Add a TopicNameRegexValidation to validate topic names

src/main/java/com/purbon/kafka/topology/TopologyValidator.java

@@ -112,4 +112,4 @@ private Class<?> getValidationClazz(String validationClass) {
       return null;
     }
   }
-}
+}

src/main/java/com/purbon/kafka/topology/validation/topology/TopicNameRegexValidation.java

@@ -0,0 +1,71 @@
+package com.purbon.kafka.topology.validation.topology;
+
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import com.purbon.kafka.topology.exceptions.ConfigurationException;
+import com.purbon.kafka.topology.exceptions.ValidationException;
+import com.purbon.kafka.topology.model.Project;
+import com.purbon.kafka.topology.model.Topic;
+import com.purbon.kafka.topology.model.Topology;
+import com.purbon.kafka.topology.validation.TopologyValidation;
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigException;
+import com.typesafe.config.ConfigFactory;
+
+public class TopicNameRegexValidation implements TopologyValidation {
+
+  private static final Logger LOGGER = LogManager.getLogger(TopicNameRegexValidation.class);
+
+  private String topicNamePattern;
+
+  public TopicNameRegexValidation() throws ConfigurationException {
+	  Config config = ConfigFactory.load();
+	  try {
+		  this.topicNamePattern = config.getString("topology.validations.regexp");
+	  } catch (ConfigException e) {
+		  throw new ConfigurationException(
+			        "TopicNameRegexValidation requires you to define your regex in config 'topology.validations.regexp'");
+	  }
+
+	  if (StringUtils.isBlank(topicNamePattern)) {
+		  throw new ConfigurationException(
+	        "TopicNameRegexValidation is configured without specifying a topic name pattern. Use config 'topology.validations.regexp'");
+	  }
+
+	  try {
+          Pattern.compile(topicNamePattern);
+      } catch (PatternSyntaxException exception) {
+		  throw new ConfigurationException(
+			        String.format("TopicNameRegexValidation configured with unvalid regex '%s'", topicNamePattern));
+      }
+  }
+
+  public TopicNameRegexValidation(String pattern) {
+    this.topicNamePattern = pattern;
+    LOGGER.info(String.format("Applying Topic Name Regex Validation [%s]", pattern));
+  }
+
+  @Override
+  public void valid(Topology topology) throws ValidationException {
+
+    for (Project project : topology.getProjects()) {
+      for (Topic topic : project.getTopics()) {
+        matches(topic.toString());
+      }
+    }
+  }
+
+  public void matches(String topicName) throws ValidationException {
+    if (!topicName.matches(topicNamePattern)) {
+      String msg =
+          String.format(
+              "Topic name '%s' does not follow regex: %s", topicName, topicNamePattern);
+      throw new ValidationException(msg);
+    }
+  }
+}