/// <summary>
/// Subscribes a delegate to an event.
/// </summary>
/// <param name="action">The delegate that gets executed when the event is published.</param>
/// <param name="threadOption">Specifies on which thread to receive the delegate callback.</param>
/// <param name="keepSubscriberReferenceAlive">When <see langword="true"/>, the <see cref="PubSubEvent"/> keeps a reference to the subscriber so it does not get garbage collected.</param>
/// <returns>A <see cref="SubscriptionToken"/> that uniquely identifies the added subscription.</returns>
/// <remarks>
/// If <paramref name="keepSubscriberReferenceAlive"/> is set to <see langword="false" />, <see cref="PubSubEvent"/> will maintain a <see cref="WeakReference"/> to the Target of the supplied <paramref name="action"/> delegate.
/// If not using a WeakReference (<paramref name="keepSubscriberReferenceAlive"/> is <see langword="true" />), the user must explicitly call Unsubscribe for the event when disposing the subscriber in order to avoid memory leaks or unexpected behavior.
/// <para/>
/// The PubSubEvent collection is thread-safe.
/// </remarks>
public SubscriptionToken Subscribe(Action action, ThreadOption threadOption, bool keepSubscriberReferenceAlive)
{
IDelegateReference actionReference = new DelegateReference(action, keepSubscriberReferenceAlive);
EventSubscription subscription;
switch (threadOption)
{
case ThreadOption.PublisherThread:
subscription = new EventSubscription(actionReference);
break;
case ThreadOption.BackgroundThread:
subscription = new BackgroundEventSubscription(actionReference);
break;
case ThreadOption.UIThread:
if (SynchronizationContext == null) throw new InvalidOperationException(Resources.EventAggregatorNotConstructedOnUIThread);
subscription = new DispatcherEventSubscription(actionReference, SynchronizationContext);
break;
default:
subscription = new EventSubscription(actionReference);
break;
}
return base.InternalSubscribe(subscription);
}
public void NullTargetInActionThrowsNonGeneric()
{
Assert.Throws<ArgumentException>(() =>
{
var actionDelegateReference = new MockDelegateReference()
{
Target = null
};
var eventSubscription = new EventSubscription(actionDelegateReference);
});
}
public void DifferentTargetTypeInActionThrowsNonGeneric()
{
Assert.Throws<ArgumentException>(() =>
{
var actionDelegateReference = new MockDelegateReference()
{
Target = (Action<int>)delegate { }
};
var eventSubscription = new EventSubscription(actionDelegateReference);
});
}
public void NullActionThrows()
{
Assert.Throws<ArgumentNullException>(() =>
{
var filterDelegateReference = new MockDelegateReference()
{
Target = (Predicate<object>)(arg =>
{
return true;
})
};
var eventSubscription = new EventSubscription<object>(null, filterDelegateReference);
});
}
public void CanInitEventSubscription()
{
var actionDelegateReference = new MockDelegateReference((Action<object>)delegate { });
var filterDelegateReference = new MockDelegateReference((Predicate<object>)delegate { return true; });
var eventSubscription = new EventSubscription<object>(actionDelegateReference, filterDelegateReference);
var subscriptionToken = new SubscriptionToken(t => { });
eventSubscription.SubscriptionToken = subscriptionToken;
Assert.AreSame(actionDelegateReference.Target, eventSubscription.Action);
Assert.AreSame(filterDelegateReference.Target, eventSubscription.Filter);
Assert.AreSame(subscriptionToken, eventSubscription.SubscriptionToken);
}
public void DifferentTargetTypeInActionThrows()
{
var actionDelegateReference = new MockDelegateReference()
{
Target = (Action<int>)delegate { }
};
var filterDelegateReference = new MockDelegateReference()
{
Target = (Predicate<string>)(arg =>
{
return true;
})
};
var eventSubscription = new EventSubscription<string>(actionDelegateReference,
filterDelegateReference);
}
public void NullTargetInFilterThrows()
{
Assert.Throws<ArgumentException>(() =>
{
var actionDelegateReference = new MockDelegateReference()
{
Target = (Action<object>)delegate { }
};
var filterDelegateReference = new MockDelegateReference()
{
Target = null
};
var eventSubscription = new EventSubscription<object>(actionDelegateReference,
filterDelegateReference);
});
}
public void GetPublishActionDoesNotExecuteActionIfFilterReturnsFalse()
{
bool actionExecuted = false;
var actionDelegateReference = new MockDelegateReference()
{
Target = (Action<int>)delegate { actionExecuted = true; }
