add enum support for mssql (#637)

Signed-off-by: Billy Yuan <billy112487983@gmail.com>

Author: BillyYccc

vertx-mssql-client/src/main/asciidoc/index.adoc

@@ -112,6 +112,24 @@ Currently the client supports the following SQL Server types
 
 Tuple decoding uses the above types when storing values
 
+=== Handling ENUM
+
+SQL Server does not have ENUM data type but the client can map the retrieved string/numeric data type to enum.
+
+You can encode Java enums as String like this:
+
+[source,$lang]
+----
+{@link examples.MSSQLClientExamples#enumeratedType01Example}
+----
+
+You can retrieve the ENUM column as Java enums like this:
+
+[source,$lang]
+----
+{@link examples.MSSQLClientExamples#enumeratedType02Example}
+----
+
 == Collector queries
 
 You can use Java collectors with the query API:

vertx-mssql-client/src/main/java/examples/MSSQLClientExamples.java

@@ -214,4 +214,30 @@ public void collector02Example(SqlClient client) {
         }
       });
   }
+
+  enum Color {
+    red, green, blue
+  }
+
+  public void enumeratedType01Example(SqlClient client) {
+    client
+      .preparedQuery("INSERT INTO colors VALUES (@p1)")
+      .execute(Tuple.of(Color.red),  res -> {
+        // ...
+      });
+  }
+
+  public void enumeratedType02Example(SqlClient client) {
+    client
+      .preparedQuery("SELECT color FROM colors")
+      .execute()
+      .onComplete(res -> {
+        if (res.succeeded()) {
+          RowSet<Row> rows = res.result();
+          for (Row row : rows) {
+            System.out.println(row.get(Color.class, "color"));
+          }
+        }
+      });
+  }
 }

vertx-mssql-client/src/main/java/io/vertx/mssqlclient/impl/MSSQLRowImpl.java

@@ -44,6 +44,15 @@ public int getColumnIndex(String columnName) {
     return rowDesc.columnNames().indexOf(columnName);
   }
 
+  @Override
+  public <T> T get(Class<T> type, int position) {
+    if (type.isEnum()) {
+      return type.cast(getEnum(type, position));
+    } else {
+      return super.get(type, position);
+    }
+  }
+
   @Override
   public Buffer getBuffer(String columnName) {
     throw new UnsupportedOperationException();
@@ -148,4 +157,20 @@ public Buffer[] getBufferArray(String columnName) {
   public UUID[] getUUIDArray(String columnName) {
     throw new UnsupportedOperationException();
   }
+
+  private Object getEnum(Class enumType, int position) {
+    Object val = getValue(position);
+    if (val instanceof String) {
+      return Enum.valueOf(enumType, (String) val);
+    } else if (val instanceof Number) {
+      int ordinal = ((Number) val).intValue();
+      if (ordinal >= 0) {
+        Object[] constants = enumType.getEnumConstants();
+        if (ordinal < constants.length) {
+          return constants[ordinal];
+        }
+      }
+    }
+    return null;
+  }
 }

vertx-mssql-client/src/main/java/io/vertx/mssqlclient/impl/codec/ExtendedQueryCommandCodec.java

@@ -190,6 +190,8 @@ private void encodeParamValue(ByteBuf payload, Object value) {
       encodeFloat8Parameter(payload, (Double) value);
     } else if (value instanceof String) {
       encodeNVarcharParameter(payload, (String) value);
+    } else if (value instanceof Enum){
+      encodeNVarcharParameter(payload, ((Enum<?>)value).name());
     } else if (value instanceof Boolean) {
       encodeBitNParameter(payload, (Boolean) value);
     } else if (value instanceof LocalDate) {

vertx-mssql-client/src/main/java/io/vertx/mssqlclient/impl/codec/MSSQLDataTypeCodec.java

@@ -47,6 +47,8 @@ static String inferenceParamDefinitionByValueType(Object value) {
     } else if (value instanceof Numeric) {
       //TODO we may need some changes in Numeric to make this work
       throw new UnsupportedOperationException();
+    } else if (value.getClass().isEnum()) {
+      return parameterDefinitionsMapping.get(String.class);
     } else {
       String paramDefinition = parameterDefinitionsMapping.get(value.getClass());
       if (paramDefinition != null) {

vertx-mssql-client/src/test/java/io/vertx/mssqlclient/data/MSSQLDataTypeTestBase.java

