internal CqlCommand(Expression expression, ITable table, StatementFactory stmtFactory, PocoData pocoData)
{
_expression = expression;
Table = table;
_statementFactory = stmtFactory;
PocoData = pocoData;
}
internal CqlUpdate(Expression expression, ITable table, StatementFactory stmtFactory, PocoData pocoData)
: base(expression, table, stmtFactory, pocoData)
{
}
internal CqlUpdate(Expression expression, ITable table, StatementFactory stmtFactory, PocoData pocoData, MapperFactory mapperFactory)
: base(expression, table, stmtFactory, pocoData)
{
_mapperFactory = mapperFactory;
}
/// <summary>
/// Creates a mapper Func for a POCO.
/// </summary>
private Func <Row, T> CreateMapperForPoco <T>(RowSet rows, PocoData pocoData)
{
// We're going to store the method body expressions in a list since we need to use some looping to generate it
ICollection <Expression> methodBodyExpressions = new LinkedList <Expression>();
// The input parameter for our Func<Row, T>, a C* Row
ParameterExpression row = Expression.Parameter(CassandraRowType, "row");
// T poco = new T();
var poco = Expression.Variable(pocoData.PocoType, "poco");
if (pocoData.PocoType.GetTypeInfo().GetConstructor(Type.EmptyTypes) != null)
{
//It has default constructor
methodBodyExpressions.Add(Expression.Assign(poco, Expression.New(pocoData.PocoType)));
}
else
{
var constructor = pocoData.PocoType.GetTypeInfo().GetConstructors().FirstOrDefault(c => c.GetParameters().Length == rows.Columns.Length);
if (constructor == null)
{
throw new ArgumentException(
string.Format("RowSet columns length is {0} but type {1} does not contain a constructor with the same amount of parameters",
rows.Columns.Length,
pocoData.PocoType));
}
var parameterInfos = constructor.GetParameters();
var parameterExpressions = new List <Expression>();
for (var i = 0; i < rows.Columns.Length; i++)
{
var c = rows.Columns[i];
var param = parameterInfos[i];
var getValueT = GetExpressionToGetColumnValueFromRow(row, c, param.ParameterType);
parameterExpressions.Add(getValueT);
}
methodBodyExpressions.Add(Expression.Assign(poco, Expression.New(constructor, parameterExpressions)));
}
// Keep track of any variables we need in the method body, starting with the poco variable
var methodBodyVariables = new List <ParameterExpression> {
poco
};
foreach (var dbColumn in rows.Columns)
{
// Try to find a corresponding column on the POCO and if not found, don't map that column from the RowSet
PocoColumn pocoColumn;
if (pocoData.Columns.TryGetItem(dbColumn.Name, out pocoColumn) == false)
{
continue;
}
// Figure out if we're going to need to do any casting/conversion when we call Row.GetValue<T>(columnIndex)
Expression getColumnValue = GetExpressionToGetColumnValueFromRow(row, dbColumn, pocoColumn.MemberInfoType);
// poco.SomeFieldOrProp = ... getColumnValue call ...
BinaryExpression getValueAndAssign = Expression.Assign(Expression.MakeMemberAccess(poco, pocoColumn.MemberInfo), getColumnValue);
// Start with an expression that does nothing if the row is null
Expression ifRowValueIsNull = Expression.Empty();
// Cassandra will return null for empty collections, so make an effort to populate collection properties on the POCO with
// empty collections instead of null in those cases
Expression createEmptyCollection;
if (TryGetCreateEmptyCollectionExpression(dbColumn, pocoColumn.MemberInfoType, out createEmptyCollection))
{
// poco.SomeFieldOrProp = ... createEmptyCollection ...
ifRowValueIsNull = Expression.Assign(Expression.MakeMemberAccess(poco, pocoColumn.MemberInfo), createEmptyCollection);
}
var columnIndex = Expression.Constant(dbColumn.Index, IntType);
//Expression equivalent to
// if (row.IsNull(columnIndex) == false) => getValueAndAssign ...
// else => ifRowIsNull ...
methodBodyExpressions.Add(Expression.IfThenElse(Expression.IsFalse(Expression.Call(row, IsNullMethod, columnIndex)),
getValueAndAssign,
ifRowValueIsNull));
}
// The last expression in the method body is the return value, so put our new POCO at the end
methodBodyExpressions.Add(poco);
// Create a block expression for the method body expressions
BlockExpression methodBody = Expression.Block(methodBodyVariables, methodBodyExpressions);
// Return compiled expression
return(Expression.Lambda <Func <Row, T> >(methodBody, row).Compile());
}
/// <summary>
/// Creates a mapper Func for a POCO.
/// </summary>
private Func <Row, T> CreateMapperForPoco <T>(RowSet rows, PocoData pocoData)
{
// We're going to store the method body expressions in a list since we need to use some looping to generate it
var methodBodyExpressions = new List <Expression>();
// The input parameter for our Func<Row, T>, a C* Row
ParameterExpression row = Expression.Parameter(CassandraRowType, "row");
// T poco = new T();
var poco = Expression.Variable(pocoData.PocoType, "poco");
if (pocoData.PocoType.GetConstructor(Type.EmptyTypes) != null)
{
//It has default constructor
methodBodyExpressions.Add(Expression.Assign(poco, Expression.New(pocoData.PocoType)));
}
else
{
var constructor = pocoData.PocoType.GetConstructors().FirstOrDefault(c => c.GetParameters().Length == rows.Columns.Length);
if (constructor == null)
{
throw new ArgumentException(
String.Format("RowSet columns length is {0} but type {1} does not contain a constructor with the same amount of parameters",
rows.Columns.Length,
pocoData.PocoType));
}
var parameterInfos = constructor.GetParameters();
var parameterExpressions = new List <Expression>();
for (var i = 0; i < rows.Columns.Length; i++)
{
var c = rows.Columns[i];
var param = parameterInfos[i];
var getValueT = GetExpressionToGetColumnValueFromRow(row, c, param.ParameterType);
parameterExpressions.Add(getValueT);
}
methodBodyExpressions.Add(Expression.Assign(poco, Expression.New(constructor, parameterExpressions)));
}
// Keep track of any variables we need in the method body, starting with the poco variable
var methodBodyVariables = new List <ParameterExpression> {
poco
};
foreach (var dbColumn in rows.Columns)
{
// Try to find a corresponding column on the POCO and if not found, don't map that column from the RowSet
PocoColumn pocoColumn;
if (pocoData.Columns.TryGetItem(dbColumn.Name, out pocoColumn) == false)
{
continue;
}
// Figure out if we're going to need to do any casting/conversion when we call Row.GetValue<T>(columnIndex)
Expression getColumnValue = GetExpressionToGetColumnValueFromRow(row, dbColumn, pocoColumn.MemberInfoType);
BinaryExpression assignValue = Expression.Assign(Expression.MakeMemberAccess(poco, pocoColumn.MemberInfo), getColumnValue);
methodBodyExpressions.Add(assignValue);
}
// The last expression in the method body is the return value, so put our new POCO at the end
methodBodyExpressions.Add(poco);
// Create a block expression for the method body expressions
BlockExpression methodBody = Expression.Block(methodBodyVariables, methodBodyExpressions);
// Return compiled expression
return(Expression.Lambda <Func <Row, T> >(methodBody, row).Compile());
}
