Refactor BinaryOperationExpressionConverter

kernel/sql-federation/compiler/src/main/java/org/apache/shardingsphere/sqlfederation/compiler/sql/ast/converter/segment/expression/ExpressionConverter.java

@@ -100,7 +100,7 @@ public static Optional<SqlNode> convert(final ExpressionSegment segment) {
             return ListExpressionConverter.convert((ListExpression) segment);
         }
         if (segment instanceof BinaryOperationExpression) {
-            return BinaryOperationExpressionConverter.convert((BinaryOperationExpression) segment);
+            return Optional.of(BinaryOperationExpressionConverter.convert((BinaryOperationExpression) segment));
         }
         if (segment instanceof ColumnSegment) {
             return ColumnConverter.convert((ColumnSegment) segment);

kernel/sql-federation/compiler/src/main/java/org/apache/shardingsphere/sqlfederation/compiler/sql/ast/converter/segment/expression/impl/BinaryOperationExpressionConverter.java

@@ -114,10 +114,10 @@ private static void registerAlias() {
      * @param segment binary operation expression
      * @return SQL node
      */
-    public static Optional<SqlNode> convert(final BinaryOperationExpression segment) {
+    public static SqlBasicCall convert(final BinaryOperationExpression segment) {
         SqlOperator operator = convertOperator(segment);
         List<SqlNode> sqlNodes = convertSqlNodes(segment, operator);
-        return Optional.of(new SqlBasicCall(operator, sqlNodes, SqlParserPos.ZERO));
+        return new SqlBasicCall(operator, sqlNodes, SqlParserPos.ZERO);
     }
 
     private static SqlOperator convertOperator(final BinaryOperationExpression segment) {

kernel/sql-federation/compiler/src/test/java/org/apache/shardingsphere/sqlfederation/compiler/sql/ast/converter/segment/expression/ExpressionConverterTest.java

@@ -116,9 +116,9 @@ void assertConvertDelegatesToAllSupportedConverters() {
         SqlNode expectedListNode = mock(SqlNode.class);
         ListExpression listSegment = new ListExpression(0, 0);
         when(ListExpressionConverter.convert(listSegment)).thenReturn(Optional.of(expectedListNode));
-        SqlNode expectedBinaryNode = mock(SqlNode.class);
+        SqlBasicCall expectedBinaryNode = mock(SqlBasicCall.class);
         BinaryOperationExpression binarySegment = new BinaryOperationExpression(0, 0, literalSegment, literalSegment, "+", "text");
-        when(BinaryOperationExpressionConverter.convert(binarySegment)).thenReturn(Optional.of(expectedBinaryNode));
+        when(BinaryOperationExpressionConverter.convert(binarySegment)).thenReturn(expectedBinaryNode);
         SqlNode expectedColumnNode = mock(SqlNode.class);
         ColumnSegment columnSegment = new ColumnSegment(0, 0, new IdentifierValue("col"));
         when(ColumnConverter.convert(columnSegment)).thenReturn(Optional.of(expectedColumnNode));

kernel/sql-federation/compiler/src/test/java/org/apache/shardingsphere/sqlfederation/compiler/sql/ast/converter/segment/expression/impl/BinaryOperationExpressionConverterTest.java

@@ -49,7 +49,6 @@
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -78,8 +77,7 @@ void assertConvertFlattensSqlNodeListOperands() {
         SqlNode secondRightNode = mock(SqlNode.class);
         when(ExpressionConverter.convert(left)).thenReturn(Optional.of(leftNode));
         when(ExpressionConverter.convert(right)).thenReturn(Optional.of(new SqlNodeList(Arrays.asList(firstRightNode, secondRightNode), SqlParserPos.ZERO)));
-        SqlBasicCall actual = (SqlBasicCall) BinaryOperationExpressionConverter.convert(expression).orElse(null);
-        assertNotNull(actual);
+        SqlBasicCall actual = BinaryOperationExpressionConverter.convert(expression);
         assertThat(actual.getOperator(), is(SqlStdOperatorTable.PLUS));
         assertThat(actual.getOperandList(), is(Arrays.asList(leftNode, firstRightNode, secondRightNode)));
     }
@@ -92,8 +90,7 @@ void assertConvertQuantifySubqueryFallsBackToOriginalOperator() {
         SqlNode rightNode = mock(SqlNode.class);
         when(ExpressionConverter.convert(left)).thenReturn(Optional.of(leftNode));
         when(ExpressionConverter.convert(right)).thenReturn(Optional.of(rightNode));
-        SqlBasicCall actual = (SqlBasicCall) BinaryOperationExpressionConverter.convert(new BinaryOperationExpression(0, 0, left, right, "AND", "")).orElse(null);
-        assertNotNull(actual);
+        SqlBasicCall actual = BinaryOperationExpressionConverter.convert(new BinaryOperationExpression(0, 0, left, right, "AND", ""));
         assertThat(actual.getOperator(), is(SqlStdOperatorTable.AND));
         assertThat(actual.getOperandList(), is(Arrays.asList(leftNode, rightNode)));
     }
@@ -106,8 +103,7 @@ void assertConvertIsOperatorVariants(final String displayName, final String righ
         LiteralExpressionSegment right = new LiteralExpressionSegment(0, 0, rightLiteral);
         SqlNode leftNode = leftSupplier.get();
         when(ExpressionConverter.convert(left)).thenReturn(Optional.of(leftNode));
-        SqlBasicCall actual = (SqlBasicCall) BinaryOperationExpressionConverter.convert(new BinaryOperationExpression(0, 0, left, right, "IS", "")).orElse(null);
-        assertNotNull(actual);
+        SqlBasicCall actual = BinaryOperationExpressionConverter.convert(new BinaryOperationExpression(0, 0, left, right, "IS", ""));
         assertThat(actual.getOperator(), is(expectedOperator));
         if (null == expectedBoolean) {
             assertThat(actual.getOperandList(), is(Collections.singletonList(leftNode)));
@@ -126,8 +122,7 @@ void assertConvertQuantifySubquery(final String operator, final String quantifyO
         SqlNode rightNode = mock(SqlNode.class);
         when(ExpressionConverter.convert(left)).thenReturn(Optional.of(leftNode));
         when(ExpressionConverter.convert(right)).thenReturn(Optional.of(rightNode));
-        SqlBasicCall actual = (SqlBasicCall) BinaryOperationExpressionConverter.convert(new BinaryOperationExpression(0, 0, left, right, operator, "")).orElse(null);
-        assertNotNull(actual);
+        SqlBasicCall actual = BinaryOperationExpressionConverter.convert(new BinaryOperationExpression(0, 0, left, right, operator, ""));
         assertThat(actual.getOperator(), is(expectedOperator));
         assertThat(actual.getOperandList(), is(Arrays.asList(leftNode, rightNode)));
     }