CQL function to convert Kind id to name

src/java/org/apache/cassandra/cql3/functions/ClusterMetadataFcts.java

@@ -0,0 +1,57 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.cassandra.cql3.functions;
+
+import java.nio.ByteBuffer;
+
+import org.apache.cassandra.db.marshal.Int32Type;
+import org.apache.cassandra.db.marshal.UTF8Type;
+import org.apache.cassandra.exceptions.InvalidRequestException;
+import org.apache.cassandra.tcm.Transformation;
+import org.apache.cassandra.utils.ByteBufferUtil;
+
+public class ClusterMetadataFcts
+{
+    public static void addFunctionsTo(NativeFunctions functions)
+    {
+        functions.add(transformationKind);
+    }
+
+    public static final NativeScalarFunction transformationKind = new TransformationKind();
+    private static final class TransformationKind extends NativeScalarFunction
+    {
+
+        private TransformationKind()
+        {
+            super("transformation_kind", UTF8Type.instance, Int32Type.instance);
+        }
+
+        @Override
+        public ByteBuffer execute(Arguments arguments) throws InvalidRequestException
+        {
+            Number id = arguments.get(0);
+            if (id.intValue() < 0 || id.intValue() > Transformation.Kind.values().length -1)
+                throw new InvalidRequestException(id + " is not a valid Transformation.Kind id");
+
+            Transformation.Kind kind = Transformation.Kind.fromId(id.intValue());
+            return ByteBufferUtil.bytes(kind.name());
+
+        }
+    }
+}

src/java/org/apache/cassandra/cql3/functions/NativeFunctions.java

@@ -47,6 +47,7 @@ public class NativeFunctions
             MathFcts.addFunctionsTo(this);
             MaskingFcts.addFunctionsTo(this);
             VectorFcts.addFunctionsTo(this);
+            ClusterMetadataFcts.addFunctionsTo(this);
         }
     };
 

test/unit/org/apache/cassandra/cql3/functions/ClusterMetadataFctsTest.java

@@ -0,0 +1,68 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.cassandra.cql3.functions;
+
+import java.nio.charset.CharacterCodingException;
+
+import org.junit.Test;
+
+import org.apache.cassandra.db.marshal.Int32Type;
+import org.apache.cassandra.exceptions.InvalidRequestException;
+import org.apache.cassandra.tcm.Transformation;
+import org.apache.cassandra.transport.ProtocolVersion;
+import org.apache.cassandra.utils.ByteBufferUtil;
+import org.assertj.core.api.Assertions;
+
+import static org.apache.cassandra.cql3.functions.ClusterMetadataFcts.transformationKind;
+import static org.junit.Assert.assertEquals;
+
+public class ClusterMetadataFctsTest
+{
+
+    @Test
+    public void testTransformationKind() throws CharacterCodingException
+    {
+        int max = -1;
+        for (Transformation.Kind kind : Transformation.Kind.values())
+        {
+            Arguments arguments = transformationKind.newArguments(ProtocolVersion.CURRENT);
+            arguments.set(0, Int32Type.instance.decompose(kind.id));
+            assertEquals(kind.name(), ByteBufferUtil.string(transformationKind.execute(arguments)));
+            if (kind.id > max)
+                max = kind.id;
+        }
+
+        for (int boundary : new int[]{-1, max+1})
+        {
+            Arguments arguments = transformationKind.newArguments(ProtocolVersion.CURRENT);
+            arguments.set(0, Int32Type.instance.decompose(boundary));
+            try
+            {
+                transformationKind.execute(arguments);
+            }
+            catch (Exception e)
+            {
+                Assertions.assertThat(e)
+                          .isInstanceOf(InvalidRequestException.class)
+                          .hasMessageContaining(boundary + " is not a valid Transformation.Kind id");
+            }
+        }
+
+    }
+}