[KAFKA] Adding new client code

Signed-off-by: david.mcweeney <david.mcweeney@est.tech>
Change-Id: I38b930b1b5f4233f961d51bbab4b1828d034e67a
Issue-ID: DMAAP-1847

1 files changed, 79 insertions, 0 deletions

diff --git a/kafkaClient/src/main/java/org/onap/dmaap/kafka/OnapKafkaClient.java b/kafkaClient/src/main/java/org/onap/dmaap/kafka/OnapKafkaClient.java
new file mode 100644
index 0000000..7986869
--- /dev/null
+++ b/kafkaClient/src/main/java/org/onap/dmaap/kafka/OnapKafkaClient.java
@@ -0,0 +1,79 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * SDC
+ * ================================================================================
+ * Copyright (C) 2022 Nordix Foundation. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dmaap.kafka;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.kafka.clients.producer.RecordMetadata;
+import org.apache.kafka.common.KafkaException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Utility class that provides a handler for Kafka interactions
+ */
+public class OnapKafkaClient {
+
+    private final Logger log = LoggerFactory.getLogger(OnapKafkaClient.class.getName());
+
+    private OnapKafkaConsumer onapKafkaConsumer = null;
+
+    private final OnapKafkaProducer onapKafkaProducer;
+
+    public OnapKafkaClient(IKafkaConfig configuration) {
+        if (!configuration.getConsumerTopics().isEmpty()) {
+            onapKafkaConsumer = new OnapKafkaConsumer(configuration);
+            onapKafkaConsumer.subscribeConsumerToTopics();
+        }
+        onapKafkaProducer = new OnapKafkaProducer(configuration);
+    }
+
+    /**
+     * @param topicName The topic from which messages will be fetched
+     * @return A list of messages from a specific topic
+     */
+    public List<String> fetchFromTopic(String topicName) {
+        List<String> messages =  new ArrayList<>();
+        if (onapKafkaConsumer != null) {
+            try {
+                log.debug("Polling for messages from topic: {}", topicName);
+                messages = onapKafkaConsumer.poll(topicName);
+                log.debug("Returning messages from topic {}", topicName);
+                return messages;
+            } catch (KafkaException e) {
+                log.error("Failed to fetch from kafka for topic: {}", topicName, e);
+            }
+        } else {
+            log.error("Consumer has not been initialised with the required topic list");
+        }
+        return messages;
+    }
+
+    /**
+     * Publish data to a given topic
+     *  @param topicName The topic to which the message should be published
+     * @param data      The data to publish to the topic specified
+     * @return
+     */
+    public RecordMetadata publishToTopic(String topicName, String data) {
+        // Should we check the data size and chunk it if necessary? Do we need to?
+        return onapKafkaProducer.sendDataSynch(topicName, data);
+    }
+}