[#207]: PR feedback

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/BaseStrategy.java

@@ -16,9 +16,9 @@ import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
 public abstract class BaseStrategy {
-  protected static final String ksqlRequestPath = "/ksql";
-  protected static final String queryRequestPath = "/query";
-  private static final String mappingExceptionMessage = "KSQL DB response mapping error";
+  protected static final String KSQL_REQUEST_PATH = "/ksql";
+  protected static final String QUERY_REQUEST_PATH = "/query";
+  private static final String MAPPING_EXCEPTION_ERROR = "KSQL DB response mapping error";
   protected String host = null;
   protected KsqlCommand ksqlCommand = null;
 
@@ -47,36 +47,39 @@ public abstract class BaseStrategy {
     return this;
   }
 
-  protected KsqlCommandResponse serializeTableResponse(JsonNode response, String path) {
-    if (response.isArray() && response.size() > 0) {
-      KsqlCommandResponse commandResponse = new KsqlCommandResponse();
-      JsonNode first = response.get(0);
-      JsonNode items = first.path(path);
-      Table table = items.isArray() ? getTableFromArray(items) : getTableFromObject(items);
-      return commandResponse.data(table);
-    }
-    throw new UnprocessableEntityException(mappingExceptionMessage);
+  protected String getRequestPath() {
+    return BaseStrategy.KSQL_REQUEST_PATH;
   }
 
-  protected KsqlCommandResponse serializeMessageResponse(JsonNode response, String path) {
-    if (response.isArray() && response.size() > 0) {
-      KsqlCommandResponse commandResponse = new KsqlCommandResponse();
-      JsonNode first = response.get(0);
-      JsonNode item = first.path(path);
-      return commandResponse.message(getMessageFromObject(item));
-    }
-    throw new UnprocessableEntityException(mappingExceptionMessage);
+  protected KsqlCommandResponse serializeTableResponse(JsonNode response, String key) {
+    JsonNode item = getResponseFirstItemValue(response, key);
+    Table table = item.isArray() ? getTableFromArray(item) : getTableFromObject(item);
+    return (new KsqlCommandResponse()).data(table);
+  }
+
+  protected KsqlCommandResponse serializeMessageResponse(JsonNode response, String key) {
+    JsonNode item = getResponseFirstItemValue(response, key);
+    return (new KsqlCommandResponse()).message(getMessageFromObject(item));
   }
 
   protected KsqlCommandResponse serializeQueryResponse(JsonNode response) {
     if (response.isArray() && response.size() > 0) {
-      KsqlCommandResponse commandResponse = new KsqlCommandResponse();
       Table table = (new Table())
           .headers(getQueryResponseHeader(response))
           .rows(getQueryResponseRows(response));
-      return commandResponse.data(table);
+      return (new KsqlCommandResponse()).data(table);
     }
-    throw new UnprocessableEntityException(mappingExceptionMessage);
+    throw new UnprocessableEntityException(MAPPING_EXCEPTION_ERROR);
+  }
+
+  private JsonNode getResponseFirstItemValue(JsonNode response, String key) {
+    if (response.isArray() && response.size() > 0) {
+      JsonNode first = response.get(0);
+      if (first.has(key)) {
+        return first.path(key);
+      }
+    }
+    throw new UnprocessableEntityException(MAPPING_EXCEPTION_ERROR);
   }
 
   private List<String> getQueryResponseHeader(JsonNode response) {
@@ -124,7 +127,7 @@ public abstract class BaseStrategy {
     if (node.isObject() && node.has("message")) {
       return node.get("message").asText();
     }
-    throw new UnprocessableEntityException(mappingExceptionMessage);
+    throw new UnprocessableEntityException(MAPPING_EXCEPTION_ERROR);
   }
 
   private List<List<String>> getTableRows(JsonNode node, List<String> keys) {
@@ -140,7 +143,7 @@ public abstract class BaseStrategy {
     if (node.isArray() && node.size() > 0) {
       return StreamSupport.stream(node.spliterator(), false);
     }
-    throw new UnprocessableEntityException(mappingExceptionMessage);
+    throw new UnprocessableEntityException(MAPPING_EXCEPTION_ERROR);
   }
 
   private List<String> getJsonObjectKeys(JsonNode node) {
@@ -149,7 +152,7 @@ public abstract class BaseStrategy {
           Spliterators.spliteratorUnknownSize(node.fieldNames(), Spliterator.ORDERED), false
       ).collect(Collectors.toList());
     }
-    throw new UnprocessableEntityException(mappingExceptionMessage);
+    throw new UnprocessableEntityException(MAPPING_EXCEPTION_ERROR);
   }
 
   private List<String> getJsonObjectValues(JsonNode node) {
@@ -159,7 +162,5 @@ public abstract class BaseStrategy {
 
   public abstract KsqlCommandResponse serializeResponse(JsonNode response);
 
-  protected abstract String getRequestPath();
-
   protected abstract String getTestRegExp();
 }

