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   *
   * 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
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  package org.apache.cassandra.cql3.selection;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.junit.BeforeClass;
  import org.junit.Test;
  
  import org.apache.cassandra.schema.ColumnMetadata;
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.schema.Schema;
  import org.apache.cassandra.cql3.*;
  import org.apache.cassandra.cql3.statements.SelectStatement;
  import org.apache.cassandra.db.marshal.*;
  import org.apache.cassandra.dht.ByteOrderedPartitioner;
  import org.apache.cassandra.exceptions.RequestExecutionException;
  import org.apache.cassandra.exceptions.RequestValidationException;
  import org.apache.cassandra.service.ClientState;
  import org.apache.cassandra.service.QueryState;
  import org.apache.cassandra.utils.ByteBufferUtil;
  
  import static java.util.Arrays.asList;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  
  public class SelectionColumnMappingTest extends CQLTester
  {
      private static final ColumnMetadata NULL_DEF = null;
      String tableName;
      String typeName;
      UserType userType;
      String functionName;
  
      @BeforeClass
      public static void setUpClass()     // overrides CQLTester.setUpClass()
      {
          daemonInitialization();
          DatabaseDescriptor.setPartitionerUnsafe(ByteOrderedPartitioner.instance);
          prepareServer();
      }
  
      @Test
      public void testSelectionColumnMapping() throws Throwable
      {
          // Organised as a single test to avoid the overhead of
          // table creation for each variant
  
          typeName = createType("CREATE TYPE %s (f1 int, f2 text)");
          tableName = createTable("CREATE TABLE %s (" +
                                  " k int PRIMARY KEY," +
                                  " v1 int," +
                                  " v2 ascii," +
                                  " v3 frozen<" + typeName + ">)");
          userType = Schema.instance.getKeyspaceMetadata(KEYSPACE).types.get(ByteBufferUtil.bytes(typeName)).get().freeze();
          functionName = createFunction(KEYSPACE, "int, ascii",
                                        "CREATE FUNCTION %s (i int, a ascii) " +
                                        "CALLED ON NULL INPUT " +
                                        "RETURNS int " +
                                        "LANGUAGE java " +
                                        "AS 'return Integer.valueOf(i);'");
          execute("INSERT INTO %s (k, v1 ,v2, v3) VALUES (1, 1, 'foo', {f1:1, f2:'bar'})");
  
          testSimpleTypes();
          testWildcard();
          testSimpleTypesWithAliases();
          testUserTypes();
          testUserTypesWithAliases();
          testWritetimeAndTTL();
          testWritetimeAndTTLWithAliases();
          testFunction();
          testNoArgFunction();
          testUserDefinedFunction();
          testOverloadedFunction();
          testFunctionWithAlias();
          testNoArgumentFunction();
          testNestedFunctions();
          testNestedFunctionsWithArguments();
          testCount();
          testDuplicateFunctionsWithoutAliases();
          testDuplicateFunctionsWithAliases();
          testSelectDistinct();
          testMultipleAliasesOnSameColumn();
          testMixedColumnTypes();
          testMultipleUnaliasedSelectionOfSameColumn();
          testUserDefinedAggregate();
          testListLitteral();
          testEmptyListLitteral();
          testSetLitteral();
          testEmptySetLitteral();
          testMapLitteral();
          testEmptyMapLitteral();
          testUDTLitteral();
          testTupleLitteral();
      }
  
      @Test
      public void testMultipleArgumentFunction() throws Throwable
      {
          // demonstrate behaviour of token() with composite partition key
          tableName = createTable("CREATE TABLE %s (a int, b text, PRIMARY KEY ((a, b)))");
          ColumnSpecification tokenSpec = columnSpecification("system.token(a, b)", BytesType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(tokenSpec, columnDefinitions("a", "b"));
          // we don't use verify like with the other tests because this query will produce no results
          SelectStatement statement = getSelect("SELECT token(a,b) FROM %s");
          verifyColumnMapping(expected, statement);
          statement.executeLocally(QueryState.forInternalCalls(), QueryOptions.DEFAULT);
      }
  
