private void Upsert(DictionaryModification <TKey, TValue> modification)
{
TValue existingValue;
if (_dictionary._state.TryGetValue(modification.Key, out existingValue))
{
try
{
var newValue = _dictionary._updateFunction(modification.Key, existingValue, modification.Value);
_dictionary._state[modification.Key] = newValue;
_dictionary._subject.OnNext(DictionaryNotification.Updated(modification.Key, newValue,
modification.Value, existingValue));
}
catch (Exception ex)
{
_dictionary._error = ex;
_dictionary._subject.OnError(
new ObservableDictionaryUpdateException("Exception thrown when updating " + modification, ex));
}
}
else
{
_dictionary._state[modification.Key] = modification.Value;
_dictionary._subject.OnNext(DictionaryNotification.Inserted(modification.Key, modification.Value));
}
}
public void OnNext(DictionaryModification <TKey, TValue> value)
{
if (DictionaryModification <TKey, TValue> .Initialised == value)
{
_dictionary._subject.OnNext(DictionaryNotification.Initialised <TKey, TValue>());
}
else
{
switch (value.Type)
{
case DictionaryModificationType.Upsert:
Upsert(value);
break;
case DictionaryModificationType.Replace:
Replace(value);
break;
case DictionaryModificationType.Remove:
Remove(value);
break;
case DictionaryModificationType.Clear:
Clear();
break;
default:
throw new ArgumentOutOfRangeException();
}
}
}
private void Upsert(DictionaryModification <TKey, TValue> modification)
{
TValue existingValue;
if (_dictionary._state.TryGetValue(modification.Key, out existingValue))
{
try
{
// TODO Check order is correct here.
var newValue = _dictionary._updateFunction.Invoke(modification.Key, existingValue,
modification.Value);
_dictionary._state[modification.Key] = newValue;
_dictionary._subject.OnNext(DictionaryNotification.Updated(modification.Key, newValue,
modification.Value, existingValue));
}
catch (Exception ex)
{
// TODO Check that this errors the whole stream.
_dictionary._error = ex;
_dictionary._subject.OnError(
new ObservableDictionaryUpdateException("Exception thrown when updating " + modification, ex));
}
}
else
{
_dictionary._state[modification.Key] = modification.Value;
_dictionary._subject.OnNext(DictionaryNotification.Inserted(modification.Key, modification.Value));
}
}
private void Remove(DictionaryModification <TKey, TValue> modification)
{
TValue removedValue;
if (_dictionary._state.TryGetValue(modification.Key, out removedValue))
{
_dictionary._state.Remove(modification.Key);
_dictionary._subject.OnNext(DictionaryNotification.Removed(modification.Key, removedValue));
}
// Design decision: We don't signal 'removed' for a value that didn't exist.
}
private void Remove(DictionaryModification <TKey, TValue> modification)
{
TValue removedValue;
if (_dictionary._state.TryGetValue(modification.Key, out removedValue))
{
_dictionary._state.Remove(modification.Key);
// TODO Should we signal 'removed' for a value that didn't exist..?
_dictionary._subject.OnNext(DictionaryNotification.Removed(modification.Key, removedValue));
}
}
private void Replace(DictionaryModification <TKey, TValue> modification)
{
TValue existingValue;
if (_dictionary._state.TryGetValue(modification.Key, out existingValue))
{
_dictionary._subject.OnNext(DictionaryNotification.Replaced(modification.Key, modification.Value,
existingValue));
}
else
{
// TODO Should we do an upsert when the item to be replaced doesn't exist, or signal replaced with a missing value?
Upsert(modification);
}
}
private void Replace(DictionaryModification <TKey, TValue> modification)
{
TValue existingValue;
if (_dictionary._state.TryGetValue(modification.Key, out existingValue))
{
_dictionary._state[modification.Key] = modification.Value;
_dictionary._subject.OnNext(DictionaryNotification.Replaced(modification.Key, modification.Value,
existingValue));
}
else
{
// Design decision: we do an upsert when the item to be replaced doesn't exist, rather than signal replaced with a missing value.
Upsert(modification);
}
}
