QueryEngine<T0>.AddFiltersFromAttribute

Description

Adds all custom filters that are identified with the method attribute TFilterAttribute.

Allows you to register a filter with a specific type.

<TFilterAttribute>: The type of the attribute defined for your custom filters.

<TTransformerAttribute>: The type of the attribute defined for your custom parameter transformers.

For more information about the custom attributes, see QueryEngineFilterAttribute and QueryEngineParameterTransformerAttribute.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using UnityEditor;
using UnityEditor.Search;
using UnityEngine;

static class Example_QueryEngine_AddFilterFromAttribute
{
    static List<MyObjectType> s_Data;

    [MenuItem("Examples/QueryEngine/AddFiltersFromAttribute")]
    public static void RunExample()
    {
        // Set up the query engine
        var queryEngine = new QueryEngine<MyObjectType>();
        queryEngine.AddFilter("id", myObj => myObj.id);
        queryEngine.SetSearchDataCallback(myObj => new[] { myObj.id.ToString(), myObj.name });
        SetupPropertyHandlers(queryEngine);

        // Register filters with our own attributes
        queryEngine.AddFiltersFromAttribute<MyObjectFilterAttribute, MyObjectFilterParameterTransformerAttribute>();

        s_Data = new List<MyObjectType>()
        {
            new MyObjectType { id = 0, name = "Test 1", values = new float[] {2, 20, 42} },
            new MyObjectType { id = 1, name = "Test 2", values = new float[] {16, 64, 128} },
            new MyObjectType { id = 2, name = "Test 3", values = new float[] {123, 48, 20}, property = new Property("size", PropertyType.Integer, 64) },
            new MyObjectType { id = 3, name = "Test 4", values = new float[] {98, 45, 1}, property = new Property("size", PropertyType.Integer, 128) },
            new MyObjectType { id = 4, name = "Test 5", values = new float[] {3, 51, 78}, property = new Property("tag", PropertyType.String, "item") },
            new MyObjectType { id = 5, name = "Test 6", values = new float[] {321, 58, 32}, property = new Property("tag", PropertyType.String, "car item") }
        };

        // Find all items with values at index 1 lower or equal to 32
        var query = queryEngine.Parse("v(1)<=32");
        var filteredData = query.Apply(s_Data).ToList();
        Debug.Assert(filteredData.Count == 1, $"There should be 1 item in the filtered list but found {filteredData.Count} items.");
        Debug.Assert(filteredData.Contains(s_Data[0]), "The first item should be in the list.");

        // Find all items with property size greater or equal to 128
        query = queryEngine.Parse("#size>=128");
        filteredData = query.Apply(s_Data).ToList();
        Debug.Assert(filteredData.Count == 1, $"There should be 1 item in the filtered list but found {filteredData.Count} items.");
        Debug.Assert(filteredData.Contains(s_Data[3]), $"The item \"{s_Data[3].name}\" should be in the list.");
    }

    static void SetupPropertyHandlers(QueryEngine<MyObjectType> qe)
    {
        qe.AddOperatorHandler(":", (Property v, int number, StringComparison sc) => PropertyIntCompare(v, number, (f, r) => f.ToString().IndexOf(r.ToString()) != -1));
        qe.AddOperatorHandler("=", (Property v, int number) => PropertyIntCompare(v, number, (f, r) => f == r));
        qe.AddOperatorHandler("!=", (Property v, int number) => PropertyIntCompare(v, number, (f, r) => f != r));
        qe.AddOperatorHandler("<=", (Property v, int number) => PropertyIntCompare(v, number, (f, r) => f <= r));
        qe.AddOperatorHandler("<", (Property v, int number) => PropertyIntCompare(v, number, (f, r) => f < r));
        qe.AddOperatorHandler(">", (Property v, int number) => PropertyIntCompare(v, number, (f, r) => f > r));
        qe.AddOperatorHandler(">=", (Property v, int number) => PropertyIntCompare(v, number, (f, r) => f >= r));
        qe.AddOperatorHandler(":", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => f.IndexOf(r, sc) != -1));
        qe.AddOperatorHandler("=", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => string.Equals(f, r, sc)));
        qe.AddOperatorHandler("!=", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => !string.Equals(f, r, sc)));
        qe.AddOperatorHandler("<=", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => string.Compare(f, r, sc) <= 0));
        qe.AddOperatorHandler("<", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => string.Compare(f, r, sc) < 0));
        qe.AddOperatorHandler(">", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => string.Compare(f, r, sc) > 0));
        qe.AddOperatorHandler(">=", (Property v, string s, StringComparison sc) => PropertyStringCompare(v, s, (f, r) => string.Compare(f, r, sc) >= 0));
    }