      private void testSimpleTypes() throws Throwable
      {
          // simple column identifiers without aliases are represented in
          // ResultSet.Metadata by the underlying ColumnMetadata
          ColumnSpecification kSpec = columnSpecification("k", Int32Type.instance);
          ColumnSpecification v1Spec = columnSpecification("v1", Int32Type.instance);
          ColumnSpecification v2Spec = columnSpecification("v2", AsciiType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(kSpec, columnDefinition("k"))
                                                                  .addMapping(v1Spec, columnDefinition("v1"))
                                                                  .addMapping(v2Spec, columnDefinition("v2"));
  
          verify(expected, "SELECT k, v1, v2 FROM %s");
      }
  
      private void testWildcard() throws Throwable
      {
          // Wildcard select represents each column in the table with a ColumnMetadata
          // in the ResultSet metadata
          ColumnMetadata kSpec = columnDefinition("k");
          ColumnMetadata v1Spec = columnDefinition("v1");
          ColumnMetadata v2Spec = columnDefinition("v2");
          ColumnMetadata v3Spec = columnDefinition("v3");
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(kSpec, columnDefinition("k"))
                                                                  .addMapping(v1Spec, columnDefinition("v1"))
                                                                  .addMapping(v2Spec, columnDefinition("v2"))
                                                                  .addMapping(v3Spec, columnDefinition("v3"));
  
          verify(expected, "SELECT * FROM %s");
      }
  
      private void testSimpleTypesWithAliases() throws Throwable
      {
          // simple column identifiers with aliases are represented in ResultSet.Metadata
          // by a ColumnSpecification based on the underlying ColumnMetadata
          ColumnSpecification kSpec = columnSpecification("k_alias", Int32Type.instance);
          ColumnSpecification v1Spec = columnSpecification("v1_alias", Int32Type.instance);
          ColumnSpecification v2Spec = columnSpecification("v2_alias", AsciiType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(kSpec, columnDefinition("k"))
                                                                  .addMapping(v1Spec, columnDefinition("v1"))
                                                                  .addMapping(v2Spec, columnDefinition("v2"));
          verify(expected, "SELECT k AS k_alias, v1 AS v1_alias, v2 AS v2_alias FROM %s");
      }
  
      private void testUserTypes() throws Throwable
      {
          // User type fields are represented in ResultSet.Metadata by a
          // ColumnSpecification denoting the name and type of the particular field
          ColumnSpecification f1Spec = columnSpecification("v3.f1", Int32Type.instance);
          ColumnSpecification f2Spec = columnSpecification("v3.f2", UTF8Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(f1Spec, columnDefinition("v3"))
                                                                  .addMapping(f2Spec, columnDefinition("v3"));
  
          verify(expected, "SELECT v3.f1, v3.f2 FROM %s");
      }
  
      private void testUserTypesWithAliases() throws Throwable
      {
          // User type fields with aliases are represented in ResultSet.Metadata
          // by a ColumnSpecification with the alias name and the type of the actual field
          ColumnSpecification f1Spec = columnSpecification("f1_alias", Int32Type.instance);
          ColumnSpecification f2Spec = columnSpecification("f2_alias", UTF8Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(f1Spec, columnDefinition("v3"))
                                                                  .addMapping(f2Spec, columnDefinition("v3"));
  
          verify(expected, "SELECT v3.f1 AS f1_alias, v3.f2 AS f2_alias FROM %s");
      }
  
      private void testWritetimeAndTTL() throws Throwable
      {
          // writetime and ttl are represented in ResultSet.Metadata by a ColumnSpecification
          // with the function name plus argument and a long or int type respectively
          ColumnSpecification wtSpec = columnSpecification("writetime(v1)", LongType.instance);
          ColumnSpecification ttlSpec = columnSpecification("ttl(v2)", Int32Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(wtSpec, columnDefinition("v1"))
                                                                  .addMapping(ttlSpec, columnDefinition("v2"));
  
          verify(expected, "SELECT writetime(v1), ttl(v2) FROM %s");
      }
  
      private void testWritetimeAndTTLWithAliases() throws Throwable
      {
          // writetime and ttl with aliases are represented in ResultSet.Metadata
          // by a ColumnSpecification with the alias name and the appropriate numeric type
          ColumnSpecification wtSpec = columnSpecification("wt_alias", LongType.instance);
          ColumnSpecification ttlSpec = columnSpecification("ttl_alias", Int32Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(wtSpec, columnDefinition("v1"))
                                                                  .addMapping(ttlSpec, columnDefinition("v2"));
  
