FX Gson

FX Gson is a set of type adapters for Google Gson to serialize JavaFX properties as their values, and deserialize values into properties.

FX Gson simply removes the property "wrapping" and delegates the serialization of the value to the Gson. This means that any configuration you add to Gson regarding a type will be taken into account when serializing a property of that type. This is true for objects and primitives.

Why use FX Gson?

In JavaFX, POJOs usually contain Property objects instead of primitives. When serialized, we usually don't want to see the internals of such Property objects in the produced JSON, but rather the actual value held by the property.

For instance, suppose the Person class is defined like this:

public class Person {
    private final StringProperty firstName;
    private final StringProperty lastName;

    public Person(String firstName, String lastName) {
        this.firstName = new SimpleStringProperty(firstName);
        this.lastName = new SimpleStringProperty(lastName);
    }
    
    // getters, setters, and property getters are omitted for brevity
}

Here is how new Person("Hans", "Muster") is serialized:

{
    "firstName": {
        "name": "",
        "value": "Hans",
        "valid": true,
        "helper": {
            "observable": {}
        }
    },
    "lastName": {
        "name": "",
        "value": "Muster",
        "valid": true,
        "helper": {
            "observable": {}
        }
    }
}

{
    "firstName": "Hans",
    "lastName": "Muster"
}

This produces a more human-readable output, and make manual modifications of the JSON easier.

Usage

All you need to know is in the wiki, but here is a quick overview.

You can use FX Gson in multiple ways depending on the degree of customization you need:

• directly create a ready-to-go Gson able to serialize JavaFX properties

  // to handle only Properties and Observable collections
  Gson fxGson = FxGson.create();
  
  // to also handle the Color & Font classes
  Gson fxGsonWithExtras = FxGson.createWithExtras();

• create a pre-configured GsonBuilder that you can further configure yourself

  Gson fxGson = FxGson.coreBuilder()
                      .registerTypeAdapterFactory(new MyFactory())
                      .disableHtmlEscaping()
                      .create();
  
  Gson fxGsonWithExtras = FxGson.fullBuilder()
                                .registerTypeAdapter(Pattern.class, new PatternSerializer())
                                .setPrettyPrinting()
                                .create();

• add JavaFX configuration to an existing GsonBuilder

  GsonBuilder builder = MyLib.getBuilder();
  Gson gson = FxGson.addFxSupport(builder).create();

• cherry-pick some pieces of FX Gson configuration and customize it to fit your needs

Java version compatiblity

There are different JRE requirements depending on the version of FX Gson:

Starting from FX Gson 4.0.0, the library has a module-info.java for compatibility with Jigsaw (Java 9+).

Starting from FX Gson 5.0.0, the library still has module-info.java compiled with Java 9, but all other class files have bytecode level 8, so it can still be used in Java 8. Thanks to @Glavo for the contribution!

Setup - adding the dependency

Manual download

You may manually download the JAR from Maven Central, although I recommend using a build tool such as Gradle.

Gradle

compile("org.hildan.fxgson:fx-gson:$VERSION")

Maven

<dependency>
   <groupId>org.hildan.fxgson</groupId>
   <artifactId>fx-gson</artifactId>
   <version>$VERSION</version> <!-- replace with latest version -->
   <type>pom</type>
</dependency>

License

Code released under the MIT license