Hibernate Validator's property name provider for Gson annotated classes.

GsonPropertyNodeNameProvider.java

package util;

import java.util.Arrays;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

import org.hibernate.validator.spi.nodenameprovider.JavaBeanProperty;
import org.hibernate.validator.spi.nodenameprovider.Property;
import org.hibernate.validator.spi.nodenameprovider.PropertyNodeNameProvider;

public class GsonPropertyNodeNameProvider implements PropertyNodeNameProvider {
    @Override
    public String getName(Property property) {
        if (property instanceof JavaBeanProperty) {
            String str = getJavaBeanPropertyName((JavaBeanProperty) property);
            return str;
        }
        return getDefaultName(property);
    }

    private String getJavaBeanPropertyName(JavaBeanProperty property) {
        return Arrays
            .stream(property.getDeclaringClass().getDeclaredFields())
            .filter(f -> f.getName().equals(property.getName()))
            .filter(f -> f.isAnnotationPresent(Expose.class))
            .filter(f -> f.getAnnotation(Expose.class).serialize()) 
            .filter(f -> f.isAnnotationPresent(SerializedName.class))
            .map(f -> f.getAnnotation(SerializedName.class).value())
            .findFirst()
            .orElse(property.getName());
    }

    private String getDefaultName(Property property) {
        return property.getName();
    }
}