          verify(expected, "SELECT writetime(v1) AS wt_alias, ttl(v2) AS ttl_alias FROM %s");
      }
  
      private void testFunction() throws Throwable
      {
          // a function such as int_as_blob(<col>) is represented in ResultSet.Metadata
          // by a ColumnSpecification with the function name plus args and the type set
          // to the function's return type
          ColumnSpecification fnSpec = columnSpecification("system.int_as_blob(v1)", BytesType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(fnSpec, columnDefinition("v1"));
  
          verify(expected, "SELECT int_as_blob(v1) FROM %s");
      }
  
      private void testNoArgFunction() throws Throwable
      {
          // a no-arg function such as now() is represented in ResultSet.Metadata
          // but has no mapping to any underlying column
          ColumnSpecification fnSpec = columnSpecification("system.now()", TimeUUIDType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping().addMapping(fnSpec, NULL_DEF);
  
          verify(expected, "SELECT now() FROM %s");
      }
  
      private void testOverloadedFunction() throws Throwable
      {
          String fnName = createFunction(KEYSPACE, "int",
                                         "CREATE FUNCTION %s (input int) " +
                                         "RETURNS NULL ON NULL INPUT " +
                                         "RETURNS text " +
                                         "LANGUAGE java " +
                                         "AS 'return \"Hello World\";'");
          createFunctionOverload(fnName, "text",
                                 "CREATE FUNCTION %s (input text) " +
                                 "RETURNS NULL ON NULL INPUT " +
                                 "RETURNS text " +
                                 "LANGUAGE java " +
                                 "AS 'return \"Hello World\";'");
  
          createFunctionOverload(fnName, "int, text",
                                 "CREATE FUNCTION %s (input1 int, input2 text) " +
                                 "RETURNS NULL ON NULL INPUT " +
                                 "RETURNS text " +
                                 "LANGUAGE java " +
                                 "AS 'return \"Hello World\";'");
          ColumnSpecification fnSpec1 = columnSpecification(fnName + "(v1)", UTF8Type.instance);
          ColumnSpecification fnSpec2 = columnSpecification(fnName + "(v2)", UTF8Type.instance);
          ColumnSpecification fnSpec3 = columnSpecification(fnName + "(v1, v2)", UTF8Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(fnSpec1, columnDefinition("v1"))
                                                                  .addMapping(fnSpec2, columnDefinition("v2"))
                                                                  .addMapping(fnSpec3, columnDefinitions("v1", "v2"));
  
          verify(expected, String.format("SELECT %1$s(v1), %1$s(v2), %1$s(v1, v2) FROM %%s", fnName));
      }
  
      private void testCount() throws Throwable
      {
          // SELECT COUNT does not necessarily include any mappings, but it must always return
          // a singleton list from getColumnSpecifications() in order for the ResultSet.Metadata
          // to be constructed correctly:
          // * COUNT(*) / COUNT(1) do not generate any mappings, as no specific columns are referenced
          // * COUNT(foo) does generate a mapping from the 'system.count' column spec to foo
          ColumnSpecification count = columnSpecification("count", LongType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping().addMapping(count, NULL_DEF);
  
          verify(expected, "SELECT COUNT(*) FROM %s");
          verify(expected, "SELECT COUNT(1) FROM %s");
  
          ColumnSpecification aliased = columnSpecification("count_alias", LongType.instance);
          expected = SelectionColumnMapping.newMapping().addMapping(aliased, NULL_DEF);
  
          verify(expected, "SELECT COUNT(*) AS count_alias FROM %s");
          verify(expected, "SELECT COUNT(1) AS count_alias FROM %s");
  
          ColumnSpecification countV1 = columnSpecification("system.count(v1)", LongType.instance);
          expected = SelectionColumnMapping.newMapping().addMapping(countV1, columnDefinition("v1"));
          verify(expected, "SELECT COUNT(v1) FROM %s");
  
