @zsmb13 Moshi: codegen
87. @JsonClass(generateAdapter = true) class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val json = burgerAdapter.toJson(Burger("Double", 18))) @zsmb13 Moshi: codegen
88. dependencies { def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-kotlin:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" } apply plugin: 'kotlin' apply plugin: 'kotlin-kapt' val moshi = Moshi.Builder() .add(KotlinJsonAdapterFactory()) .build() @zsmb13 Moshi: mixed use
89. Moshi: mixed use dependencies { def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-kotlin:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" } apply plugin: 'kotlin' apply plugin: 'kotlin-kapt' val moshi = Moshi.Builder() .add(KotlinJsonAdapterFactory()) .build() @zsmb13
90. dependencies { def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-kotlin:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" } apply plugin: 'kotlin' apply plugin: 'kotlin-kapt' val moshi = Moshi.Builder() .add(KotlinJsonAdapterFactory()) .build() @zsmb13 Moshi: mixed use
91. class CustomBurgerAdapter { TODO("Implement deserialization") @ToJson fun toJson(writer: JsonWriter, value: Burger?) { TODO("Implement serialization") } } @FromJson fun fromJson(reader: JsonReader): Burger? { } @zsmb13 Moshi: custom adapters
92. @FromJson fun fromJson(reader: JsonReader): Burger? { } @zsmb13 Moshi: custom adapters
93. Moshi: custom adapters @FromJson fun fromJson(reader: JsonReader): Burger? { var name: String? = null var price: Int? = null } @zsmb13
94. Moshi: custom adapters @FromJson fun fromJson(reader: JsonReader): Burger? { var name: String? = null var price: Int? = null reader.beginObject() reader.endObject() } @zsmb13
95. Moshi: custom adapters @FromJson fun fromJson(reader: JsonReader): Burger? { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { } reader.endObject() } @zsmb13
96. Moshi: custom adapters @FromJson fun fromJson(reader: JsonReader): Burger? { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.nextName()) { "name" -> name = reader.nextString() "price" -> price = reader.nextInt() else -> reader.skipValue() } } reader.endObject() } @zsmb13
97. @FromJson fun fromJson(reader: JsonReader): Burger? { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.nextName()) { "name" -> name = reader.nextString() "price" -> price = reader.nextInt() else -> reader.skipValue() } } reader.endObject() return Burger(name!!, price!!) } @zsmb13 : custom adapters Moshi
98. class BurgerJsonAdapter( moshi: Moshi ) : JsonAdapter<Burger>() { override fun toString(): String = buildString(28) { append("GeneratedJsonAdapter(").append("Burger").append(')') } private val options: JsonReader.Options = JsonReader.Options.of("name", "price") private val stringAdapter: JsonAdapter<String> = moshi.adapter(String::class.java, emptySet(), "name") private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() return Burger( name = name ?: throw Util.missingProperty("name", "name", reader), price = price ?: throw Util.missingProperty("price", "price", reader) ) } override fun toJson(writer: JsonWriter, value: Burger?) { if (value == null) { throw NullPointerException( "value was null! Wrap in .nullSafe() to write nullable values.") } writer.beginObject() writer.name("name") stringAdapter.toJson(writer, value.name) writer.name("price") intAdapter.toJson(writer, value.price) writer.endObject() } } @zsmb13 Moshi’s generated adapter
99. class BurgerJsonAdapter( moshi: Moshi ) : JsonAdapter<Burger>() { override fun toString(): String = buildString(28) { append("GeneratedJsonAdapter(").append("Burger").append(')') } private val options: JsonReader.Options = JsonReader.Options.of("name", "price") private val stringAdapter: JsonAdapter<String> = moshi.adapter(String::class.java, emptySet(), "name") private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") @zsmb13 Moshi’s generated adapter
100. class BurgerJsonAdapter( moshi: Moshi ) : JsonAdapter<Burger>() { override fun toString(): String = buildString(28) { append("GeneratedJsonAdapter(").append("Burger").append(')') } private val options: JsonReader.Options = JsonReader.Options.of("name", "price") private val stringAdapter: JsonAdapter<String> = moshi.adapter(String::class.java, emptySet(), "name") private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") Moshi’s generated adapter @zsmb13
101. private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() Moshi’s generated adapter @zsmb13
102. private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() Moshi’s generated adapter @zsmb13
103. private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() Moshi’s generated adapter @zsmb13
104. private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() Moshi’s generated adapter @zsmb13
105. private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() Moshi’s generated adapter @zsmb13
106. override fun toString(): String = buildString(28) { append("GeneratedJsonAdapter(").append("Burger").append(')') } private val options: JsonReader.Options = JsonReader.Options.of("name", "price") private val stringAdapter: JsonAdapter<String> = moshi.adapter(String::class.java, emptySet(), "name") private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) Moshi’s generated adapter @zsmb13
