ig-json-parser
Fast JSON parser for java projects.
Getting started
The easiest way to get started is to look at maven-example. For more comprehensive examples, check out the unit tests or the demo.
Gradle
For Java projects, to use this library, add this to your build.gradle file:
allprojects {
repositories {
maven {
url 'https://jitpack.io'
}
}
}
... dependencies {
compile 'com.github.instagram.ig-json-parser:runtime:master-SNAPSHOT' // the runtime
compile 'com.github.instagram.ig-json-parser:processor:master-SNAPSHOT' // the annotation processor
}
For Android projects using Android Studio 3.0+ or Gradle 4.0+, you can enable the annotation processor as following:
allprojects {
repositories {
maven {
url 'https://jitpack.io'
}
}
}
... dependencies {
annotationProcessor 'com.github.instagram.ig-json-parser:processor:master-SNAPSHOT'
implementation 'com.github.instagram.ig-json-parser:runtime:master-SNAPSHOT'
}
If you are using older gradle versions, you can use old apt plugin to integrate the annotation processor:
allprojects {
repositories {
maven {
url 'https://jitpack.io'
}
}
}
... apply plugin: 'com.neenbedankt.android-apt' dependencies {
apt 'com.github.instagram.ig-json-parser:processor:master-SNAPSHOT'
compile 'com.github.instagram.ig-json-parser:runtime:master-SNAPSHOT'
}
If you are using other build sytems, please find instructions here
Requirements for model classes
There should be a package-visible no-argument constructor for each of your model classes. The fields also need to be package-visible.
Each class that needs a serializer/deserializer generated should be annotated with @JsonType. Each field that needs to be mapped to/from JSON should be annotated with @JsonField. The @JsonField annotation has one mandatory argument, which is the fieldname for the field in the JSON.
The following is an example of a very simple model class:
@JsonType class Dessert {
@JsonField(fieldName="type")
String type;
@JsonField(fieldName="rating")
float rating;
}
Serializer/deserializer
Compiling your model classes with the annotations will automatically generate the serializer and deserializer. They will be in a generated class with the same name as your class, except with the suffix __JsonHelper. For example, to deserialize the Dessert class above, simply run the code:
Dessert parsed = Dessert__JsonHelper.parseFromJson(inputJsonString);
To serialize a class, run:
String serialized = Dessert__JsonHelper.serializeToJson(dessertObject);
Supported data types
The following scalar types are supported:
- String
- boolean/Boolean
- int/Integer
- long/Long
- float/Float
- double/Double
If a json field is another dictionary, it can be represented by another model class. That model class must also have the @JsonType annotation.
Lists of objects are supported either as Java Lists or Queues.
Proguard
Add the following lines to your proguard-rules file:
-dontwarn sun.misc.Unsafe -dontwarn javax.annotation.** Advanced features
Postprocessing
TODO: Document this. See the documentation in common/src/main/java/com/instagram/common/json/annotation/JsonType.java in the meanwhile.
Customized parsing code
TODO: Document this. See the documentation in common/src/main/java/com/instagram/common/json/annotation/JsonField.java in the meanwhile.
Optional serializer generation
To save generating serializer code if you only need deserialization, serializer generation can be disabled or enabled globally and per-class. The default is to generate serializers for all classes. To disable generation globally, pass
-AgenerateSerializer=false to the command-line arguments of javac. To override the default generation option for a single class, see JsonType.generateSerializer().