          ColumnSpecification countV1Alias = columnSpecification("count_v1", LongType.instance);
          expected = SelectionColumnMapping.newMapping().addMapping(countV1Alias, columnDefinition("v1"));
          verify(expected, "SELECT COUNT(v1) AS count_v1 FROM %s");
      }
  
      private void testUserDefinedFunction() throws Throwable
      {
          // UDFs are basically represented in the same way as system functions
          String functionCall = String.format("%s(v1, v2)", functionName);
          ColumnSpecification fnSpec = columnSpecification(functionCall, Int32Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(fnSpec, columnDefinitions("v1", "v2"));
          verify(expected, "SELECT " + functionCall + " FROM %s");
      }
  
      private void testFunctionWithAlias() throws Throwable
      {
          // a function with an alias is represented in ResultSet.Metadata by a
          // ColumnSpecification with the alias and the type set to the function's
          // return type
          ColumnSpecification fnSpec = columnSpecification("fn_alias", BytesType.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(fnSpec, columnDefinition("v1"));
  
          verify(expected, "SELECT int_as_blob(v1) AS fn_alias FROM %s");
      }
  
      public void testNoArgumentFunction() throws Throwable
      {
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(columnSpecification("system.now()",
                                                                                            TimeUUIDType.instance),
                                                                        NULL_DEF);
          verify(expected, "SELECT now() FROM %s");
      }
  
      public void testNestedFunctionsWithArguments() throws Throwable
      {
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(columnSpecification("system.blob_as_int(system.int_as_blob(v1))",
                                                                                            Int32Type.instance),
                                                                        columnDefinition("v1"));
          verify(expected, "SELECT blob_as_int(int_as_blob(v1)) FROM %s");
      }
  
      public void testNestedFunctions() throws Throwable
      {
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(columnSpecification("system.to_unix_timestamp(system.now())",
                                                                                            LongType.instance),
                                                                        NULL_DEF);
          verify(expected, "SELECT to_unix_timestamp(now()) FROM %s");
      }
  
      public void testDuplicateFunctionsWithoutAliases() throws Throwable
      {
          // where duplicate functions are present, the ColumnSpecification list will
          // contain an entry per-duplicate but the mappings will be deduplicated (i.e.
          // a single mapping k/v pair regardless of the number of duplicates)
          ColumnSpecification spec = columnSpecification("system.int_as_blob(v1)", BytesType.instance);
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(spec, columnDefinition("v1"))
                                                            .addMapping(spec, columnDefinition("v1"));
          verify(expected, "SELECT int_as_blob(v1), int_as_blob(v1) FROM %s");
      }
  
      public void testDuplicateFunctionsWithAliases() throws Throwable
      {
          // where duplicate functions are present with distinct aliases, they are
          // represented as any other set of distinct columns would be - an entry
          // in theColumnSpecification list and a separate k/v mapping for each
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(columnSpecification("blob_1", BytesType.instance),
                                                                        columnDefinition("v1"))
                                                            .addMapping(columnSpecification("blob_2", BytesType.instance),
                                                                        columnDefinition("v1"));
          verify(expected, "SELECT int_as_blob(v1) AS blob_1, int_as_blob(v1) AS blob_2 FROM %s");
      }
  
      public void testSelectDistinct() throws Throwable
      {
          SelectionColumns expected = SelectionColumnMapping.newMapping().addMapping(columnSpecification("k",
                                                                                                         Int32Type.instance),
                                                                                     columnDefinition("k"));
          verify(expected, "SELECT DISTINCT k FROM %s");
  
      }
  
      private void testMultipleAliasesOnSameColumn() throws Throwable
      {
          // Multiple result columns derived from the same underlying column are
          // represented by ColumnSpecifications
          ColumnSpecification alias1 = columnSpecification("alias_1", Int32Type.instance);
          ColumnSpecification alias2 = columnSpecification("alias_2", Int32Type.instance);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(alias1, columnDefinition("v1"))
                                                                  .addMapping(alias2, columnDefinition("v1"));
  
          verify(expected, "SELECT v1 AS alias_1, v1 AS alias_2 FROM %s");
      }
  
      private void testMultipleUnaliasedSelectionOfSameColumn() throws Throwable
      {
          // simple column identifiers without aliases are represented in
          // ResultSet.Metadata by the underlying ColumnMetadata
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(columnSpecification("v1", Int32Type.instance),
                                                                        columnDefinition("v1"))
                                                            .addMapping(columnSpecification("v1", Int32Type.instance),
                                                                        columnDefinition("v1"));
  
