Adds support for table * (#710)

* allows using just a wildcard with table command, added new tests

* updated wildcard fixes after related fixes done in PTH_03

Author: Abigael-JT

src/main/java/com/teragrep/pth_10/ast/commands/transformstatement/TableTransformation.java

@@ -88,14 +88,19 @@ private Node tableTransformationEmitCatalyst(DPLParser.TableTransformationContex
 
     @Override
     public Node visitT_table_wcfieldListParameter(DPLParser.T_table_wcfieldListParameterContext ctx) {
-        List<String> listOfFields = new ArrayList<>();
+        final List<String> listOfFields = new ArrayList<>();
 
         ctx.t_table_fieldType().forEach(fieldType -> {
             String fieldName = ((StringNode) visit(fieldType)).toString();
 
-            if (!fieldName.equals("")) {
+            if (!fieldName.isEmpty()) {
                 listOfFields.addAll(Arrays.asList(fieldName.split(",")));
             }
+            else {
+                throw new IllegalStateException(
+                        "table command is missing field names, it requires at least one valid field name."
+                );
+            }
         });
 
         return new StringListNode(listOfFields);

src/test/java/com/teragrep/pth_10/TableTransformationTest.java

@@ -192,4 +192,45 @@ public void testTableWithMultipleWildcards() {
                     );
         });
     }
+
+    @Test
+    @DisabledIfSystemProperty(
+            named = "skipSparkTest",
+            matches = "true"
+    )
+    public void testTableWithOnlyWildcard() {
+        streamingTestUtil.performDPLTest("index=index_A | table *", testFile, ds -> {
+            final StructType expectedSchema = new StructType(new StructField[] {
+                    new StructField("_time", DataTypes.TimestampType, true, new MetadataBuilder().build()),
+                    new StructField("id", DataTypes.LongType, true, new MetadataBuilder().build()),
+                    new StructField("_raw", DataTypes.StringType, true, new MetadataBuilder().build()),
+                    new StructField("index", DataTypes.StringType, true, new MetadataBuilder().build()),
+                    new StructField("sourcetype", DataTypes.StringType, true, new MetadataBuilder().build()),
+                    new StructField("host", DataTypes.StringType, true, new MetadataBuilder().build()),
+                    new StructField("source", DataTypes.StringType, true, new MetadataBuilder().build()),
+                    new StructField("partition", DataTypes.StringType, true, new MetadataBuilder().build()),
+                    new StructField("offset", DataTypes.LongType, true, new MetadataBuilder().build())
+            });
+            Assertions
+                    .assertEquals(
+                            expectedSchema, ds.schema(),
+                            "Batch handler dataset contained an unexpected column arrangement !"
+                    );
+        });
+    }
+
+    @Test
+    @DisabledIfSystemProperty(
+            named = "skipSparkTest",
+            matches = "true"
+    )
+    public void testTableWithoutFieldNames() {
+        String q = "index=index_A | table";
+        String e = "table command is missing field names, it requires at least one valid field name.";
+        IllegalStateException exception = this.streamingTestUtil
+                .performThrowingDPLTest(IllegalStateException.class, q, this.testFile, res -> {
+                });
+
+        Assertions.assertEquals(e, exception.getMessage());
+    }
 }