/// <summary>
/// Tries to instantiate an object of a specific type. This performs
/// application specific instantiation and subclasses should override
/// this method to perform their own logic. If the instantiated object is
/// null, then InstantiationData.Null should be returned.
/// </summary>
/// <param name="node">JSON node to create the instance from. This
/// might be used to decide the type of the object or for the arguments
/// of a constructor.</param>
/// <param name="targetType">Target type of the object.</param>
/// <param name="referingType">Refering type that is only set if this
/// is a substitute type for another type.</param>
/// <param name="options">Instantiation options.</param>
/// <param name="deserializer">Deserializer to use for the instantiation.</param>
protected virtual bool TryInstantiate(
JSONNode node,
Type targetType,
Type referingType,
NodeOptions options,
Deserializer deserializer,
out InstantiationData instantiationData)
{
instantiationData = InstantiationData.Null;
return(false);
}
private InstantiationData _InstantiateWithConstructor(
JSONNode node,
Type targetType,
NodeOptions options,
Deserializer deserializer)
{
if (node.IsNull || node.Tag == JSONNodeType.None)
{
return(InstantiationData.Null);
}
JSONObjectAttribute objectAttribute = Util.GetAttribute <JSONObjectAttribute> (targetType);
bool useTupleFormat = objectAttribute != null
? objectAttribute.options.ShouldUseTupleFormat() : false;
if (useTupleFormat && !node.IsArray)
{
throw new InstantiationException("Expected JSON array, found " + node.Tag);
}
else if (!useTupleFormat && !node.IsObject)
{
throw new InstantiationException("Expected JSON object, found " + node.Tag);
}
ConstructorInfo[] constructors = targetType.GetConstructors(
BindingFlags.Instance |
BindingFlags.Public |
BindingFlags.NonPublic);
foreach (ConstructorInfo constructorInfo in constructors)
{
var constructorAttribute = Util.GetAttribute <JSONConstructorAttribute> (constructorInfo);
if (constructorAttribute != null)
{
return(_InstantiateWithConstructor(node, constructorInfo, deserializer, useTupleFormat));
}
}
try {
InstantiationData instantiationData = new InstantiationData();
instantiationData.instantiatedObject = Activator.CreateInstance(targetType);
instantiationData.needsDeserialization = node.Count != 0;
return(instantiationData);
} catch (Exception) {
return(_HandleError(options, "Type " + targetType
+ " does not have a suitable constructor."));
}
}
private InstantiationData _InstantiateWithConstructor(
JSONNode node,
ConstructorInfo constructorInfo,
Deserializer deserializer,
bool useTupleFormat)
{
ParameterInfo[] parameters = constructorInfo.GetParameters();
object[] parameterValues = new object[parameters.Length];
HashSet <string> ignoredKeys = new HashSet <string> ();
for (int i = 0; i < parameterValues.Length; i++)
{
var nodeAttribute = Util.GetAttribute <JSONNodeAttribute> (parameters [i]);
var restrictAttribute = Util.GetAttribute <RestrictTypeAttribute> (parameters [i]);
string key = nodeAttribute != null && nodeAttribute.key != null
? nodeAttribute.key : parameters [i].Name;
JSONNode parameterNode = useTupleFormat ? node [i] : node [key];
ObjectTypes restrictedTypes = restrictAttribute == null
? ObjectTypes.JSON : restrictAttribute.types;
Type[] customTypes = restrictAttribute == null ? null : restrictAttribute.customTypes;
parameterValues [i] = deserializer.Deserialize(
parameterNode,
parameters [i].ParameterType,
nodeAttribute == null ? NodeOptions.Default : nodeAttribute.options,
restrictedTypes,
customTypes);
if (!useTupleFormat)
{
ignoredKeys.Add(key);
}
}
InstantiationData instantiationData = new InstantiationData();
instantiationData.instantiatedObject = constructorInfo.Invoke(parameterValues);
instantiationData.needsDeserialization = !useTupleFormat && ignoredKeys.Count != node.Count;
instantiationData.ignoredKeys = ignoredKeys;
return(instantiationData);
}