@@ -42,38 +42,58 @@ protected <T> void testQueryDecodeGenericWithoutTable(TestContext ctx,
                                                         String columnName,
                                                         String type,
                                                         String value,
-                                                        T expected) {
+                                                        Consumer<Row> checker) {
     MSSQLConnection.connect(vertx, options, ctx.asyncAssertSuccess(conn -> {
       conn
         .query("SELECT CAST(" + value + " AS " + type + ") AS " + columnName)
         .execute(ctx.asyncAssertSuccess(result -> {
           ctx.assertEquals(1, result.size());
           Row row = result.iterator().next();
-          ctx.assertEquals(expected, row.getValue(0));
-          ctx.assertEquals(expected, row.getValue(columnName));
+          checker.accept(row);
           conn.close();
         }));
     }));
   }
 
+  protected <T> void testQueryDecodeGenericWithoutTable(TestContext ctx,
+                                                        String columnName,
+                                                        String type,
+                                                        String value,
+                                                        T expected) {
+    testQueryDecodeGenericWithoutTable(ctx, columnName, type, value, row -> {
+      ctx.assertEquals(expected, row.getValue(0));
+      ctx.assertEquals(expected, row.getValue(columnName));
+    });
+  }
+
   protected <T> void testPreparedQueryDecodeGenericWithoutTable(TestContext ctx,
                                                                 String columnName,
                                                                 String type,
                                                                 String value,
-                                                                T expected) {
+                                                                Consumer<Row> checker) {
     MSSQLConnection.connect(vertx, options, ctx.asyncAssertSuccess(conn -> {
       conn
         .preparedQuery("SELECT CAST(" + value + " AS " + type + ") AS " + columnName)
         .execute(ctx.asyncAssertSuccess(result -> {
           ctx.assertEquals(1, result.size());
           Row row = result.iterator().next();
-          ctx.assertEquals(expected, row.getValue(0));
-          ctx.assertEquals(expected, row.getValue(columnName));
+          checker.accept(row);
           conn.close();
         }));
     }));
   }
 
+  protected <T> void testPreparedQueryDecodeGenericWithoutTable(TestContext ctx,
+                                                                String columnName,
+                                                                String type,
+                                                                String value,
+                                                                T expected) {
+    testPreparedQueryDecodeGenericWithoutTable(ctx, columnName, type, value, row -> {
+      ctx.assertEquals(expected, row.getValue(0));
+      ctx.assertEquals(expected, row.getValue(columnName));
+    });
+  }
+
   protected <T> void testQueryDecodeGeneric(TestContext ctx,
                                             String tableName,
                                             String columnName,

vertx-mssql-client/src/test/java/io/vertx/mssqlclient/data/MSSQLEnumDataTypeTest.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2011-2020 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+ * which is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+ */
+
+package io.vertx.mssqlclient.data;
+
+import io.vertx.ext.unit.TestContext;
+import io.vertx.ext.unit.junit.VertxUnitRunner;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(VertxUnitRunner.class)
+public class MSSQLEnumDataTypeTest extends MSSQLDataTypeTestBase {
+  @Test
+  public void testQueryDecodeStringToJavaEnum(TestContext ctx) {
+    testQueryDecodeGenericWithoutTable(ctx, "test_enum", "varchar", "'large'", row -> {
+      ctx.assertEquals(Size.large, row.get(Size.class, 0));
+      ctx.assertEquals(Size.large, row.get(Size.class, "test_enum"));
+      ctx.assertEquals("large", row.get(String.class, 0));
+      ctx.assertEquals("large", row.get(String.class, "test_enum"));
+      ctx.assertEquals("large", row.getString(0));
+      ctx.assertEquals("large", row.getString("test_enum"));
+    });
+  }
+
+  @Test
+  public void testPreparedQueryDecodeStringToJavaEnum(TestContext ctx) {
+    testPreparedQueryDecodeGenericWithoutTable(ctx, "test_enum", "varchar", "'large'", row -> {
+      ctx.assertEquals(Size.large, row.get(Size.class, 0));
+      ctx.assertEquals(Size.large, row.get(Size.class, "test_enum"));
+      ctx.assertEquals("large", row.get(String.class, 0));
+      ctx.assertEquals("large", row.get(String.class, "test_enum"));
+      ctx.assertEquals("large", row.getString(0));
+      ctx.assertEquals("large", row.getString("test_enum"));
+    });
+  }
+
+  @Test
+  public void testPreparedQueryEncodeJavaEnumToString(TestContext ctx) {
+    testPreparedQueryEncodeGeneric(ctx, "nullable_datatype", "test_varchar", Size.medium, row -> {
+      ctx.assertEquals(Size.medium, row.get(Size.class, 0));
+      ctx.assertEquals(Size.medium, row.get(Size.class, "test_varchar"));
+      ctx.assertEquals("medium", row.get(String.class, 0));
+      ctx.assertEquals("medium", row.get(String.class, "test_varchar"));
+      ctx.assertEquals("medium", row.getString(0));
+      ctx.assertEquals("medium", row.getString("test_varchar"));
+    });
+  }
+
+  private enum Size {
+    x_small, small, medium, large, x_large;
+  }
+}