107. private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() Moshi’s generated adapter @zsmb13
108. private val options: JsonReader.Options = JsonReader.Options.of("name", "price") private val stringAdapter: JsonAdapter<String> = moshi.adapter(String::class.java, emptySet(), "name") private val intAdapter: JsonAdapter<Int> = moshi.adapter(Int::class.java, emptySet(), "price") override fun fromJson(reader: JsonReader): Burger { var name: String? = null var price: Int? = null reader.beginObject() while (reader.hasNext()) { when (reader.selectName(options)) { 0 -> name = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("name", "name", reader) 1 -> price = intAdapter.fromJson(reader) ?: throw Util.unexpectedNull("price", "price", reader) -1 -> { Moshi’s generated adapter @zsmb13
109. throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() return Burger( name = name ?: throw Util.missingProperty("name", "name", reader), price = price ?: throw Util.missingProperty("price", "price", reader) ) } } Moshi’s generated adapter @zsmb13
110. throw Util.unexpectedNull("price", "price", reader) -1 -> { reader.skipName() reader.skipValue() } } } reader.endObject() return Burger( name = name ?: throw Util.missingProperty("name", "name", reader), price = price ?: throw Util.missingProperty("price", "price", reader) ) } } @zsmb13 Moshi’s generated adapter
111. val moshi = Moshi.Builder().build() val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) @zsmb13 : built-in types Moshi
112. val moshi = Moshi.Builder().build() val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) @zsmb13 Moshi: built-in types
113. Moshi: built-in types val moshi = Moshi.Builder().build() val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) Exception in thread "main" java.lang.IllegalArgumentException: Platform class java.util.Date requires explicit JsonAdapter to be registered @zsmb13
114. Moshi: built-in types def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" val moshi = Moshi.Builder().build() val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) @zsmb13
115. Moshi: built-in types def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" implementation "com.squareup.moshi:moshi-adapters:$moshi_version" val moshi = Moshi.Builder().build() val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) @zsmb13
116. def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-adapters:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) .build() val moshi = Moshi.Builder() @zsmb13 Moshi: built-in types
117. val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-adapters:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" .add(Date::class.java, Rfc3339DateJsonAdapter()) .build() val moshi = Moshi.Builder() @zsmb13 Moshi: built-in types 2021-10-29T : : Z 21 22 13
118. val adapter: JsonAdapter<Date> = moshi.adapter(Date::class.java) def moshi_version = '1.12.0' implementation "com.squareup.moshi:moshi:$moshi_version" implementation "com.squareup.moshi:moshi-adapters:$moshi_version" kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version" .add(Date::class.java, Rfc3339DateJsonAdapter()) 2021-10-29T : : Z .build() val moshi = Moshi.Builder() @zsmb13 Moshi: built-in types 21 22 22
119. @zsmb13 Moshi: field naming
120. @JsonClass(generateAdapter = true) data class Burger( @Json(name = "name") val name: String, @Json(name = "total_cost") val totalCost: Int, @Json(name = "sales_price") val salesPrice: Int ) @zsmb13 Moshi: field naming
121. @JsonClass(generateAdapter = true) data class Burger( @Json(name = "name") val name: String, @Json(name = "total_cost") val totalCost: Int, @Json(name = "sales_price") val salesPrice: Int ) moshi.adapter(Burger::class.java) .toJson(Burger("Classic", 10, 13)) @zsmb13 Moshi: field naming
122. @JsonClass(generateAdapter = true) data class Burger( @Json(name = "name") val name: String, @Json(name = "total_cost") val totalCost: Int, @Json(name = "sales_price") val salesPrice: Int ) moshi.adapter(Burger::class.java) .toJson(Burger("Classic", 10, 13)) {"name":"Classic","total_cost":10,"sales_price":13} @zsmb13 Moshi: field naming
123. @JsonClass(generateAdapter = true) data class Burger( val name: String, val total_cost: Int, val sales_price: Int ) moshi.adapter(Burger::class.java) .toJson(Burger("Classic", 10, 13)) {"name":"Classic","total_cost":10,"sales_price":13} @zsmb13 Moshi: field naming
124. @JsonClass(generateAdapter = true) data class Burger( val name: String, val price: Int ) @zsmb13 Moshi: missing data
125. @JsonClass(generateAdapter = true) data class Burger( val name: String, val price: Int ) Moshi: missing data @zsmb13
126. @JsonClass(generateAdapter = true) data class Burger( val name: String, val price: Int ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) @zsmb13
127. @JsonClass(generateAdapter = true) data class Burger( val name: String, val price: Int ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) Exception in thread "main" com.squareup.moshi.JsonDataException: Required value 'price' missing at $ @zsmb13
128. @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) @zsmb13
129. @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) @zsmb13
130. @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) Exception in thread "main" com.squareup.moshi.JsonDataException: Required value 'description' missing at $ @zsmb13
