added basic rabbitmq implementation

faircommons-services/common/src/main/java/eu/fairkom/faircommons/common/rabbitmq/RabbitMqConfiguration.java

+package eu.fairkom.faircommons.common.rabbitmq;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.amqp.core.Queue;
+import org.springframework.amqp.rabbit.annotation.EnableRabbit;
+import org.springframework.amqp.rabbit.config.SimpleRabbitListenerContainerFactory;
+import org.springframework.amqp.rabbit.connection.ConnectionFactory;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.amqp.support.converter.Jackson2JsonMessageConverter;
+import org.springframework.amqp.support.converter.MessageConverter;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@EnableRabbit
+public class RabbitMqConfiguration {
+    public static final String HASHING_QUEUE = "hashing-queue";
+
+    @Bean
+    Queue hashingQueue() {
+        return new Queue(HASHING_QUEUE, true);
+    }
+}

faircommons-services/common/src/main/java/eu/fairkom/faircommons/common/rabbitmq/RabbitMqReceiver.java

+package eu.fairkom.faircommons.common.rabbitmq;
+
+import org.springframework.amqp.rabbit.annotation.RabbitHandler;
+
+public interface RabbitMqReceiver<T> {
+    @RabbitHandler
+    void receive(T message) throws InterruptedException;
+}

faircommons-services/common/src/main/java/eu/fairkom/faircommons/common/rabbitmq/RabbitMqService.java

+package eu.fairkom.faircommons.common.rabbitmq;
+
+import eu.fairkom.faircommons.common.rabbitmq.message.HashingMessage;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.stereotype.Service;
+
+import static eu.fairkom.faircommons.common.rabbitmq.RabbitMqConfiguration.HASHING_QUEUE;
+
+@Service
+public class RabbitMqService {
+    private final RabbitTemplate rabbitTemplate;
+
+    public RabbitMqService(RabbitTemplate rabbitTemplate) {
+        this.rabbitTemplate = rabbitTemplate;
+    }
+
+    public void sendMessage(HashingMessage hashingFileMessage) {
+        rabbitTemplate.convertAndSend(HASHING_QUEUE, hashingFileMessage);
+    }
+}

faircommons-services/common/src/main/lombok/eu/fairkom/faircommons/common/rabbitmq/message/HashingMessage.java

+package eu.fairkom.faircommons.common.rabbitmq.message;
+
+import lombok.Data;
+
+import java.io.Serializable;
+
+@Data
+public class HashingMessage implements Serializable {
+    private HashingMessageType type;
+    private String name;
+}

faircommons-services/common/src/main/lombok/eu/fairkom/faircommons/common/rabbitmq/message/HashingMessageType.java

+package eu.fairkom.faircommons.common.rabbitmq.message;
+
+import java.io.Serializable;
+
+public enum HashingMessageType implements Serializable {
+    FILE, META
+}

faircommons-services/common/src/main/lombok/eu/fairkom/faircommons/common/rabbitmq/message/IpfsMessage.java

+package eu.fairkom.faircommons.common.rabbitmq.message;
+
+public class IpfsMessage {
+}

faircommons-services/common/src/main/lombok/eu/fairkom/faircommons/common/rabbitmq/message/IpfsMessageType.java

+package eu.fairkom.faircommons.common.rabbitmq.message;
+
+import java.io.Serializable;
+
+public enum IpfsMessageType implements Serializable {
+    FILE, META
+}