value-processor

Helper for creating annotation processors that create/read value objects.

Download

Gradle

dependencies {
  compile 'me.tatarka.value:value-processor:0.2'
}

Maven

<dependency>
  <groupId>me.tatarka.value</groupId>
  <artifactId>value-processor</artifactId>
  <version>0.2</version>
</dependency>

Usage

First you create a ValueCreator with the processing environment.

public class MyProcessor extends AbstractProcessor {

    private ValueCreator valueCreator;

    @Override
    public synchronized void init(ProcessingEnvironment processingEnv) {
        super.init(processingEnv);
        valueCreator = new ValueCreator(processingEnv);
    }

Then create a Value from an Element. There are various methods based on what you have annotated. For example, the below creates it from the target class.

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        for (TypeElement annotation : annotations) {
            Set<? extends Element> elements = roundEnv.getElementsAnnotatedWith(annotation);
            for (Element element : elements) {
               try {
                   Value value = valueCreator.fromClass((TypeElement) element);
               } catch (ElementException e) {
                   e.printMessage(messenger);
               }
            }
        }
        return false;
    }

You can then iterate through the properties to generate your code.

// all properties
for (Property<?> property : value.getProperties()) {
    ...
}
// of a specific kind
for (Property.Getter getter : value.getProperties().getGetters()) {
    ...
}

Supported Classes

Note: Classes are expected to be treated as immutable. This meas you can only create instances with properties or read properties on and instance.

Fields

public class Foo {
    public String bar;
}

Getters

public class Foo {
    public String getBar() { ... }
}

Constructor Params

public class Foo {
    public Foo(String bar) { ... }
}

Factory Method Params

public static Foo createFoo(String bar) { ... }

Builder

public class FooBuilder {
    public FooBuilder setBar(String bar) { ... }
    public Foo build() { ... }
}

Builder Constructor Params

public class FooBuilder {
    public FooBuilder(String bar) { ... }
    public Foo build() { ... }
}

Builder Factory Params

public static FooBuilder builder(String bar) { ... }

Kotlin Data Classes

data class Foo(val bar: String)