};
var filterDelegateReference = new MockDelegateReference((Predicate<int>)delegate
{
return false;
});
var eventSubscription = new EventSubscription<int>(actionDelegateReference, filterDelegateReference);
var publishAction = eventSubscription.GetExecutionStrategy();
publishAction.Invoke(new object[] { null });
Assert.IsFalse(actionExecuted);
}
public void StrategyPassesArgumentToDelegates()
{
string passedArgumentToAction = null;
string passedArgumentToFilter = null;
var actionDelegateReference = new MockDelegateReference((Action<string>)(obj => passedArgumentToAction = obj));
var filterDelegateReference = new MockDelegateReference((Predicate<string>)(obj =>
{
passedArgumentToFilter = obj;
return true;
}));
var eventSubscription = new EventSubscription<string>(actionDelegateReference, filterDelegateReference);
var publishAction = eventSubscription.GetExecutionStrategy();
publishAction.Invoke(new[] { "TestString" });
Assert.Equal("TestString", passedArgumentToAction);
Assert.Equal("TestString", passedArgumentToFilter);
}
public void GetPublishActionReturnsNullIfFilterIsNull()
{
var actionDelegateReference = new MockDelegateReference((Action<object>)delegate { });
var filterDelegateReference = new MockDelegateReference((Predicate<object>)delegate { return true; });
var eventSubscription = new EventSubscription<object>(actionDelegateReference, filterDelegateReference);
var publishAction = eventSubscription.GetExecutionStrategy();
Assert.NotNull(publishAction);
filterDelegateReference.Target = null;
publishAction = eventSubscription.GetExecutionStrategy();
Assert.Null(publishAction);
}
public void GetPublishActionReturnsNullIfActionIsNullNonGeneric()
{
var actionDelegateReference = new MockDelegateReference((Action)delegate { });
var eventSubscription = new EventSubscription(actionDelegateReference);
var publishAction = eventSubscription.GetExecutionStrategy();
Assert.NotNull(publishAction);
actionDelegateReference.Target = null;
publishAction = eventSubscription.GetExecutionStrategy();
Assert.Null(publishAction);
}
public void GetPublishActionReturnsDelegateThatExecutesTheFilterAndThenTheAction()
{
var executedDelegates = new List<string>();
var actionDelegateReference =
new MockDelegateReference((Action<object>)delegate { executedDelegates.Add("Action"); });
var filterDelegateReference = new MockDelegateReference((Predicate<object>)delegate
{
executedDelegates.Add(
"Filter");
return true;
});
var eventSubscription = new EventSubscription<object>(actionDelegateReference, filterDelegateReference);
var publishAction = eventSubscription.GetExecutionStrategy();
Assert.NotNull(publishAction);
publishAction.Invoke(null);
Assert.Equal(2, executedDelegates.Count);
Assert.Equal("Filter", executedDelegates[0]);
Assert.Equal("Action", executedDelegates[1]);
}
public void CanInitEventSubscriptionNonGeneric()
{
var actionDelegateReference = new MockDelegateReference((Action)delegate { });
var eventSubscription = new EventSubscription(actionDelegateReference);
var subscriptionToken = new SubscriptionToken(t => { });
eventSubscription.SubscriptionToken = subscriptionToken;
Assert.Same(actionDelegateReference.Target, eventSubscription.Action);
Assert.Same(subscriptionToken, eventSubscription.SubscriptionToken);
}
public void NullFilterThrows()
{
var actionDelegateReference = new MockDelegateReference()
{
Target = (Action<object>)delegate { }
};
var eventSubscription = new EventSubscription<object>(actionDelegateReference,
null);
}
public void NullTargetInActionThrows()
{
var actionDelegateReference = new MockDelegateReference()
{
Target = null
};
var filterDelegateReference = new MockDelegateReference()
{
Target = (Predicate<object>)(arg =>
{
return true;
})
};
var eventSubscription = new EventSubscription<object>(actionDelegateReference,
filterDelegateReference);
}
public void NullActionThrowsNonGeneric()
{
Assert.Throws<ArgumentNullException>(() =>
{
var eventSubscription = new EventSubscription(null);
});
}
public void DifferentTargetTypeInFilterThrows()
{
Assert.Throws<ArgumentException>(() =>
{
var actionDelegateReference = new MockDelegateReference()
{
Target = (Action<string>)delegate { }
};
var filterDelegateReference = new MockDelegateReference()
{
Target = (Predicate<int>)(arg =>
{
return true;
})
};
var eventSubscription = new EventSubscription<string>(actionDelegateReference,
filterDelegateReference);
});
}