    static bool PropertyStringCompare(Property p, string s, Func<string, string, bool> comparer)
    {
        if (p.type != PropertyType.String)
            return false;
        return comparer((string)p.value, s);
    }

    static bool PropertyIntCompare(Property p, int number, Func<int, int, bool> comparer)
    {
        if (p.type != PropertyType.Integer)
            return false;
        return comparer((int)p.value, number);
    }

    // Define a filter for a "value" property
    [MyObjectFilter("v", "ParseFilterValuesIndex")]
    static float FilterValues(MyObjectType myObj, int index)
    {
        return myObj.values[index];
    }

    // Define the parameter transformer for the filter "FilterValues"
    [MyObjectFilterParameterTransformer]
    static int ParseFilterValuesIndex(string param)
    {
        if (int.TryParse(param, NumberStyles.Number, new NumberFormatInfo(), out var i))
            return i;
        return 0;
    }

    // Define a regular expression filter for the property "property".
    [MyObjectFilter("#([\\w.]+)", true)]
    static Property FilterProperty(MyObjectType myObj, string filterMatch)
    {
        if (myObj.property.name == filterMatch)
            return myObj.property;
        return Property.invalid;
    }


    // Create a new attribute in order to register filters of this type only
    class MyObjectFilterAttribute : QueryEngineFilterAttribute
    {
        public MyObjectFilterAttribute(string token, string[] supportedOperators = null)
            : base(token, supportedOperators) {}

        public MyObjectFilterAttribute(string token, StringComparison options, string[] supportedOperators = null)
            : base(token, options, supportedOperators) {}

        public MyObjectFilterAttribute(string token, string paramTransformerFunction, string[] supportedOperators = null)
            : base(token, paramTransformerFunction, supportedOperators) {}

        public MyObjectFilterAttribute(string token, string paramTransformerFunction, StringComparison options, string[] supportedOperators = null)
            : base(token, paramTransformerFunction, options, supportedOperators) {}

        public MyObjectFilterAttribute(string token, bool useRegularExpression, string[] supportedOperators = null)
            : base(token, useRegularExpression, supportedOperators) {}

        public MyObjectFilterAttribute(string token, bool useRegularExpression, StringComparison options, string[] supportedOperators = null)
            : base(token, useRegularExpression, options, supportedOperators) {}

        public MyObjectFilterAttribute(string token, bool useRegularExpression, string paramTransformerFunction, string[] supportedOperators = null)
            : base(token, useRegularExpression, paramTransformerFunction, supportedOperators) {}

        public MyObjectFilterAttribute(string token, bool useRegularExpression, string paramTransformerFunction, StringComparison options, string[] supportedOperators = null)
            : base(token, useRegularExpression, paramTransformerFunction, options, supportedOperators) {}
    }

    class MyObjectFilterParameterTransformerAttribute : QueryEngineParameterTransformerAttribute {}

    enum PropertyType
    {
        None,
        Integer,
        String,
        Integer_Array
    }

    struct Property
    {
        public string name { get; }
        public PropertyType type { get; }
        public object value { get; set; }

        public Property(string name, PropertyType type, object value)
        {
            this.name = name;
            this.type = type;
            this.value = value;
        }

        public static Property invalid = new Property(string.Empty, PropertyType.None, null);
    }

    class MyObjectType
    {
        public int id { get; set; }
        public string name { get; set; } = string.Empty;
        public Vector2 position { get; set; } = Vector2.zero;
        public bool active { get; set; }
        public float[] values { get; set; } = new float[0];
        public Property property { get; set; } = Property.invalid;

        public override string ToString()
        {
            return $"({id}, {name}, ({position.x}, {position.y}), {active})";
        }
    }
}