131. @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String? ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) @zsmb13
132. @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String? ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) Burger(name=Cheeseburger, description=null) @zsmb13
133. Burger(name=Cheeseburger, description=null) @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String = "One of our best burgers!" ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) @zsmb13
134. Burger(name=Cheeseburger, description=null) @JsonClass(generateAdapter = true) data class Burger( val name: String, val description: String = "One of our best burgers!" ) Moshi: missing data val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\"}" ) Burger(name=Cheeseburger, description=One of our best burgers!) @zsmb13
135. val moshi = Moshi.Builder() Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) .build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\", \"price\": 13}" ) @zsmb13
136. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) .add(...) val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\", \"price\": 13}" ) .build() val moshi = Moshi.Builder() @zsmb13
137. val moshi = Moshi.Builder() Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) .build() val burgerAdapter = moshi.adapter(Burger::class.java) val burger = burgerAdapter.fromJson( "{\"name\": \"Cheeseburger\", \"price\": 13}" ) @zsmb13
138. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) JsonAdapter<Burger> @zsmb13
139. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) @zsmb13
140. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int?) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) @zsmb13
141. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int?) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.toJson(Burger("Cancelled", null)) @zsmb13
142. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int?) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.toJson(Burger("Cancelled", null)) {"name":"Cancelled"} @zsmb13
143. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int?) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .serializeNulls() burgerAdapter.toJson(Burger("Cancelled", null)) {"name":"Cancelled","price":null} @zsmb13
144. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int?) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .serializeNulls() burgerAdapter.toJson(Burger("Cancelled", null)) {"name":"Cancelled","price":null} @zsmb13 JsonAdapter<Burger>
145. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int?) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .serializeNulls() burgerAdapter.toJson(Burger("Cancelled", null)) {"name":"Cancelled","price":null} @zsmb13
146. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.toJson(null) @zsmb13
147. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.toJson(null) null @zsmb13
148. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .nullSafe() burgerAdapter.toJson(null) null @zsmb13
149. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .nonNull() burgerAdapter.toJson(null) @zsmb13
150. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .nonNull() burgerAdapter.toJson(null) Exception in thread "main" com.squareup.moshi.JsonDataException: Unexpected null at $ @zsmb13
151. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) @zsmb13
152. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.fromJson( "{\"name\":\"Cheeseburger\",\"price\": 13}" ) @zsmb13
153. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.fromJson( "{\"name\":\"Cheeseburger\",\"price\": 13}" ) Burger(name=Cheeseburger, price=13) @zsmb13
154. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.fromJson( "{\"name\":\"Cheeseburger\",\"price\": 13,\"rating\":4.2}" ) @zsmb13
155. Moshi: customization options @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) burgerAdapter.fromJson( "{\"name\":\"Cheeseburger\",\"price\": 13,\"rating\":4.2}" ) Burger(name=Cheeseburger, price=13) @zsmb13
156. @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .failOnUnknown() burgerAdapter.fromJson( "{\"name\":\"Cheeseburger\",\"price\": 13,\"rating\":4.2}" ) Moshi: customization options @zsmb13
157. @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) val moshi = Moshi.Builder().build() val burgerAdapter = moshi.adapter(Burger::class.java) .failOnUnknown() burgerAdapter.fromJson( "{\"name\":\"Cheeseburger\",\"price\": 13,\"rating\":4.2}" ) Moshi: customization options Exception in thread "main" com.squareup.moshi.JsonDataException: Cannot skip unexpected NAME at $.rating @zsmb13
158. Moshi: malformed data @zsmb13
159. @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) @zsmb13 Moshi: malformed data
160. @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" @zsmb13 Moshi: malformed data
161. @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" val restaurant = adapter.fromJson(json, Restaurant::class.java) @zsmb13 Moshi: malformed data
162. Moshi: malformed data @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" val restaurant = adapter.fromJson(json, Restaurant::class.java) Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price @zsmb13
