private bool WriteGroup(EntityFilter entityFilter)
{
// check for group start
var hasGroup = entityFilter.Filters != null && entityFilter.Filters.Any();
if (!hasGroup)
{
return(false);
}
var logic = string.IsNullOrWhiteSpace(entityFilter.Logic)
? EntityFilterLogic.And
: entityFilter.Logic;
var wroteFirst = false;
_expression.Append("(");
foreach (var filter in entityFilter.Filters)
{
if (wroteFirst)
{
_expression.Append($" {logic} ");
}
Visit(filter);
wroteFirst = true;
}
_expression.Append(")");
return(true);
}
private void Visit(EntityFilter entityFilter)
{
if (WriteGroup(entityFilter))
{
return;
}
WriteExpression(entityFilter);
}
/// <summary>
/// Builds a string base Linq expression from the specified <see cref="EntityFilter"/>.
/// </summary>
/// <param name="entityFilter">The entity filter to build expression from.</param>
public void Build(EntityFilter entityFilter)
{
_expression.Length = 0;
_values.Clear();
if (entityFilter == null)
{
return;
}
Visit(entityFilter);
}
private void WriteExpression(EntityFilter entityFilter)
{
// name require for expression
if (string.IsNullOrWhiteSpace(entityFilter.Name))
{
return;
}
// parameter index number
int index = _values.Count;
var name = entityFilter.Name;
var value = entityFilter.Value;
// translate operator
var o = string.IsNullOrWhiteSpace(entityFilter.Operator) ? "==" : entityFilter.Operator;
_operatorMap.TryGetValue(o, out string comparison);
if (string.IsNullOrEmpty(comparison))
{
comparison = o.Trim();
}
// use function call
var negation = comparison.StartsWith("!") || comparison.StartsWith("not", StringComparison.OrdinalIgnoreCase) ? "!" : string.Empty;
if (comparison.EndsWith(EntityFilterOperators.StartsWith, StringComparison.OrdinalIgnoreCase))
{
_expression.Append($"{negation}{name}.StartsWith(@{index})");
}
else if (comparison.EndsWith(EntityFilterOperators.EndsWith, StringComparison.OrdinalIgnoreCase))
{
_expression.Append($"{negation}{name}.EndsWith(@{index})");
}
else if (comparison.EndsWith(EntityFilterOperators.Contains, StringComparison.OrdinalIgnoreCase))
{
_expression.Append($"{negation}{name}.Contains(@{index})");
}
else
{
_expression.Append($"{name} {comparison} @{index}");
}
_values.Add(value);
}
public EntitySelect(EntityFilter filter, IEnumerable <EntitySort> sort)
{
Filter = filter;
Sort = sort;
}
public EntitySelect(EntityFilter filter)
: this(filter, null)
{
}
public EntitySelectQuery(IPrincipal principal, EntityFilter filter, IEnumerable <EntitySort> sort)
: base(principal)
{
Filter = filter;
Sort = sort;
}
public EntitySelectQuery(IPrincipal principal, EntityFilter filter, EntitySort sort)
: this(principal, filter, new[] { sort })
{
}
public EntitySelectQuery(IPrincipal principal, EntityFilter filter)
: this(principal, filter, (IEnumerable <EntitySort>)null)
{
}
public EntitySelectQuery(IPrincipal principal, EntityFilter filter, IEnumerable <EntitySort> sort)
: this(principal, new EntitySelect(filter, sort))
{
}
public EntitySelectQuery(IPrincipal principal, EntityFilter filter)
: this(principal, new EntitySelect(filter))
{
}