/// <summary>
/// Eliminates the empty nodes (nodes that consist of only logical elements).
/// </summary>
/// <param name="nodes">The nodes.</param>
/// <returns></returns>
protected virtual FilterExpressionNodeCollection EliminateEmptyNodes(FilterExpressionNodeCollection nodes)
{
FilterExpressionNodeCollection expressions = new FilterExpressionNodeCollection();
foreach (FilterExpressionNode node in nodes)
{
if (node.NodeType == FilterExpressionNodeType.Element ||
node.NodeType == FilterExpressionNodeType.MethodBlock)
{
expressions.Add(node);
}
else
{
// Only add node if it has the actual "Element's" and does not consist of only logical AND's and OR's
if (node.HasChildNodes)
{
FilterExpressionNodeCollection subTree = EliminateEmptyNodes(node.ChildNodes);
if (subTree != null && subTree.Count > 0)
{
expressions.Add(node);
}
}
}
}
return(expressions);
}
/// <summary>
/// Adds the expression as node.
/// </summary>
/// <param name="col">The col.</param>
/// <param name="expr">The expr.</param>
protected virtual void AddExpressionAsNode(ref FilterExpressionNodeCollection col, CodeExpression expr)
{
if (expr is CodeBinaryOperatorExpression)
{
AddExpressionAsNode(ref col, (CodeBinaryOperatorExpression)expr);
}
else if (expr is CodeMethodInvokeExpression)
{
col.Add(ConvertExpressionToNode((CodeMethodInvokeExpression)expr));
}
}
/// <summary>
/// Adds the expression as node.
/// </summary>
/// <param name="col">The col.</param>
/// <param name="expr">The expr.</param>
protected virtual void AddExpressionAsNode(ref FilterExpressionNodeCollection col, CodeBinaryOperatorExpression expr)
{
if (expr.Left is CodeMethodInvokeExpression)
{
col.Add(ConvertExpressionToNode((CodeMethodInvokeExpression)expr.Left));
}
else if (expr.Left is CodeBinaryOperatorExpression)
{
AddExpressionAsNode(ref col, expr.Left);
}
// Only need an operator if right is an expression
FilterExpressionNode blockNode = null;
if (expr.Right is CodeBinaryOperatorExpression)
{
if (expr.Operator == CodeBinaryOperatorType.BooleanAnd)
{
blockNode = new FilterExpressionNode(FilterExpressionNodeType.AndBlock, String.Empty);
}
else if (expr.Operator == CodeBinaryOperatorType.BooleanOr)
{
blockNode = new FilterExpressionNode(FilterExpressionNodeType.OrBlock, String.Empty);
}
col.Add(blockNode);
FilterExpressionNodeCollection blockCol = new FilterExpressionNodeCollection();
AddExpressionAsNode(ref blockCol, expr.Right);
blockNode.ChildNodes = blockCol;
}
if (expr.Right is CodeMethodInvokeExpression)
{
col.Add(ConvertExpressionToNode((CodeMethodInvokeExpression)expr.Right));
}
}