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/CreateStrategy.java

@@ -6,16 +6,11 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class CreateStrategy extends BaseStrategy {
-  private static final String responseValueKey = "commandStatus";
+  private static final String RESPONSE_VALUE_KEY = "commandStatus";
 
   @Override
   public KsqlCommandResponse serializeResponse(JsonNode response) {
-    return serializeMessageResponse(response, responseValueKey);
-  }
-
-  @Override
-  protected String getRequestPath() {
-    return BaseStrategy.ksqlRequestPath;
+    return serializeMessageResponse(response, RESPONSE_VALUE_KEY);
   }
 
   @Override

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/DescribeStrategy.java

@@ -6,16 +6,11 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class DescribeStrategy extends BaseStrategy {
-  private static final String responseValueKey = "sourceDescription";
+  private static final String RESPONSE_VALUE_KEY = "sourceDescription";
 
   @Override
   public KsqlCommandResponse serializeResponse(JsonNode response) {
-    return serializeTableResponse(response, responseValueKey);
-  }
-
-  @Override
-  protected String getRequestPath() {
-    return BaseStrategy.ksqlRequestPath;
+    return serializeTableResponse(response, RESPONSE_VALUE_KEY);
   }
 
   @Override

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/DropStrategy.java

@@ -6,16 +6,11 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class DropStrategy extends BaseStrategy {
-  private static final String responseValueKey = "commandStatus";
+  private static final String RESPONSE_VALUE_KEY = "commandStatus";
 
   @Override
   public KsqlCommandResponse serializeResponse(JsonNode response) {
-    return serializeMessageResponse(response, responseValueKey);
-  }
-
-  @Override
-  protected String getRequestPath() {
-    return BaseStrategy.ksqlRequestPath;
+    return serializeMessageResponse(response, RESPONSE_VALUE_KEY);
   }
 
   @Override

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/ExplainStrategy.java

@@ -6,16 +6,11 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class ExplainStrategy extends BaseStrategy {
-  private static final String responseValueKey = "queryDescription";
+  private static final String RESPONSE_VALUE_KEY = "queryDescription";
 
   @Override
   public KsqlCommandResponse serializeResponse(JsonNode response) {
-    return serializeTableResponse(response, responseValueKey);
-  }
-
-  @Override
-  protected String getRequestPath() {
-    return BaseStrategy.ksqlRequestPath;
+    return serializeTableResponse(response, RESPONSE_VALUE_KEY);
   }
 
   @Override

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/SelectStrategy.java

@@ -14,7 +14,7 @@ public class SelectStrategy extends BaseStrategy {
 
   @Override
   protected String getRequestPath() {
-    return BaseStrategy.queryRequestPath;
+    return BaseStrategy.QUERY_REQUEST_PATH;
   }
 
   @Override

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/ShowStrategy.java

@@ -8,9 +8,9 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class ShowStrategy extends BaseStrategy {
-  private final List<String> showStatements =
+  private static final List<String> SHOW_STATEMENTS =
       List.of("functions", "topics", "streams", "tables", "queries", "properties");
-  private final List<String> listStatements =
+  private static final List<String> LIST_STATEMENTS =
       List.of("functions", "topics", "streams", "tables");
   private String responseValueKey = "";
 
@@ -21,7 +21,7 @@ public class ShowStrategy extends BaseStrategy {
 
   @Override
   public boolean test(String sql) {
-    Optional<String> statement = showStatements.stream()
+    Optional<String> statement = SHOW_STATEMENTS.stream()
         .filter(s -> testSql(sql, getShowRegExp(s)) || testSql(sql, getListRegExp(s)))
         .findFirst();
     if (statement.isPresent()) {
@@ -31,11 +31,6 @@ public class ShowStrategy extends BaseStrategy {
     return false;
   }
 
-  @Override
-  protected String getRequestPath() {
-    return BaseStrategy.ksqlRequestPath;
-  }
-
   @Override
   protected String getTestRegExp() {
     return "";
@@ -46,7 +41,7 @@ public class ShowStrategy extends BaseStrategy {
   }
 
   protected String getListRegExp(String key) {
-    if (listStatements.contains(key)) {
+    if (LIST_STATEMENTS.contains(key)) {
       return "list " + key + ";";
     }
     return "";

kafka-ui-api/src/main/java/com/provectus/kafka/ui/strategy/ksql/statement/TerminateStrategy.java

@@ -6,16 +6,11 @@ import org.springframework.stereotype.Component;
 
 @Component
 public class TerminateStrategy extends BaseStrategy {
-  private static final String responseValueKey = "commandStatus";
+  private static final String RESPONSE_VALUE_KEY = "commandStatus";
 
   @Override
   public KsqlCommandResponse serializeResponse(JsonNode response) {
-    return serializeMessageResponse(response, responseValueKey);
-  }
-
-  @Override
-  protected String getRequestPath() {
-    return BaseStrategy.ksqlRequestPath;
+    return serializeMessageResponse(response, RESPONSE_VALUE_KEY);
   }
 
   @Override