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using System;using System.Collections;using System.Collections.Generic;using System.Diagnostics.CodeAnalysis;using System.Globalization;using System.Linq;using System.Reflection;
namespace ICSSoft.WebAPI.Areas.HelpPage{ /// <summary>
/// This class will create an object of a given type and populate it with sample data.
/// </summary>
public class ObjectGenerator { internal const int DefaultCollectionSize = 2; private readonly SimpleTypeObjectGenerator SimpleObjectGenerator = new SimpleTypeObjectGenerator();
/// <summary>
/// Generates an object for a given type. The type needs to be public, have a public default constructor and settable public properties/fields. Currently it supports the following types:
/// Simple types: <see cref="int"/>, <see cref="string"/>, <see cref="Enum"/>, <see cref="DateTime"/>, <see cref="Uri"/>, etc.
/// Complex types: POCO types.
/// Nullables: <see cref="Nullable{T}"/>.
/// Arrays: arrays of simple types or complex types.
/// Key value pairs: <see cref="KeyValuePair{TKey,TValue}"/>
/// Tuples: <see cref="Tuple{T1}"/>, <see cref="Tuple{T1,T2}"/>, etc
/// Dictionaries: <see cref="IDictionary{TKey,TValue}"/> or anything deriving from <see cref="IDictionary{TKey,TValue}"/>.
/// Collections: <see cref="IList{T}"/>, <see cref="IEnumerable{T}"/>, <see cref="ICollection{T}"/>, <see cref="IList"/>, <see cref="IEnumerable"/>, <see cref="ICollection"/> or anything deriving from <see cref="ICollection{T}"/> or <see cref="IList"/>.
/// Queryables: <see cref="IQueryable"/>, <see cref="IQueryable{T}"/>.
/// </summary>
/// <param name="type">The type.</param>
/// <returns>An object of the given type.</returns>
public object GenerateObject(Type type) { return GenerateObject(type, new Dictionary<Type, object>()); }
[SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "Here we just want to return null if anything goes wrong.")] private object GenerateObject(Type type, Dictionary<Type, object> createdObjectReferences) { try { if (SimpleTypeObjectGenerator.CanGenerateObject(type)) { return SimpleObjectGenerator.GenerateObject(type); }
if (type.IsArray) { return GenerateArray(type, DefaultCollectionSize, createdObjectReferences); }
if (type.IsGenericType) { return GenerateGenericType(type, DefaultCollectionSize, createdObjectReferences); }
if (type == typeof(IDictionary)) { return GenerateDictionary(typeof(Hashtable), DefaultCollectionSize, createdObjectReferences); }
if (typeof(IDictionary).IsAssignableFrom(type)) { return GenerateDictionary(type, DefaultCollectionSize, createdObjectReferences); }
if (type == typeof(IList) || type == typeof(IEnumerable) || type == typeof(ICollection)) { return GenerateCollection(typeof(ArrayList), DefaultCollectionSize, createdObjectReferences); }
if (typeof(IList).IsAssignableFrom(type)) { return GenerateCollection(type, DefaultCollectionSize, createdObjectReferences); }
if (type == typeof(IQueryable)) { return GenerateQueryable(type, DefaultCollectionSize, createdObjectReferences); }
if (type.IsEnum) { return GenerateEnum(type); }
if (type.IsPublic || type.IsNestedPublic) { return GenerateComplexObject(type, createdObjectReferences); } } catch { // Returns null if anything fails
return null; }
return null; }
private static object GenerateGenericType(Type type, int collectionSize, Dictionary<Type, object> createdObjectReferences) { Type genericTypeDefinition = type.GetGenericTypeDefinition(); if (genericTypeDefinition == typeof(Nullable<>)) { return GenerateNullable(type, createdObjectReferences); }
if (genericTypeDefinition == typeof(KeyValuePair<,>)) { return GenerateKeyValuePair(type, createdObjectReferences); }
if (IsTuple(genericTypeDefinition)) { return GenerateTuple(type, createdObjectReferences); }
Type[] genericArguments = type.GetGenericArguments(); if (genericArguments.Length == 1) { if (genericTypeDefinition == typeof(IList<>) || genericTypeDefinition == typeof(IEnumerable<>) || genericTypeDefinition == typeof(ICollection<>)) { Type collectionType = typeof(List<>).MakeGenericType(genericArguments); return GenerateCollection(collectionType, collectionSize, createdObjectReferences); }
if (genericTypeDefinition == typeof(IQueryable<>)) { return GenerateQueryable(type, collectionSize, createdObjectReferences); }
Type closedCollectionType = typeof(ICollection<>).MakeGenericType(genericArguments[0]); if (closedCollectionType.IsAssignableFrom(type)) { return GenerateCollection(type, collectionSize, createdObjectReferences); } }
if (genericArguments.Length == 2) { if (genericTypeDefinition == typeof(IDictionary<,>)) { Type dictionaryType = typeof(Dictionary<,>).MakeGenericType(genericArguments); return GenerateDictionary(dictionaryType, collectionSize, createdObjectReferences); }
