/// <summary>
/// Attaches the specified component to an entity.
///
/// If a component of the same type is already attached to the entity, then nothing happens
/// and the method returns false.
/// </summary>
public bool Add(IEntityRecord entity, IComponent component)
{
bool componentSuccessfullyAttached = false;
bool entityWasAlreadyRegistered = true;
lock (_keyhole) {
if (component != null)
{
IEntityRecord previousRecord = component.Record;
if (previousRecord != null)
{
if (!previousRecord.Equals(entity))
{
Remove(previousRecord, component);
}
}
}
IDictionary <Type, IComponent> components = GetComponentsForRecord(entity);
if (components == null)
{
components = new Dictionary <Type, IComponent>(1);
entityWasAlreadyRegistered = false;
_records[entity] = components;
}
if (component != null)
{
Type key = component.GetType();
if (!entityWasAlreadyRegistered || !components.ContainsKey(key))
{
components.Add(key, component);
if (component.Record == null || !component.Record.Equals(entity))
{
component.Record = entity;
}
PrepareComponentForSynchronization(component);
componentSuccessfullyAttached = true;
}
}
}
if (!entityWasAlreadyRegistered)
{
OnEntered(entity);
}
return(componentSuccessfullyAttached);
}
