julian
102 lines
4.7 KiB
C#
102 lines
4.7 KiB
C#
using System.Collections;
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namespace adas_core.Domain.Utils;
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/// <summary>
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/// Provides static utility methods for working with collections.
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/// </summary>
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/// <!-- aidoc:v1 sig=50818c2 -->
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public static class CollectionsUtils
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{
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/// <summary>
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/// Determines whether the specified list is null or contains no elements.
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/// </summary>
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/// <param name="value">The list to evaluate.</param>
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/// <returns><see langword="true"/> if the list is null or empty; otherwise, <see langword="false"/>.</returns>
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/// <!-- aidoc:v1 sig=dfb5373 body=1cd2a38 -->
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public static bool IsNullOrEmpty<T>(this List<T>? value)
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{
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return value == null || !value.Any();
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}
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/// <summary>
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/// Determines whether the specified list is <see langword="null"/> or contains no elements.
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/// </summary>
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/// <param name="value">The list to evaluate.</param>
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/// <returns><see langword="true"/> if the list is <see langword="null"/> or empty; otherwise, <see langword="false"/>.</returns>
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/// <!-- aidoc:v1 sig=5038079 body=1cd2a38 -->
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public static bool IsEmptyOrNull<T>(List<T>? value)
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{
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return value == null || !value.Any();
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}
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/// <summary>
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/// Determines whether the specified list contains at least one element, returning <c>false</c> when the list is <c>null</c> or empty.
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/// </summary>
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/// <param name="value">The list to evaluate. May be <c>null</c>.</param>
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/// <returns><c>true</c> if <paramref name="value"/> is not <c>null</c> and contains one or more elements; otherwise, <c>false</c>.</returns>
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/// <!-- aidoc:v1 sig=2c3b8ff body=0269891 -->
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public static bool HasElements<T>(List<T>? value)
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{
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return value != null && value.Any();
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}
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/// <summary>
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/// Determines whether the specified list is neither null nor empty by negating the result of <see cref="IsEmptyOrNull{T}(List{T})"/>.
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/// </summary>
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/// <param name="value">The list to evaluate.</param>
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/// <returns><see langword="true"/> if the list is not null and contains at least one element; otherwise, <see langword="false"/>.</returns>
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/// <!-- aidoc:v1 sig=61945f3 body=2b7a733 -->
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public static bool IsNotEmpty<T>(List<T> value)
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{
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return !IsEmptyOrNull(value);
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}
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/// <summary>
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/// Returns the provided list as-is when it is not null, or an empty list when it is null, ensuring a non-null result for safe iteration.
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/// </summary>
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/// <param name="value">The list to evaluate; may be <see langword="null"/>.</param>
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/// <returns>The original <paramref name="value"/> if it is not null; otherwise, an empty <see cref="List{T}"/>.</returns>
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/// <!-- aidoc:v1 sig=4b33799 body=5556777 -->
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public static List<T> EmptyIfNull<T>(List<T>? value)
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{
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return value ?? [];
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}
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/// <summary>
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/// Returns <c>null</c> when the specified list is null or contains no elements; otherwise, returns the list as-is.
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/// </summary>
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/// <param name="value">The list to evaluate.</param>
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/// <returns>The original <paramref name="value"/> when it is not null and not empty; otherwise, <c>null</c>.</returns>
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/// <!-- aidoc:v1 sig=a05f7fc body=74812a2 -->
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public static List<T>? NullIfEmpty<T>(List<T> value)
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{
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return IsEmptyOrNull(value) ? null : value;
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}
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/// <summary>
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/// Converts the specified collection into a strongly typed array of the given element type.
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/// </summary>
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/// <param name="collection">The source collection whose elements are copied into the new array.</param>
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/// <param name="type">The element <see cref="Type"/> of the array to create.</param>
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/// <returns>A new <see cref="Array"/> of the specified type containing the elements copied from the collection.</returns>
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/// <!-- aidoc:v1 sig=98732cd body=d08ef3a -->
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public static Array ToArray(ICollection collection, Type type)
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{
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var result = Array.CreateInstance(type, collection.Count);
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collection.CopyTo(result, 0);
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return result;
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}
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/// <summary>
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/// Returns the provided default list when the input list is null or empty; otherwise returns the input list unchanged.
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/// </summary>
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/// <param name="list">The list to evaluate for a null or empty state.</param>
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/// <param name="defaultList">The fallback list returned when <paramref name="list"/> is null or empty.</param>
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/// <returns>The original <paramref name="list"/> when it contains items; otherwise <paramref name="defaultList"/>.</returns>
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/// <!-- aidoc:v1 sig=c865748 body=df53ea7 -->
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public static List<string> IfEmptyOrNull(List<string> list, List<string> defaultList)
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{
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return IsEmptyOrNull(list) ? defaultList : list;
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}
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} |