Type closedDictionaryType = typeof(IDictionary<,>).MakeGenericType(genericArguments[0], genericArguments[1]); if (closedDictionaryType.IsAssignableFrom(type)) { return GenerateDictionary(type, collectionSize, createdObjectReferences); } }
if (type.IsPublic || type.IsNestedPublic) { return GenerateComplexObject(type, createdObjectReferences); }
return null; }
private static object GenerateTuple(Type type, Dictionary<Type, object> createdObjectReferences) { Type[] genericArgs = type.GetGenericArguments(); object[] parameterValues = new object[genericArgs.Length]; bool failedToCreateTuple = true; ObjectGenerator objectGenerator = new ObjectGenerator(); for (int i = 0; i < genericArgs.Length; i++) { parameterValues[i] = objectGenerator.GenerateObject(genericArgs[i], createdObjectReferences); failedToCreateTuple &= parameterValues[i] == null; } if (failedToCreateTuple) { return null; } object result = Activator.CreateInstance(type, parameterValues); return result; }
private static bool IsTuple(Type genericTypeDefinition) { return genericTypeDefinition == typeof(Tuple<>) || genericTypeDefinition == typeof(Tuple<,>) || genericTypeDefinition == typeof(Tuple<,,>) || genericTypeDefinition == typeof(Tuple<,,,>) || genericTypeDefinition == typeof(Tuple<,,,,>) || genericTypeDefinition == typeof(Tuple<,,,,,>) || genericTypeDefinition == typeof(Tuple<,,,,,,>) || genericTypeDefinition == typeof(Tuple<,,,,,,,>); }
private static object GenerateKeyValuePair(Type keyValuePairType, Dictionary<Type, object> createdObjectReferences) { Type[] genericArgs = keyValuePairType.GetGenericArguments(); Type typeK = genericArgs[0]; Type typeV = genericArgs[1]; ObjectGenerator objectGenerator = new ObjectGenerator(); object keyObject = objectGenerator.GenerateObject(typeK, createdObjectReferences); object valueObject = objectGenerator.GenerateObject(typeV, createdObjectReferences); if (keyObject == null && valueObject == null) { // Failed to create key and values
return null; } object result = Activator.CreateInstance(keyValuePairType, keyObject, valueObject); return result; }
private static object GenerateArray(Type arrayType, int size, Dictionary<Type, object> createdObjectReferences) { Type type = arrayType.GetElementType(); Array result = Array.CreateInstance(type, size); bool areAllElementsNull = true; ObjectGenerator objectGenerator = new ObjectGenerator(); for (int i = 0; i < size; i++) { object element = objectGenerator.GenerateObject(type, createdObjectReferences); result.SetValue(element, i); areAllElementsNull &= element == null; }
if (areAllElementsNull) { return null; }
return result; }
private static object GenerateDictionary(Type dictionaryType, int size, Dictionary<Type, object> createdObjectReferences) { Type typeK = typeof(object); Type typeV = typeof(object); if (dictionaryType.IsGenericType) { Type[] genericArgs = dictionaryType.GetGenericArguments(); typeK = genericArgs[0]; typeV = genericArgs[1]; }
object result = Activator.CreateInstance(dictionaryType); MethodInfo addMethod = dictionaryType.GetMethod("Add") ?? dictionaryType.GetMethod("TryAdd"); MethodInfo containsMethod = dictionaryType.GetMethod("Contains") ?? dictionaryType.GetMethod("ContainsKey"); ObjectGenerator objectGenerator = new ObjectGenerator(); for (int i = 0; i < size; i++) { object newKey = objectGenerator.GenerateObject(typeK, createdObjectReferences); if (newKey == null) { // Cannot generate a valid key
return null; }
bool containsKey = (bool)containsMethod.Invoke(result, new object[] { newKey }); if (!containsKey) { object newValue = objectGenerator.GenerateObject(typeV, createdObjectReferences); addMethod.Invoke(result, new object[] { newKey, newValue }); } }
return result; }
private static object GenerateEnum(Type enumType) { Array possibleValues = Enum.GetValues(enumType); if (possibleValues.Length > 0) { return possibleValues.GetValue(0); } return null; }
private static object GenerateQueryable(Type queryableType, int size, Dictionary<Type, object> createdObjectReferences) { bool isGeneric = queryableType.IsGenericType; object list; if (isGeneric) { Type listType = typeof(List<>).MakeGenericType(queryableType.GetGenericArguments()); list = GenerateCollection(listType, size, createdObjectReferences); } else { list = GenerateArray(typeof(object[]), size, createdObjectReferences); } if (list == null) { return null; } if (isGeneric) { Type argumentType = typeof(IEnumerable<>).MakeGenericType(queryableType.GetGenericArguments()); MethodInfo asQueryableMethod = typeof(Queryable).GetMethod("AsQueryable", new[] { argumentType }); return asQueryableMethod.Invoke(null, new[] { list }); }