          verify(expected, "SELECT v1, v1 FROM %s");
      }
  
      private void testListLitteral() throws Throwable
      {
          ColumnSpecification listSpec = columnSpecification("[k, v1]", ListType.getInstance(Int32Type.instance, false));
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(listSpec, asList(columnDefinition("k"),
                                                                                               columnDefinition("v1")));
  
          verify(expected, "SELECT [k, v1] FROM %s");
      }
  
      private void testEmptyListLitteral() throws Throwable
      {
          ColumnSpecification listSpec = columnSpecification("(list<int>)[]", ListType.getInstance(Int32Type.instance, false));
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(listSpec, (ColumnMetadata) null);
  
          verify(expected, "SELECT (list<int>)[] FROM %s");
      }
  
      private void testSetLitteral() throws Throwable
      {
          ColumnSpecification setSpec = columnSpecification("{k, v1}", SetType.getInstance(Int32Type.instance, false));
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(setSpec, asList(columnDefinition("k"),
                                                                                               columnDefinition("v1")));
  
          verify(expected, "SELECT {k, v1} FROM %s");
      }
  
      private void testEmptySetLitteral() throws Throwable
      {
          ColumnSpecification setSpec = columnSpecification("(set<int>){}", SetType.getInstance(Int32Type.instance, false));
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(setSpec, (ColumnMetadata) null);
  
          verify(expected, "SELECT (set<int>){} FROM %s");
      }
  
      private void testMapLitteral() throws Throwable
      {
          ColumnSpecification mapSpec = columnSpecification("(map<text, int>){'min': system.min(v1), 'max': system.max(v1)}", MapType.getInstance(UTF8Type.instance, Int32Type.instance, false));
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(mapSpec, asList(columnDefinition("v1")));
  
          verify(expected, "SELECT (map<text, int>){'min': min(v1), 'max': max(v1)} FROM %s");
      }
  
      private void testEmptyMapLitteral() throws Throwable
      {
          ColumnSpecification mapSpec = columnSpecification("(map<text, int>){}", MapType.getInstance(UTF8Type.instance, Int32Type.instance, false));
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(mapSpec, (ColumnMetadata) null);
  
          verify(expected, "SELECT (map<text, int>){} FROM %s");
      }
  
      private void testUDTLitteral() throws Throwable
      {
          UserType type = new UserType(KEYSPACE, ByteBufferUtil.bytes(typeName),
                                        asList(FieldIdentifier.forUnquoted("f1"),
                                               FieldIdentifier.forUnquoted("f2")),
                                        asList(Int32Type.instance,
                                               UTF8Type.instance),
                                        false);
  
          ColumnSpecification spec = columnSpecification("(" + KEYSPACE + "." + typeName + "){f1: v1, f2: v2}", type);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(spec, asList(columnDefinition("v1"),
                                                                                           columnDefinition("v2")));
  
          verify(expected, "SELECT ("+ typeName + "){f1: v1, f2: v2} FROM %s");
      }
  
      private void testTupleLitteral() throws Throwable
      {
          TupleType type = new TupleType(asList(Int32Type.instance, UTF8Type.instance));
  
          ColumnSpecification setSpec = columnSpecification("(tuple<int, text>)(v1, v2)", type);
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(setSpec, asList(columnDefinition("v1"),
                                                                                              columnDefinition("v2")));
  
          verify(expected, "SELECT (tuple<int, text>)(v1, v2) FROM %s");
      }
  
      private void testMixedColumnTypes() throws Throwable
      {
          ColumnSpecification kSpec = columnSpecification("k_alias", Int32Type.instance);
          ColumnSpecification v1Spec = columnSpecification("writetime(v1)", LongType.instance);
          ColumnSpecification v2Spec = columnSpecification("ttl_alias", Int32Type.instance);
          ColumnSpecification f1Spec = columnSpecification("v3.f1", Int32Type.instance);
          ColumnSpecification f2Spec = columnSpecification("f2_alias", UTF8Type.instance);
          ColumnSpecification f3Spec = columnSpecification("v3", userType);
  
