public QueryEngineCustomOperators()
{
GenerateData(1000);
// Setup the query engine
m_QueryEngine = new QueryEngine <MyCustomObjectType>();
// Id supports all operators
m_QueryEngine.AddFilter("id", myObj => myObj.Id);
// Setup what data will be matched against search words
m_QueryEngine.SetSearchDataCallback(myObj => new[] { myObj.Id.ToString() });
// Extend the set of operators and type parsers
// Modulo operator will work on all filters that are integers
const string moduloOp = "%";
m_QueryEngine.AddOperator(moduloOp);
m_QueryEngine.AddOperatorHandler(moduloOp, (int ev, int fv) => ev % fv == 0);
// List operator will work on al filters that have an integer as left hand side and
// a list of integers as right hand side
var listOp = "?";
m_QueryEngine.AddOperator(listOp);
m_QueryEngine.AddOperatorHandler(listOp, (int ev, List <int> values) => values.Contains(ev));
// To correctly parse this new type (because it is not supported by default), we add a type parser
m_QueryEngine.AddTypeParser(s =>
{
var tokens = s.Split(',');
if (tokens.Length == 0)
{
return(new ParseResult <List <int> >(false, null));
}
var numberList = new List <int>(tokens.Length);
foreach (var token in tokens)
{
if (TryConvertValue(token, out int number))
{
numberList.Add(number);
}
else
{
return(new ParseResult <List <int> >(false, null));
}
}
return(new ParseResult <List <int> >(true, numberList));
});
// We an also extend existing operators
// Position supports =, !=, <, >, <=, >=
m_QueryEngine.AddFilter("p", myObj => myObj.Position, new[] { "=", "!=", "<", ">", "<=", ">=" });
// Extend the =, !=, <, >, <=, >= operators to support comparing Vector2's magnitude
m_QueryEngine.AddOperatorHandler("=", (Vector2 ev, Vector2 fv) => Math.Abs(ev.magnitude - fv.magnitude) < float.Epsilon);
m_QueryEngine.AddOperatorHandler("!=", (Vector2 ev, Vector2 fv) => Math.Abs(ev.magnitude - fv.magnitude) > float.Epsilon);
m_QueryEngine.AddOperatorHandler("<", (Vector2 ev, Vector2 fv) => ev.magnitude < fv.magnitude);
m_QueryEngine.AddOperatorHandler(">", (Vector2 ev, Vector2 fv) => ev.magnitude > fv.magnitude);
m_QueryEngine.AddOperatorHandler("<=", (Vector2 ev, Vector2 fv) => ev.magnitude <= fv.magnitude);
m_QueryEngine.AddOperatorHandler(">=", (Vector2 ev, Vector2 fv) => ev.magnitude >= fv.magnitude);
// Add a new type parser for Vector2
m_QueryEngine.AddTypeParser(s =>
{
if (!s.StartsWith("[") || !s.EndsWith("]"))
{
return(new ParseResult <Vector2>(false, Vector2.zero));
}
var trimmed = s.Trim('[', ']');
var vectorTokens = trimmed.Split(',');
var vectorValues = vectorTokens.Select(token => float.Parse(token, CultureInfo.InvariantCulture.NumberFormat)).ToList();
Assert.AreEqual(vectorValues.Count, 2);
var vector = new Vector2(vectorValues[0], vectorValues[1]);
return(new ParseResult <Vector2>(true, vector));
});
// If you don't want to add a multitude of operator handlers, you can define
// a generic filter handler that will handle all existing operators on a filter
m_QueryEngine.AddFilter <string>("is", IsFilterResolver);
}