return Queryable.AsQueryable((IEnumerable)list); }
private static object GenerateCollection(Type collectionType, int size, Dictionary<Type, object> createdObjectReferences) { Type type = collectionType.IsGenericType ? collectionType.GetGenericArguments()[0] : typeof(object); object result = Activator.CreateInstance(collectionType); MethodInfo addMethod = collectionType.GetMethod("Add"); bool areAllElementsNull = true; ObjectGenerator objectGenerator = new ObjectGenerator(); for (int i = 0; i < size; i++) { object element = objectGenerator.GenerateObject(type, createdObjectReferences); addMethod.Invoke(result, new object[] { element }); areAllElementsNull &= element == null; }
if (areAllElementsNull) { return null; }
return result; }
private static object GenerateNullable(Type nullableType, Dictionary<Type, object> createdObjectReferences) { Type type = nullableType.GetGenericArguments()[0]; ObjectGenerator objectGenerator = new ObjectGenerator(); return objectGenerator.GenerateObject(type, createdObjectReferences); }
private static object GenerateComplexObject(Type type, Dictionary<Type, object> createdObjectReferences) { object result = null;
if (createdObjectReferences.TryGetValue(type, out result)) { // The object has been created already, just return it. This will handle the circular reference case.
return result; }
if (type.IsValueType) { result = Activator.CreateInstance(type); } else { ConstructorInfo defaultCtor = type.GetConstructor(Type.EmptyTypes); if (defaultCtor == null) { // Cannot instantiate the type because it doesn't have a default constructor
return null; }
result = defaultCtor.Invoke(new object[0]); } createdObjectReferences.Add(type, result); SetPublicProperties(type, result, createdObjectReferences); SetPublicFields(type, result, createdObjectReferences); return result; }
private static void SetPublicProperties(Type type, object obj, Dictionary<Type, object> createdObjectReferences) { PropertyInfo[] properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance); ObjectGenerator objectGenerator = new ObjectGenerator(); foreach (PropertyInfo property in properties) { if (property.CanWrite) { object propertyValue = objectGenerator.GenerateObject(property.PropertyType, createdObjectReferences); property.SetValue(obj, propertyValue, null); } } }
private static void SetPublicFields(Type type, object obj, Dictionary<Type, object> createdObjectReferences) { FieldInfo[] fields = type.GetFields(BindingFlags.Public | BindingFlags.Instance); ObjectGenerator objectGenerator = new ObjectGenerator(); foreach (FieldInfo field in fields) { object fieldValue = objectGenerator.GenerateObject(field.FieldType, createdObjectReferences); field.SetValue(obj, fieldValue); } }
private class SimpleTypeObjectGenerator { private long _index = 0; private static readonly Dictionary<Type, Func<long, object>> DefaultGenerators = InitializeGenerators();
[SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity", Justification = "These are simple type factories and cannot be split up.")] private static Dictionary<Type, Func<long, object>> InitializeGenerators() { return new Dictionary<Type, Func<long, object>> { { typeof(Boolean), index => true }, { typeof(Byte), index => (Byte)64 }, { typeof(Char), index => (Char)65 }, { typeof(DateTime), index => DateTime.Now }, { typeof(DateTimeOffset), index => new DateTimeOffset(DateTime.Now) }, { typeof(DBNull), index => DBNull.Value }, { typeof(Decimal), index => (Decimal)index }, { typeof(Double), index => (Double)(index + 0.1) }, { typeof(Guid), index => Guid.NewGuid() }, { typeof(Int16), index => (Int16)(index % Int16.MaxValue) }, { typeof(Int32), index => (Int32)(index % Int32.MaxValue) }, { typeof(Int64), index => (Int64)index }, { typeof(Object), index => new object() }, { typeof(SByte), index => (SByte)64 }, { typeof(Single), index => (Single)(index + 0.1) }, { typeof(String), index => { return String.Format(CultureInfo.CurrentCulture, "sample string {0}", index); } }, { typeof(TimeSpan), index => { return TimeSpan.FromTicks(1234567); } }, { typeof(UInt16), index => (UInt16)(index % UInt16.MaxValue) }, { typeof(UInt32), index => (UInt32)(index % UInt32.MaxValue) }, { typeof(UInt64), index => (UInt64)index }, { typeof(Uri), index => { return new Uri(String.Format(CultureInfo.CurrentCulture, "http://webapihelppage{0}.com", index)); } }, }; }
public static bool CanGenerateObject(Type type) { return DefaultGenerators.ContainsKey(type); }
public object GenerateObject(Type type) { return DefaultGenerators[type](++_index); } } }}
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