/// <summary>
/// Apply orderby to the given resouce expression
/// </summary>
/// <param name="rootExpression"></param>
/// <param name="entityInstanceType"></param>
/// <param name="uriParser"></param>
/// <param name="orderByClause"></param>
/// <returns></returns>
public static Expression ApplyOrderBy(this Expression rootExpression, Type entityInstanceType, ODataUriParser uriParser, OrderByClause orderByClause)
{
ParameterExpression parameter = Expression.Parameter(entityInstanceType, "it");
NodeToExpressionTranslator nodeToExpressionTranslator = new NodeToExpressionTranslator()
{
ImplicitVariableParameterExpression = parameter,
UriParser = uriParser,
};
Expression orderByNodeExpression = nodeToExpressionTranslator.TranslateNode(orderByClause.Expression);
var keyType = EdmClrTypeUtils.GetInstanceType(orderByClause.Expression.TypeReference);
if (orderByClause.Expression.TypeReference.IsNullable && keyType.IsValueType)
{
keyType = typeof(Nullable <>).MakeGenericType(keyType);
}
var method = orderByClause.Direction == OrderByDirection.Ascending ? "OrderBy" : "OrderByDescending";
//OrderBy<TSource, TKey>(this IQueryable<TSource> source, Expression<Func<TSource, TKey>> keySelector)
var expression = Expression.Call(
typeof(Enumerable),
method,
new Type[] { entityInstanceType, keyType },
rootExpression,
Expression.Lambda(orderByNodeExpression, parameter)) as Expression;
var thenBy = orderByClause.ThenBy;
while (null != thenBy)
{
expression = expression.ApplyThenBy(entityInstanceType, uriParser, thenBy);
thenBy = thenBy.ThenBy;
}
return(expression);
}
/// <summary>
/// Apply filter to the given resouce expression
/// </summary>
/// <param name="rootExpression"></param>
/// <param name="entityInstanceType"></param>
/// <param name="uriParser"></param>
/// <param name="filterClause"></param>
/// <returns></returns>
public static Expression ApplyFilter(this Expression rootExpression, Type entityInstanceType, ODataUriParser uriParser, FilterClause filterClause)
{
ParameterExpression parameter = Expression.Parameter(entityInstanceType, "it");
NodeToExpressionTranslator nodeToExpressionTranslator = new NodeToExpressionTranslator()
{
ImplicitVariableParameterExpression = parameter,
UriParser = uriParser,
};
Expression filterNodeExpression = nodeToExpressionTranslator.TranslateNode(filterClause.Expression);
// IQueryable<TSource> Where<TSource>(this IQueryable<TSource> source, Expression<Func<TSource, bool>> predicate);
// translate to rootExpression.Where(filterNodeExpression)
return(Expression.Call(
typeof(Enumerable),
"Where",
new Type[] { entityInstanceType },
rootExpression,
Expression.Lambda(filterNodeExpression, parameter)));
}
/// <summary>
/// Visit an AnyNode
/// </summary>
/// <param name="nodeIn">The node to visit</param>
/// <returns>The translated expression</returns>
public override Expression Visit(AnyNode nodeIn)
{
var instanceType = EdmClrTypeUtils.GetInstanceType(nodeIn.RangeVariables[0].TypeReference);
ParameterExpression parameter = Expression.Parameter(instanceType, nodeIn.RangeVariables[0].Name);
NodeToExpressionTranslator nodeToExpressionTranslator = new NodeToExpressionTranslator()
{
ImplicitVariableParameterExpression = parameter,
UriParser = this.UriParser,
DataSource = this.DataSource,
};
Expression conditionExpression = nodeToExpressionTranslator.TranslateNode(nodeIn.Body);
Expression rootExpression = this.TranslateNode(nodeIn.Source);
return(Expression.Call(
typeof(Enumerable),
"Any",
new Type[] { instanceType },
rootExpression,
Expression.Lambda(conditionExpression, parameter)));
}
/// <summary>
/// Apply thenOrderBy to the given resouce expression
/// </summary>
/// <param name="rootExpression"></param>
/// <param name="entityInstanceType"></param>
/// <param name="uriParser"></param>
/// <param name="thenBy"></param>
/// <returns></returns>
public static Expression ApplyThenBy(this Expression rootExpression, Type entityInstanceType, ODataUriParser uriParser, OrderByClause thenBy)
{
ParameterExpression parameter = Expression.Parameter(entityInstanceType, "it");
NodeToExpressionTranslator nodeToExpressionTranslator = new NodeToExpressionTranslator()
{
ImplicitVariableParameterExpression = parameter,
UriParser = uriParser,
};
Expression orderByNodeExpression = nodeToExpressionTranslator.TranslateNode(thenBy.Expression);
var keyType = EdmClrTypeUtils.GetInstanceType(thenBy.Expression.TypeReference);
var method = thenBy.Direction == OrderByDirection.Ascending ? "ThenBy" : "ThenByDescending";
//ThenBy<TSource, TKey>(this IQueryable<TSource> source, Expression<Func<TSource, TKey>> keySelector)
return(Expression.Call(
typeof(Enumerable),
method,
new Type[] { entityInstanceType, keyType },
rootExpression,
Expression.Lambda(orderByNodeExpression, parameter)));
}
/// <summary>
/// Translate OperationSegment to linq expression.
/// </summary>
/// <param name="segment">The OperationSegment</param>
/// <returns>The linq expression</returns>
public override Expression Translate(OperationSegment segment)
{
IEdmOperation operation = segment.Operations.First();
List <Expression> arguments = new List <Expression>();
if (operation.IsBound)
{
arguments.Add(this.ResultExpression);
}
if (operation is IEdmFunction)
{
NodeToExpressionTranslator nodeToExpressionTranslator = new NodeToExpressionTranslator()
{
UriParser = this.queryContext.UriParser,
DataSource = this.dataSource,
};
arguments.AddRange(segment.Parameters.Select(p => nodeToExpressionTranslator.TranslateNode((QueryNode)p.Value)));
var operationProvider = this.dataSource.OperationProvider;
operationProvider.QueryContext = this.queryContext;
this.ResultExpression = Expression.Call(Expression.Constant(operationProvider), operation.Name, new Type[] { }, arguments.ToArray());
}
else if (operation is IEdmAction)
{
arguments.AddRange(this.ActionInvokeParameters);
var operationProvider = this.dataSource.OperationProvider;
operationProvider.QueryContext = this.queryContext;
this.ResultExpression = Expression.Call(Expression.Constant(operationProvider), operation.Name, new Type[] { }, arguments.ToArray());
}
else
{
throw new NotImplementedException("Unsupported operation type.");
}
this.LastProcessedSegment = segment;
return(this.ResultExpression);
}
