io.vertx.up.uca.rs.config.MediaResolver Maven / Gradle / Ivy

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package io.vertx.up.uca.rs.config;

import io.reactivex.Observable;
import io.vertx.up.fn.Fn;
import io.vertx.up.log.Annal;
import io.vertx.up.util.Ut;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;

/**
 * Media resolver
 * 1. consumes ( default = application/json )
 * 2. produces ( default = application/json )
 */
class MediaResolver {

    private static final Annal LOGGER = Annal.get(MediaResolver.class);

    private static final Set DEFAULTS = new HashSet() {
        {
            add(MediaType.WILDCARD_TYPE);
        }
    };

    /**
     * Capture the consume mime types
     *
     * @param method method reference
     * @return return MIME
     */
    public static Set consumes(final Method method) {
        return resolve(method, Consumes.class);
    }

    /**
     * Capture the produces mime types
     *
     * @param method method reference
     * @return return MIME
     */
    public static Set produces(final Method method) {
        return resolve(method, Produces.class);
    }

    private static Set resolve(final Method method,
                                          final Class
                                                  mediaCls) {
        return Fn.getNull(() -> {
            final Annotation anno = method.getAnnotation(mediaCls);
            return Fn.getSemi(null == anno, LOGGER,
                    () -> DEFAULTS,
                    () -> {
                        final String[] value = Ut.invoke(anno, "value");
                        final Set result = new HashSet<>();
                        // RxJava 2
                        Observable.fromArray(value)
                                .filter(Objects::nonNull)
                                .map(MediaType::valueOf)
                                .filter(Objects::nonNull)
                                .subscribe(result::add)
                                .dispose();
                        return result.isEmpty() ? DEFAULTS : result;
                    });
        }, method, mediaCls);
    }
}