163. val json = val restaurant = adapter.fromJson(json, Restaurant::class.java) """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" Moshi: malformed data @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price @zsmb13
164. """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price @zsmb13
165. Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" @zsmb13
166. Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" @zsmb13
167. Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" @zsmb13
168. Moshi: malformed data @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = val restaurant = adapter.fromJson(json, Restaurant::class.java) """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price @zsmb13
169. Moshi: malformed data @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = val restaurant = adapter.fromJson(json, Restaurant::class.java) """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "crocodile" @zsmb13
170. Moshi: malformed data @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = val restaurant = adapter.fromJson(json, Restaurant::class.java) """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "crocodile" } ] }""" Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was crocodile at path $.menu[2].price Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "crocodile" @zsmb13
171. Moshi: malformed data @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = val restaurant = adapter.fromJson(json, Restaurant::class.java) """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "" } ] }""" Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was at path $.menu[2].price Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "" @zsmb13
172. @JsonClass(generateAdapter = true) data class Burger(val name: String, val price: Int) @JsonClass(generateAdapter = true) data class Restaurant(val menu: List<Burger>) val json = val restaurant = adapter.fromJson(json, Restaurant::class.java) """{ "menu": [ { "name": "Classic", "price": 10 }, { "name": "Cheeseburger", "price": 13 }, { "name": "Double", "price": "" } ] }""" Moshi: malformed data Exception in thread "main" com.squareup.moshi.JsonDataException: Expected an int but was at path $.menu[2].price Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "" @zsmb13
173. def retrofit_version = '2.9.0' implementation "com.squareup.retrofit2:retrofit:$retrofit_version" @zsmb13 Moshi: Retrofit integration
174. def retrofit_version = '2.9.0' implementation "com.squareup.retrofit2:retrofit:$retrofit_version" implementation "com.squareup.retrofit2:converter-moshi:$retrofit_version" @zsmb13 Moshi: Retrofit integration
175. Retrofit.Builder() .baseUrl("...") .addConverterFactory(MoshiConverterFactory.create()) .build() def retrofit_version = '2.9.0' implementation "com.squareup.retrofit2:retrofit:$retrofit_version" implementation "com.squareup.retrofit2:converter-moshi:$retrofit_version" @zsmb13 Moshi: Retrofit integration
176. Retrofit.Builder() .baseUrl("...") .addConverterFactory(MoshiConverterFactory.create()) .build() def retrofit_version = '2.9.0' implementation "com.squareup.retrofit2:retrofit:$retrofit_version" implementation "com.squareup.retrofit2:converter-moshi:$retrofit_version" val moshi = Moshi.Builder() .add(KotlinJsonAdapterFactory()) .add(...) .build() @zsmb13 Moshi: Retrofit integration
177. def retrofit_version = '2.9.0' implementation "com.squareup.retrofit2:retrofit:$retrofit_version" implementation "com.squareup.retrofit2:converter-moshi:$retrofit_version" val moshi = Moshi.Builder() .add(KotlinJsonAdapterFactory()) .add(...) .build() @zsmb13 Moshi: Retrofit integration )) Retrofit.Builder() .baseUrl("...") .addConverterFactory(MoshiConverterFactory.create( .build()
178. Retrofit.Builder() .baseUrl("...") .addConverterFactory(MoshiConverterFactory.create( .build() def retrofit_version = '2.9.0' implementation "com.squareup.retrofit2:retrofit:$retrofit_version" implementation "com.squareup.retrofit2:converter-moshi:$retrofit_version" val moshi = Moshi.Builder() .add(KotlinJsonAdapterFactory()) .add(...) .build() @zsmb13 Moshi: Retrofit integration )) moshi
179. More Moshi… •Other built-in adapters •Intermediate objects while parsing •Annotated types •Parsing arrays and other generic types •KSP support •A lot more under-the-hood details! @zsmb13
180. Resources •A Few Ok Libraries (Jake Wharton, Square) – Droidcon Montreal 2015 • https://www.youtube.com/watch?v=WvyScM_S88c •Upgrading to Moshi (Eric Cochran, Pinterest) - droidcon NYC 2017 • https://www.youtube.com/watch?v=xHFs7cccnXU •JSON Explained (Jesse Wilson, Square) – Chicago Roboto 2019 • https://www.youtube.com/watch?v=1PwdqkKDCSo @zsmb13
181. Resources •Moshi, another JSON Processor (Jesse Wilson) • https://developer.squareup.com/blog/moshi-another-json-processor/ •Exploring Moshi’s codegen (Zac Sweers) • https://www.zacsweers.dev/exploring-moshis-kotlin-code-gen/ •Reflection Machines (Jesse Wilson) • https://publicobject.com/2016/03/24/reflection-machines/ •Advanced JSON parsing techniques using Moshi and Kotlin (Christophe Beyls) • https://medium.com/@BladeCoder/advanced-json-parsing-techniques- using-moshi-and-kotlin-daf56a7b963d @zsmb13
182. zsmb.co/talks zsmb13 Márton Braun › Reflection or codegen › Kotlin-friendly › Really fast › Great failure modes › Neat APIs Say “hi” to Moshi