streams - Übungen - Microservices - Schritt 03

[demos/microservices] / validate-order / src / main / java / de / trion / microservices / validateorder / ValidateOrderService.java

diff --git a/validate-order/src/main/java/de/trion/microservices/validateorder/ValidateOrderService.java b/validate-order/src/main/java/de/trion/microservices/validateorder/ValidateOrderService.java
new file mode 100644 (file)
index 0000000..1ad46ce
--- /dev/null
+++ b/validate-order/src/main/java/de/trion/microservices/validateorder/ValidateOrderService.java
@@ -0,0 +1,101 @@
+package de.trion.microservices.validateorder;
+
+
+import de.trion.microservices.avro.Order;
+import de.trion.microservices.avro.OrderState;
+import de.trion.microservices.avro.OrderValidation;
+import static de.trion.microservices.avro.OrderValidationResult.FAIL;
+import static de.trion.microservices.avro.OrderValidationResult.PASS;
+import static de.trion.microservices.avro.OrderValidationType.ORDER_DETAILS_CHECK;
+import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Properties;
+import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
+import org.apache.kafka.common.serialization.Serdes;
+import org.apache.kafka.streams.KafkaStreams;
+import org.apache.kafka.streams.StreamsBuilder;
+import org.apache.kafka.streams.Topology;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+
+@Component
+public class ValidateOrderService
+{
+  final static Logger LOG = LoggerFactory.getLogger(ValidateOrderService.class);
+
+  private final String orders;
+  private final String validation;
+  private final KafkaStreams streams;
+
+
+  public ValidateOrderService(ApplicationProperties config)
+  {
+    orders = config.ordersTopic;
+    validation = config.validationTopic;
+
+    Properties properties = new Properties();
+    properties.put("bootstrap.servers", config.bootstrapServers);
+    properties.put("application.id", "validate-order");
+    properties.put("schema.registry.url", config.schemaRegistryUrl);
+    properties.put("default.key.serde", Serdes.String().getClass());
+    properties.put("default.value.serde", SpecificAvroSerde.class);
+
+    StreamsBuilder builder = new StreamsBuilder();
+    builder
+        .<String,Order>stream(orders)
+        .filter((id, order) -> order.getState() == OrderState.CREATED)
+        .mapValues((order) ->
+        {
+          List<CharSequence> messages = new LinkedList<>();
+
+          if (order.getCustomerId() < 1)
+            messages.add("Customer-ID must be greater than 0");
+          if (order.getProductId() < 1)
+            messages.add("Product-ID must be greater than 0");
+          if (order.getQuantity() < 1)
+            messages.add("The ordered quantity must be greater than 0");
+
+          return
+              OrderValidation
+                  .newBuilder()
+                  .setOrderId(order.getId())
+                  .setCheckType(ORDER_DETAILS_CHECK)
+                  .setValidationResult(messages.isEmpty() ? PASS : FAIL)
+                  .setMessages(messages)
+                  .build();
+        })
+        .to(validation);
+
+    Topology topology = builder.build();
+    streams = new KafkaStreams(topology, properties);
+    streams.setUncaughtExceptionHandler((Thread t, Throwable e) ->
+    {
+      LOG.error("Unexpected error in thread {}: {}", t, e.toString());
+      try
+      {
+        streams.close();
+      }
+      catch (Exception ex)
+      {
+        LOG.error("Could not close KafkaStreams!", ex);
+      }
+    });
+  }
+
+
+  @PostConstruct
+  public void start()
+  {
+    streams.start();
+  }
+
+  @PreDestroy
+  public void stop()
+  {
+    streams.close();
+  }
+}