          SelectionColumnMapping expected = SelectionColumnMapping.newMapping()
                                                                  .addMapping(kSpec, columnDefinition("k"))
                                                                  .addMapping(v1Spec, columnDefinition("v1"))
                                                                  .addMapping(v2Spec, columnDefinition("v2"))
                                                                  .addMapping(f1Spec, columnDefinition("v3"))
                                                                  .addMapping(f2Spec, columnDefinition("v3"))
                                                                  .addMapping(f3Spec, columnDefinition("v3"));
  
  
          verify(expected, "SELECT k AS k_alias," +
                           "       writetime(v1)," +
                           "       ttl(v2) as ttl_alias," +
                           "       v3.f1," +
                           "       v3.f2 AS f2_alias," +
                           "       v3" +
                           " FROM %s");
      }
  
      private void testUserDefinedAggregate() throws Throwable
      {
          String sFunc = parseFunctionName(createFunction(KEYSPACE, "int",
                                                          " CREATE FUNCTION %s (a int, b int)" +
                                                          " RETURNS NULL ON NULL INPUT" +
                                                          " RETURNS int" +
                                                          " LANGUAGE java" +
                                                          " AS ' return a + b;'")).name;
  
          String aFunc = createAggregate(KEYSPACE, "int, int",
                                         " CREATE AGGREGATE %s (int)" +
                                         " SFUNC " + sFunc +
                                         " STYPE int" +
                                         " INITCOND 0");
  
          String plusOne = createFunction(KEYSPACE, "int",
                                          " CREATE FUNCTION %s (a int)" +
                                          " RETURNS NULL ON NULL INPUT" +
                                          " RETURNS int" +
                                          " LANGUAGE java" +
                                          " AS ' return a + 1;'");
  
          String sqFunc = createFunction(KEYSPACE, "int",
                                         " CREATE FUNCTION %s (a int)" +
                                         " RETURNS NULL ON NULL INPUT" +
                                         " RETURNS int" +
                                         " LANGUAGE java" +
                                         " AS ' return a * a;'");
  
          ColumnMetadata v1 = columnDefinition("v1");
          SelectionColumns expected = SelectionColumnMapping.newMapping()
                                                            .addMapping(columnSpecification(aFunc + "(v1)",
                                                                                            Int32Type.instance),
                                                                        v1);
          verify(expected, String.format("SELECT %s(v1) FROM %%s", aFunc));
  
          // aggregate with nested udfs as input
          String specName = String.format("%s(%s(%s(v1)))", aFunc, sqFunc, plusOne);
          expected = SelectionColumnMapping.newMapping().addMapping(columnSpecification(specName, Int32Type.instance),
                                                                    v1);
          verify(expected, String.format("SELECT %s FROM %%s", specName));
      }
  
      private void verify(SelectionColumns expected, String query) throws Throwable
      {
          SelectStatement statement = getSelect(query);
          verifyColumnMapping(expected, statement);
          checkExecution(statement, expected.getColumnSpecifications());
      }
  
      private void checkExecution(SelectStatement statement, List<ColumnSpecification> expectedResultColumns)
      throws RequestExecutionException, RequestValidationException
      {
          UntypedResultSet rs = UntypedResultSet.create(statement.executeLocally(QueryState.forInternalCalls(),
                                                                                 QueryOptions.DEFAULT).result);
  
          assertEquals(expectedResultColumns, rs.one().getColumns());
      }
  
      private SelectStatement getSelect(String query) throws RequestValidationException
      {
          CQLStatement statement = QueryProcessor.getStatement(String.format(query, KEYSPACE + "." + tableName),
                                                               ClientState.forInternalCalls());
          assertTrue(statement instanceof SelectStatement);
          return (SelectStatement)statement;
      }
  
      private void verifyColumnMapping(SelectionColumns expected, SelectStatement select)
      {
          assertEquals(expected, select.getSelection().getColumnMapping());
      }
  
      private Iterable<ColumnMetadata> columnDefinitions(String...names)
      {
          List<ColumnMetadata> defs = new ArrayList<>();
          for (String n : names)
              defs.add(columnDefinition(n));
          return defs;
      }
  
      private ColumnMetadata columnDefinition(String name)
      {
          return Schema.instance.getTableMetadata(KEYSPACE, tableName).getColumn(new ColumnIdentifier(name, true));
  
      }
  
      private ColumnSpecification columnSpecification(String name, AbstractType<?> type)
      {
          return new ColumnSpecification(KEYSPACE,
                                         tableName,
                                         new ColumnIdentifier(name, true),
                                         type);
      }
  }
  