Specification pattern: Difference between revisions

Revision as of 18:58, 27 September 2016

Revision as of 12:14, 19 November 2016

Line 314:

<source lang="csharp">

var InvoiceCollection = Service.GetInvoices();

foreach (Invoice currentInvoiceinvoice in InvoiceCollection) {

currentInvoiceinvoice.SendToCollectionIfNecessary();

}

//.. in the Invoice partial classmethods:

public bool ShouldSendToCollection { get { return currentInvoice.OverDue && currentInvoice.NoticeSent && currentInvoice.InCollection == false; }}

public void SendToCollectionIfNecessary()

{

if (!ShouldSendToCollection()) return;

//Guard condition - with each of those new properties

{

if (!ShouldSendToCollection) return;

this. SendToCollection();

}

}

public bool ShouldSendToCollection()

{

return currentInvoice.OverDue

&& currentInvoice.NoticeSent

&& !currentInvoice.InCollection;

}

</source>This alternative uses foundation concepts of Get-Only Properties, Condition-Logic, and Functions. The key alternative here is Get-Only Properties, which are well-named to maintain the Domain-Driven language, and enable the continued use of the natural && operator, instead of the Specification Pattern's And() function. Furthermore, the creation of a well-named function SendToCollectionIfNecessary is potentially more useful and descriptive, than the previous example (which could also be contained in such a function, except not directly on the object apparently).